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Biology 🦠 > Chapter 6: Transport in Humans > Flashcards

Chapter 6: Transport in Humans Flashcards

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1
Q

Components of human transport system

A
  • a series of blood vessels
  • blood
  • heart
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2
Q

Main components of blood

A
  • plasma
  • red blood cells
  • white blood cells
  • platelets
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3
Q

Plasma

A
  • yellowish-liquid in blood
  • contains mainly water & substances such as glucose, salts, proteins, amino acids, fats, vitamins, hormones & excretory products such as urea
  • also contains red & white blood cells
  • transport blood cells, nutrients, excretory products and hormones
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4
Q

Red blood cells

A
  • main function is to transport oxygen from lungs to other parts of the body
  • contains haemoglobin that combine reversibly with oxygen. In lungs, O2 concentration is high, haemoglobin binds to O2 to form oxyhemoglobin. In tissues, O2 concentration is low, oxyhemoglobin releases oxygen to cells
  • they have biconcave shape to increase surface area-to-volume ratio which increases rate of absorption and release of oxygen
  • they are flexible 👉 can change into bell-shaped structures so that they can flow easily through narrow blood capillaries
  • no nucleus 👉 more space for haemoglobin to be stored
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5
Q

White blood cells

A
  1. Phagocytes
  2. Lymphocytes
    - they are irregular in shape and have a nucleus
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6
Q

Phagocytes

A
  • performs phagocytosis
  • process whereby white blood cell engulfs and destroys foreign particles such as bacterial
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7
Q

Lymphocytes

A
  • recognise foreign particles
  • destroy disease-causing organisms such as bacteria and viruses
  • causes bacteria to clump together for easy ingestion by phagocytes
  • neutralise toxins produced by bacteria
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8
Q

Platelets

A
  • fragments of cytoplasm
  • contains enzymes that catalyses the conversion of fibrinogen to fibrin threads
  • these threads form a network that entangles red blood cells to form a clot
  • the clot prevents excessive blood loss and entry of harmful organisms into the bloodstream
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9
Q

How does blood clot

A
  • when tissues are damaged at the site of the cut, platelets release thrombokinase
  • thrombokinase catalyses the conversion of blood protein prothrombin into thrombin in the presence of calcium ions
  • thrombin catalyses conversion of soluble fibrinogen threads into insoluble threads of fibrin
  • fibrin threads entangle blood cells and the whole mass forms a clot/scab
  • the clot seals the wound, preventing entry of microorganisms and excessive blood loss
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10
Q

Organ transplant and tissue rejection

A
  • happens when a person’s tissue/organ is damaged or diseased and it is replaced by a healthy tissue or organ from the donor
  • this new organ may be treated as a foreign body and when the white blood cell recognise the tissue/organ as foreign, they produce antibodies to destroy the foreign tissue. This is known as tissue rejection
  • hence, tissue of both donor and recipient must be as genetically similar as possible
  • another way to reduce risk of tissue rejection is the use of drugs which inhibits the responses of the recipient’s immune system
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11
Q

Blood types

A
  • special proteins on surface of red blood cells is antigens
  • antibodies are produced by white blood cells and float in your blood
  • your antigens and antibodies will not react with each other, but may react with antigens and antibodies of another person’s blood 👉 causes clumping of red blood cell (agglutinate)
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12
Q

4 blood groups

A

A: antigen A, antibody b
B: antigen B, antibody a
AB: antigen A & B but no antibody
O: no antigen but have antibody a & b

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13
Q

What is the Heart

A
  • pumps blood to ensure blood constantly circulates throughout body
  • when heart relaxes, it fills up with blood
  • when heart contracts, blood is squeezed out with great force
  • blood then circulates through the blood vessels, which directs blood flow around the body
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14
Q

What is the Arteries

A
  • blood vessels that carry blood away from the heart
  • large artery that leaves left side of the heart is the aorta
  • aorta branches out into smaller arterioles
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15
Q

what is the Arterioles

A
  • arteries branch out to form arterioles
  • arterioles branch out to form capillaries
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16
Q

what is the Blood capillaries

A
  • microscopic blood vessels that are found between the cells of almost all tissues
  • walls made out of a single layer of flattened cells (short diffusion distance)
  • capillary walls are partially permeable, enabling certain substances to diffuse through it
  • small arteries branch out to form capillaries
  • numerous branches provide larger surface area for the exchange of substances between blood and tissue cells
  • the total cross-sectional area of the blood vessels also increases, lowering blood pressure, hence flow of blood slows down, giving more time for exchange of substances
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17
Q

what is the Venules

A
  • before capillaries leave an organ, they will unite to form small vessels called venules
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18
Q

what is the Veins

A
  • venules join to form bigger veins, with carry blood back to the heart
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19
Q

Arteries

A
  • receives blood directly from the heart
  • blood that flows in arteries are fast moving 👉 walls are thick, muscular and elastic
  • elastic layer is much thicker in the arteries closest to the heart
  • thick elastic walls help withstand high blood pressure
  • elasticity enables wall to stretch and spring back 👉 pushes blood in spurts along artery, giving rise to the pulse
  • when muscles in wall contract, artery constrict, lumen narrows and less blood flows through it
  • when muscles in wall relax, artery dilates, lumen widens and more blood flows through it
  • carries oxygenated blood (except pulmonary artery)
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20
Q

Veins

A
  • transports blood towards heart
  • blood pressure in veins are much lower than that of arteries
  • blood flows more slowing and smoothly in veins, hence walls are not as thick and muscular
  • veins contain less elastic tissue
  • most veins have internal valves along length to prevent back flow of blood
  • carries deoxygenated blood
21
Q

How are substances transferred between capillaries and tissue fluids

A
  • tiny spaces between tissue cells contain colourless liquid, tissue fluid
  • tissue fluid transports dissolved substances between tissue cells & blood capillaries
  • dissolved food substances & oxygen diffuse from blood in blood capillaries into tissue fluid and move into cells
  • metabolic & excretory products diffuse from the cells into the tissue fluid and then transferred through the blood capillary walls into the blood
  • blood transports waste products to excretory organs for removal
22
Q

How does blood circulate in body

A
  1. Pulmonary arteries carry blood from heart to lungs
  2. Oxygen enter blood at lungs, oxygenated blood is returned to the heart via the pulmonary vein
  3. Oxygenated blood leaves the left side of the heart and is distributed by arteries to all parts of the body except lungs
  4. Veins carry blood from all parts of the body back to right side of heart
23
Q

Structure of heart

A
  1. Vena Cava
  2. Pulmonary arteries
  3. Aorta
  4. Pulmonary veins
  5. Tricuspid valve
  6. Semi-lunar valve
  7. Bicuspid valve
  8. Right atrium
  9. Right ventricle
  10. Left atrium
  11. Left ventricle
24
Q

Atria

A
  • 2 chambres (right atrium/left atrium)
  • atria receive blood from veins
  • atria have comparatively thin muscular walls since they only force blood into ventricles that lie directly below them, which does not require high pressure
25
Q

Ventricles

A
  • 2 larger lower chambers
  • thicker muscle walls than atrium
  • left ventricle muscles is thicker since it pumps blood around whole body and this requires high pressure
  • right ventricle has thinner walls since it only pumps blood to lungs, which is closer
26
Q

Median septum

A
  • muscular wall that separates right & left side of heart.
  • runs down middle of heart
  • prevents mixing deoxygenated blood with oxygenated blood
  • mixing of deoxygenated and oxygenated blood reduces amount of oxygen carried to the rest of the body
27
Q

Flow of blood in heart

A
  1. deoxygenated blood from body is retuned to right atrium by vena cave. The upper one transports blood from head, neck and arms back to heart. The lower one transports blood from rest of body back to heart
  2. from right atrium, blood passes through tricuspid valve into right ventricle.
  3. From right ventricle, blood leaves heart by pulmonary arteries to lungs
  4. Pulmonary veins transports oxygenated blood from lungs to left atrium
  5. Blood passes from left atrium, through bicuspid valve into left ventricle
  6. From left ventricle, blood leave heart & enters aorta to be distributed around body through different arteries. 2 small coronary arteries emerge from aorta, bringing oxygen and nutrients to heart muscles
28
Q

Tricuspid valve

A
  • consists of 3 flaps that point downwards into ventricle
  • flaps are attached to the walls of right ventricle by chordae tendineae
  • prevents back flow of blood from right ventricle to right atrium
29
Q

Bicuspid valve

A
  • consists of 2 flaps that point downwards into left ventricle
  • chordae tendineae prevents flaps from being reverted into atrium when right ventricular muscles constract
  • prevents back flow of blood from right ventricle to right atrium
30
Q

Aortic valve

A
  • semi-lunar valve in aorta
  • prevents backflow of blood from aorta to left ventricle
31
Q

Pulmonary valve

A
  • semi-lunar valve in pulmonary artery
  • prevents backflow of blood from pulmonary artery to right ventricle
32
Q

What happens if there is a hole in the heart?

A
  • may be present in median septum
  • blood will flow through hole mostly from left side of heart to right side since pressure in left side is higher than right
  • leads to mixing of oxygenated and deoxygenated blood
  • less oxygen is transported to body cells for respiration
  • patients may suffer from shortness of breath, fatigue, & in serious cases, heart failure
  • thankfully most patients do not have symptoms, so they are fine
33
Q

Cardiac cycle (1-3)

A
  1. atrial muscles contract, forcing blood into ventricles
  2. after short pause, ventricular muscles contract 👉 pressure in ventricle increases 👉causes bicuspid and tricuspid valve to close to prevent backflow of blood into atria 👉 loud ‘lub’ sound produced. Semi-lunar valve open & blood flow from right ventricle and left ventricle into pulmonary artery and aorta respectively
  3. as ventricular muscles contract, atrial muscles relax. Right atrium receives blood from venae cavae while the left atrium receives blood from pulmonary veins
34
Q

Cardiac cycle (4 & 5)

A
  1. Ventricular muscles then relax. Fall in pressure causes semi-lunar valves to close to prevent back flow of blood from pulmonary artery and aorta into ventricles 👉 produces “dub” sound. Bicuspid and tricuspid valve also opens and blood flows from atria into ventricles
  2. atrial muscles contract again and whole cycle repeats
35
Q

Systole & diastole

A
  • 2 phases in cardiac cycle
  • systole occur when ventricular or atrial muscles contract.
  • diastole occurs when ventricular or atrial muscles relax
  • a ventricular systole and diastole makes up 1 heartbeat
36
Q

How does the heart control blood pressure

A
  • blood pressure is the force that blood exerts in walls of blood vessels
  • bp in arteries are highest during ventricular systole when blood is forced into the arteries
  • bp decreases during ventricular diastole
  • bp varies in different parts of body
  • highest near aorta & gets weaker the further the arteries are from heart
  • bp in veins are low
37
Q

The pulse

A
  • produced after every ventricular contraction as heart pumps blood
  • by counting no of pulse beats every minute, we get the heart rate of sb
38
Q

Pressure changes in heart (1-4)

A
  1. slight increase in ventricular pressure during to contraction of left atrial muscles, forcing blood into ventricle
  2. ventricular muscles contract, bicuspid valve closes
  3. ventricular continue to contract without change in volume of blood, pressure continues to rise
  4. pressure in ventricle becomes higher than that in aorta. aortic valve opens. volume of blood in ventricle decreases as blood is forced out into aorta
39
Q

Pressure changes in heart (5-8)

A
  1. ventricular muscles begin to relax. drop in pressure causes aortic valve to close to prevent backflow of blood into ventricle
  2. ventricular muscles continue to relax without change in volume of blood
  3. bicuspid valve opens when pressure in ventricle becomes lower than that in atrium
  4. pressure in ventricle rises as blood continues to enter the ventricle from atrium
40
Q

Main blood vessels

A
  1. Pulmonary artery
  2. Pulmonary vein
  3. Vena Cava
  4. Aorta
  5. Hepatic Vein
  6. Hepatic artery
  7. Hepatic portal vein
  8. Renal vein
  9. Renal artery
41
Q

What happens during a heart attack

A
  • during a heart attack, blood flow to a particular part of the heart may be completely blocked
  • due to blocked blood flow, that part of the heart does not receive sufficient oxygen and nutrients
  • that region of heart muscles dies
  • extensive heart damage is often fatal as heart is no longer able to pump blood to various parts of body
42
Q

What are the causes of coronary heart disease

A
  • fatty substances such as cholesterol and saturated fats may be deposited on inner surface of the coronary arteries
  • narrows lumen of arteries and increases blood pressure
  • artery will develop a rough inner surface
  • increases risk of blood clot being formed in artery
  • if it occurs in coronary arteries, supply of oxygen and blood to heart muscles may be completely cut off
  • oxygen is needed in aerobic respiration to release energy for activities of muscle cells
  • w/o oxygen, heart muscle cells may be damaged and heart attack occurs
43
Q

Risk factors of heart diseases

A
  1. smoking
  2. unhealthy diet
  3. genetice factors
  4. age
  5. sedentary lifestyle
44
Q

Smoking on heart disease

A
  • cigarette smoking contains carbon monoxide & nicotine which can increase risk of coronary heart disease
  • nicotine increases blood pressure 👉 increasing risk of blood clot in arteries
45
Q

Unhealthy diet on heart disease

A
  • diet high in cholesterol, saturated fats and salt content increases risk of high blood pressure and heart attacks
46
Q

Genetic factors on heart disease

A
  • high blood pressure and high cholesterol runs in families
47
Q

Age on heart disease

A
  • risk increases as you grow older
  • majority of people suffering from coronary heart disease is 65 and above
48
Q

Sedentary lifestyle on heart disease

A
  • lack of exercise and being inactive leads to build-up of fatty deposits that block arteries
  • increases risk of getting coronary heart disease
49
Q

Ways to reduce risk of coronary heart disease

A
  1. healthy diet (substitute animal fat with polyunsaturated plant fat) 👉 lowers cholesterol levels in blood
  2. avoid smoking
  3. regular exercise 👉strengthens heart and maintains elasticity of arterial walls & reduces risk of high blood pressure and hypertension

Biology 🦠 (18 decks)

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