Chapter 1 transport

CHAPTER 1: TRANSPORT

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TRANSPORT SYSTEM

MULTICELLULAR ORGANISMS

Needed by

animals plants

Occurs in

3

Plants

Water & mineral

Food

xylem phloem

Vascular tissues

involves

stem root leaf

structure

translocation

need

Transported by

Relate toRelate

to

involvesRoot

pressure

Transpirational pull

Factors1. Air movement2. Temperature3. Light intensity4. Relative

humidity

Capillary action

affectingTranspiratio

n

Results in

Found in

4

animals

Circulatory system

blood clotting mechanism

Lymphatic systemLymph

Lymphatic vessels

Lymph nodes

Defense system

immune system

Blood

Blood vessel

heart

Closed system

Open system

doublesingle

incomplete

complete

types

Divided into

includes

needs

contributes

includes

Made up of

comprises

When damaged

Blood cells, blood plasma

comprises

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Defence system

specificNon specific

1st line 2nd line3rd line

•Skin •mucous membrane

Phagocyte

Phagocytosis

lymphocyte

antibody

passive active

naturalartificial

natural artificial

immunisation

immunity

Divided into Divided into is

through produc

e

givesDivided into

Divided into Divided into

are

Carry out

eg

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The circulatory system• Delivers nutrients and oxygen to cells• Carries waste products away from

the cells• Protects the body from infections• It has three major components;

– A medium– A pump– Vessels

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• A medium is required to carry materials around the circulatory system

• In human and animals blood

• In invertebrates (insects) haemolymph

• The blood is a type of connective tissue made up of plasma, blood cells and platelets.

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• The heart functions as a muscular pump that circulates the blood throughout the body.

• The blood vessels are vessels consisting of arteries, capillaries and veins that are connected to the heart to deliver blood to all body tissues.

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The functions of blood

• Transports oxygen from the lungs to the cells of the whole body, carbon dioxide from cells to the lungs.

• Transport nutrients, hormones and antibodies throughout the body.

• Transport waste products away from the cells to the organs of the excretory system.

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• Regulates– The pH of body fluids– The body temperature– The water content of cells

• Protects us– From excessive blood loss in an injury

through the mechanism of blood clotting helps to heal wounds.

– From diseases and helps to fight against infections

The functions of blood…cont

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The function of haemolymph

• Transports water, inorganic salts and organic compounds throughout the haemocoel.

• Does not transport respiratory gases• In insect, respiratory gases are

transported via the tracheal system.

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The composition of human blood

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The differences between arteries, capillaries and veins

Characteristic Arteries Capillarie

s Veins

WallThick,

muscular, elastic

One-cell thick, no muscle

or elastic tissue

Thin, less muscular

, less elastic

Lumen Small Very small Large

Valve No valve No valve Have valves

Blood pressure High Very low Low

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Characteristic Arteries Capillaries Veins

Direction of

blood flow

From the heart to the

organs

From arteries to

veins

From all parts of the body to the

heart

Blood content

Oxygenated blood

except the pulmonary

artery

Oxygenated blood at the

arteriole ends &

deoxygenated blood at the venule

ends

Deoxygenated blood except the pulmonary

artery

Function

To transport

blood quickly at

high pressure from the

heart to the tissues

Allow rapid gaseous

exchange between the

blood and the body cell by diffusion

Allow blood from the tissues to return to the heart

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The human heart

12

3

4

5

6

1

24

3

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The flow of blood in the heart1. Oxygenated blood from the

lungs enters the left atrium through the pulmonary veins.

2. Deoxygenated blood from the rest of the body enters the right atrium via the vena cava.

3. As blood fills the atria contract and push the blood through the bicuspid and tricuspid valves into the two ventricles. 20

The flow of blood in the heart… cont4. When the ventricles contract, the

semi-lunar valves are forced open and blood is pushed into the pulmonary arteries and the aorta.

5. Deoxygenated blood is pumped through the pulmonary arteries to the lungs.

6. Oxygenated blood is pump through the aorta to the rest of the body. 21

The pumping of the heart• Each time the heart contracts, it

acts as a pump which sends blood throughout the body.

• The heart is made up of a strong muscle, called the cardiac muscle.

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The pumping of the heart… cont

• The cardiac muscle cells are interconnected

• This interconnection allows electrical impulses to spread rapidly through the heart and, at the same time, stimulates the cardiac muscle cells to contract in a coordinated movement.

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• The cardiac muscle is myogenic.

• This means it contracts and relaxes without the need to receive stimulation by nerve impulses to make it contract.

• The contractions of the heart are initiated and coordinated by a pacemaker.

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• The pacemaker is a cluster of specialised heart ,muscle cells that set the rate of contraction.

• It is located in the wall of the right atrium.

• The pacemaker generates electrical impulses which spread rapidly over the walls of both atria, causing the atria to contract rhythmically. 25


• The heart’s primary pacemaker is the sinoatrial (SA) node because it keeps the heartbeats regular.

• From the SA node, the impulses are relayed to the atrioventricular (AV) node, located at the bottom of the right atrium.

• From the AV node, bundle of His fibres, bundle branches and Purkinje fibres send the impulses to the apex of the heart and throughout the walls of the ventricles. 26

The sequence of contractions of the

heart muscle result in the pumping of the

heart

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1. The SA node generates electrical impulses.

2. The electrical impulses spread rapidly over the walls of both atria, making the walls contract simultaneously. Contractions of the atria help to pump blood into the ventricles.

3. The electrical signals reach the AV node. The bundle of His fibres, bundle branches and Purkinje fibres send the impulses to the apex of the heart.

4. The electrical impulses spread to the ventricles, causing them to pump and push blood out to the lungs and body

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The regulatory mechanism of blood

pressure

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The regulatory mechanism of blood pressure• Blood pressure is the force that pumps

blood along the arteries and the capillaries.• When blood flows along a vessel, it exerts

pressure against the walls of the blood vessel.

• Blood pressure is greater in arteries than in veins.

• Blood flows from areas of high pressure to areas of lower pressure.

• During the contraction of the ventricles, blood pressure is the highest in the aorta and large arteries when blood is pumped into the aorta and pulmonary arteries.

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The regulatory mechanism of blood pressure… cont.

• At rest, a healthy adult has a blood pressure of 120/80 mm Hg

• The first number is the systolic pressure, the highest recorded pressure in an artery when the ventricles contract (systole stage).

• The second number, the diastolic pressure, is the lowest recorded pressure during the relaxation phase of the heartbeats (diastole stage)

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ProduceTrombokinase

Wound in skin

Platelet gather StickyForms a temporary plug in leaking vessel

Fibrinogen

Fibrin

Forms the threads of the clot

LaterHarden (scab)

Mechanism of blood clotting

Need Vitamin K

Trombokinase

Ion Calcium ProthrombinThrombin

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Whenever an injury occurs a chain reaction is set off.

Wound in skin

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Wound in skin

Platelets gather at a site of the injury and become sticky

Platelet

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Forming a temporary plug in the leaking vessel

Wound in skin

Temporary plug

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Prothrombin (non-active enzyme) need ion calcium to convert into thrombin.

Need Vitamin K

Trombokinase

Ion CalciumProthrombinThrombin

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Thread of clot

•Thrombin converts soluble fibrinogen (plasma protein formed by the liver) into insoluble fibrin.

•Fibrin forms the threads of the clot.•A mesh-like network of fibrin traps red

blood cells together, forming the blood clot, which later hardens into a scab.

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Consequences of an impaired Blood Clotting Mechanism

• Haemophilia is a hereditary disease due to the lack of certain gene for the production of certain clotting factors.

• This is an impaired clotting mechanism which causes serious bleeding particularly in the joints.

• The afflicted person may die as a result of excessive bleeding from even minor cuts and bruises because blood clotting cannot take place.

Haemophilia

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• Sometimes a local blood clot (thrombus) is formed on the damaged rough inner wall of the artery. This may cause blockage of the artery, a condition known as thrombosis.

• When a thrombus dislodges and is carried away by blood circulation, it is known as an embolus. The embolus may be trapped in a small artery where it blocks the blood flow. This condition is called embolism.

Thrombosis

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• The blocked coronary artery cuts off the supply of oxygen and nutrients to the heart muscles, hence causes heart attack.

Thrombosis

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Formation of the Interstitial Fluid and Lymph

CO2O2

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Formation of the Interstitial Fluid and Lymph• When the blood flows from arteries into

capillaries, there is higher hydrostatic pressure at the arterial end of the capillaries.

• This high pressure forces some fluid out through the capillary walls into the intercellular spaces between the cells.

• Once the fluid leaves the capillary walls, it is called interstitial or tissue fluid. The interstitial fluids fills the spaces between the cells and constantly bathes the cells.

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Formation of the Interstitial Fluid and Lymph• The interstitial fluid that has not

been reabsorbed into the bloodstream goes into the lymph capillaries. Once inside the lymph capillaries, the fluid is known as lymph.

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Composition of the Interstitial Fluid• The composition of the

interstitial fluid is similar to the blood plasma.– Consists of water, dissolved

nutrients, hormones, waste products, gases, small proteins and leucocytes.

– Has no erythrocytes, platelets and large protein molecules (albumin, globulin and fibrinogen) 51

Importance of the Interstitial Fluid• Interstitial fluid is important because

:– It forms the internal environment of

the body.– It bathes the cells and supplies them

with oxygen and nutrients which diffuse from the blood through the interstitial fluid into the cells.

– Excretory waste products (carbon dioxide and urea) diffuse out of the cells into the interstitial fluid. 52

Structure of the Lymphatic System• The lymphatic system is a one-way system

consisting of a network of lymph capillaries, lymphatic vessels and lymph nodes.

• The lymph capillaries are blind-ended tubes located in the spaces between the cells.

• The interstitial fluid that has not been reabsorbed into the bloodstream goes into the lymph capillaries. Once inside the lymph capillaries, the fluid is known as lymph. 53

Structure of the Lymphatic System• Lymph is the colourless fluid found

in the lymphatic vessels.• Lymph capillaries converge into

larger lymphatic vessels.• Lymph nodes are located at

intervals along the lymphatic vessels. The lymph nodes produce lymphocytes that help to protect the body against infections.

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Structure of the Lymphatic System• Lymph contains a higher number

of lymphocytes than blood.• Within the lymphatic vessels are

one-way valves to ensure the continuous flow of the lymph to prevent the backflow of the lymph.

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The Relationship between the Lymphatic System and Circulatory System• Lymph is returned to the circulatory

system via the thoracic duct and the right lymphatic duct.

• The vessels from the left side of the body flow into the thoracic duct. The thoracic duct is the largest lymphatic vessel in the body that carries lymph to the left subclavian vein back into the bloodstream.

• The right lymphatic duct transport lymph from the right side of the head and chest into the right subclavian vein.56

Role of the Lymphatic System in Transport• Collects the interstitial fluid and returns

it to the circulatory system.• Fats and fat-soluble vitamins are absorb

through lacteals and transported to the blood circulatory system.

• The lymph nodes filter out bacteria and other foreign particles. Phagocytes present in the nodes engulf and destroy foreign particles.

• Lymphocytes produce antibodies which aid in the destruction of pathogens and the neutralization of toxins.

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ROLE OF CIRCULATORY SYSTEM IN THE BODY’S DEFENCE SYSTEM

• Beside transport function, our circulatory system also defends the body against disease abolition of the disease-causing microorganisms or pathogens.

• There are three lines of defence mechanisms in our body:– The first line of defence: prevention of pathogens

entering the body.– The second line of defence: killing the pathogens that

entered our body by action or phagocytic white blood cells.

– The third line of defence: killing the pathogens by means of antibody actions.

Body’s Defence Mechanisms

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• Prevention of pathogens entering the body by mean of physical and chemical barriers.

• A non-specific defence, that is never differentiate among various type of pathogens.

i. Skin– As a physical barrier, skin is made up of a dead

keratinised layer, tough enough for pathogens to penetrate.

– If there is a scratch or cut, the blood clots to seal the wound and avoids infections.

– Also acts as chemical barrier as it secretes sweat which contains salt. Sebaceous glands produce sebum which contains acid and oil. All these substances are unfavourable for growth of microorganisms.

– Sweat also contain lysozyme which destroy pathogens.

The First Line of Defence

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ii. Tears and Saliva– Contain lysozymes which protect the eyes

and mouth from pathogen invasion.iii. Gastric juice in stomach

– Contain hydrochloric acid which destroys most pathogens in foods and drinks taken.

iv. Mucous membranes– Secrete mucus in nasal cavity and trachea

to trap the dust particles and spores.– The cilia in the respiratory track sweep the

trapped particles to the pharynx and stimulates sneeze or cough to expel out the pathogens.

The First Line of Defence

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• The killing action brought by some of the white blood cells like neutrophil and monocyte. They are called phagocytes and the process is phagocytosis.

• It is also a non-specific defence.• Phagocytosis occur when pathogens get

through the first line defence. Phagocytes move to the infected area due to the stimulation by chemicals released by damaged cells, example cut skin.

• Sometimes the phagocytes are killed by toxins produced by the pathogens.

• Dead bacteria, tissue cells and phagocytes may accumulate to form pus at the site of injury

The Second Line of Defence

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• The steps involved in phagocytosis by a phagocyte e.g. Neutrophil

pathogen

pseudopodium

vacuole

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• Neutrophil moves toward a bacterium by using its pesudopodia.

• Pseudopodia elongate and surround the bacterium.

• Neutrophil engulfs the bacterium to form a vacuole.

• Enzymes (lysozyme) are released into the vacuole to digest the pathogen.

• Useful product of digestion is the absorbed and assimilated by phagocyte

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• The third line of defence in the body is antibody.• Antibody is a kind of protein released by

lymphocyte in response to the presence of foreign substance, called antigen in our body.

• Lymphocytes are white blood cells found in lymph nodes and in the blood circulatory system. There are two types of lymphocytes, B-lymphocyte that secretes antibodies and T-lymphocyte that helps B-lymphocyte in antibody production.

• An antigen is a substance (usually protein) normally found on the outer surface of pathogen. Different types of pathogen act as different types of antigen.

The Third Line of Defence

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• The third line of defence is a specific defence because when a specific antigen invades the body, lymphocyte is stimulated and produces specific antibody to destroy these specific antigens.

• This response is known as immune response because it resists the body from pathogens or diseases.

• After any infection, some lymphocytes remain in the body as memory cells which may last for several months or years. This memory cells help to defend the body against next infection by the same antigen. During this period, someone is sad to be immuned for that particular disease.

• Therefore, the word ‘immunity’ refers to the ability of an organisms to defend itself against infection by pathogens.


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• What is the mechanism used by antibodies to destroy antigen?

– Antibody binds to the specific antigen binding site

– Hence, inactivates antigen by several ways


NeutralisationAntibody or antitoxin coats the bacterial toxin or viral binding sites

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AgglutinationAgglutinates bacteria cell and stops their moving and stimulate phagocytosis

Disintegration (lysis)Breakdown the bacterial cell wall.

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Opsonisation Attaches itself to the bacteria surface and stimulates phagocytosis.

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AIDS• Acquired Immunodeficiency Syndrome• Caused by HIV – Human

Immunodeficiency Virus• Attacks the central nervous system and

helper T-cells in the body’s immune system.

• Helper T-cells are essential to activate B-cell lymphocyte in antibody production.

• HIV needs 8-10 years of incubation period before the symptom appears.

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AIDS• The immune system of infected person

gradually becomes weakened and defenceless against many pathogens.

• Decreases in function of central nervous system followed by body weight loss.

• Eventually death occurs. The patient does not die from AIDS itself but from other secondary infections such as pneumonia and meningitis, tuberculosis, fungal infections or certain forms of cancer like Kaposi’s sarcoma 71

AIDS – Transmission Methods• HIV only survive in body fluid such as

semen, blood and vaginal fluid.• Therefore, HIV can be transmitted through :

– sexual intercourse– Blood transfusion– Injection with contaminated needle used to

inject drugs• HIV infected mother can pass HIV to her

baby through placenta or breast milk.• HIV cannot be spread by touching, sharing

of food or through the use of public toilets.72

Appreciating a Healthy Cardiovascular System

• Disorder of the heart and blood circulatory system; hypertension, artherosclerosis, coronary thrombosis, arteriosclerosis, angina, stroke.

• Factors that contribute to cardiovascular diseases;– Obesity– A diet high in saturated fat and cholesterol in

daily life and low in fibres.– Salty foods– Lack of exercise– Cigarette smoking– Mental stress 73

Chapter 1 transport

Education

Transcript of Chapter 1 transport