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Wrong Exam Qs > transport in animals🦒🐘🐠 > Flashcards

transport in animals🦒🐘🐠 Flashcards

1
Q

role of the san and avn in the cardiac cycle

A

san- pacemaker/initiates heartbeat, sends impulse over atria

avn- delays impulse, sends impulse down bundle of his

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2
Q

artery and vein wall differences

A
  • artery has smaller lumen
  • artery has thicker wall
  • artery has no valves
  • artery has more muscle
  • artery has more collagen
  • artery has endothelium folded
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3
Q

how is high hydrostatic pressure in the arteries generated in the heart

A

contraction of ventricle

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4
Q

why does hydrostatic pressure of the blood drop as the blood moves away from the heart

A
  • more vessels
  • vessels have larger total lumen
  • reduced resistance to blood flow
  • arteries stretch
  • loss of fluid from capillaries
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5
Q

describe what happens to blood plasma at arterial end of capillary

A
  • plasma moves out of capillary down pressure gradient
  • forms tissue fluid
  • plasma proteins remain in capillary as too large to pass through wall
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6
Q

how are hydrogencarbonate ions produced

A
  • co2 diffuses into erythrocyte, reacts with water to form carbonic acid -catalysed by carbonic anhydrase
  • carbonic acid dissociates to form h+ and hco3- ions
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7
Q

what is single circulatory system

A

blood passes through heart once for each circulation

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8
Q

what is closed circulatory system

A

blood is maintained inside blood vessels

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9
Q

describe how the action of the heart is initiated and coordinated

A
  • SAN initiates excitation
  • wave of excitation spreads over atrial wall
  • atrial systole
  • delay at AVN
  • excitation spreads down septum through Bundle of His
  • ventricular systole from apex through purkinje fibres
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10
Q

what is tachycardia and bradycardia

A

tachycardia- increase in heart rate

bradycardia-decrease in heart rate

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11
Q

in a condition where electrical signals leak from atria directly to top of ventricles, causing ventricles to contract twice for every atrial contraction. what effect might this have on blood flow

A
  • less blood leaves heart for every contraction

- as ventricles are not full before contracting

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12
Q

in the fetus blood flows directly from right to left atrium why

A
  • lungs not functioning
  • blood oxygenated in placenta
  • lungs bypassed
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13
Q

difference between adult and fetal hb and why is it essential

A
  • higher affinity for o2

- must be able to bind to o2 at lower po2

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14
Q

why no erythrocytes in tissue fluid

A

-too large to pass through gaps in capillary walls

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15
Q

role of haemoglobin in transporting oxygen

A
  • hb has high affinity for oxygen
  • oxygen binds to hb in lungs
  • forms oxyhaemoglobin
  • oxygen released in tissues
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16
Q

what is the bohr effect

A
  • high concentrations of carbon dioxide in the blood reduce the amount of oxygen transported by haemoglobin
  • co2 reduced hb affinity for o2
  • alters shape of hb
  • more o2 released
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17
Q

how does smoking affect cardiovascular system

A
  • nicotine
  • increases stickiness of platelets
  • thrombosis
  • reduced blood flow
  • carbon monoxide
  • combines with hb
  • reduced o2 carrying capacity of blood
  • atherosclerosis
  • increased blood pressure
  • CHD
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18
Q

why is fetal hb more saturated at lower po2

A
  • placenta has low po2
  • adult hb releases o2 at low po2
  • fetal hb has higher affinity for o2
  • fetal hb still able to take up o2 at low po2 in placenta
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19
Q

how do substances disssolved in blood plasma enter tissue fluid from capillaries

A
  • hydrostatic pressure inside capillaries is higher than in tissue fluid
  • capillary walls are leaky
  • diffusion down concentration gradient
  • plasma forced out of capillary
  • small molecules leave with plasma as a result of mass flow
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20
Q

describe pressure changes in blood as it flows from aorta to veins

A
  • pressure drops as distance from heart increases
  • greatest pressure drop when blood flows through arteries
  • pressure is constant in veins
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21
Q

explain what causes change in pressure from aorta to arteries and from arteries to capillaries

A
  • blood flows into larger number of vessels
  • total cross sectional area of arteries is greater than that of aorta
  • total cross sectional area of capillaries is greater than that of arteries
22
Q

advantages of keeping blood inside vessels

A
  • maintain pressure

- increase rate of flow

23
Q

how is artery wall adapted to withstand and maintain pressure

A

withstand- folded endothelium

  • thick wall
  • collagen
  • which provides strength

maintain- smooth muscle narrows lumen
-elastin to cause recoil

24
Q

why is left ventricle thicker than left atrium

A
  • more muscle to create more force
  • because needs to create higher pressure
  • to push blood against greater resistance
  • as it pumps blood to all parts of body
25
Q

how do pressure changes in the heart cause the AV valves to close

A
  • ventricle contracts
  • raises ventricular pressure
  • pressure greater in ventricles than in atria
  • pressure generated by ventricular contraction pushes valves shut
26
Q

which component of mammalian circulatory system maintains pressure

A

aorta/arteries

27
Q

which component of the mammalian circulatory system is the exchange surface

A

capillaries

28
Q

what detail would a scaning electron microscope reveal in a blood smear

A

3D shape

surface detail

29
Q

what are the benefits of bohr shift to actively respiring tissue

A
  • actively respiring tissue needs more oxygen
  • for aerobic respiration
  • actively respiring tissue produces more carbon dioxide
  • hb is involved in the transport of co2
  • less hb available to combine with o2
  • bohr shift causes more o2 to be released
30
Q

explain gas exchange in fish

A
  • mouth opens buccal cavity expands
  • buccal cavity vol increases pressure decreases
  • water moves into buccal cavity down pressure gradient
  • opercular cavity expands opercular valves are shut
  • opercular cavity vol increases pressure decreases
  • water moves from buccal cavity to opercular cavity across gills down pressure gradient
  • both buccal and opercular cavity constrict
  • vol decreases and pressure increases in both
  • water pushes valves open and leaves opercular cavity to outside down pressure gradient
31
Q

adaptations of gills for gas exchange

A
  • lamallae increase surface area
  • secondary lamallae on lamallae increase sa
  • short diffusion distance between blood and water
  • good blood supply maintains concentration gradient
  • thin layers for short diffusion distance
  • countercurrent exchange system (blood and water flow in opposite directions) maintains concentration gradient
32
Q

how to dissect fish gill

A
  • remove operculum
  • cut out a gill arch which contains the gill filaments
  • place in petri dish containing water
33
Q

difference between mammal and insect gas exchange

A
  • mammal trachae lined with cartilage, insect lined with chitin
  • insect trachae branch into tracheoles, mammal trachae branches into bronchi
  • mammals have one trachae insects have multiple
34
Q

explain movement of fluid in and out of capillary

A
  • at arterial end hydrostatic pressure is greater than oncotic pressure so plasma moves out of capillary
  • at venous end hydrostatic pressure is lower than oncotic pressure so tissue fluid moves into capillary
35
Q

where does right semilunar valve lead to

A

pulmonary artery

36
Q

why do people with a hole in the septum of the heart easily become tired

A
  • blood leaks from left to right
  • less oxygen carried to tissues
  • less aerobic respiration
  • more oxygenated blood delivered to lungs
  • less oxygenated blood pumped around body
37
Q

heart valves make lub sound at beginning of ventricular systole, what is happening

A

atrioventricular valves closing and blood leaving ventricles

38
Q

in mammals where is oxygenated blood

A
  • pulmonary vein
  • left side of heart
  • aorta
39
Q

in mammals where is deoxygenated blood

A
  • vena cava
  • right side of heart
  • pulmonary artery
40
Q

advantages of double circulation

A
  • only passes through one capillary network before returning to heart (has to pass through two in single)
  • blood pressure drops in capillary network
  • so double has higher pressure and speed of flow
  • maintains steeper concentration gradient
41
Q

describe insect circulatory system

A
  • open
  • haemolymph carried directly from heart to body cavity (haemocoel)
  • direct exchange between haemolymph and cells
  • haemolymph returns to heart via open ended vessel
42
Q

how does blood flow through arterioles

A

arteries-> arterioles-> capillaries

43
Q

how does blood flow venules

A

capillaries-> venules-> veins

44
Q

what is hydrostatic pressure

A

pressure exerted by a liquid

45
Q

what is oncotic pressure

A

osmotic pressure exerted by plasma proteins within a blood vessel, it usually pulls water into the circulatory system

46
Q

at what end of capillary does tissue fluid form

A

arteriole

-hydrostatic greater than oncotic

47
Q

why is tissue fluid reabsorbed

A
  • at venous end, the hydrostatic pressure within capillary is reduced
  • water potential gradient between the capillary and the tissue fluid remains the same as at the arterial end
  • water begins to flow back into the capillary from the tissue fluid
48
Q

how does lymph form

A
  • some tissue fluid reenters lymph capillaries instead of regular capillaries
  • lymph capillaries have closed capillaries and large pores
  • larger molecules that cant enter capillaries enter lymph
  • liquid moves along by compression
  • backflow prevented by valves
  • lymph reenters bloodstream through veins close to heart
  • plasma proteins reenter blood through lymph
  • lipids transported from gut to blood via lymph
49
Q

why does tissue fluid not have plasma proteins

A

water potential lowered so tissue fluid would not be able to be reabsorbed

50
Q

how does heart receive blood

A

coronary arteries on surface

Wrong Exam Qs (41 decks)

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