Transport in Plants and Animals - Questions and Answers - Home of Knowledge

Transport in Plants and Animals – Questions and Answers

Class 9 Biology Notes – Chapter 9 Transport

 

Question#1): What is the primary function of transport system?

Answer:The primary function of transport system is to maintain a link between all cells of

the body and the external environment. It transports the nutrients and water to the points where they are to be used.

 

Question#2) Descibe the importance of water for plants and other organisms?

Answer: Water plays an important role in our daily life:

  1. i) It is an important active constituent of living matter, the protoplasm.
  2. ii) It serves as a medium in many physiological processes.

iii) It is a universal solvent and a medium of transport.

Question#3) Write a short note on transport of water and food in plants?

Answer: TRANSPORT IN PLANTS

Transport of water: Water is vital to plant life. It is necessary not just for photosynthesis and turgor, but much of the cellular activities occur in the presence of water molecules. Internal temperature of plant body is also regulated by water. Land plants get water and minerals from soil. After absorption by roots, water and minerals have to be transported to the aerial parts of body.

Transport of food: food is manufactured in leaves (by photosynthesis). This food is transported to other parts of body for utilization and storage. All land plants (except for mosses and liverworts), have developed complex vascular tissues (xylem and phloem) that move water and food throughout plant body.

 

Recalling: Cells are the primary sites for metabolic processes. That is why they are regarded as the units of life.

 

Question#4) How water, ion and water uptake occurs in plants?  “OR”  How would you relate the internal structure of root with the uptake of water and salts?

Answer: Plants have two types of vascular tissues called xylem and phloem. Xylem transport water and minerals from roots to leaves. Most the gymnosperms lack these vessels and they have tracheids. Each tracheid is an elongated, dead cell with lignified walls, and intact end walls.

Water travels upward through two paths: –

  1. i) Along the cell wall.
  2. ii) Through the cells.

Uptake of water and minerals by Root:

  • First of all root hairs absorbs water and minerals from soil due to their spongy nature. Root hairs provide large surface area for absorption.
  • Water from soil, move towards root through osmosis.
  • The entry of water into the root hairs dilutes its sap.
  • Now sap of root hair is more than next cell. So water from hairs move into the

root cells.

  • The water from the epidermal cells then passes into the xylem vessel and

ascends up the stem.

  • This upward movement of water and salts is called ascent of sap.

 

For your information: Water always moves from an area of higher water potential to an area of lower water potential. The relationship between the concentration of solute and water potential is inverse. When there is a lot of solute ( i.e. hypertonic solution), the water potential is low and vice versa.

 

For your information: Plants also form beneficial relationships with soil bacteria and fungi in order to increase absorption of minerals.

 

Question#5) Define transpiration and relate it with cell surface and with stomatal opening and closing? 3. How do different factors affect the rate of transpiration?

Answer: Transpiration: • The loss of water in the form of vapour from aerial parts of the plants, especially

through stomata is called transpiration.

  • Potometer is used to measure the rate of transpiration.
  • The difference of osmotic pressure is present between lower and upper parts of

a plant. This difference produces a pull or tension, which pull the water form high

pressure to lower pressure. This pull or suction force is produced in xylem tissue

and is called transpiration pull.

  • Due to transpiration pull of water molecules, water moves up in xylem as an

unbroken channel called transpiration stream.

Common types of transpiration: Most common types of transpiration are; 1) Stomatal transpiration: Transpiration through stomata is called Stomatal transpiration. 2)cuticular transpiration: Transpiration takes place through cuticle is called cuticular transpiration. 3) Lenticular transpiration: Transpiration through lenticles is called lenticular transpiration.

 

Factors affecting the transpiration:

Temperature: –

  1. i) High temperature increases the rate of transpiration.
  2. ii) Low temperature decreases the rate of transpiration.

Humidity: –

  1. i) In dry conditions or low humidity the rate of transpiration increases.
  2. ii) In wet conditions or high humidity the rate of transpiration decreases.

Light: –

  1. i) In day time, in presence of light stomata remains open. They cause

increase in rate of transpiration.

  1. ii) In night time, in darkness stomata remain closed. They cause decrease in

rate of transpiration.

Air movement:

Wind (air in motion) carries away the evaporated water from leaves and it causes an increase in the rate of evaporation from the surfaces of mesophyll. When air is still, the rate of transpiration is reduced.

 

Atmospheric Pressure: –

  1. i) Low atmospheric pressure increases the rate of transpiration.
  2. ii) High atmospheric pressure decreases the rate of transpiration.

Leaf surface area:

The rate of transpiration also depends upon the surface area of leaf. More surface area provides more stomata and there is more transpiration .

Question#6) Transpiration is a necessary evil. Give comments? OR  What are the advantages or importance of transpiration?

 

Answer: Importance of transpiration:

  • Transpiration is very important in the plant life as it provides the forces to pull the

sap up in the xylem vessels form root to the leaves.

  • Transpiration also keeps the cell surface moist to facilitate the exchange of gases

in dissolved st•ate.

  • Tiny openings present on the lower side of leaves are called stomata. Each stoma

is surrounded by sausage shaped cells called guard cells.

  1. i) Stomata remain open when guard cells are turgid.
  2. ii) Stomata remain close when the guard cells loose their turgidity.

 

For your information: Roughly 90% of the water that enters a plant is lost via transpiration.

 

 

Question#7) How opening and closing of stomata regulates transpiration?

Answer:

Opening and closing of stomata and Transpiration: The stomata regulate the transpiration by the action of guard cells. The two guard cells of a stoma are attached to each other at their ends. The inner concave sides of guard cells that enclose a stoma are thicker than the outer convex sides. When guard cells get water and become turgid, their shapes are like two beans and the stoma between them opens. When guard cells loose water and become flaccid, their inner sides touch each other and stoma closes. the concentration of soluts (glucose) in guard cells is responsible for the opening and closing of stomata. Recent studies have revealed that light causes the movement of potassium ions from epidermal cells into guard cells. Water follows these ions and enters guard cells. Thus their turgidity increases and stoma opens. As the day progresses, guard cells make glucose i.e. become hypertonic. So water stays in them. At the end of the day, potassium ions flow back from guard cells to epidermal cells and the concentration of glucose also falls. Due to it, water moves to epidermal cells and guard cells loose turgor. It causes the closure of stoma.

Figure :Opening and closing of stoma.

 

 

For your information: There is strong evidence that even mild water stress results in reduced growth rate in plants.

 

Question#8) Explain the movement of water in terms of transpirational pull?

 

Answer: TRANSPORT AND MOVEMENT OF WATER AND TRANSPIRATION PULL:

According to cohesion tention theory, the force which carries water (and dissolved materials) upward through the xylem is transpirational pull. The pulling force created by the transpiration of water is called transpirational pull. Transpiration creates a pressure difference that pulls water and salts up from roots.

When a leaf transpires (loses water), the water concentration of its mesophyll cells drops. This drop causes water to move by osmosis from the xylem of leaf into mesophyll cells. When one water molecule moves up in the xylem of the leaf, it creates a pulling force that continues all the way to root.

 

 Transpirational pull causes water to move transversely (from root epidermis to cortex and pericycle). Following are the reasons for the creation of transpirational pull.

  • Water is held in a tube (xylem) that has small diameter.
  • Water molecules adhere to the walls of xylem tube (adhesion). The forces of attraction between unlike molecules is called adhesive forces. Or the forces of attraction between liquid molecules and the wall of materials in which it was placed is called adhesive forces(adhesion).
  • Water molecules cohere to each other (cohesion). The attractive forces between same liquid substances that resist separation between molecules of liquids is called cohesive forces.

These attractions make an overall tension among water molecules. This tension forms ‘columns’ of water. The columns of water move from root to shoot and the water content of the soil enters in these ‘columns’.

 

Question#9)Describe the theory of pressure flow mechanism to explain the translocation of food in plants?

Answer: TRANSPORT OF FOOD : The transport of food in plants is called translocation.

Tissues responsible for translocation: Phloem is responsible for transporting food substance throughout plant body.

Sucrose formation : •The glucose formed during photosynthesis in mesophyll cells, is used in respiration and the excess of it is converted into sucrose. In most plants, food is transported in the form of sucrose.

Pressure flow mechanism (Hypothesis): Transport of food is through pressure-flow mechanism. This theory propose that water containing food molecules flows under presssure through the phloem. In pressure-flow mechanism, food is moved from sources to sinks. Sources include the exporting organs, typically a mature leaf or storage organ. Sinks are the areas of active metabolism or storage e.g. roots, tubers, developing fruits and leaves, and growing regions. A storage organ is capable of storing food and exporting the stored materials. For example; root of beet is a sink in first growing season, but becomes source in next growing season, when sugars are utilized in the growth of new shoots.

 

 

At source, food (sugars) is moved by active transport into the sieve tubes of phloem. Due to the presence of sugar in sieve tubes, their solute concentration increases and water enters them from xylem (via osmosis). This results in higher pressure of water in these tubes, which drives the solution of food towards sink.

At the sink end, food is unloaded by active transport. Water also exits from the sieve tubes. The exit of water decreases pressure in sieve tubes, which causes a mass flow from the higher pressure at the source to the now lowered pressure at the sink.

 

 

 

 

 

For your information: Xylem is a one way street from roots to leaves for water and salts. Phloem is a two way street for food. The direction of the movement of food is decided by supply and demand in sources and sinks

For your information: Plants need a lot of water. Young Brassica plants take up an amount of water equal to their shoot weight in about 5 hours – if that applied to us, we would have to drink 3 gallons of water an hour to stay alive!

Recalling: Some invertebrates like arthropods have open circulatory system.

 

Question#10) How transport of materials takes place in humans?

Answer: TRANSPORT IN HUMAN; In human transport of materials takes place through two systems.

  • Lymphatic system: A complex network of vessels, tissues and organs that maintains the fluid balance in the body is called Lymphatic system. From the bloodstream plasma leaks. This plasma is accumulated by the lymphtic system and transported back to the bloodstream.
  • Circulatory system: organ system that conveys blood through vessels to and from all parts of the body, carrying nutrients and oxygen to tissues and removing carbon dioxide and other wastes is called circulatory system.

Types of circulatory system

There are two types of circulatory system: –

Open Circulatory System: –

  • In this type blood is pumped through heart in open spaces called sinuses.
  • The blood is in direct contact with tissues and after exchange of materials it

returns back to heart.

Closed Circulatory System: –

  • In this type muscular heart is present with its incoming (veins) and out going

(arteries) vessels. The blood remains confined to the blood vessels during

circulation.

  • It is elaborated, complicated and efficient system.

Question#11) What are the basic components of blood circulatory system?

Answer: Components of the human blood circulatory system:

The main components of the human blood circulatory system are blood, heart and blood vessels.

 

Question#12) List the functions of the components of blood?

Answer: BLOOD: Blood is a specialized body fluid (a connective tissue) that is composed of a liquid called blood plasma and blood cells. A reddish fluid in animals that contain water, cell bodies and other substances and is used for transport of materials is called blood. The weight of blood in our body is about 1/12th of our body. The average adult body has about 5 litres of blood.

In a healthy person, plasma constitutes about 55% by volume of blood, and cells or cell-like bodies are about 45% by volume of the blood.

 

Functions of blood:

  1. i) It helps to transport materials in all the body.
  2. ii) It transports oxygen from lungs to all body cells.

iii) It bring back CO2 from all body cells to lungs.

  1. iv) It brings all wastes from body to kidney for their removal.
  2. v) Blood carries hormones from glands to all body parts.

 

BLOOD PLASMA

Plasma is primarily water in which proteins, salts, metabolites and wastes are dissolved.Water constitutes about 90-92% of plasma and 8-10% are dissolved substances. Salts make up 0.9 % of plasma, by weight. Sodium chloride (the table salt) and salts of bicarbonate are present in considerable amounts. Ca, Mg, Cu, K and Zn are found in trace amounts. Changes in the concentration of any salt can change the pH of blood(normal is 7.4). Proteins make 7-9 % by weight of plasma. The important proteins present in plasma are antibodies, fibrinogen (blood clotting protein), albumin (maintains the water balance of blood) etc. Plasma also contains the digested food (absorbed from digestive system), nitrogenous wastes and hormones. Respiratory gases i.e. CO2and O2 are present in the plasma.

 

How is plasma separated from blood?

Blood is taken from an artery and an anticoagulant (chemical that inhibits blood clotting) is mixed in it. After about 5 minutes, plasma separates from blood cells, which settle down.

 

 

 

 

 

 

BLOOD CELLS and cell-like bodies:

These include red blood cells (erythrocytes), white blood cells (leukocytes) and platelets (thrombocytes).

 

Red Blood Cells (Erythrocytes “erythro means red and cyte means cell”)

  • These are the most numerous of blood cells. A cubic millimeter of blood contains 5 to 5.5 million of RBCs in males, and 4 to 4.5 million in females.
  • When RBCs are formed, they have nucleus. In mammals, when a red blood cell matures, its nucleus is lost. After the loss of nucleus, RBC enters blood.
  • About 95% of the cytoplasm of RBCs is filled with hemoglobin, which transports O2 and small amounts of CO2.
  • The remaining 5% consists of enzymes, salts and other proteins.
  • RBCs are biconcave and have an elastic cell membrane. In the embryonic and foetal life, they are formed in liver and spleen. In adults, they are formed in the red bone marrow of short and flat bones, such as sternum, ribs and vertebrae.
  • Average life span of RBC is about four months (120 days) after which it breaks down in liver and spleen by phagocytosis.

 

 

 

For your information: In a normal person about 2-10 million red blood cells are formed and destroyed every second.

 

White Blood Cells (Leukocytes)

  • These are colourless, because they do not contain pigments.
  • They are irregular in shape.
  • They have nucleus.
  • They are not confined to blood vessels and also migrate out into tissue fluid.
  • One cubic millimeter of blood contains 7000 to 8000 WBCs.
  • Their life span ranges from months to even years, depending on body’s needs. WBCs function as the main agents in body’s defence system.
  • They are produced in bone marrow, thymus gland and lymph nodes.

Types of WBC: There two main types of WBCs.

Granulocytes: Granulocytes have granular cytoplasm. These include neutrophils (destroy small particles by phagocytosis), eosinophils (break inflammatory substances and kill parasites) and basophils (prevent blood clotting).

Agranulocytes: Agranulocytes have clear cytoplasm and include monocytes(produce macrophages which engulf germs) and B and T lymphocytes (produce antibodies and kill germs).

 

Platelets (Thrombocytes)

  • They are not cells, but are fragments of large cells of bone marrow, called megakaryocytes.
  • They do not have any nucleus and any pigment. Plateletes of vertebrates except mammals are complete cells.
  • One cubic millimeter of blood contains 250,000 platelets.
  • The average life span of a blood platelet is about 7 to 8 days.
  • Platelets help in blood clotting. The clot serves as a temporary seal at the damaged area.

 

For your information: WBCs die in the process of killing the germs. These dead cells accumulate and make the white substance called pus, seen at infection sites.

 

For your information: In dengue fever , there is a sharp decrease in the number of platelets in blood. Because of this, patients bleed from the nose, gums and under the skin.

 

 

Composition of blood

Plasma

Description

Amount in %age

Functions

Liquid portion of blood

55% by volume

Carries blood cells and important blood proteins, hormones, salts etc.

Cell Types

Description

Average

Number

present

Functions

Red Blood Cells

(Erythrocytes)

Like a biconcave disc; without nucleus; contain haemoglobin

5,000,000 per mm3

Transport Oxygen and a small amount of CO2

White Blood Cells

(Leukocytes)

Granular and agranular; contain nucleus Larger in size than

RBCs

7500 per mm3

Play role in body’s defense by different ways like: Engulf small particles Release anticoagulants Produce antibodies

Platelets

(Thrombocytes)

Fragments of bone marrow cells

(megakaryocytes)

250,000 per mm3

Involved in blood clotting

 

Analyzing and Interpreting:

Identify red blood cells, white blood cells and platelets in specimens of prepared slides or diagrams.

 

 

 

 

Question#13) State the signs and symptoms, causes and treatments of leukemia and thallassemia?

Answer: BLOOD DISORDERS:

Following are important blood disorders. 

 

Leukaemia (blood cancer)

Definition: Leukaemia is the production of great number of immature and abnormal white blood cells.

Causes: This is caused by a cancerous mutation (change in gene) in bone marrow or lymph tissue cells. The mutation results in uncontrolled production of defective white blood cells (leukocytes).

Treatment: It is a very serious disorder and patient needs to change blood regularly with normal blood, got from donors. It can be cured by bone marrow transplant. It is effective in most cases , but very expensive treatment.

 

 

Thalassaemia (g. thalassa = sea; haem = blood) :Thalassemia (Greek: “sea blood”) is so called because it was first discovered among peoples around the Mediterranean Sea, among whom its incidence is high.

It is also called Cooley’s anaemia on the name of Thomas B. Cooley, an American physician (1945A.D). It is a genetic problem due to mutations in the gene of haemoglobin. The mutation results in the production of defective haemoglobin and the patient cannot transport oxygen properly.

The blood of these patients is to be replaced regularly, with normal blood. It can be cured by bone marrow transplant but it does not give 100% cure rate.

 

 

For your information: The world celebrates the International Thalassaemia Day on 8th of May. This day is dedicated to raise public awareness about thalassaemia and to highlight the importance of the care for thalassaemia patients.

 

For your information: There are about 60-80 million people in the world who carry thalassaemia. India, Pakistan and Iran are seeing a large increase of thalassaemia patients. Pakistan alone has 250,000 such patients. The patients require blood transfusions for lifetime. (Source: The Thalassaemia International Foundation).

 

For your information: A total of 29 human blood group systems are now recognized by the International Society of Blood Transfusion (ISBT).

 

 

Question#14) How do we classify blood groups in terms of the ABO and the Rh blood group systems?

Answer: Blood group systems:

Blood group systems are a classification of blood based on the presence or absence of antigens on the surface of red blood cells. An antigen is a molecule that can stimulate an immune response (antibody production etc.).

ABO Blood Group System

It is the most important blood group system in humans.

Discoverer: It was discovered by the Austrian scientist Karl Landsteiner, who found four different blood groups (blood types) in 1900. He was awarded the Nobel Prize in Medicine for his work.

Different blood groups according to ABO blood group systems: In this system, there are four different blood groups which are distinct from each other on the basis of specific antigens (antigen A and B) present on the surface of RBCs.

  • A person having antigen A has blood group A. People with blood group A have antibody B.
  • A person having antigen B has blood group B. People with blood group B have antibody A.
  • A person having both antigens has blood group AB. People with blood group AB have no antibody.
  • A person having none of the A and B antigens has blood group O. People with blood group O have both antibody A and B.

 

Presence and absence of antigens and antibodies in ABO blood group system.

 

 

 

 

 

For your information: A number of infectious diseases (such as AIDS, hepatitis B and hepatitis C etc.) can pass from the affected blood donor to recipient. Before blood transfusion, the blood of donor is checked for the presence of germs etc.

 

 

 

Blood transfusions in ABO blood group system

1)Persons with blood group O are called universal donors . They do not

have any antigens A or B so they can donate their blood to a person with

any type of blood group.

  • Persons with blood group AB are called universal recipient. They can receive each type of blood because they have no antibody and have both antigens.
  • Persons with blood group A can donate blood only to A group peoples.
  • Persons with blood group B can donate blood only to B group peoples.

Rh Blood Group System (+ ve & – ve blood group system)

In 1930’s, Karl Landsteiner discovered the Rh-blood group system. In this system, there are two blood groups i.e. Rh-positive and Rh-negative. These blood groups are distinct from each other on the basis of antigens called Rh factors (first discovered in Rhesus monkey), present on the surface of RBCs. A person having Rh factors has blood group Rh-positive while a person not having Rh factors has blood group Rh-negative. Unlike the naturally occurring anti-A & anti-B antibodies of the ABO-system, an Rh-negative person does not produce anti-Rh antibodies unless Rh-factor enters in his / her blood.

Blood transfusions in Rh blood group system

Rh-positive blood group can be transfused to Rh-positive recipient because recipient’s blood already has Rh-antigens and it will not produce anti-Rh antibody. Rh-negative blood group can be transfused to Rh-negative because donor’s blood does not have Rh-antigen and so recipient’s blood will not produce anti-Rh antibody. If an Rh-negative person receives Rh-positive blood, he / she will produce anti-Rh antibodies against Rh-factors. Rh-negative blood can be transfused to Rh-positive recipient, only if donor’s blood (Rh-negative) has never been exposed to Rh-antigens and does not contain any anti-Rh antibody.

 

Recalling: Cardiac muscles are involuntary in action and are composed of branched striated cells,each with a single nucleus.

Useful intresting information: The heart is usually felt to be on the left side because the left chamber of the heart i.e. (left ventricle) is stronger (it pumps blood to all body parts).

 

Useful intresting information: The walls of left ventricle are the thickest one. These are about a halfinch thick. They have enough force to push blood into the body. This gives an evidence that the structures of the parts of heart are adaptive to their functions.

 

 

Question#15) What four chambers make the human heart and how blood flows through these chambers?

Answer: HUMAN HEART:

Structure of Heart: –

  • Human heart is muscular contractile organ responsible for pumping blood through blood vessels by repeated contractions.
  • Location: Human heart is located in between the two lungs, in the middle of chest cavity beneath the breast bone.
  • Heart is protected by ribs.
  • Moreover heart is enclosed in tough, fibrous and extensible membrane called pericardium. There is a fluid between heart walls and pericardium called pericardial fluid. Its functions are as under:
  1. It acts as shock absorber.
  2. It protects the heart from friction(pericardial fluid).
  3. It prevents the over flow of blood.
  4. It keeps the heart moist.
  • Heart muscles are called cardiac muscles.
  • Heart consists of four chambers.
  1. Two upper atria (Single Atrium).
  2. Two lower ventricles.

Function of Heart: –

  1. i) Atria are thin walled independent chambers. They receive blood.
  2. ii) Right atrium receives deoxygenated blood from all parts of the body and left atrium receives oxygenated blood from lungs.

iii) Ventricles are thick walled chambers. They pump blood.

  1. iv) Right ventricle pump deoxygenated blood to lungs and left ventricle pump

blood to all parts of body through aorta.

  1. v) Valves are present between atria and ventricles which prevents the

backward flow of blood.

  1. vi) The right atrio-ventricular valve consists of three tissues and called tricuspid

valve.

vii) The left atrio-ventricular valve consists of two tissues and called bicuspid

valve.

viii) The alternating contraction and relaxation of the heart chambers is called the

cardiac cycle.

  1. ix) The period of ventricular contraction is called systole and their relaxation is called

 

WORKING OF HEART

Blood from all parts of the body is collected in right atrium. At same time left atrium receive oxygenated blood from lungs through pulmonary veins. This is diastolic phase of atria. After this both atria contract and blood is pumped to the respective ventricles through bicuspid and tricuspid valves. This is systolic phase of atria.

After this both ventricles contract and blood is pumped to lungs from right ventrical and to all parts of the body from left ventrical. This is ventricular systole.

 

 

Pulmonary and systemic circulation

The pathway on which deoxygenated blood is carried from heart to lungs and in return oxygenated blood is carried from lungs to heart is called pulmonary circulation or pulmonary circuit. Similarly, the pathway on which oxygenated blood is carried from heart to body tissues and in return deoxygenated blood is carried from body tissues to heart is called systemic circulation or systemic circuit.

 

 

Question#16) Write a note on Heart beat?

Answer: Heartbeat:

The relaxation of heart chambers fills heart with blood and contraction of chambers propels blood out of heart. The alternating relaxations and contractions make up the cardiac cycle and one complete cardiac cycle makes one heartbeat. Complete cardiac cycle consists of the following steps. Atria and ventricles relax and blood is filled in atria. This period is called cardiac diastole. Immediately after their filling, both atria contract and pump blood towards ventricles. This period in cardiac cycle is called atrial systole. Now, both ventricles contract and pump blood towards body and lungs.

 

The period of ventricular contraction is called ventricular systole. In one heartbeat, diastole lasts about 0.4 seconds, atrial systole takes about 0.1 seconds, and ventricular systole lasts about 0.3 seconds (Figure 9.17). When ventricles contract, tricuspid and bicuspid valves close and “lubb” sound is produced. Similarly when ventricles relax, the semilunar valves close and “dubb” sound is produced. “Lubb-dubb” can be heard with the help of a stethoscope.

 

Question#17) What do you know about heart rate?

Answer: Heart rate and Pulse rate

Heart rate is the number of times the heart beats per minute. At rest or during normal activities, the normal heart rate is 70 times per minute in men and 75 times per minute in women. The heart rate fluctuates a lot depending on factors such as activity level and stress level.

Heart rate can be measured by feeling the pulse. Pulse is the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of heart.Pulse can be felt at areas where artery is close to skin for example at wrist, neck, groin or top of foot. Most commonly, people measure their pulse in their wrist.

 

 

 

Question#18) Compare the structure and function of an artery, a vein and a capillary?

Answer: BLOOD VESSELS:

2-Blood Vessels: –

Blood vessels consists of Arteries, Capillaries and Veins.

Arteries:

  1. i) The vessels that carry blood from heart to all parts of the body are

called arteries.

  1. ii) They are made up of three layers.
  2. Innermost layer is called endothelium.
  3. Middle layer is made up of smooth muscles and elastic tissues.
  4. Outer layer is made up of collagen fibers and other supporting

tissues.

iii) Because of elastic walls, the arteries stretched when blood enters and

then recoil slowly. It is called pulse. They withstand the high blood pressure and maintain the flow of blood.

  1. iv) All the arteries carries oxygenated blood with the exception of pulmonary arteries that carry deoxygenated blood from heart to lungs.

Capillaries: –

  1. i) Arteries on reaching to different body parts divides into very small vessels

called capillaries.

  1. ii) They are very thin walled. They consist of single celled layer.

iii) They are so narrow that only one RBC can move in line.

  1. iv) Gases, hormones, and other wastes are exchanged by simple diffusion.
  2. v) They join to form veins.

Veins: –

  1. i) The vessels that bring blood back from all parts of body to heart are called
  2. ii) They are less elastic.

iii) Valves are present in veins which prevent the backflow of blood.

  1. iv) All veins carry deoxygenated blood with the exception of pulmonary vein that carry oxygenated blood to heart from lungs.

 

 

 

 

 

 

 

General Plan of Human Blood Circulatory System

Many scientists worked for discovering the facts about the circulation of blood in human body. Two important scientists who revealed much knowledge of blood circulatory system were Ibn-e-Nafees and William Harvey. Ibn-e-Nafees (1210-1286 AD) was a physician and he is honoured as the first scientist who described the pathway of blood circulation. William Harvey (1578-1657 AD) discovered the pumping action of heart and the pathway of blood in major arteries and veins.

 

Question#19) Draw diagrams which can illustrate the origins, locations and target areas of the main arteries in human blood circulatory system?

 

Answer: Arterial System:

  • Large pulmonary trunk emerges from right ventricle and divides into right and left pulmonary arteries, which carry the deoxygenated blood to right and left lungs.
  • The oxygenated blood leaving the left ventricle of heart is carried in a large artery i.e. aorta. It ascends and forms an aortic arch. The arch curves left and descends inferiorly into body. From the upper surface of aortic arch, three arteries emerge, which supply blood to head, shoulders and arms. As aorta passes down through thorax, it becomes dorsal aorta. It gives off many branches and the important ones are listed here. Several intercostal arteries supply blood to ribs. Caeliac artery and superior mesenteric artery supply blood to digestive tract while hepatic artery supplies blood to liver. Inferior to these, there are a pair of renal arteries that supply blood to kidneys. Gonadal arteries supply blood to gonads. Just below the gonadal arteries, is inferior mesenteric artery, which supplies blood to a part of the large intestine and rectum.Then aorta divides into two common iliac arteries, each of which divides into an internal iliac artery and an external iliac artery. Each external iliac becomes femoral artery in upper thigh. It gives branches to thigh, knee, shank, ankle and foot.

 

 

 

 

 

 

Question#20) Draw diagrams which can illustrate the areas and locations of the main veins in human blood circulatory system?

 

Answer: Venous System:

Veins from lungs, called pulmonary veins return the oxygenated blood to the left atrium of heart.

Two major veins i.e. superior vena cavaand inferior vena cava carry the deoxygenated blood from rest of the body and empty into right atrium.

Superior vena cava forms when different veins from head, shoulders and arms join together. From legs, the deoxygenated blood is returned to heart by many veins which empty into inferior vena cava. Veins carrying blood from calf, foot and knee join together to form femoral vein. It empties into external iliac vein which joins with the internal iliac and both empty into common iliac vein. Right and left common iliac veins join to form inferior vena cava. Many short veins empty into inferior vena cava. Among these are hepatic vein, renal veins, andgonadal veins. All veins coming from stomach,spleen, pancreas and intestine drain into hepatic portal vein, which carries blood to liver. From liver, a hepatic vein carries blood and empties into inferior vena cava. Two renal veins carry blood from kidneys while two gonadal veins carry blood from gonads to inferior vena cava. In thoracic cavity, inferior vena cava also receives veins from thoracic walls and ribs.

 

For your information: Vascular surgery is a field in surgery in which diseases of arteries and veins (like thrombosis etc.) are managed by surgical methods. A vascular surgeon treats the diseases of all parts of blood circulatory system except that of heart and brain.

 

For your information: Even though the heart chambers are continually bathed with blood, this does not nourish heart muscles. The blood supply to heart muscles is provided by coronary arteries, which emerge from the base of aorta. Heart muscles are drained by coronary veins, which empty into right atrium. Coronary arteries and veins are collectively called coronary circulation and it is a part of systemic circulation.

 

 

Question#21) What do you mean by Cardiovascular disorders?

Answer: CARDIOVASCULAR DISORDERS:

The diseases that involve the heart or blood vessels are collectively called cardiovascular disorders. These diseases have similar causes, mechanisms, and treatments.

The risk factors that lead to cardiovascular disorders include advanced age, diabetes, high blood concentration of low density lipids (e.g. cholesterol) and triglycerides, tobacco smoking, high blood pressure (hypertension), obesity, and sedentary lifestyle.

Question#22) Define Arteriosclerosis and Atherosclerosis? How would you differentiate between atherosclerosis and arteriosclerosis?

Answer: ATHEROSCLEROSIS AND ARTERIOSCLEROSIS:

Atherosclerosis and arteriosclerosis are the diseases of arteries. These diseases also lead to heart diseases.

 

Atherosclerosis : Atherosclerosis is commonly referred to as a “narrowing” of arteries. It is a chronic disease in which there is accumulation of fatty materials,cholesterol, or fibrin in arteries. When this condition is severe, arteries can no longer expand and contract properly, and blood moves through them with difficulty.

Accumulation of cholesterol is the prime contributor to atherosclerosis. It results in the formation of multiple deposits called plaques within arteries. Plaques can form blood clots called thrombus within arteries. If a thrombus dislodges and becomes free floating,it is called an embolus.

Arteriosclerosis is a general term describing any hardening of arteries. It occurs when calcium is deposited in the walls of arteries. It can happen when atherosclerosis is severe.

Difference between Arteriosclerosis and atherosclerosis: Arteriosclerosis is a defect in the artery artery walls. In this problem hardening of the flexible walls of blood arteries takes place and thus arteries loss elasticity. In young age the arteries are flexible due to the presence of a protein called elastin. As age advances , there is loss of these elastin proteins cause thickening of arterial walls. In atherosclerosis fat plaques and cholestrols are deposited on the arteries and thus causing narrowing of the arteries.

Question#23) State the causes, treatments and prevention of myocardial infarction?

Answer: MYOCARDIAL INFARCTION

The term myocardial infarction is derived from myocardium (the heart muscle) and infarction (tissue death). It is more commonly known as a heart attack. It occurs when blood supply to a part of heart is interrupted and leads the death of heart muscles. It is a medical emergency, and the leading cause of death for both men and women all over the world.

Causes: Heart attack may be caused by blood clot in coronary arteries.

Symptoms: Severe chest pain is the most common symptom of myocardial infarction and may be in the form of sensation of tightness, pressure, or squeezing. Pain radiates most often to left arm, but may also radiate to lower jaw, neck, right arm and back. Loss of consciousness and even sudden death can occur in myocardial infarction.

Prevention and Treatment: Immediate treatment for suspected acute myocardial infarction includes oxygen supply,aspirin, and sublingual tablet of glyceryl trinitrate. Most cases of myocardial infarction are treated with angioplasty (mechanical widening of a narrowed or totally obstructed blood vessel) or bypass surgery (surgery in which arteries or veins from elsewhere in the patient’s body are grafted to the coronary arteries to improve blood supply to heart muscles). Use of less fatty food materials and exercises is the major preventive methods.

 

 

 

 

For your information: Approximately one fourth of all myocardial infarctions are silent i.e. without chest pain or other symptoms. A silent heart attack is more common in the elderly, in patients with diabetes mellitus and after heart transplantation,……..

 

 

For your information: Angina pectoris means “chest pain”. It is not as severe as heart attack. The pain may occur in heart and often in left arm and shoulder. It is a warning sign that blood supply to heart muscles is not sufficient but shortage is not enough to cause tissue death.

 

For your information: World Heart Day is held on 28th September every year throughout the world. Its objective is to help people better understand their personal risks of cardiovascular disorders.

 

For your information: Cardiovascular disorders are the cause of 12% of adult deaths in Pakistan (Source: Federal Bureau of Statistics of Pakistan). Hypertension (blood pressure higher than normal) is the most common cause of cardiovascular disorders in Pakistan.

  • There are over 12 million hypertension patients in Pakistan.
  • About 10% of our population is diabetic.
  • According to the World Health Organization,in Pakistan 1 in 7 urban adults is obese.

 

Understanding The Concept.

  1. How would you relate the internal structure of root with the uptake of water and salts?

Answer: Please see answer of question number 4.

  1. Define transpiration and relate it with cell surface and with stomatal opening and closing?

Answer: Please see answer of question number 5.

  1. How do different factors affect the rate of transpiration?

Answer: Please see answer of question number 5.

  1. Transpiration is a necessary evil. Give comments.

Answer: Please see answer of question number 6.

  1. Explain the movement of water in terms of transpirational pull.

Answer: Please see answer of question number 8.

  1. Describe the theory of pressure flow mechanism to explain the translocation of food in plants.

Answer: Please see answer of question number 9.

  1. List the functions of the components of blood.

Answer: Please see answer of question number 12.

  1. How do we classify blood groups in terms of the ABO and the Rh blood group systems?

Answer: Please see answer of question number 14.

  1. State the signs and symptoms, causes and treatments of leukemia and thallassemia.

Answer: Please see answer of question number 13.

  1. What four chambers make the human heart and how blood flows through these chambers?

Answer: Please see answer of question number 15.

  1. Compare the structure and function of an artery, a vein and a capillary?

Answer: Please see answer of question number 18.

  1. Draw diagrams which can illustrate the origins, locations and target areas of the main arteries in human blood circulatory system.

Answer: Please see answer of question number 19.

  1. Draw diagrams which can illustrate the areas and locations of the main veins in human blood circulatory system.

Answer: Please see answer of question number 20.

  1. How would you differentiate between atherosclerosis and arteriosclerosis?

Answer: Please see answer of question number 22.

  1. State the causes, treatments and prevention of myocardial infarction.

Answer: Please see answer of question number 23.

 

SHORT ANSWERS QUESTIONS.

Question#1) What are lenticels and where are they found in plant body?

Answer: pores on the stem of a woody plant that allows gas exchanges between the atmosphere and the internal tissues. These are located on woody parts of the plant such as stem and branches.

Q#2)What is the role of potassium ions in the opening of stomata?

Answer: Recent studies have revealed that light causes the movement of potassium ions from epidermal cells into guard cells. Water follows these ions and enters guard cells. Thus their turgidity increases and stoma opens. As the day progresses, guard cells make glucose i.e. become hypertonic. So water stays in them. At the end of the day, potassium ions flow back from guard cells to epidermal cells and the concentration of glucose also falls. Due to it, water moves to epidermal cells and guard cells loose turgor. It causes the closure of stoma.

Question#3) Define the cohesion-tension theory?

Answer: Cohesion tention theory explains how water move from roots to the tip of the plant. According to this theory the main mechanism involve in this process is transpiration pull. That is developed due to the attractive forces between the molecules.

Question#4) What do you mean by sources and sinks according to the pressure flow mechanism?

Answer: Sources are parts of plants where fixation of carbon dioxide occurs and food is formed. Sinks are the parts where the foods are stored and used in plants.

Question#5) What are the two main types of white blood cell? How do they differ?

Answer: Types of WBC: There two main types of WBCs.

Granulocytes: Granulocytes have granular cytoplasm. These include neutrophils (destroy small particles by phagocytosis), eosinophils (break inflammatory substances and kill parasites) and basophils (prevent blood clotting).

Agranulocytes: Agranulocytes have clear cytoplasm and include monocytes(produce macrophages which engulf germs) and B and T lymphocytes (produce antibodies and kill germs).

Difference between granulocytes and agranulocytes:

        Granulocytes

          Agranulocytes

1) They have granules in their cytoplasm.

1) They donot have granule in their body.

2) They have rough cytoplasm.

2) They have smooth cytoplasm.

3) They are developed in bone marrow.

3) they are developed from lymphoid or myloid (resembling to bone marrow)  tissues.

4) It consists of eosinophills, basophills and neutrophills.

4) It consists of lymphocytes and monocytes .

5) They have nuclei with lobes.

5) They donot have lobed nuclei.

 

Question#6) You see pus at the site of infection on your skin. How is it formed?

Answer: Formation of pus: Pus are nothing but a rich protein fluid and dead leukocytes (neutrophills). WBC fight foreign invaders that inter to the body. When they find disease causing bacteria in any of the body. They send message to other WBC to attract them to fight against these bacteria. During the fight some of the WBC will die and their body will start piling up forming a wall between the bacteria and the rest of the body. These dead WBC along with some proteins of the body form a yellowish white substance called pus. So even in dead form, they will still help to protect the body from bacterial invasion.

Question#7) What role does the pericardial fluid play?

Answer: Role OR functions of pericardial fluid: Pericardial fluid reduces friction within the pericardium by lubricating the epicardial surface allowing the membranes to easily glide over each other with each heart beat.

Question#8) Define the terms systole and diastole?

Answer: Systole: The contraction or period of contraction of the heart, specially of the ventricles, during which blood is forced into the aorta and pulmonary artery is called systole.

Diastole: The normal dilation of the heart during which heart refill with blood is called diastole.

 

Question# 9) Write a note on chemical composition of blood antigen?

Answer: Blood group antigens are antigens on the membranes of red blood cells. The membranes of each red blood cell contains millions of antigens. Antigens of ABO blood groups are sugars and that of Rh blood group are proteins.

 

Question#10) Define the following terms?

ABO system: A type of blood group system in which bloods are grouped on the basis of presence or absence of antigen A and B.

Agglutination: The formation of aggregate (clusture) of antigen and antibody is called agglutination.

Agranulocytes: The type of white blood cells that have clear cytoplasm and include monocytes(produce macrophages which engulf germs) and B and T lymphocytes (produce antibodies and kill germs).

 

Albumin: a type of protein that is soluble in water and in water half saturated with a salt such as ammonium sulfate. Serum albumin is a component of blood serum;

Angina pectoris: Chest pain due to an inadequate supply of oxygen to the heart muscles is called angina pectoris.

Anti-A antibody: A type of antibody present in blood against the antigen B is called Anti-A antibody.

Anti-B antibody: A type of antibody present in blood against the antigen A is called Anti-B antibody.

Antigen : Foreign invaders in the body that trigger an immune response.

Antigen A : An antigen present on the membrane of erythrocytes responsible for blood group A is called antigen A.  It is named due to the presence acetylglucosamine chemical.

Antigen B: A sugar containing antigen present on red blood cells against anti-A-antibody responsible for blood group B is called Antigen B.

Anti-Rh antibody: An antibody present on the membrane surface of red blood cells of organisms having Rh-negative blood group.

Aorta: The great arterial trunk that carries blood from the heart to be distributed by branch arteries through the body is called aorta. OR  The largest artery in the body is called aorta.

Aortic arch: The curved transverse part of the aorta that connects the ascending aorta with the descending aorta is called aortic arch.

Arteriole: Any of the small terminal twigs of an artery that ends in capillaries are called arterioles.

Arteriosclerosis: A disease in which arteries becomes harden due to accumulation of calcium is called arteriosclerosis.

Ascending aorta: The first section of the aorta , which starts from the left ventricle of the heart and extends to the aortic arch is called ascending aorta. The right and left coronary arteries that supply blood to the heart muscles arise from the ascending aorta.

Dorsal aorta or descending aorta : The main trunk of the aorta carrying blood from the left side of heart to the arteries of all limbs and organs except the lungs is called dorsal aorta.

This is the part of the aorta that runs down through the chest and the abdomen. This starts after the arch of the aorta and ends by splitting into two great arteries, the iliac arteries that go to the legs. Descending aorta further divided into thoracic aorta and abdominal aorta. Thoracic vertebra runs to the diaphragm, supply blood to chest cage and organs within the chest while abdominal aorta is the final section of the aorta, begins at diaphragm as a continuation of the thoracic aorta and splits into two iliac (limbic) arteries.

Lymphocytes : A type of White blood cells which attack pathogens is called lymphocytes.

Lymphogenous: (lymphpo means related to lymph and genous means origin). Any material produce from lymph or in lymphatic vessels or spread through lymph is termed as lymphogenous.

Lymphogenous cells: Cells of the lymphatic system are called lymphogenous cells.

Megakaryocytes : A large cell that has a lobulated nucleus, is found esp. in the bone marrow, and is the source of blood platelets

Monocytes :A large white blood cell with finely granulated chromatin dispersed throughout the nucleus that is formed in the bone marrow

Myocardial Infarction: A disease of heart in which blood supply to a part of heart is interrupted and leads the death of heart muscles. It is also called heart attack.

Neutrophils: the type of white blood cells that destroy small solid harmful particles by phagocytosis are called neutrophils.

Pericardial fluid; The fluid in between the heart walls and pericardium is called pericardial fluid.

Pericardium: The heart is enclosed in tough, fibrous and extensible membrane called pericardium.

Pericycle: A thin layer of parenchymatous or sclerenchymatous cells that surrounds the vascular tissues in most vascular plants is called pericycle.

Phloem : Compound tissues through which food is transported in a plant is called phloem.

Plasma : Liquid non cellular part of the blood is called plasma.

Platelets: white blood cells fragments which circulate in the blood and assist in clotting are called platelets.

Pulmonary artery: The artery that carries deoxygenated blood to lungs is called pulmonary artery.

Pulmonary circulation: The pathway on which deoxygenated blood is carried from heart to lungs and in return oxygenated blood is carried from lungs to heart is called pulmonary circulation or pulmonary circuit.

Pulmonary vein: A vein that carries oxygenated blood from lungs to heart is called pulmonary vein.

Pulse: The regular expansion of an artery caused by the ejection of blood into the arterial system by the contractions of the heart is called pulse.

“OR”The edible seeds of various crops (as peas, beans) of the legume family is called pulse.

 

Arteries : The thick walled blood vessels which carry blood away from the heart.

Atherosclerosis: An arteriosclerosis characterized by atheromatous deposits (an abnormal fatty deposits in an artery) in and fibrosis(increase in fibrous tissues) of the inner layer of the arteries is called atherosclerosis.

Atrial systole :The contraction of the heart through which blood is pumped to all the parts of the body is called systole.

Atrium: Either of the chambers of the heart that receives blood from the veins and forces it into the ventricle or ventricles is called atrium (auricle).

B lymphocytes: any of the lymphocytes that have antigen-binding antibody molecules on the surface, that comprise the antibody-secreting plasma cells when mature.

Basophils: The type of white blood cells that prevent clotting are called basophills.

Bicuspid valve OR Mitral valve:A cardiac valve consisting of two triangular flaps which allow only unidirectional blood flow from the left atrium to the ventricle IS called bicuspid valve.

Blood group system; A system in which blood are grouped into various categories based on presence or absence of specific antigens.

Capillary: Extremely narrow tubes which carries blood around our tissues.

Cardiac cycle: The alternating contraction and relaxation heart makes a cycle that carries blood towards and away from the heart is called cardiac cycle.

Cardiovascular system: A system involving blood and associated vessels that circulates blood in all parts of the body is called cardiovascular system.

Cohesion-tension theory: Cohesion tention theory explains how water move from roots to the tip of the plant. According to this theory the main mechanism involve in this process is transpiration pull. That is developed due to the attractive forces between the molecules.

Coronary artery:  Either of two arteries that arise one from the left and one from the right side of the aorta is called coronary artery.

Cortex: The typically parenchymatous layer of tissues external to the vascular tissue and internal to the epidermal tissues of a green plant is called cortex.

Red Blood Cells: Cells which contain haemoglobin and carry oxygen are called RBC.

Rh factors (Rhesus factor) : A proteinacious antigen responsible for the Rh blood group is called Rh factor. It was first discovered in rhesus monkey so named as rhesus.

Rh-blood group system: A system in which blood are arranged into groups on the basis of presence or absence of rhesus (RH) antigen.

Root hair : A filamentous extension of an epidermal cell near the tip of a root that functions in absorption of water and minerals.

Semilunar valve: The crescent shaped valve in between the heart and aorta and in between the heart and the pulmonary artery is called semilunar valve.

Stoma (Plural ‘stomata’): Thin pores in the epidermis of a leaf that controle water loss and gas exchange by opening and closing.

Systemic circulation: The pathway on which oxygenated blood is carried from heart to body tissues and in return deoxygenated blood is carried from body tissues to heart is called systemic circulation or systemic circuit.

T lymphocytes: A type of leukocytes (white blood cells) that originates in the bone marrow, matures in thymus and is an essential part of body defense system.

Thalassaemia: A genetic blood disorder in which oxygen cannot properly transported to body parts due to mutation in the gene of haemoglobin.

Thrombocytes: Fragments of white blood cells that are involved in blood clotting are called thrombocytes or platelets.

Thrombus: (Thrombus means clot)  A clot of blood formed within a blood vessel and remaining attached to its place of origin. Or  a blood clot that forms in a vein is called thrombus.

Transpiration: The loss of water from the aerial parts of the plant by evaporation is called transpiration:Transpirational pull

Tricuspid valve: A valve of three flaps that prevents reflux of blood from the right ventricle to the right atrium.

Veins: Thin walled tubes which carry blood back to the heart are called veins.

 

Vena cava: Any of the large veins by which the blood is returned to the right atrium of the heart.

Diastole: The dilatation of the cavities of the heart during which they fill with blood is called diastole.

 

Embolus; (plural emboli) : An abnormal particle circulating in the blood usually blood clot or air bubble that travels in the blood vessels. It usually blocks the blood vessels.

Endodermis: The innermost tissue of the cortex in many roots and stems is called endodermis.

Eosinophil: Type of  white blood cells that break inflammatory substances and kill parasites is called eosinophil.

Erythrocyte: Hemoglobin-containing blood cells that carry oxygen to the tissues and are responsible for the red color of vertebrate blood are called erythrocytes or red blood cells.

Fibrin: A white insoluble fibrous protein formed from fibrinogen by the action of thrombin protein especially in the clotting of blood.

Fibrinogen: A plasma protein that is produced in the liver and is converted into fibrin during blood clot formation.

Granulocytes: Type of white blood cells that have granular cytoplasm is called granulocytes.

Guard cell: Bean shaped cells which control the opening and closing of stomata are called guard cells.

Haemoglobin: The red protein found in red blood cells that transport oxygen is called haemoglobin.

Heart rate: Heart rate is the number of times the heart beats per minute.

Lenticels: pores on the stem of a woody plant that allows gas exchanges between the atmosphere and the internal tissues. These are located on woody parts of the plant such as stem and branches.

Leucocytes: The colourless large irregular shaped cells involved in the defense system of the body are called leukocytes or white blood cells.

Leukaemia; An acute or chronic disease in humans and other warm-blooded animals characterized by an abnormal increase in the number of white blood cells in the tissues and often in the blood.

Ventricle: Ventricles are thick walled chambers that pump the blood.

Ventricular systole; The contraction of the heart by which the blood is forced onward and the circulation kept up is called ventricular systole.

Venule: The minute veins connecting the capillaries with the larger systemic veins are called venules.

White Blood Cells: The colourless large irregular shaped cells involved in the defense system of the body are called leukocytes or white blood cells.

Wilting: The loss of rigidity of a non woody part of a plant is called wilting.

Xylem: Compound tissues which transports water and minerals to upper parts plant are called xylem

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