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o level biology > transport in humans > Flashcards

transport in humans Flashcards

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1
Q

what does blood consist of?

A

55% plasma
45% blood cells and platelets
- RBC
- WBC

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2
Q

what are the components in plasma?

A
  1. soluble proteins; fibrinogen, prothrombin (blood clotting) and antibodies (fight diseases)
  2. dissolved minerals; hydrogencarbonate, sulfate and phosphate of calcium, sodium and potassium. (blood clotting)
  3. food substances; glucose, amino acids, fats and vitamins
  4. excretory products; urea, uric acid and creatinine
  5. hormones; insulin
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3
Q

what are the features of the red blood cells

A
  1. it contains a red pigment called haemoglobin which combines reversibly with oxygen. this enables the RBC to transport oxygen from the lungs to the body
  2. it has a circular biconcave shape. this is for an inc in surface area to volume ratio for more effective absorption and release of blood.
  3. it does not have a nucleus; this is for more storage of haemoglobin and thus more oxygen
  4. its elastic and can squeeze through blood vessels smaller than the cell
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4
Q

what are the features of white blood cells?

A
  1. there is significantly less WBC to RBC with a ratio of 1:700.
  2. it is colourless due the lack of presence of haemoglobin
  3. it contains a nucleus and have an irregular shape
  4. it can move nd change it’s shape, squeeze through smallest blood vessels
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5
Q

what are the 2 types of WBC

A

lymphocytes and phagocytes
(helps fight diseases, and have a life span of a few days even tho there’s a nucleus present)

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6
Q

what are the functions of blood

A
  1. it’s a transport medium for substances
  2. it protects the body against diseases
  3. blood clotting prevents excessive loss of blood and bacteria entering the bloodstream
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7
Q

how does blood transportation work?

A
  1. blood passes through the lungs and oxygen diffuses from the alveoli into the blood
  2. haemoglobin combined with oxygen and become oxyhaemoglobin
  3. oxyhemoglobin release oxygen into tissues containing low oxygen.
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8
Q

process of clotting?

A
  1. releases an enzyme known as thrombokinase
  2. this enzyme will then covert prothrombin into thrombin. (calcium ion MUST be present b4 this can happen)
  3. thrombin catalyst the conversion of fibrinogen into fibrin.
  4. fibrin enrages blood cells and forms a clot or scab
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9
Q

define phagocytosis

A

it’s the process of engulfing or ingesting foreign particles, such as bacteria, by the WBC

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10
Q

how does antibodies work?

A
  1. they destroy the bacteria by attaching themselves and causing the bacterial surface membrane to rupture
  2. agglutinate bacteria so it can be easily ingested by phagocytes
  3. neutralise the harmful substances
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11
Q

how to prevent tissue rejection?

A
  1. a tissue match is necessary (as close as possible)
  2. immunosuppressive drugs

problems of point #2:
- lower resistance to infections
- must continue taking the drugs for the rest of their lives

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12
Q

what is the function of the heart?

A

it keeps the blood circulating throughout the body. when it relaxes, it is filled with blood whilst when it contracts, blood is squeezed out w/ great force

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13
Q

what is the function of arterioles?

A
  • arteries form arterioles which divide and become capillaries
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14
Q

blood capillaries

A
  • they have walls made up of endothelium which is partially permeable
  • the numerous of branches inc SA for the exchange of substance between blood and tissue
  • when arterioles branches into capillaries, the total cross-sectional area Inc. this lowers the BP in the capillaries. the blood is then slowed down which gives it time for the exchange of substance
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15
Q

what are venules:

A

before capillaries leave an organ/tissue, they unite and become venules

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16
Q

what are veins

A

venules form bigger veins which carry blood from the body back to the heart

17
Q

what are the functions of arteries

A
  1. the arteries receive blood directly from the heart.
  2. they are able to withstand immense pressure as blood is forced out of the heart. they can do this due to their thick, muscular and elastic walls
  3. the elasticity allows it to stretch and recoil.
  4. when an artery constricts, the lumen becomes narrower and less blood flows through it whilst when an artery dilates, it’s lumen become wider and more blood flows through it
  5. most carry oxygenated blood (only pulmonary artery carry deoxygenated blood)
18
Q

what are the FUNCTIONS of veins

A
  1. the BP in veins are significantly lower than those in an artery. thus, their walls aren’t as thick or muscular and less elastic.
  2. they do however have valves to prevent the back flow of blood. and have semi-lunar valves
  3. transport deoxygenated blood (except the artery which transport oxygenated blood)
19
Q

single circulation

A

fishes are an example of single circulation. arteries carry blood from the heart to the gills, and take in oxygen. the arteries that leave the gills contain oxygenated blood go other parts of the body. by the time the blood enter the vein, it is poor in oxygen and transported back into the heart.

20
Q

pulmonary circulation

A
  • the pulmonary arteries carry blood from the heart to the lungs
  • oxygenated blood is returned to the heart by the pulmonary veins
21
Q

what is systemic circulation and function

A
  1. oxygenated blood leaves through the left side of the heart nd distributed to all parts of the body
  2. veins carry blood from the body back to the right side of the heart
22
Q

advantage of systemic circulation

A
  • blood entering the lungs have a lower BP and this ensures blood flows slowly and smoothly which allows enough time for the blood to be well oxygenated before returning to the heart
  • blood leaving the heart has a high BP so that oxygen can be distributed faster
23
Q

the structure of the heart

A
  1. it is surrounded by the pericardium which is made up of 2 membranes. the inner membrane has contact with tissues making up the heart. in between both layers of membrane, there is a fluid that helps to reduce friction when the heart is beating
  • atria have thin muscular walls as they only force blood into the ventricles this no need of HBP
  • the ventricles have thick walls(esp the left) as it needs to pump blood from the heart to the body.
  • right ventricle have thinner walls as it transports blood from the heart to the lungs (close)
  • the sides of the heart is separated by the median septum. this is to avoid the mixing of oxygenated blood from the left side with deoxygenated blood from the right side
24
Q

coronary heart disease

A

the coronary arteries lie outside the heart nd carry blood to the muscles in the arteries of the heart. this can greatly reduce blood supply due to the occlusion or blockage of coronary arteries. which can cause a heart attack

25
Q

heart attack

A
  1. blood flow in a particular part mayb completely blocked
  2. lack of nutrition and oxygen and thus the muscles die
26
Q

causes of coronary heart disease

A
  1. fatty substance such as cholesterol and saturated fats mayb deposited on the inner surface of the coronary arteries (atherosclerosis), this is a problem as it narrows the lumen and inc BP. it then develops a rough inner surface which inc the risk of blood clotting (thrombosis). blood supply is completely cut off and no oxygen is transported. oxygen is needed in aerobic respiration to release energy. without oxy, the heart cells may be damaged and thus a heart attack
27
Q

factors of coronary heart disease

A
  • a diet rich in cholesterol and saturated animal fats
  • emotional stress
  • smoking
28
Q

preventive measures against coronary heart disease

A
  • proper diet is important. subside animal fats for polyunsaturated plant fats
  • stress management
  • smoking contain nicotine and carbon monoxide which increases the risk of coronary heart disease
  • regular exercise; strengthens and maintains the elasticity of the arterial walls. the risk of HBP and hypertension is greatly reduced

o level biology (1 decks)

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