Chapter 8: Respiration and Circulation [ Exercise,Solutions,Notes ]

Plant Water Relation [ Exercise,Solutions,Notes ]

Choose the correct alternative,.

Exercise | Q 1.01 | Page 180

 The muscular structure that separates the thoracic and abdominal cavity is _______.

pleura

diaphragm

trachea

epithelium

Solution:

The muscular structure that separates the thoracic and abdominal cavity is diaphragm.

Exercise | Q 1.02 | Page 180

What is the minimum number of the plasma membrane that oxygen has to diffuse across to pass from air in the alveolus to haemoglobin inside a RBC?

Two

Three

Four

Five

Solution:

Five

Exercise | Q 1.03 | Page 180

 ________ is a sound-producing organ.

Larynx

Pharynx

Tonsils

Trachea

Solution:

Larynx is a sound-producing organ

Exercise | Q 1.04 | Page 180

The maximum volume of gas that is inhaled during breathing in addition to T.V is _______.

residual volume

I.R.V.

G.R.V.

Vital capacity

Solution:

The maximum volume of gas that is inhaled during breathing in addition to T.V is I.R.V..

Exercise | Q 1.05 | Page 180

_______ muscles contract when the external intercostal muscles contract.

Internal abdominal

Jaw

Muscles in bronchial walls

Diaphragm

Solution:

Diaphragm muscles contract when the external intercostal muscles contract.

Exercise | Q 1.06 | Page 180

Movement of cytoplasm in unicellular organisms is called __________.

diffusion

cyclosis

circulation

thrombosis

Solution:

Movement of cytoplasm in unicellular organisms is called cyclosis.

Exercise | Q 1.07 | Page 180

Which of the following animals do not have closed circulation?

Earthworm

Rabbit

Butterfly

Shark

Solution:

Butterfly

Exercise | Q 1.08 | Page 180

Diapedesis is performed by ______.

erythrocytes

thrombocytes

adipocytes

leucocytes

Solution:

Diapedesis is performed by leucocytes.

Exercise | Q 1.09 | Page 180

Pacemaker of heart is _________.

SA node

AV node

His bundle

Purkinje fibers

Solution:

Pacemaker of heart is SA node.

Exercise | Q 1.1 | Page 180

Which of the following is without a nucleus?

Red blood corpuscle

Neutrophil

Basophil

Lymphocyte

Solution:

Red blood corpuscle

Exercise | Q 1.11 | Page 180

Cockroach shows which kind of circulatory system?

Open

Closed

Lymphatic

Double

Solution:

Open

Exercise | Q 1.12 | Page 180

Diapedesis can be seen in _________ cell.

RBC

WBC

Platelet

Neuron

Solution:

Diapedesis can be seen in WBC cell.

Exercise | Q 1.13 | Page 180

 Opening of inferior vena cava is guarded by _______.

bicuspid valve

tricuspid valve

Eustachian valve

Thebesian valve

Solution:

Opening of inferior vena cava is guarded by Eustachian valve.

Exercise | Q 1.14 | Page 180

_______ wave in ECG represent atrial depolarization.

P

QRS complex

Q

T

Solution:

P wave in ECG represent atrial depolarization.

Exercise | Q 1.15 | Page 180

The fluid seen in the intercellular spaces in human is _________

blood

lymph

interstitial fluid

water

Solution:

The fluid seen in the intercellular spaces in humans is interstitial fluid.

Exercise | Q 2 | Page 180

Match the Respiratory surface to the organism in which it is found.

Respiratory surface	Organism
Plasma membrane	Insect
Lungs	Salamander
External gills	Bird
Internal gills	Amoeba
Trachea	Fish

Solution:

Respiratory surface	Organism
Plasma membrane	Amoeba
Lungs	Bird
External gills	Salamander
Internal gills	Fish
Trachea	Insect

Very short answer question,.

Exercise | Q 3.1 | Page 180

Why does trachea have ‘C’ shaped rings of cartilage?

Solution:

The trachea has ‘C’ shaped rings of cartilage as they prevent the trachea from collapsing.

Exercise | Q 3.2 | Page 180

Why is respiration in insect called direct respiration?

Solution:

In insects, the respiratory system is independent of its circulatory system as blood does not play a direct role in oxygen transport but the tracheal tubes directly transport oxygen to the entire body. Therefore, respiration in the insect is called direct respiration.

Exercise | Q 3.3 | Page 180

Why is a gas exchange very rapid at the alveolar level?

Solution:

Alveoli are lined by layer of simple squamous epithelial epithelium. This thin, single layer of epithelium allows the rapid exchange of gases in alveolar region.

Exercise | Q 3.4 | Page 180

Name the organ which prevents the following the entry of food into the trachea while eating.

Solution:

Epiglottis

Short answer question,.

Exercise | Q 4.1 | Page 181

Why is it advantageous to breathe through the nose than through the mouth?

Solution:

i. Nose filters and warms the inhaled air. Hair in the nose prevents the entry of microbes, dust, and other impurities which may harm the lungs.

ii. Mouth lacks any such structures for filtering and warming the air that is inhaled during inspiration. Hence, it is advantageous to breathe through the nose than through the mouth.

Exercise | Q 4.2 | Page 181

 Identify the incorrect statement and correct it,

a. A respiratory surface area should have a large surface area.

b. A respiratory surface area should be kept dry.

c. A respiratory surface area should be thin, maybe 1mm or less.

Solution:

b. A respiratory surface should be kept dry.

Correct statement – A respiratory surface should be moist in order to facilitate the exchange of gases.

Exercise | Q 4.3 | Page 181

Given below is the characteristic of some modified respiratory movements. Identify them.

Spasmodic contraction of muscles of expiration and forceful expulsion of air through nose and mouth.

Solution:

Sneezing is the Spasmodic contraction of muscles of expiration and forceful expulsion of air through the nose and mouth.

Exercise | Q 4.3 | Page 181

Given below is the characteristic of some modified respiratory movement. Identify them.

An inspiration followed by many short convulsive expirations accompanied by facial expression.

Solution:

Crying

Exercise | Q 4.4 | Page 181

Write a note on blood plasma.

Solution:

Blood plasma is a yellowish coloured liquid component of blood that normally holds the blood cells in whole blood in suspension; this makes plasma the extracellular matrix of blood cells. It makes up about 55% of the body's total blood volume. It is the intravascular fluid part of extracellular fluid (all body fluid outside cells).

Plasma consists of water, proteins (albumin, globulin, properdin, prothrombin, fibrinogen), inorganic salts (Na, K, Mg, Ca, Fe, Mn and Cl-, HCO

, and PO

), food (glucose, amino acids, fatty acids, triglycerides), wastes (urea, uric acid and creatinine), regulators (hormones, enzymes, vitamins), anticoagulants (heparin), cholesterol and antibodies, dissolved gases (O2, CO2, N2). Plasma contains 90% water, 7-8% proteins, inorganic salts – 1% and other substances 1-2%.

Functions of plasma -

It carries blood cells and metabolic waste.

It helps in maintaining water content and temperature.

Contains clotting factors to form a blood clot.

Plasma also serves as the protein reserve of the human body.

It plays a vital role in an intravascular osmotic effect that keeps electrolytes in balanced form and protects the body from infection and other blood disorders.

Exercise | Q 4.5 | Page 181

Explain blood clotting in short.

Solution:

Clotting or coagulation is the process of converting liquid blood into a solid form. This process may be initiated by contact of blood with any foreign surface (intrinsic process) or with damaged tissue (extrinsic process).

Intrinsic and extrinsic processes involve the interaction of various substances called clotting factors by a stepwise or cascade mechanism.

There are in all twelve clotting factors numbered as I to XIII (factor VI is not in active use). Interaction of these factors occurs in a cascade manner leading to the formation of the enzyme thrombin.

Thromboplastin helps in the formation of the enzyme prothrombinase. This enzyme inactivates heparin and also converts inactive prothrombin into its active thrombin.

Thrombin converts soluble blood protein fibrinogen into insoluble fibrin. Fibrin forms a mesh in which platelets and other blood cells are trapped to form the clot.

Exercise | Q 4.6 | Page 181

Describe pericardium.

Solution:

The heart is enclosed in a membranous sac called the pericardium. The pericardium is formed of two main layers - outer fibrous and inner serous pericardium. Serous pericardium is soft, moist, and elastic. It is formed of squamous epithelium and is further divisible into two layers as a parietal and visceral layer. Parietal and visceral layers of serous pericardium are separated by a pericardial space. This space is filled with pericardial fluid (about 50ml) which acts as a shock absorber and protects the heart from mechanical injuries. It also keeps the heart moist and acts as a lubricant.

Exercise | Q 4.7 | Page 181

 Describe valves of human heart.

Solution:

Both the atria open into ventricles of their respective sides by atrioventricular apertures. The atrio-ventricular apertures are guarded by cuspid valves.

i. Cuspid valves:

These are bicuspid and tricuspid valves. The bicuspid valve also known as the mitral valve is present in the left atrio-ventricular aperture. Tricuspid valve is present in the right AV aperture.

ii. Eustachian valve:

It is present on the opening of the post-caval vein (inferior vena cava).

iii. Thebesian valve:

It guards the opening of the coronary sinus into the right atrium.

iv. Semilunar valves:

These three valves guard the opening between the right ventricle and pulmonary artery and left ventricle and aorta.

Exercise | Q 4.8 | Page 181

What is the role of papillary muscles and chordae tendinae in the human heart?

Solution:

The bicuspid and tricuspid valves are connected to chordae tendineae which in turn are connected to the papillary muscles present on the ventricular wall. Chordae tendineae and papillary muscles regulate the opening and closing of valves.

Exercise | Q 4.9 | Page 181

Explain in brief the factors affecting blood pressure..

Solution:

The factors affecting blood pressure are:

1. Cardiac output:

The normal cardiac output is 5 litres/min. An increase in cardiac output increases systolic pressure.

2. Peripheral resistance:

It depends upon the diameter of blood vessels. A decrease in the diameter of arterioles and capillaries under the effect of vasoconstrictors like vasopressin or ADH cause increase in peripheral resistance and thereby increase in blood pressure.

3. Blood volume:

Blood loss in accidents decreases blood volume, and thus the blood pressure.

4. Viscosity of blood:

Blood pressure is directly proportional to the viscosity of blood.

5. Age:

Blood pressure increases with age due to the increase in inelasticity of blood vessels.

6. Venous return:

The amount of blood brought to the heart via the veins per unit time is called the venous return. It is directly proportional to blood pressure.

7. Length of blood vessel:

Blood pressure is also directly proportional to the total length of the blood vessel. Blood pressure can also be affected by vasoconstriction or vasodilation.

8. Gender:

Females have slightly lower BP than males before the age of menopause. However, the risk of high B. P. increases in the females after menopause sets in.

Exercise | Q 5.1 | Page 181

Give scientific reason.

Closed circulation is more efficient than open circulation.

Solution:

1. In open circulation, blood is not enclosed in blood vessels but pumped directly into the cavity called haemocoel whereas, in the closed type of circulation, blood flows within the blood vessels and does not come in direct contact with cells and body tissues.

2. Therefore, in closed blood circulation blood flows under high pressure and allows the blood to pass faster and achieve a high level of distribution within the body.

Thus, closed circulation is more efficient than open circulation.

Exercise | Q 5.2 | Page 181

Give scientific reason.

Human heart is called as myogenic and autorhythmic.

Solution:

The human heart is capable of generating a cardiac contraction independent of the nervous system. It can generate its own rhythm due to the presence of nodal tissues.

The nodal tissue SA node (Sinoatrial node) is capable of generating the wave on contraction and making the pace of contraction.

Thus, human heart is myogenic and autorhythmic.

Exercise | Q 5.3 | Page 181

Give scientific reason.

Person who has undergone a heart transplant needs lifetime supply of immunosuppressants.

Solution:

a. Immunosuppressants are the drugs that reduce the level of immune activity and the risk of rejection of foreign bodies such as transplant organs.

b. After transplantation, there is a risk of graft rejection as the body may recognize the transplanted organ/tissue as foreign and may trigger an immune response thereby damaging the transplanted organ.

Therefore, the heart recipient has to rely upon lifetime supply of immunosuppressants.

Exercise | Q 5.4 | Page 181

Arteries are thicker than veins.

Solution:

i. Arteries carry oxygenated blood away from the heart to the body.

ii. The blood pumped out by the heart is under high pressure and to withstand this pressure arteries are thick-walled.

iii. Veins carry deoxygenated blood from the body back to the heart.

iv. They are thin-walled as the blood that flows through veins is under low pressure. Hence, arteries are thicker than veins.

Exercise | Q 5.5 | Page 181

Left ventricle is thick than all other chambers of heart.

Solution:

i. The thickness of the myocardium of the four chambers varies according to the functions of each chamber.

ii. The thin-walled atria deliver blood into adjacent respective ventricles.

iii. As compared to the right ventricle, the left ventricle pumps blood at great distances to all other parts of the body at higher pressure, and resistance to blood flow is larger. Therefore, the left ventricle is thick as it requires strength to withstand the high pressure.

Exercise | Q 6.1 | Page 181

Distinguish between open and closed circulation.

Solution:

Open circulation	Closed circulation
1. In open circulation, blood is circulated through the body cavities (haemocoels).	1. In closed circulation, blood circulates the blood vessels and does not come in direct contact with cells and body tissues.
2. The blood flows with low pressure.	2. The blood flows with high pressure.
3. Exchange of material takes place directly between blood and cells or tissues of the body.	3. Exchange of material between blood and body tissues is through intermediate fluid called lymph.
4. It usually does not contain any respiratory pigment like haemoglobin so it does not transport respiratory gases	4. It contains respiratory pigments like haemoglobin for transportation of respiratory gases.
e.g. Arthropods and molluscs	e.g. All vertebrates, higher molluscs and annelids

Exercise | Q 6.2 | Page 181

Distinguish between Arteries and Veins

Solution:

Arteries	Veins
1. They carry blood away from the heart to various parts/organs of the body.	1. The carry blood towards the heart from various parts /organs of the body.
2. Blood flows under great pressure.	2. Blood flows under less pressure.
3. They are thick-walled.	3. They are thin-walled.
4. Arteries branch into arterioles and further into fine capillaries	4. Venules are small vessels that continue from capillaries and merge to form veins.
5. These are deeply situated except a few like the radial, brachial, femoral, etc. which are superficially located.	5. Mostly superficial in location.
6. They carry oxygenated blood, except pulmonary artery.	6. They carry deoxygenated blood, except pulmonary vein.
7. Tunica media is comparatively thicker.	7. Tunica media is comparatively thinner.
8. They do not have valves.	8. They have valves to prevent the backflow of the blood.

Exercise | Q 6.3 | Page 181

Distinguish between Blood and lymph.

Solution:

Blood	lymph
1. It is reddish in colour.	1. It is pale yellow in colour.
2. It has two main components - fluid plasma and formed elements (blood cells).	2. It has almost similar composition to the blood except for RBCs, platelets, and some proteins.
3. It flows through blood vessels.	3. It flows through lymph vessels.
4. It transports materials from one organ to another.	4. It transports material from tissues cells to blood and vice-versa.

Exercise | Q 6.4 | Page 181

Distinguish between Blood capillary and lymph capillary

Solution:

Blood capillary	lymph capillary
1. Its diameter is smaller than lymph capillary.	1. Its diameter is larger than blood capillary.
2. It contains blood.	2. It contains lymph.
3. It is less permeable than lymph.	3. It is more permeable than blood capillary.
4. Blood capillaries provide oxygen and other substances to the tissues.	4. Lymph capillaries absorb the excess of tissue fluid.

Exercise | Q 6.5 | Page 181

Distinguish between Intrinsic and extrinsic process of clotting

Solution:

Intrinsic pathway	Extrinsic pathway
1. It is stimulated by damage to blood vessels.	1. It is stimulated by damage to tissue outside the vessel.
2. It is more complex and takes more time than the extrinsic pathway.	2. It occurs rapidly as it has fewer steps as compared to the intrinsic pathway.
3. Tissue factor is not involved in the activation of the intrinsic pathway.	3. Tissue factor also known as thromboplastin activates extrinsic pathways.
4. It involves factor VIII, IX, XI, and XII.	4. It involves factors VII, X, and V.

Exercise | Q 7.01 | Page 181

Smita was working in a garage with the doors closed and automobile's engine running. After some time she felt breathless and fainted. What would be the reason? How can she be treated?Solution:

SOLUTION

1. Smita felt breathless and fainted due to the presence of excess carbon monoxide released from automobile engines.

2. Carbon monoxide can be fatal if not treated. The affected person can be treated by administering pure oxygen. This will speed up the separation of carbon monoxide from hemoglobin.

Long answer question,

Exercise | Q 7.02 | Page 181

Shreyas went to a garden on a wintry morning. When he came back, he found it difficult to breathe and started wheezing. What could be the possible condition and how can he be treated?

Solution:

1. The symptoms - difficulty in breathing, wheezing indicate that Shreyas could be suffering from asthma.

2. Inhalers in which open-air passageways are used to treat asthma.

Exercise | Q 7.03 | Page 181

 Why can you feel a pulse when you keep a finger on the wrist or neck but not when you keep them on a vein?

Solution:

Pulse is the series of pressure waves that travel through arteries due to ventricular systole.

It is strongest in the arteries closer to the heart and gradually becomes weak in arteries away from the heart and will be the weakest till it reaches the vein.

Exercise | Q 7.04 | Page 181

A man’s pulse rate is 68 and cardiac output is 5500 cm3 . Find the stroke volume.

Solution:

	=	stroke volume
	=	end-diastolic volume
	=	end-systolic volume

Cardiac output = Stroke volume × Heart rate

∴ 5500 = Stroke volume × 68

Stroke volume = 

= 80.882 ≈ 80.88mL

Exercise | Q 7.05 | Page 181

Which blood vessel of the heart will have the maximum content of oxygen and why?

Solution:

Pulmonary vein carries the maximum content of oxygen.

Pulmonary circulation moves deoxygenated blood from the heart to the lungs for oxygenation and it returns to the heart as oxygenated blood. Systemic circulation pushes the oxygenated blood from the heart towards various body parts (except lungs) and returns back to the heart as deoxygenated blood.

Pulmonary vein is the only blood vessel that carries freshly oxygenated blood from the lungs to the heart for distribution to the body.

Exercise | Q 7.06 | Page 181

 If the duration of the atrial systole is 0.1 sec and that of complete diastole is 0.4 sec, then how does one cardiac cycle complete in 0.8 sec?

Solution:

1. One cardiac cycle includes atrial systole, ventricular systole, and joint/complete diastole.

2. The duration for atrial systole is 0.1 sec, duration for complete diastole is 0.4 sec, which means if one cardiac cycle completes in 0.8 sec then the duration for ventricular systole is 0.3 sec.

3. Therefore, the duration of one cardiac cycle

= Atrial systole + Ventricular systole + Complete diastole

= 0.1 sec +0.3 sec + 0.4 sec = 0.8 sec

4. Also the relaxation period shortens as the heart beats faster whereas the durations of atrial systole and diastole shortens slightly. Hence, one cardiac cycle completes in 0.8 sec.

Exercise | Q 7.07 | Page 181

How blood is kept moving in the large veins of the legs?

Solution:

1. The blood in the large veins of legs is kept moving by the means of azygos system (located on either side of the vertebral column and drains the viscera within the mediastinum, as well as the back and thoracoabdominal walls).

2. It serves as a bypass for the inferior vena cava that drains blood from the lower body.

3. Several small veins link the azygos system directly with inferior vena cava. Large veins drain the lower limbs and abdomen, conducts blood into the azygos system.

4. If the inferior vena cava or hepatic portal vein becomes obstructed, the azygos system returns blood from the lower body to the superior vena cava.

Exercise | Q 7.08 | Page 181

Describe the histological structure of the artery, vein, and capillary.

Solution:

The three structural layers of a generalized blood vessel from innermost to outermost are the tunica interna (intima), tunica media, and tunica externa. Modifications in this basic design account for the five types of blood vessels and the structural and functional differences among the various vessel types. In the transverse section of an artery, three layers can be seen. They are:

T. S. of Artery, Vein and Capillary-

1. Tunica externa or tunica adventitia:

It is a thick, tough layer of collagen fibers.

2. Tunica media:

It is the middle layer made up of smooth muscle fibers and a network of elastic fibers. This thick muscular and elastic layer makes the arterial wall pulsatile.

3. Tunica interna or intima:

The innermost tunica interna is a single layer of flat compact endothelial cells surrounding the lumen. The angular margin around the lumen shows tessellations. Arterial lumen is devoid of valves and blood flows through it rapidly and with high pressure.

Exercise | Q 7.09 | Page 181

What is blood pressure? How is it measured? Explain the factors affecting blood pressure.

Solution:

The pressure exerted by blood on the wall of the blood vessels is called blood pressure.

It is measured by the sphygmomanometer. It is usually measured from the arteries.

The factors affecting blood pressure are:

1. Cardiac output:

The normal cardiac output is 5 litres/min. An increase in cardiac output increases systolic pressure.

2. Peripheral resistance:

It depends upon the diameter of blood vessels. A decrease in the diameter of arterioles and capillaries under the effect of vasoconstrictors like vasopressin or ADH causes an increase in peripheral resistance and thereby increase in blood pressure.

3. Blood volume:

Blood loss in accidents decreases blood volume, and thus the blood pressure.

4. Viscosity of blood:

Blood pressure is directly proportional to the viscosity of blood.

5. Age:

Blood pressure increases with age due to an increase in the inelasticity of blood vessels.

6. Venous return:

The amount of blood brought to the heart via the veins per unit time is called the venous return. It is directly proportional to blood pressure.

7. Length of blood vessel:

Blood pressure is also directly proportional to the total length of the blood vessel. Blood pressure can also be affected by vasoconstriction or vasodilation.

8. Gender:

Females have slightly lower BP than males before the age of menopause. However, the risk of high B. P. increases in the females after menopause sets in.

Exercise | Q 7.1 | Page 181

Describe human blood and give its functions.

Solution:

Human blood consists of plasma and blood corpuscles or blood cells

Plasma: It is a straw-coloured, slightly alkaline, viscous fluid. It constitutes 55% of the blood. Plasma consists of water, proteins (albumin, globulin, properdin, prothrombin, fibrinogen), inorganic salts (Na, K, Mg, Ca, Fe, Mn and Cl-, HCO

 and PO

), food (glucose, amino acids, fatty acids, triglycerides), wastes (urea, uric acid and creatinine), regulators (hormones, enzymes, vitamins), anticoagulants (heparin), cholesterol and antibodies, dissolved gases (O2, CO2, N2) Plasma contains 90% water, 7-8% proteins, inorganic salts – 1% and other substances 1-2%.

Blood Corpuscles: It constitutes 44% of the blood. Blood corpuscles are of three types as given below:

1. RBC (Red Blood Corpuscles) or Erythrocytes:

a. Erythrocytes are the most abundant cells in the human body.

b. They are circular, biconcave and enucleated (in camel and llama they are nucleated).

c. The red colour or RBCs is due to an oxygen-carrying pigment, the haemoglobin, in their cytoplasm.

d. In males, the RBC count is about 5.1–5.8 million/mm3 (per μL) and in females about 4.3–5.2 million/mm3.

e. The average life span of RBCs is 120 days.

f. The process of formation of RBCs is called erythropoiesis.

g. RBCs are produced from haemocytoblasts/reticulocytes.

h. The erythropoeitic organ of the foetus is the liver and spleen and in the adult, it is mainly the red bone marrow.

i. Vitamin B12, folic acid and heme protein are required for the production of RBCs. The old and worn-out RBCs are destroyed in the liver and spleen (graveyard of RBCs).

j. Polycythemia is the condition in which the number of RBCs increase and erythrocytopenia is a decrease in the number of RBCs.

k. The hormone erythropoietin produced by the kidney cells stimulates the bone marrow for production of RBCs.

l. Mature erythrocyte is devoid of nucleus, mitochondria or other membrane-bound cell organelles. Its cytoplasm (stroma) is rich in haemoglobin and O2 carrying proteinaceous pigment that gives the red colour to the RBCs and blood. It also contains an enzyme, carbonic anhydrase.

m. Erythrocytes are responsible for the transport of respiratory gases O2 and CO2, maintaining pH and viscosity of blood. They also contribute in the process of blood clotting.

n. The ratio of the volume of RBCs to the total blood volume of blood is hematocrit. It is different for men and women.

2. WBC (White Blood Corpuscles) or Leucocytes:

a. Leucocytes are colorless, nucleated, and amoeboid cells larger than RBCs.

b. These are colourless, irregular nucleated cells and show polymorphism (exist in variable forms)

c. Due to their amoeboid movement they can move out of the capillary walls by a process called diapedesis.

d. A normal adult has on average, 5000-11000 WBCs per mm3 of blood.

e. Decrease in the number of WBCs (<4000) is called leucopenia (common in HIV, AIDS, and TB patients or those exposed to radiations, shock, etc.). A temporary increase in the number of WBCs is called leucocytosis. It is due to infection. It also occurs during pregnancy and in newborn babies. An uncontrolled increase in the number of WBCs is a type of blood cancer called leukemia. WBCs are mainly concerned with defense mechanisms i.e. protection.

3. Blood Platelets or Thrombocytes:

a. Thrombocytes are cellular fragments formed from the large cells called megakaryocytes.

b. These are produced in the bone marrow. They are very small, oval-shaped cell fragments without a nucleus.

c. Normal count of thrombocytes in human blood is about 2.5 – 4.5 lakh / mm3 of blood. If the number of thrombocytes decreases than normal, the condition is called as thrombocytopenia. This condition causes internal bleeding (haemorrhage).

4. Platelets secrete platelet factors which are essential in blood clotting. They also seal the ruptured blood vessels by the formation of platelet plug/ thrombus. They secrete serotonin a local vasoconstrictor.

5. Functions of Blood: Blood perform various functions like transport, homeostasis, and protection.

Respiration and Circulation | respiration and circulation notes

All living organisms require energy to carry out various life processes. The energy that is stored in the body in the form of complex organic compounds (potential energy) is however not usable by the organisms unless it is converted into usable form. This conversion is achieved through the process of respiration.

Respiration : It is a biochemical process of oxidation of organic compounds in an orderly manner for the liberation of chemical energy in the form of ATP. C6 H12O6 + 6O2 6 CO2 + 6H2 O + 38 ATP For this, the process of gaseous exchange takes place between the organism and the environment. The site of gaseous exchange is called the respiratory surface.  

What are the Organs of Respiratory Exchange ?

8.1 Organs of Respiratory Exchange : Respiratory exchange is a simple physical process. For efficient gaseous exchange, the respiratory surface should have the following features :

a. It should have a large surface area. 

b. It should be thin, highly vascular and permeable to allow exchange of gases. 

c. It should be moist

What are the Gaseous exchange in plants ?

Gaseous exchange in plants : The shape and structure of plants facilitate gaseous exchange by diffusion. A terrestrial flowering plant has many air spaces between the cells of stem, leaf and root. These air spaces are continuous. Oxygen diffuses into the air space through stomata (the pores on leaves and young stems), carbon dioxide and water vapour diffuse out. In the aerated soil, the oxygen dissolves in the film of moisture or water around the root tissue and enters it by diffusion. Woody flowering plants (trees and shrubs) have an external impervious bark. Here, gaseous exchange occurs through small pores in the stem surface, called lenticels.

What are the Respiration in Animals ?

Respiration in Animals : As compared to plants, animals show wide variety of respiratory surfaces or organs. The respiratory surfaces differ in various animals. In animals, depending upon the complexity of organization and the surrounding medium, certain parts of the body have become specialized into different types of respiratory organs. In the higher animals, these respiratory organs are also associated with a transport system.

 

What are the Human Respiratory system ?

8.2 Human Respiratory system: The respiratory system brings about inspiration, expiration and exchange of gases in the lungs. These are then transported by blood from the lungs to the different tissues and parts of the body. The respiratory system and be divided into an upper respiratory system having external nares, nasal cavities, internal nares, nasopharynx, nose, throat and associated structures. The lower respiratory system refers to the larynx, trachea, bronchi, bronchioles and lungs.

What are the Nose ?

Nose : The nose has a pair of slit like openings called external nares or nostrils for entry of air into the nasal cavity. The nasal cavity is divisible into right and left nasal chambers by a mesethmoid cartilage. Each nasal chamber is further divided into three regions.

What are the Vestibule ?

i. Vestibule : It is the proximal part about the nostrils. Its skin has hair for filtering the air and traping the dust and suspended particles in the inhaled air.

What are the Respiratory part ?

ii. Respiratory part (conditioner) : The middle thin walled highly vascular part for warming and moistening the inhaled air. 

What are the Olfactory or sensory chamber ?

iii. Olfactory or sensory chamber : The uppermost part is lined by olfactory epithelium for detection of smell. 

What are the Pharynx ?

Pharynx : It is divisible into three parts. The nasopharynx is the uppermost part from the nasal chamber it leads into oropharynx (common passage for food and air). This continues below as the laryngopharynx. Between the nasopharynx and oropharynx is the palate bone. The pharynx has a set of lymphoid organs called tonsils. 

What are the Larynx ?

Larynx : It is called voice box. It is the part of the respiratory tract which contains vocal cords for producing sound. The larynx extends from the laryngopharynx and the hyoid bone to the trachea. It is a hollow, tubular structure. Its wall is made up of cartilage plates held by membranes and muscles. Internally, it is lined by a pair of folds of elastic vocal cords (true vocal cords). Voice is produced by passage of air between the vocal cords and modulations created by tongue, teeth, lips and nasal cavity. The larynx opens into the layngopharynx through a slit like opening called glottis. This opening of the trachea or wind pipe is guarded by a leaf like flap called epiglottis. It prevents the entry of food into trachea.

What are the Hypertension ?

Hypertension : Persistently raised blood pressure higher than the normal is called hypertension. 140/90 mmHg is called as threshold of hypertension and the 180/120 mmHg and higher readings are dangerous to the health. It may damage the heart, brain and kidneys. Under the condition of hypertension, heart uses more energy for pumping which causes angina pectoris- the chest pains due to lowered blood supply to cardiac muscles and may lead to myocardial infarction. There are more chances of brain hemorrhage due to hypertension as arteries in brain are less protected by surrounding tissues as compared to other organs. In kidney, hypertension may cause kidney failure.

What are the Coronary Artery Disease ?

Coronary Artery Disease (CAD) :- It is also known as atherosclerosis. In this, calcium, fat cholesterol and fibrous tissues gets deposited in blood vessels suppling blood to the heart muscles making the lumen narrow.

What are the Angina Pectoris ?

Angina Pectoris : It is the pain in the chest resulting from a reduction in the blood supply to the cardiac muscles because of atherosclerosis or arteriosclerosis. It is charactarized by severe pain and heaviness in the chest. The pain may spread to the neck, lower jaw, left arm and left shoulder. The pain usually results from exertion, when there is more demand of oxygen by the heart, but the supply does not meet the requirement.

What are the Angiography ?

Angiography : X-ray imaging of the cardiac blood vessels to locate the position of blockages  is called angiography. Depending upon the degree of blockage, remedial procedures like angioplasty or by-pass surgery are performed. In angioplasty, a stent is inserted at the site of blockage to restore the blood supply while in by-pass surgery, the atherosclerotic region is by-passed with part of vein or artery taken from any other suitable part of the body, like hands or legs.

What are the Heart Transplant ?

Heart Transplant : Replacement of severely damaged heart by normal heart from brain-dead or recently dead donor is called heart transplant. Heart transplant is necessary in case of patients with end-stage heart failure and severe coronary arterial disease.

What are the Silent Heart Attack ?

Silent Heart Attack : Silent heart attack, also known as silent myocardial infarction is a type of heart attack that lacks the general symptoms of classic heart attack like extreme chest pain, hypertension, shortness of breath, sweating and dizziness. Symptoms of silent heart attack are so mild that a person often confuses it for regular discomfort and thereby ignores it. It has been studied that men are more affected by silent heart attack than women.

What are the Lymphatic System?

8.18 Lymphatic System : Lymphatic system consists of lymph, lymphatic vessels, some organs and tissues. The word ‘lymph’ means ‘clear water’ and it is a fluid connective tissue with almost similar composition to the blood except RBCs, platelets and some proteins. Fluid from intercellular spaces of the body tissue enters into the lymphatic vessels, from here it is discharged into the blood vessels (veins) through the thoracic duct and the right lymphatic duct.

respiration and circulation 12th class | respiration and circulation 12th class notes

Balbharati solutions for Biology 12th Standard HSC for Maharashtra State Board
Chapter 1: Reproduction in Lower and Higher Plants
Chapter 2: Reproduction in Lower and Higher Animals
Chapter 3: Inheritance and Variation
Chapter 4: Molecular Basis of Inheritance
Chapter 5: Origin and Evolution of Life
Chapter 6: Plant Water Relation
Chapter 7: Plant Growth and Mineral Nutrition
Chapter 8: Respiration and Circulation
Chapter 9: Control and Co-ordination
Chapter 10: Human Health and Diseases
Chapter 11: Enhancement of Food Production
Chapter 12: Biotechnology
Chapter 13: Organisms and Populations
Chapter 14: Ecosystems and Energy Flow
Chapter 15: Biodiversity, Conservation and Environmental Issues