Respiration Respiration: is the process of obtaining energy from food substance. Respiration

process occurs in all living cells in the mitochondria.

Importance of energy for living organisms:

1. It helps in doing all the body activities and movement.

2. It keeps the body temperature constant (heat energy)

3. It is used in active transport.

4. Helps in building the body and growth.

-Types of respiration:

There are two types of respiration, aerobic respiration and anaerobic respiration.

1. Aerobic respiration:

It is the process of obtaining energy form food in the presence of oxygen.

Food (glucose) + oxygen - carbon dioxide + water + energy

The energy in this type is produced in large amounts.

The products of respiration are CO2 and water, but there is no lactic acid or

alcohol.

It occurs in the mitochondria.

2. Anaerobic respiration:

It is the process of obtaining energy from food in the absence of oxygen.

Food (glucose) carbon dioxide + ethanol + energy [in yeast]

The energy is produced in small amounts.

The products may be alcohol or lactic acid.

It occurs in cytoplasm.

Examples of anaerobic respiration:

1. In yeast fungus (alcoholic fermentation--brewing)

a. Formation of beer:

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-germinating barley seeds are dissolved in a warm water with maltose sugar.

-yeast then is added to the mixture.

-The mixture is covered. (anaerobic)

-the yeast will break down the sugar in the anaerobic respiration into ethanol (alcohol)

and CO2.

b. Formation of wine:

The yeast breaks down the sugar of grapes to change by anaerobic respiration into

ethyl alcohol.

c. Making bread:

The carbon dioxide which comes out from the anaerobic reaction will blow the dough

by the effect of the gas.

2. In human muscles:

During exercise the muscles needs larger amounts of energy which comes form

burning more food with oxygen, so

- the rate of inhalation and exhalation increases to obtain more amount of O2 and to

get rid of CO2.

- the heart rate increases to supply the muscles with O2 and food.

- but at a certain time the body can not supply O2 in a proper amount so the muscle

performs anaerobic respiration and the glucose will break down to energy and

lactic acid.

- Lactic acid causes fatigue to the muscles so it should be cleared by the action of

oxygen which is obtained again by increasing rate of breathing even after

stopping exercise.

- oxygen debt: is the compensation for the body with oxygen after a period of

obtaining energy by the anaerobic respiration as if the body is paying for getting

energy in the absence of O2.

The Human Respiratory system

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In order to supply the body with oxygen to get energy and then to clear the body from

carbon dioxide, breathing occurs, breathing happens in the respiratory system and is

divided into:

-inhalation: getting in oxygen.

-Gaseous exchange between O2 in and CO2 out.

-exhalation: getting carbon dioxide out.

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- The structure of the human respiratory system:

STRUCTURE FUNCTIONS (adaptation)

1. NOSE

-contains hair to trap dusts

-contains mucus to moist air entering the respiratory tract.

-lined with blood capillaries to warm the air due to the effect of blood

flow.

2. PHARYNXa common passage between digestive and respiratory system.

-it has the soft palate to close nasal cavity during swallowing.

3. LARYNX

-it contains the vocal cords which vibrate to produce sound.

-it contains the epiglottis which closes the respiratory tract during

swallowing to prevent food from getting in it.

4. TRACHEA

-it is kept open all the time due to the presence of cartilage rings.

-it has cilia in its wall to swap out dusts.

-it contains goblet cells that secrete mucus which trap dusts and

microbes.

5. BRONCHI

-they are two, each one enters a lung.

-they contain cilia to brush dusts away.

-the goblet cells secret mucus to stick dusts.

6. BRONCHIO

LES

-they are the branches of the two bronchi.

-they end by the alveoli.

7. LUNGS

-the right lung is formed of three lobes, the left lung is formed of two

loves due to the presence of the heart.

-it is covered by a membrane called pleural membrane full of pleural

fluid to prevent friction of the lungs with the ribs.

-it contains millions of air sacs called alveoli where gas exchange takes

place

-adaptation of alveoli:

1.thin wall to help diffusion. 3 .moist wall to facilitate diffusion.

2.large surface area. 4. surrounded by numerous blood capillaries.

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8. INTERCOS

TAL

MUSCLES

-they are present in between the ribs to help in the breathing process by

relaxing and contracting to increase or decrease the volume of the

chest cavity by moving the ribs.

9. DIAPHRAG

M

-it is a muscle sheeth separating the chest cavity and the abdominal

cavity.

-it the relaxing state the diaphragm is dome shaped.

-Gaseous exchange in the alveoli:

-Oxygen passes from high concentration in the alveoli to the low concentration in

blood. (inhalation)

-Carbon dioxide diffuses also from high concentration in blood to the low concentration

in alveoli to be exhaled outside (exhalation).

-Effect of exercise on breathing:

Remember that during exercise the body needs more oxygen to burn more food to get

more energy, and also the body needs to get rid of the excess CO2. So the adrenal gland

secrets adrenaline hormone to increase the rate and depth of breathing to:

1. supply the muscles with excess O2.

2. clear CO2 produced from respiration.

3. clear lactic acid produced due to anaerobic respiration by transferring the lactic acid

by blood to the liver to be destroyed.

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-The effect of smoking on the respiratory system:

the cigarette contains tar, nicotine and CO results from partial burning of tobacco.

EFFECT

1.Nicotine 1.increases heart rate.

2. increases blood pressure.

3. increases amount of fat precipitation on the vessel's wall

leading to clots.

4. causing dependence and addiction.

2.Tar 1.lungcancer. (tar is carcinogenic)

2.precipitation in the inner wall of alveoli which affects gas

exchange. And leads to rupture of alveoli causing

emphysema.

3.bronchitis :. Bad effects on the cilia which wont do its

function leading to entering of dusts and microbes causing

continues infection of the bronchi.

3.Carbonmonoxide It combines with the hemoglobin in the red blood cells

instead of oxygen Decreasing O2 supply to cells.

N.B. Babies born to smoking mothers are smaller than normal as the CO decreases the

blood supply to the baby due to narrowing of the vessels of the placenta depriving his

body cells from O2 and nutrients.

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Heart Blood Blood vessels

Transport in Human

Each cell gets energy from burning of food in the presence of Oxygen, for the cells to

get food and oxygen there should be a transport system to transfer these substance to

and from the cells.

Human transport system

1. The Heart:

-The heart is a muscular pump which pumps blood to all the body cells.

-The heart muscle contracts and relaxes all the time.

-The heart muscle gets its energy needed for the contraction and relaxation through the

blood supply of the coronary arteries.

-Structure of the heart:

1. The heart is formed of four chambers, upper two atria (right atrium and left atrium)

and lower two ventricles (right and left).

2. the right side of the heart is separated from the left side by a muscular layer called

septum, as not to mix the oxygenated blood of the left side with the deoxygenated blood

of the right side.

3. there is a valve separating the right atrium from the right ventricle known as tricuspid

valve.

4.the valve separating the left atrium from the left ventricle is called the bicuspid valve.

5.there are some vessels which are connected to the heart as: four pulmonary veins

connected to the left atrium, aorta to the left ventricle, vena cava connected to the right

atrium and pulmonary artery connected to the right ventricle.

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-Functions of different parts of the heart:

1. Pulmonary veins: carry oxygenated blood from the lungs to the left atrium.

2. Left atrium: receives oxygenated blood from the pulmonary veins and then pump it

to the left ventricle.

3. Bicuspid valve: it is a one way valve which prevents blood from going back to left

atrium when the left ventricle contracts.

4. Left ventricle: it receives blood from the left atrium and then pumps the oxygenated

blood to all body parts, its wall is thicker than the atria and the right ventricle as it needs

to contract powerfully to pump blood to all body parts.

5. Aorta: it is the largest artery with a thick wall as it distributes the ixygenated blood

from the left ventricle to all body parts.

6.Vena cava: there are superior and inferior vena cava, they are large veins that receive

deoxygenated blood from all body parts to the right atrium.

7. Right atrium: receives the deoxygenated blood from the vena cava then pumps it to

the right ventricle.

8. Tricuspid valve: it prevents the backflow of deoxygenated blood from the right

ventricle to the right atrium when the ventricle contracts.

9.Right ventricle: receives the deoxygenated blood from the right atrium and pumps it

to the pulmonary artery to deliver it to the lungs.

10. Pulmonary artery: carries deoxygenated blood to the lungs.

11. Semi-lunar valves: they prevent the backflow of blood from aorta and pulmonary

artery to the ventricles when the ventricles relax.

12. Tendons: they are connected to the valves to prevent them from flopping upwards.

-Circulation of blood through the heart:

1.Oxygenated blood:

It passes from the lungs carrying large amount of oxygen to the pulmonary veins that

carry the oxygenated blood to the left atrium, then left atrium contracts and pumps the

blood to the left ventricle which when filled with blood makes the bicuspid valve close

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to prevent backflow. Then the left ventricle contacts and pumps the blood through the

biggest artery the aorta to all the body parts.

2.Deoxygenated blood:

It passes from all body parts carrying very low amount of oxygen and also

carbondioxide as a result of respiration process in the cells, to the vena cava (the upper

part through superior vena cava and the lower part through inferior vena cava) to the

right atrium which contracts to pump the blood to the right ventricle through the

atrioventricular valve (tricuspid) then the right ventricle contracts, the tricuspid closes

then the blood is pushed through the pulmonary artery to the lungs which gets rid of the

carbondioxide from the blood.

-Double circulation:

Humans has double circulation because the blood passes through the heart twice in one

complete round, as the blood enters through the pulmonary veins to the heart and leaves

through the aorta, AND the blood enters from vena cava then leaves through the

pulmonary artery.

So we can say that there are two circulations:

1. Pulmonary circulation:

Right side of the heart lungs left side of the heart.

2. Systemic circulation:

Left side of the heart body cells right side of the heart.

-Heart beats:

The hearts normally beats regularly as the cardiac muscle contracts and squeezed, this is

called systole, and when the muscle relaxes this is called diastole. The flow of blood

during heart beats which is systole and diastole is called the blood pressure which

should measure in the healthy person 120 for systole and 80 for diastole, the changes in

the blood pressure can detect many diseases.

-Heart attack:

The heart as a muscle in a continues contraction and relaxation which need energy all

the time to do its function properly, this supply comes from the coronary arteries which

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surround the heart, but when one or more of these arteries are narrowed or blocked due

to precipitation of fats in its inner wall, or due to blood clot, the heart then will be

deprived from the oxygen which will lead to death of the affected part in the heart

muscle, this is known as heart attack.

Causes of heart attack:

1. Increase intake of fats and salt in dietary content which leads to atheroma or high

blood pressure.

2. Smoking which contains nicotine which increases the precipitation of fats on the wall

of arteries.

3. Sedentary life with decrease exercising.

Nervousness and suffering from high levels of stress.

Prophylaxis (prevention):

1. Dietary control: eating low amount of fats and salts on the other hand iccrease intake

of vegetables and fruits.

2. Avoid smoking.

3. Changing life style as doing ,ore exercise.

4. Avoid nervousness and stress.

-What is the effect of regular exercise on the heart:

In normal rest cases the heart rate is 60-80 beats/min., during exercise all the muscle

needs more blood flow which carries more oxygen and food to the cells to get more

energy, the heart rate then increases to supply the cells with enough blood this in order

increases the clearance of wastes from the cells, but surprisingly the hear rate of the

athletes is lower than other people because their heart muscle is stronger which can

supply the body with the needed amount of blood with less contractions (less beats).

2. Blood Vessels:

In the transport system there are three vessels

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Arteries Veins Capillaries

Function Carry blood

from heart to

body

Return blood to

the heart

Provide cells

with food

Oxygen and take

away wastes

from them.

Structure

of wall

Thick, strong

containing

muscles &

elastic fibers, to

resist blood

pressure.

Thinner than

arteries, Less

elastic as no

need for

resistance

Very thin, as to

allow blood to be

in close contact

with tissues.

Width of

lumen

Narrow lumen,

No valves.

Wide contains

valves to To

prevent

backflow.

Narrow lumen.,

no valves

Blood

flow

Rapid Low Moving of blood

is due to

difference in

pressure between

arteries & veins

Blood

Rressure

High Low Low

All arteries carry blood directed from the heart to all body parts.

All arteries carry oxygenated blood except pulmonary artery.

All veins carry blood directed from the body to the heart.

All veins carry deoxygenated blood except four pulmonary vein.

3. Blood:

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It is the red fluid that flows in the vessels. This fluid consists of:

Structure Function

1. Red

blood cells

Biconcave disc, no nucleus,

contains Haemoglobin, small

in size formed in bone

marrow.

-transport oxygen. (the only cells

which carry O2)

-transport small amount of CO2.

2. White

blood cells

Variable, have nucleus, large

in size No haemoglobin.

-engulf and destroy bacteria as

phagocytes (phagocytosis)

-make antibodies as lymphocytes.

3. Platelets Small particles with no

nucleus.

Has a role in blood clotting.

4. Plasma The fluid content of the

blood, Formed of water, ions

& proteins

-liquid medium in which cells

float.

-transport many substances like:

CO2, food, urea, hormones,

antibodies

{People living in high altitudes have larger number of red blood cells to compensate the

decrease in oxygen level, so as to increase the cells which transport O2 to the cells}

Functions of blood:

1. Transportation of:

a. oxygen from lunges to cells.

b. carbondioxide from cells to lungs.

c. digested food from small intestine to cells.

d. urea and wastes from the liver to kidneys.

Heat from levers and muscles to different parts of the body avoiding destruction of

the liver and keeps the rest of the body warm.

2. Immunity:

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a. the phagocytes engulf and digests bacteria.

b. the lymphocytes produce antibodies to defeat microbes.

3. Blood clotting:

Blood platelets play an important role in formation of blood clot which closes the

wound and prevent bleeding, and heals the wound.

Tissue fluid:

It is the fluid consisting of plasma without proteins and cells, which was leaked

out through the wall of the capillaries to accumulate in between the tissues.

Importance:

1. Supplying tissues with food and oxygen

2. Carrying wastes away from tissues.

Drainage: either through lymph vessels to form lymph, or back to capillaries.

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