Transportation

 Biology XI Notes - Transportation - Short Questions Answers

Q.1: Write a note on Diffusion?

Ans: Diffusion:

• The movement of ions or molecules from an area of higher concentration to an area of lower concentration.

Example:

• Dropping crystals of KMnO₄ or copper sulfate in water causes them to dissolve and spread, coloring the water.

Factors Affecting Diffusion:

• Size and nature of molecules
• Temperature
• Concentration gradient

Importance of Diffusion:

• Assists in water absorption from soil.
• Aids in water movement between plant cells.
• Plays a role in transpiration, photosynthesis, and respiration.

Q.2: What is facilitated diffusion?

Ans: Facilitated Diffusion:

• Involves the movement of ions or molecules with the help of carrier proteins in the cell membrane.
• Carrier proteins create water-filled pores for transporting water-soluble substances across the membrane.
• This process does not require energy.

Q.3: Write a note on Osmosis?

Ans: Osmosis:

• Defined as the movement of water from an area of higher concentration to an area of lower concentration through a semi-permeable membrane.
• Discovered by Nullet in 1746.

Experiment:

• In a U-shaped tube with a semi-permeable membrane, one side (A) contains pure water, and the other side (B) has a 20% sugar solution.
• Water moves from A to B faster due to concentration differences, causing the level in side B to rise, demonstrating osmosis.

Importance of Osmosis in Plants:

• Essential for water absorption through root hairs.
• Facilitates water movement between cells.
• Helps in mineral salt absorption and transport of food.
• Maintains turgidity (strength) in plant tissues, helping them retain shape.
• Controls the opening of stomata by maintaining guard cell turgidity.

Q.4: What is Active Transport?

Ans: Active Transport:

• Opposite to diffusion, active transport moves molecules or ions across the cell membrane from lower to higher concentration using the cell's metabolic energy (ATP).
• Cells with active transport processes contain numerous mitochondria and high ATP levels.

Examples:

• Sodium and Potassium Transport in Nerve Cells: Potassium (K) concentration is higher inside the cell, while sodium (Na) is higher outside. Nerve cells pump Na out and K in through active transport.
• Glucose Transport in Intestines: Glucose is transported from low concentration in the intestine to high concentration in the blood.
• Food Transport in Phloem: In plants, food is transported from mesophyll cells (low sucrose concentration) to phloem (high sucrose concentration).

Importance of Active Transport:

• Essential for nutrient intake and waste expulsion against the concentration gradient.

Q.5: Write a note on Imbibitions?

Ans: Imbibitions:

• The absorption of water by hydrophilic substances, causing them to swell and increase in volume.
• Common in materials like proteins, starch, and cellulose, and can be observed in phenomena such as swollen wooden doors during rainy seasons.
• Imbibition generates heat and increases temperature when water is absorbed, and is affected by temperature.

Importance of Imbibition:

• Cell walls and protoplasm absorb water through imbibition, essential for plant physiological processes.

Q.6: Write a note on Water Potential?

Ans: Water Potential:

• Water molecules possess kinetic energy; the difference in energy between pure water and water in a solution is called water potential.
• Represented by the Greek letter Ψ (Psi), measured in bars. Pure water has a potential of zero, while solutions have negative water potential.

Uses of Water Potential:

• Controls water flow direction across cell membranes.
• Important for water transport by osmosis and measuring plant water status.

Q.7: Write a note on Osmotic Potential (Solute Potential)?

Ans: Osmotic Potential:

• Pressure exerted to prevent solvent passage into a solution separated from pure water by a membrane.
• Always negative, with lower potential indicating higher solute concentration.

Q.8: Describe the water relations of plant cells?

Ans: Water Relations of Plant Cells:

• Solute potential (Ψs) refers to the concentration of solute particles in cell sap, which lowers the cell's water potential. Higher solute concentration results in more negative water potential.

• When a cell is placed in pure water or a solution with higher water potential, water enters the cell via osmosis, creating pressure and making the cell turgid. This increases the pressure potential. The total water potential formula is:

• Water Potential (Ψ) = Solute Potential (Ψs) + Pressure Potential (Ψp)
• In a fully turgid cell, Ψ = 0, as Ψp and Ψs are equal and opposite.

Q.9: What are plasmolysis and deplasmolysis?

Ans: Plasmolysis:

• Plasmolysis occurs when a cell loses water due to exosmosis in a hypertonic solution, causing the protoplasm to shrink and form an oval shape at the cell's center.
• Incipient Plasmolysis: When protoplasm begins to separate from the cell wall.
• Full Plasmolysis: Complete detachment of protoplasm from the cell wall.

Deplasmolysis:

• The reverse process, occurring in a hypotonic solution where water enters the cell, restoring the protoplasm to its original position.

Q.10: Describe the water and mineral uptake by roots?

Ans: Water and Minerals Uptake by Roots:

• Water and salts are absorbed from the soil through three pathways:
• Cell-to-Cell Pathway: Water moves from root hairs into epidermal cells and then cell to cell until it reaches the xylem.
• Symplast Pathway: Water moves through the cytoplasm and plasmodesmata connecting root cells.
• Apoplast Pathway: Water flows through the cell walls and intercellular spaces, facilitated by hydrophilic cell walls.

• Apoplast Pathway:

• Water flows freely through the hydrophilic cell walls of epidermal and cortical cells. The Casparian strip in endodermis acts as a checkpoint, preventing entry into the xylem via apoplast

Q.11: What is the Ascent of Sap and its pathway?

Ans: Ascent of Sap:

• The upward movement of water from roots to leaves, countering gravity, is called ascent of sap.
• Path of Ascent of Sap: Conducted by xylem tissue, specifically tracheae (vessels) and tracheids.

Q.12: What is the Root Pressure Theory of Ascent of Sap?

Ans: Root Pressure Theory:

• Root pressure is a force generated by the alternate expansion and contraction of root cortical cells, creating a pumping effect for water movement.

Root Pressure Theory (continued):

• Objections on Root Pressure Theory:
  • It does not fully explain the ascent of sap as it only raises water a few meters.
  • Tall trees often lack root pressure, yet sap still ascends.

Q.13: What is Guttation?

Ans: Guttation:

• Small droplets of water appear on the tips of grass leaves in the early morning. This process, called guttation, occurs from specialized structures called hydathodes at the leaf tips or margins. It was termed by Burgerstein.

Q.14: Describe the Dixon Theory about Ascent of Sap?

Ans: Transpiration Pull and Adhesion-Cohesion Theory (Dixon Theory):

• This theory attributes the ascent of sap to:
• Transpiration Pull: Water loss from mesophyll cells reduces water content, creating tension that pulls water up from the roots.
• Adhesion Force: Attraction between water molecules and xylem walls.
• Cohesion Force: Attraction among water molecules, forming a continuous column of water from roots to leaves.

Dixon Theory (continued):

• Transpiration pull, adhesion, and cohesion forces work together to move water up the plant, even to great heights. This process is considered solar-powered, relying on sunlight rather than metabolic energy.

Q.15: What is Transpiration? What are the Types of Transpiration?

Ans: Transpiration:

• The loss of water vapor from aerial parts of plants into the atmosphere.

Types of Transpiration:

• Cuticular Transpiration: Water loss through the cuticle on the epidermis.
• Lenticular Transpiration: Water loss through lenticels in woody plants.
• Stomatal Transpiration: Major form, occurring through stomata on leaves.

Lenticular Transpiration:

• Lenticels are natural openings in the epidermis that allow gas exchange due to secondary growth. Water loss through these lenticels is termed lenticular transpiration.

Stomatal Transpiration:

• Stomata in the leaf epidermis facilitate maximum water evaporation due to their minimal resistance.

Q.16: Describe the mechanism of Transpiration?

Ans: Mechanism of Transpiration:

• Transpiration involves water evaporation from mesophyll cell walls into intercellular spaces, followed by diffusion into the atmosphere.
• Relative Humidity: High relative humidity decreases water loss, as the dry air promotes higher diffusion pressure, aiding in water vapor diffusion through stomata from high to low vapor pressure.

Q.17: Describe the structure and opening of stomata?

Ans: Structure of Stomata:

• Stomata are tiny pores in the epidermis with kidney-shaped guard cells that regulate opening and closing based on their turgidity. When guard cells become flaccid, stomata close, and when turgid, stomata open.

Factors Influencing Stomatal Opening and Closing:

• Light: Stomata open in light due to the formation of sugars, which increases osmotic pressure in guard cells, leading to water intake by endosmosis. In darkness, carbohydrates are consumed, lowering osmotic pressure, causing guard cells to lose water and close stomata.
• Potassium (K⁺) Ions: In some plants, guard cell turgidity is regulated by K⁺ ions. Accumulation of K⁺ in guard cells during the day lowers osmotic potential, drawing water in and opening stomata. Lower K⁺ concentration leads to closing.

Q.18: What are the factors which influence the opening and closing of stomata?

Ans: FACTORS INFLUENCE THE OPENING AND CLOSING OF STOMATA:
There are two factors which influence the opening and closing of stomata.

• Light
• Concentration of K⁺ ions

Light:
Light plays an important role in the opening and closing of stomata. The stomata open in light and close in the night. The guard cells contain Chlorophyll, they manufacture carbohydrates during sunlight. By the formation of sugars the osmotic pressure of guard cells increases, so water enters the guard cells due to endosmosis from the neighboring cells of epidermis. It increases the turgidity of guard cells which open stomata.

In the darkness, carbohydrates are consumed in the guard cells or these are transferred into other cells. It decreases the osmotic pressure of guard cells; due to this process exosmosis takes place, guard cells become flaccid and stomata are closed.

Concentration Of K⁺ Ions:
In some plants the turgidity of guard cells is regulated by K⁺ ion concentration. During the day time the guard cells get K⁺ ions from neighboring cells, due to their accumulation the osmotic potential of guard cells is lowered and they get water from epidermal cells, so guard cells become turgid and stomata are opened. Less concentration of K⁺ ions results in the closing of stomata.

Q.19: What are the Factors of Transpiration?

Ans: Factors Affecting Transpiration:

• Light: Controls stomatal opening, indirectly affecting transpiration rate.
• Temperature: Increases leaf temperature, raising transpiration.
• Humidity: Lower humidity increases water loss.
• Wind: Promotes transpiration by moving water vapor away.
• Soil Water: Availability of soil water impacts transpiration rate.

Factors Affecting Transpiration:

• Temperature: Higher temperatures increase the rate of transpiration.
• Humidity: Lower humidity results in increased transpiration, while higher humidity reduces it.
• Wind Velocity: Wind replaces humid air with dry air, increasing transpiration.
• Soil Water: More water in soil leads to faster transpiration.

Q.20: What is the Importance of Transpiration?

Ans: Importance of Transpiration:

• Advantages:
  • Links water absorption to transpiration.
  • Removes excess water from the plant, preventing cell rupture.
  • Facilitates mineral salt intake by roots.
  • Helps regulate plant temperature by cooling through evaporation.
• Disadvantages:
• Requires significant energy for water evaporation.
• Excessive water loss can lead to plant stress or death.
• Some plants adapt by losing leaves or modifying them to reduce transpiration.

Q.21: Describe Briefly the Translocation of Food?

Ans: Translocation:

• The movement of materials within the plant, mainly from sources (leaves) to sinks (storage areas), via the phloem.

Path of Translocation:

• Known as source-to-sink movement.

Mechanism of Phloem Translocation:

• Pressure Flow or Mass Flow Hypothesis (Münch Theory): Proposed in 1930, this theory explains translocation as a flow of solution due to an osmotic pressure gradient. Water moves from high turgor pressure areas (source) to low turgor pressure areas (sink) through plasmodesmata in the phloem.

Q.22: Describe Transportation in Hydra and Planaria?

Ans: Transportation in Hydra:

• Hydra, a diploblastic animal, has two body layers: ectoderm (outer) and endoderm (inner). Oxygen enters through the body surface via diffusion and is distributed to all parts. Food is digested in the body cavity and transported by diffusion.

Transportation in Planaria:

• In Planaria, both oxygen and food transport occurs via diffusion. Food is moved to various parts of the body through branches of the intestine, facilitated by muscle contractions.

Q.23: What are Open and Closed Types of Circulatory System?

Ans: Open Type Circulatory System:

• In open systems, blood does not flow within vessels but directly in the body cavity (haemocoel), where it contacts tissues. This system, common in arthropods and mollusks, has low pressure and the blood is called haemolymph.

Closed Type Circulatory System:

• Blood flows through vessels, distributing it to organs under higher pressure, which allows better control and is found in more active animals.

Q.24: What are the Single Circuit and Double Circuit Plans?

Ans: Single Circuit Plan (e.g., in Fish):

• Fish have a single circuit where blood flows in one direction. Their two-chambered heart (one atrium, one ventricle) pumps deoxygenated blood to the gills for oxygenation, and the oxygenated blood flows to the body.

Double Circuit Plan (e.g., in Amphibians, Reptiles, Birds, Mammals):

• Double circulation includes two circuits: systemic (to the body) and pulmonary (to the lungs). This system allows oxygenated blood to be separated from deoxygenated blood, enhancing efficiency.

• Incomplete Double Circulation: In amphibians and reptiles, the three-chambered heart partially mixes oxygenated and deoxygenated blood in a single ventricle.

• Complete Double Circulation: In birds and mammals, the four-chambered heart completely separates oxygenated and deoxygenated blood.

Q.25: What is the Evolution of Heart in Vertebrates?

Ans: Evolution of Heart in Vertebrates:

• The heart has undergone significant changes from fishes to mammals.

Heart of Fishes:

• Fish have a two-chambered, S-shaped heart with one atrium and one ventricle. Deoxygenated blood flows from the body into the atrium, then into the ventricle, which pumps it to the gills for oxygenation. The heart itself does not receive oxygenated blood.

Heart of Amphibians:

• Amphibians have a three-chambered heart with two atria and one ventricle. The left atrium receives oxygenated blood from the lungs, and the right atrium receives deoxygenated blood from the body. These blood types partially mix in the single ventricle before being pumped to the body.

Heart of Reptiles:

• Reptiles have a partially divided ventricle, with two atria. In most reptiles, oxygenated and deoxygenated blood partially mix in the ventricle. However, in crocodiles, the ventricle is fully divided, allowing complete separation of blood types, with oxygenated blood being supplied to body organs.

Heart of Birds and Mammals:

• Birds and mammals have a four-chambered heart with two atria and two ventricles, allowing complete separation of oxygenated and deoxygenated blood, ensuring that only oxygenated blood is supplied to all parts of the body.

Q.26: Write a Note on Blood?

Ans: Blood:

• Blood is a red-colored fluid that functions as connective tissue in the body of humans and other animals. It consists of two main components:
  • Plasma
  • Blood Corpuscles

Plasma:

• The liquid part of blood, constituting 55% of its volume. It is non-living, with 90% water and 10% dissolved substances (inorganic salts, blood proteins, glucose, amino acids, triglycerides, urea, hormones, enzymes, and autotoxins). Plasma also contains antibodies for disease immunity.

Blood Corpuscles:

• Comprising 40% of blood, corpuscles are of two types:
• Red Blood Corpuscles (RBCs):
• Also called erythrocytes, these are circular, oval-shaped, biconcave, and lack a nucleus. They contain hemoglobin, an iron-based pigment that absorbs oxygen and transports it to all body cells, forming bright red oxy-hemoglobin.

White Blood Corpuscles (WBCs):

• Also called leucocytes, they are colorless, irregularly shaped cells with a nucleus and are generally larger than RBCs but fewer in number. Produced in bone marrow, spleen, and lymph vessels, they have a short life span of 20-30 hours and are classified into:
  • Granulocytes: Contain fine granules in their cytoplasm, including neutrophils, eosinophils, and basophils.
  • Agranulocytes: Have clear cytoplasm without granules, such as lymphocytes and monocytes, which produce antitoxins and absorb bacteria.

Function of White Blood Corpuscles:

• WBCs destroy bacteria and protect the body. Neutrophils and monocytes are phagocytic, engulfing bacteria and foreign particles, while lymphocytes produce antitoxins.

Blood Platelets:

• Small, oval, colorless, biconvex, non-nucleated cells. They are fragments of bone marrow cells and assist in blood clotting.

Q.27: What are the Functions of Blood?

Ans: Functions of Blood:

• Functions of Plasma:
• Transport of Nutrition: Blood transports food, water, and other nutrients from the alimentary canal to various body parts for storage, oxidation, and assimilation.
• Transport of Waste Substances: Blood carries waste from body tissues to excretory organs for removal.

Functions of Blood Components:

• Transport of Metabolic By-Products: Blood transports by-products from metabolism to other parts of the body.
• Transport of Hormones: Blood transfers hormones from endocrine glands to target areas.
• Distribution of Body Heat: Circulates heat throughout the body to maintain a constant temperature.

Functions of RBCs:

• Transport of O₂ and CO₂: Carries oxygen from lungs to the body and CO₂ back to the lungs.

Functions of WBCs:

• Defense Against Diseases: Destroys germs, producing antibodies and antitoxins.

Functions of Platelets:

• Assists in blood clotting after injuries.

Q.28: Describe the Heart of Man Briefly:

Ans: Heart of Man:

• The heart consists of four chambers:

  • Right and Left Atria (Auricles)
  • Right and Left Ventricles

• The atria are separated by the inter-atrial septum, where deoxygenated blood enters the right atrium, and oxygenated blood from the lungs enters the left atrium.

• Ventricles: Form the posterior part of the heart, separated by the inter-ventricular septum. Right atrium opens into the right ventricle, guarded by a tricuspid valve, preventing backward flow. The left atrium opens into the left ventricle, guarded by a bicuspid valve.

Q.29: Describe the Cardiac Cycle (Action of Heart):

Ans: Cardiac Cycle (Action of Heart):

• The heart operates systematically, with myogenic muscles (self-contracting). The cycle of one heartbeat involves:
• Systole (contraction) and Diastole (relaxation).
• During diastole, the atria receive blood (deoxygenated in the right, oxygenated in the left).
• Atrial Systole transfers blood into ventricles.
• Ventricular Systole then sends blood to the lungs (right ventricle) and body (left ventricle).

Q.30: Write a note on Heart beat?

Ans:
Heart BEATS:
When chambers of the heart contract in a systematic and regular manner, it is called a heartbeat. A normal heart shows 72 beats per minute. Heartbeats are also known as heart sounds, which can be listened to easily. Heartbeat begins before birth and continues until death.

During a heartbeat, when the ventricles contract (systole), blood is pushed against the closed atrioventricular (AV) valves, producing the first sound ("LUB"). Following systole, the ventricles relax (diastole), and high pressure in the aorta forces some blood back toward the ventricles, closing the aortic valves, producing the second sound ("DUP"). Each heartbeat cycle includes one systole and one diastole, taking about 0.8 seconds. When there is a defect in one or more valves, it may cause a "heart murmur," detectable as a hissing sound.

Q.31: What is Sino-atrial node (S-A Node)?

Ans:
SINO-ATRIAL NODE (S-A NODE):
The sino-atrial node, located at the top of the right atrium near the superior vena cava, generates electrical impulses and initiates heart contractions, earning it the nickname "pacemaker." It comprises cardiac muscle fibers with few nerve endings from the autonomic nervous system.

Q.32: What is Atrio-ventricular node (A-V Node)?

Ans:
ATRIO-VENTRICULAR NODE (A-V NODE):
Located below the S-A node in the right atrium, the A-V node transfers excitation to all parts of the ventricles through muscle fiber bundles. It includes fibers of the bundle of His and Purkinje fibers, which propagate impulses throughout the ventricular walls. A delay of 0.15 seconds occurs between the S-A and A-V nodes to complete atrial systole before ventricular systole.

Q.33: Describe different blood diseases of man?

Ans:
DISEASES OF BLOOD:

• Leukaemia:
  A blood cancer caused by the uncontrolled production of white blood cells (WBCs), leading to their increase. Bone marrow cells spread through the body, disrupting normal WBC formation. Symptoms include frequent bleeding, and treatment options include bone marrow transplantation, although this is expensive.

• Thalassemia:
  A genetic disorder causing reduced hemoglobin production. In severe cases, patients need regular blood replacement. Children with thalassemia may have an enlarged spleen and kidneys.

Q.34: What is artificial pacemaker?

Ans:
ARTIFICIAL PACEMAKER:
When the natural pacemaker (S-A node) fails, an artificial pacemaker, which supplies electrical impulses to maintain a regular heartbeat, is implanted under the chest skin, powered by battery or electrical wires.

Q.35: What are blue babies?

Ans:
BLUE BABIES:
A condition in newborns characterized by blue skin (cyanosis) due to oxygenated and deoxygenated blood mixing, often caused by defects in the heart's septum.

Q.36: Describe different kinds of blood vessels?

Ans:
BLOOD VESSELS:
The vessels through which blood flows are called blood vessels. These vessels carry blood from the heart to body organs and bring back the blood from body parts to the heart.

The blood vessels are of two types:

• Arteries
• Veins

ARTERIES:
Arteries are the blood vessels which carry the blood from the heart to different parts of the body. Their walls are composed of three layers.

• Tunica externa: outer layer
• Tunica media: middle layer
• Tunica interna: inner layer

Outer Layer:
It is composed of connective tissues which are hard and fibrous, called collagen fibers. They can resist the internal blood pressure.

Middle Layer:
It consists of smooth muscles which are elastic. By their contraction and relaxation, their cavity (lumen) can be decreased or increased. They also control the amount of blood. The cavity of arteries is smaller than veins.

Inner Layer:
It is made up of an endothelial layer. The smallest arteries are called arterioles which control the flow of blood into the capillaries. The arterioles contain valves (sphincters) at their capillary ends, which control the blood flow into capillaries. The arteries carry oxygenated blood from the heart to different parts of the body, but in pulmonary arteries, deoxygenated blood is present, which is carried to the lungs.

VEINS:
The blood vessels which carry the blood from various parts of the body back to the heart are called veins. They are thin-walled vessels. Their walls are composed of three layers.

Outer Layer:
It is made up of hard and fibrous connective tissues, known as collagen fibers.

Middle Layer:
It has smooth elastic muscles.

Inner Layer:
It consists of endothelial layer.

The inner cavity (lumen) of veins is much larger than arteries. The veins have valves which prevent the backward flow of blood. Due to the larger diameter of veins, there is less resistance in the flow of blood, and it can flow in large volume. The smallest veins are called venules which obtain blood from capillaries. The largest vein is termed as caval vein which enters the heart. The veins contain deoxygenated blood except pulmonary veins, which bring blood from lungs to the heart.

Capillaries:
In the transport system, the function of blood circulation is to supply the important materials from one part to another. In this way, a close contact is necessary between circulation and tissues. This contact is in the form of blood capillaries. These are very fine blood vessels which are thin-walled and narrower than arteries and veins. Their diameter is about 7-10.

The wall of capillaries consists of a single layer, called endothelium, through which the diffusion of substances occurs easily. The capillaries are connected to the cells and tissues, so the exchange of important materials between tissue fluid and blood of capillaries takes place by diffusion or active transport. From the blood, $O_2$ is diffused out into body tissues and $CO_2$ of tissues is diffused into the blood. Blood capillaries also help to filter the harmful nitrogenous substances into the excretory organs for their excretion.

Q.37: Write a note on blood pressure?

Ans: BLOOD PRESSURE:
The hydrostatic force exerted by the blood against the walls of blood vessels is called blood pressure. This pressure is produced by the ventricle systole i.e. contraction of ventricles. It helps in the flow of blood from the heart to all parts of the body. When blood flows in the arteries, their walls are stretched due to elasticity, it is called pulse. This pulsation can be felt easily.

Blood pressure is measured in millimeters of Hg (Mercury). Mercury manometer is widely used throughout the world, called sphygmomanometer. The blood pressure is determined by cardiac output and by the diameter of arterioles. When constriction takes place in the walls of arterioles, it is called vasoconstriction. It rises the blood pressure and when walls of arterioles are dilated, it is called vasodilatation, it falls the blood pressure. The smooth muscles of arterioles help in constriction and relation of arterioles and these muscles are controlled by nerve impulses and hormones.

In a normal healthy person the blood pressure during systole is about 120mm high, visible in the glass tube of monometer and during diastole of ventricles is about 80mm high. It is expressed as Blood Pressure (B.P) of 120/80. The difference between systolic and diastolic pressure is called pulse pressure.

Blood Flow:
The flow of blood is very fast in larger arteries. It is highest in aorta, and then gradually reduces in arteries and much slower in capillaries. The total diameter of capillaries is greater than arteries, so the blood flows slowly in capillaries. It helps in the exchange of materials between blood and interstitial tissues.

• Drainage System:
  The lymphatic vessels take part in the returning of water and plasma proteins back to the bloodstream, which have leaked away from blood. Otherwise, death may occur in 24 hours.

• Defence Of The Body:
  The lymphatic system helps to maintain body resistance. The microorganisms, foreign bodies, and broken cells are removed by macrophages found in the lymphatic nodes.

• Absorption And Delivery Of Fats:
  The lacteals of villi absorb digested fats, which are changed into droplets. After that, these fats are returned back to the blood.

• Bathing Of Tissues:
  The lymphatic vessels bathe the tissues and keep them moist.

(Image of the Lymphatic System of Man)

Q.38: Describe Lymphatic System in the body of man?

Ans: LYMPHATIC SYSTEM:
Lymph is a tissue fluid, passes out from the walls of capillaries into the space surrounding the cells. It is actually obtained from the blood-plasma. It is colorless and without proteins. It is involved in osmotic changes between cell-protoplasm and blood.

The lymph passes through vessels, called lymphatic vessels. They form a separate network and constitute the lymphatic system. These vessels carry the fluid to the heart and blood. These vessels also contain valves due to which the backward flow is prevented. In addition to lymphatic vessels and lymph, this system also consists of lymph nodes, spleen, thymus, tonsils and some patches of tissues in appendix and small intestine.

Lymph Capillaries:
The lymph vessels produce lymph capillaries, which form a network in every organ except the nervous system. The lymph capillaries unite together to form larger lymphatic vessels; these are connected with subclavia vein.

Lacteals:
Within the villi of intestine, the lymph vessels are called Lacteals. The lymph circulates through the lymph vessels by the contraction of skeletal muscles in one direction i.e. to the heart. These vessels form collecting ducts, which are connected with veins in the lower neck.

Lymphatic Nodes:
At certain points, the lymph vessels contain special masses of connective tissues, called lymph nodes. In these nodes, lymphocytes are present. Lymphocytes are the cells of the immune system. Through lymph nodes, lymph is filtered. The lymph nodes are of different size, from microscopic size to one inch. Many lymphatic vessels carry the lymph into the lymphatic node, but from this node, a single large vessel comes out. When lymph is filtered through the lymph nodes, the lymphocytes and macrophages present here neutralize it and kill the microorganisms.

Functions Of Lymphatic System:
The lymphatic system performs the following functions:

Q.39: Write a note on Edema?

Ans: EDEMA:
Edema is an "Abnormal condition" caused by lymphatic system when it is not functioning normally. When tissue fluid is not returning into the blood by lymphatic system and it is accumulated in the body tissues and it causes swelling, it is called edema. The excess fluid may be in the cells or outside the cells. Edema results in high blood pressure, kidney failure and heart failure etc.

Causes Of Edema:

• Protein deficiency causes edema. When proteins are not used in food, the body consumes its own blood proteins, so blood cannot absorb tissue fluid, it is accumulated in the body tissues. It causes edema.
• Lymphatic system becomes fail to return fluid due to any obstruction, it results edema.
• When renal system retains salts and water, it causes edema.
• Filariasis is also a cause of edema. It is a disease due to nematodes.
• Due to burns or allergic reactions permeability of capillaries is increased, It causes edema.

Q.40: Name the various cardiovascular diseases?

Ans: CARDIOVASCULAR DISORDERS (CVD):
Diseases of heart, blood vessels and blood circulation are known as cardiovascular disorders (CVD). Some of these disorders are as follows:

• Atherosclerosis
• Hypertension
• Thrombus formation
• Coronary thrombosis
• Myocardial infarction (Heart attack)
• Stroke
• Haemorrhage

Q.41: Write a note on Atherosclerosis?

Ans: ATHEROSCLEROSIS:
Atherosclerosis is the disorder of blood vessels, in which arteries become harden. The inner walls of arteries become narrow, lose their elasticity, due to the formation of raised patches of fats in their inner lining, called athermanous plaques. In such condition flow of blood is disturbed. These raised patches consist of low density lipoprotein (LDL) i.e. cholesterol and proteins, fibrous tissues, decaying muscle cells, clusters of blood platelets or calcium.

Causes:
The causes of atherosclerosis are:

• Smoking

Q.42: What is Hypertension?

Ans: HYPERTENSION:
When the blood pressure is higher than the normal blood pressure, it is called hypertension and the person is called hypertensive. When under resting condition the mean arterial pressure is greater than 110 mmHg, it is considered as high blood pressure and hypertension. It takes place when diastolic blood pressure is greater than 90mmHg and systolic blood pressure is greater than 135-140 mmHg.

Causes:
The causes of high blood pressure hypertension are:

• Use of higher amount of salts in food
• Hereditary factor
• Smoking
• Obesity (Fatness)
• Disorders of kidneys or adrenal glands

Effects:

• Continuous high blood pressure damages the lining of blood vessels, so heart muscles become weak, and its pumping function is affected.
• It causes stroke or heart attack, even no symptom earlier, so it is called silent killer.
• It promotes atherosclerosis.
• Heart may be enlarged.

Q.43: What Is Thrombus formation?

Ans: THROMBUS FORMATION:
The clotting of blood in the blood vessels is called thrombus formation. The main cause of thrombus is atherosclerotic plaques i.e. patches of fats in the blood vessels. These patches damage the inner layer endothelium of blood vessels, then in the damaged regions platelets are deposited, it results blood clotting. By the continuous process the inner cavity lumen of arteries becomes narrow or blocked. it reduces or stops the blood supply.

Q.44: What is Coronary Thrombosis?

Ans: CORONARY THROMBOSIS:
When thrombus i.e. blood clot occurs in coronary arteries (arteries which supply blood to heart muscles) and these arteries are narrowed or blocked, it is called coronary thrombosis. Due to thrombosis O₂ is not supplied to any part of heart, so it becomes inactive or dead. It causes coronary heart disease. By thrombosis heart attack may occur.

Q.45: Write a note on myocardial infarction (Heart attack)?

Ans: MYOCARDIAL INFARCTION (HEART ATTACK):
When the blood vessels of heart are blocked either by thrombus (clotting of blood) or embolus (clotted blood comes into serum), it causes death of the part of heart and continuous chest pain, it is called myocardial infarction, commonly it is known as heart attack.

When the coronary arteries of heart are blocked and they do not supply O₂ to particular organs, that heart muscle does not work properly and gradually become dead. Such muscles of heart are called infracted and the mechanism is known as myocardial infarction. When a small part of heart is damaged, the person may recover from heart attack, but when large part is damaged, it may cause death of person.

Precautions:

• Persons should not use fatty food, rich with cholesterol.
• Body should not be over-weight.
• Blood pressure should be maintained normal by exercise.
• Smoking should be avoided.

Q.46: Write a note on stroke?

Ans: STROKE:
When any blood vessel in the brain is blocked by blood clotting (thrombus) or embolus (transfer of clotted blood in serum) and there is no proper supply of blood to the brain or sometime there is leakage of blood from blood vessels, it causes a stroke. As a result of stroke the parts of the body are paralyzed which are controlled by damaged part. The sensation, movement or function of these parts is badly affected. When any one cerebral hemisphere is damaged, it causes weakness or paralysis of one side of the body, it is called hemiplegia.

Q.47: What is Hemorrhage?

Ans: HEMORRHAGE:
When there is leakage or discharge of blood from blood vessels, it is called hemorrhage. When any blood vessel in the brain is ruptured, it causes brain hemorrhage. It is very serious and dangerous. The main cause of brain hemorrhage is hypertension. The massive accumulation of blood within the tissue is called hematoma.

Q.48: What is immune system? What are the types of immune system?

Ans: THE IMMUNE SYSTEM:
The ability of a living organism to resist the infection by parasitic microorganisms, their toxins, foreign cells or abnormal cells of the body is called immunity, and the system which shows response to the infection is known as immune system. Immunity is an essential requirement for survival, since the body of man and animals is attacked by viruses, bacteria, fungi, and parasitic animals.

Types Of Immune System:
There are two types of immune system.

• Innate immune system
• Adaptive immune system

Q.49: Describe the innate immune system?

Ans: INNATE IMMUNE SYSTEM (NON-SPECIFIC IMMUNE SYSTEM)
It is the natural immune system and non-specific, i.e., this immunity prevents the infection of all microorganisms. This system is responsible to control the activity of microorganisms. In innate immune system there are two systems of defense.

• Physical body organs (First line of defence)
• Internal body system (Second line of defence)

Physical Body Organs: (First Line Of Defence)

Skin and mucous membrane are very important organs, which act as the first line of defence i.e., prevent the attack of microorganisms. Skin does not allow the entry of infectious agents. Mucous membrane is present along the lining of digestive, respiratory, and urogenital tracts. Through the mucous membrane, microorganisms can enter the body, but mucus and certain secretions destroy these microorganisms.

Internal Body System: (Second Line Of Defence)
When due to certain reasons microorganisms enter the body, there is another line of defence for the protection of the body from microorganisms. These are:

• Phagocytes
• Antimicrobial proteins
• Inflammatory response

Phagocytes:
These are a type of W.B.C. These cells destroy microorganisms and other particles.

Antimicrobial Proteins:
In the body, certain proteins are produced which destroy infectious microorganisms; these are called antimicrobial proteins.

Inflammatory Response:
It is the condition of fire in any certain part of the body due to any injury or infection of microorganisms. In such a condition, the infected part becomes swollen, reddish, and feels heat and pain.

By infection and inflammation, fever is caused in warm-blooded animals. It is due to the release of a substance by certain W.B.C.s, called pyrogen. It increases the body temperature. Moderate fever is useful to the body because it prevents the growth of microorganisms.

Q.50: Describe the adaptive immune system?

Ans: ADAPTIVE IMMUNE SYSTEM: (SPECIFIC IMMUNE SYSTEM)
It is the specific immune response against specific microorganisms, which is developed in the body specifically against many organisms, tumor cells, transplanted tissues, and toxins. It is considered as third line defence and works with the second line defence system. It is also called specific immune response system. In adaptive immune system, special types of lymphocytes play an important role, called B-cells and T-cells. These cells are produced in bone marrow or thymus.

In adaptive immune system, two types of immunity are developed.

• Humoral immunity: (HI)
  Immunity develops due to B-cells against bacteria.
• Cell mediated Immunity: (CMI)

Q.51: What are the hormones of immune system?

Ans: HORMONES OF IMMUNE SYSTEM (CYTOKINES OR LYMPHOKINES):
The hormones of the immune system are called cytokines or lymphokines. These are protein molecules. These hormones regulate the immune responses. There are many hormones, such as interleukins (IL), interferons. Interferon's are used in response to viral infection and other stimuli. They control the growth of viruses and increase the activity of natural killer cells (NK cells).

Q.52: Describe primary and secondary immune responses?

Ans: PRIMARY & SECONDARY IMMUNE RESPONSES:
When there is the first entry of an antigen to form effect or cells, there is a response in the immunity system, it is called primary immune response. From the time of infection to the formation of maximum effect or cells 5 to 10 days are required. When there is a second infection by the same pathogen, the response takes place more quickly and rapidly by the immune system, it is called secondary immune response. The time for this response is 3 to 5 days. This quicker response is due to immunological memory of the immune system. During the primary immune response, some memory cells are formed. These cells play a role in the quicker secondary response, and also help in lifelong protection against some dangerous diseases like chicken pox.

Q.53: Describe active and passive immunity?

Ans: ACTIVE & PASSIVE IMMUNITY:
According to the function, there are two types of immunity:

• Active immunity
• Passive immunity

Active Immunity:
The immunity develops by the response of the own immune system of the body, it is called active immunity. It is of two types:

1. Natural Active Immunity:
   When the immune system is developed in the body by its own response in a natural way, it is called natural active immunity.
2. Artificial Active Immunity:
   Active immunity can be developed artificially by vaccination; it is called artificial active immunity. By vaccination, long-life protection is provided, for example, chicken pox.

Passive Immunity:
When antibodies are introduced into the body from another person or an animal, it is called passive immunity. This immunity may be natural or artificial.

• Natural Passive Immunity:
  In natural passive immunity, the antibodies are transferred from the body of a person to another person of the same species. For example, antibodies from the mother are transferred into the body of a newborn baby through the placenta.

• Artificial Passive Immunity:
  In artificial passive immunity, antibodies are obtained from the body of animals or human beings who are already immune to that disease, and these are transferred into another person. For example, antibodies for rabies are obtained from already vaccinated persons and then introduced into the body of an affected person. It is a rapid process of immunity, but it is also short-lived.

Q.54: What is immunization?

Ans: IMMUNIZATION:
Immunization is the resistance against diseases, carried out by vaccination. By effective vaccination, many dangerous diseases have been controlled properly throughout the world, such as diphtheria, measles, polio, smallpox, and hepatitis. Immunization was first introduced by the scientist Edward Jenner.