Blood Circulatory System heart, blood and blood vessels fileBlood Circulation Pulmonary Circulation...

Chapter 2 –Blood Circulatory System of 10

Kenneth Wong 019-363 9338

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Blood Circulatory System

- Consists of heart, blood and blood vessels

- Functions :

o Transport oxygen and nutrients to all body cells

o Transport waste products (carbon dioxide and urea) for elimination

o Transport chemicals such as hormones and antibodies

- Humans have a closed blood circulatory system which means blood flows in closed vessels and

exchange of food and gas takes place in the walls of the capillaries

Artery Vein

Blood Capillaries

- All arteries carry blood out

of the heart except the

pulmonary artery

- Thick, muscular, strong

elastic wall to support high

pressure

- Small lumen (hole) and has

no valves

- All veins carry blood to the heart

except the pulmonary vein

- Thin, less muscular and less

elastic wall because there is no need

to withstand the low pressure

- Large lumen (hole) and has valves

to ensure blood flows in one

direction

- Fine blood vessels which act as connectors that join the blood vessel system of

arteries and veins

- Functions :

o Carry blood from the artery to the vein

o Carry oxygenated blood from artery to body cells

o Carry deoxygenated blood from body cells to the vein

- Blood flows slowly due to low pressure which enables diffusion and exchange

of substances to proceed at maximum rate

- It is one cell thick, has a small lumen and has no valves



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Structure of the Heart and its Function

Heart

- Muscular organ which contracts and relaxes simultaneously to pump and circulate blood to the whole body

- Situated in the thoracic cavity between the left lung and the right lung with 4 large chambers : left atrium

and right atrium (upper chambers), left ventricle and right ventricle (lower chambers)

- Ventricles have a larger space, thicker and more muscular walls than the atria

- The wall of the left ventricle is thicker and more muscular than the right ventricle because stronger

pressure is needed to pump blood to the whole body while the right ventricle only has to pump to the lungs

- Valves in the heart prevent back flow and makes sure it flows in only one direction

- The left chamber of the heart contains oxygenated blood while the right deoxygenated

Vena Cava Aorta

Channels deoxygenated blood from all parts of the

body to the right atrium

Carries oxygenated blood from the heart to the whole

body

Pulmonary Artery Pulmonary Vein

Carries deoxygenated blood from the heart to the

lungs

Carries oxygenated blood from the lungs to the heart

Valves in the Heart

Tricuspid Valve : Prevents blood in the right ventricle

from flowing back to the right atrium

Bicuspid Valve : Prevents blood in the left ventricle

from flowing back to the left atrium

Semilunar Valve : Prevents blood leaving the heart

from flowing back



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Blood Circulation

Pulmonary Circulation Systemic Circulation

- Transport blood from the heart to the lungs and back to the heart

- Ensures that blood lacking in oxygen gets a new supply of oxygen

- Carbon Dioxide is eliminated in the lungs

- Oxygen diffuses into the blood from the lungs

- Oxygenation of red blood cells occurs in the alveolus

- Goes to the lungs through the pulmonary artery and comes back

through the pulmonary vein

- Consists of all blood vessels from the heart to all the parts of the

body (except the lungs) and back to the heart

- Blood that reaches the body tissues through the blood capillaries will

release oxygen and digested food (nutrients) to the body tissues

- Pumps blood to the whole body through the aorta and collects

deoxygenated blood through the vena cava

- Blood lacking oxygen is collected through the veins

Pathway of Blood Flow

Vena Cava (collected deoxygenated blood) → Right Atrium → Tricuspid Valve → Right Ventricle → Semilunar Valve → Pulmonary Artery → Lungs →

Pulmonary Vein → Left Atrium → Bicuspid Valve → Left Ventricle → Semilunar Valve → Aorta → Whole Body → Vena Cava (repeat)



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Difference between Oxygenated Blood and Deoxygenated Blood

Oxygenated Blood Deoxygenated Blood

High Oxygen Concentration Low Oxygen Concentration

Low Carbon Dioxide Concentration High Carbon Dioxide Concentration

High Concentration of digested food (glucose and amino acid) Low Concentration of digested food (glucose and amino acid)

No waste products present (Urea) Waste products present (Urea)

Artery and Pulmonary Vein carries it Vein and Pulmonary Artery carries it

Bright Red Colour Dark Red Colour

Maintaining a Healthy Heart

- Balanced food intake, exercise, low work pressure and reduced intake of food rich

in fat (cholesterol) helps

- Causes of heart diseases :

o Damage to valves in the heart

o Failure of ventricles and atrium muscular walls to contract

o Blockage of blood supply to the heart (cholesterol deposits)

- Importance :

o Avoid contracting heart disease which can cause death

o Ensure cells get enough supply of oxygen and food



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Human Blood

- Contains : plasma, red blood cells, white blood cells and platelets

- Functions :

o Transport oxygen and digested food (nutrients) to cells

o Transport waste products (urea and carbon dioxide) from body tissues to

excretory organs

o Maintain a body temperature at 37 oc by spreading heart to all parts of the body

o Carry hormones to body tissues, regulate body processes and fight diseases

Red Blood Cells Platelets

- Biconcave-disc shaped with no nucleus

- Functions to transport oxygen to body cells with a lifespan of 4

months

- They are destroyed in the liver and the spleen but created in the

bone marrow

- Small pieces in the blood that has no definite shape

- They do not have a nucleus and is very small

- Functions to clot blood in a wound to prevent excessive blood loss

- It is produced in the bone marrow and dies within a few hours to

nine days



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Plasma

White Blood Cells

- Liquid part of the blood, yellow and has alkaline properties

- Slightly sticky and contains dissolved substances

Composition of Plasma

Component Percentage (%)

Water 92

Protein 6 - Larger in size than red blood cells but does not have a definite

shape

- They have a nucleus and is part of the body’s defense system

- Functions to protect the body from pathogens (microorganisms)

like bacteria and viruses

- They are produced in the bone marrow and lymph glands

- They can kill bacteria in the blood or produce antibodies to

neutralize toxins (poisonous substances) produced by

microorganisms

Mineral Salts 0.8

Lipid 0.6

Glucose (blood sugar) 0.1

Others 0.5

Blood Groups

- Classified into 4 groups : A, B, AB, O

- Blood Donor : one who donates blood

- Recipient : one who receives blood

- Blood Transfusion : Transfer of blood from a donor to a recipient

- The blood of the recipient and the donor has to be compatible or

blood clotting (agglutination) will occur which can cause death

- People with blood group O are universal donors

- People with blood group AB are universal recipients



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Blood Donation Storage and handling of

Blood

- An accident or an operation causes loss of blood

- This blood needs to be replaced with blood transfused from

another person

- Massive blood loss can damage bodily functions and cause death

- Must be carried out with care to prevent blood coagulation

- Blood transfused has to be suitable and compatible

- Important because there is no substitute

- Two types of transfusion :

o Through blood kept in a bank

o Direct channeling from the donor to the recipient

- Each blood donor must be

tested to know the blood

group and examined if

they are healthy

- The blood must be tested

for diseases like Hepatitis

B and C, HIV and

venereal diseases like

syphilis

- Blood must be stored in a

cold place before use



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Transpiration

- Process in plants where water is lost through evaporation

from the surface of the leaves

- If too much water is lost, the cells of the plant would lose

turgor (support) pressure and wilt then die

- If a plant is wrapped in a bag, droplets of water will be

formed on the surface of the bag

- The presence of water vapour can be tested with dry cobalt

chloride paper which turns from blue to red

Stomata

- Pores / openings on the surface of the leaves and normally

found on the undersurface of leaves

- Most water vapour is lost through the stomata of leaves

- The pore size is controlled by the guard cells to control the

loss of water from the plants

Factors Affecting the Rate of Transpiration

- When the plant is put under a hot Sun, the

water droplets are more than when it was not

exposed to the Sun

- When the plant is put under a fan without the

plastic bag, the weight of the plant will decrease

- When the plant is put in the forest (high

humidity), the plant does not lose as much water

as it did when it was under the fan

Temperature Wind Intensity

Higher temperature, higher transpiration rate Higher wind intensity, higher transpiration rate

Light Intensity Humidity (surrounding water)

Higher light intensity, higher transpiration rate Higher humidity, lower transpiration rate

Importance of Transpiration

Get rid of excess water from plants Cool plants on hot days Transport water and mineral salts



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Transport in Plants through Xylem and Phloem

Monocotyledonous Plant Dicotyledonous plant

- One Cotyledon Seed

- Parallel Veins

(leaves)

- Fibrous Roots

- Flower Parts in

Threes or multiples

of Threes

- Two Cotyledon Seed

- Network-like Veins

(leaves)

- Tap Roots

- Flower parts in Four

or Fives or multiples

of Four and Fives

Leaf Leaf

Stem Stem

Root Root



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Functions of Phloem and Xylem

Test for Xylem Test for Phloem

Experiment :

1. A few drops of red colouring is added to the

water

2. The plant is observed after a few days

3. The xylem appears to be reddish and proves

that water flows through the xylem vessels

4. Coloured water is added to make the

transport visible

Experiment :

1. A plant is ringed and is observed after a few

days

2. A little paraffin oil is applied to the exposed part

3. There seems to be a swelling on the upper part

of the stem

4. However the plant has still not wilted because

there is still a supply of water

Facts :

Xylem is a vessel that transports water and

mineral salts from the roots to the leaves

Facts :

Phloem is a vessel that transports food (glucose) from

the leaves to the stem and roots after synthesizing it

through photosynthesis

Examples of Monocotyledonous Plants Examples of Dicotyledonous Plants

Legumes (pea, beans, lentils, peanuts) daisies, mint,

lettuce, tomato and oak

Balsam Plant, Rambutan Tree, Hibiscus Plant, Grains,

(wheat, corn, rice, millet) lilies, daffodils, sugarcane,

banana, palm, ginger, onions, bamboo, sugar, cone, palm

tree, banana tree, and grass

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