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HL Bio > 6.2 blood system > Flashcards

6.2 blood system Flashcards

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Biology 101 flashcards
1
Q

what does blood comprise of? fill in

  • ???
  • RBC
  • WBC
  • platelets
  • ions
  • ???
A

plasma, plasma proteins

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2
Q

the left side of the heart pumps [ox/deox] blood to ______

A

oxygenated, the body

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3
Q

the right side of the heart pumps [ox/deox] blood to _______

A

deoxygenated, lungs

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4
Q

which type of blood vessel transports blood at high pressure from the heart ventricles to body tissues and lungs?

A

arteries

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5
Q

what are the structural features of arteries? (4)

A
  1. narrow lumen
    • maintain high b.p.
  2. thick wall w outer layer of collagen
    • withstand high pressure needed to pump blood to e rest of e body
  3. inner layer of smooth muscle
    • for contraction/dilation to alter diameter of lumen and thus control local b.p.
  4. elastic fibres
    • allow artery walls to stretch + recoil
    • maintains pressure + helps pump the blood
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6
Q

what are the structural features of capillaries? (3)

A
  1. 1-cell thick endothelium w permeable basement membrane only
    • quick exchange of materials
  2. narrow
    • penetrate all parts of tissues to deliver blood close to the cells
  3. large total cross-sectional area (of capillary bed)
    • slow blood flow allows time for exchange
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7
Q

what are sinusodial capillaries?

A

capillaries w open spaces between cells

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8
Q

what are capillaries with pores called?

A

fenestrated capillaries

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9
Q

capillaries that limit permeability of large molecules are usually ___________capillaries

A

continuous

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10
Q

veins function to…

A

collect blood from the tissues and transport it at low pressure to the atria of the heart

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11
Q

what are the structural features of veins?

A
  1. very wide lumen
    • maximise blood flow
  2. thin wall containing less muscle and elastic fibres
    • as pressure is low
  3. valves
    • prevent backflow of blood
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12
Q

why would backflow of blood occur in veins?

A

venous pressure it too low to readily pump blood back to the heart against gravity

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13
Q

what assists blood flow in veins? (short)

A

skeletal muscular activity

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14
Q

identify the blood vessels

A

-

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15
Q

what moves into tissues from the bloodstream?

A
  • O2
  • nutrients
  • hormones
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16
Q

what moves out of the tissues from the bloodstream?

A
  • CO2
  • nitrogenous waste
  • hormones
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17
Q

William Harvey discovered that…

A

the heart pumped blood around the body

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18
Q

what are the advantages of double circulation? (2 short)

A
  • ensures ox and deox blood do not mix
  • lower b.p. in pulmonary circuit to facilitate gaseous exchange at the lungs
  • higher b.p. for systemic circuit to pump blood throughout body
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19
Q

label a diagram of a heart

A

-

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20
Q

label a dissected heart

A

-

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21
Q

the heart beat is initiated by the…

A

sinoatrial node

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22
Q

what is the sinoatrial (SA) node and its function?

A

a group of specialised muscle cells which generate electric impulses to control the rate and timing at which cardiac muscle cell contract

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23
Q

the SA node acts as a __________

A

pacemaker

24
Q

how does the SA node control the heartbeat?

A

they spontaneously produce an electrical impulse

25
Q

why is there a delay between the ‘lub’ and ‘dub’ heart sounds?

A
  • SA node spontaneously produces an electrical impulse
  • impulse is first propagated through the wall of the atrias, causing atria to contract
  • AV node is stimulated by impulses and sends a signal across to the septum via Bundle of His and then Purkinje fibres
  • causes ventricular contraction
  • sequence of events allows delay between atrial and ventricular contraction
  • thus delay between ‘lub’ and ‘dub’ heart sounds
26
Q

why is a delay between atrial and ventricular contraction necessary?

A

to allow time for the ventricles to fill w blood

27
Q

what is the basal heart rate?

A

the heart rate when a person is at rest

28
Q

what determines the basal heart rate?

A

sinoatrial node

29
Q

what is a trigger that can cause changes in heart rate?

A

changes to conc of CO2 (changes in blood pH)

30
Q

the transmission of _________ and the release of _____ can cause changes in heart rate

A

nerves impulses, hormones

31
Q

what does ‘autonomic’ in autonomic nervous system (ANS) mean?

A

involuntary

32
Q

what are the two main pathways in the autonomic nervous system

A

parasympathetic and sympathetic

33
Q

what is the part of the brain that sends nerve impulses to cause changes in the heart rate?

A

medulla oblongata

34
Q

the two nerves that are help regulate the heart rate are…

A

parasympathetic nerve and sympathetic nerve

35
Q

the parasympathetic and sympathetic nerves release… (1 word)

A

neurotransmitters

36
Q

what neurotransmitter does the parasympathetic nerve release?

A

acetylcholine

37
Q

the sympathetic nerves releases the neurotransmitter __________

A

noradrenaline

38
Q

nerve impulses are sent down the _____________ pathway via the ________ nerve to cause a decrease in heart rate

A

parasympathetic, vagus nerve

39
Q

what nerve does the sympathetic pathway use to send nerve impulses?

A

cardiac sympathetic nerve

40
Q

parasympathetic and sympathetic pathways represent ______________ (relationship) control of the autonomic nervous system

A

antagonistic

41
Q

recap: what are hormones?

A

chemical messengers released into the bloodstream that act specifically on distant target sites

42
Q

what hormone is released to increase heart rate?

A

adrenaline

43
Q

what is another name for adrenaline?

A

epinephrine

44
Q

from where is adrenaline released?

A

from the adrenal glands

45
Q

how does adrenaline affect the heart during fight-or-flight response? (1, short)

A
  • incr heart rate by incr force of contraction in preparation for vigorous physical activity
46
Q

what happens to the heart during a fight-or-flight response? (5)

A
  1. nerve response
    - the medulla oblongata sends nerve impulses down the sympathetic pathway via cardiac sympathetic nerve
    - nerve releases neurotransmitter noradrenaline
    - causes SA node to speed up heart rate + incr force of contraction
  2. hormone response
    - adrenaline is released by adrenal glands
    - causes SA node to incr heart rate
    • this incr the transport of O2 and glucose for vigorous physical activity
47
Q

what does systole mean? hint: sustain

A

contraction

48
Q

what does diastole mean? hint: dilate

A

relaxation

49
Q

briefly name the events of the cardiac cycle

A

atrial systole -> ventricular systole/atrial diastole -> ventricular diastole

50
Q

what happens during ventricular systole/atrial diastole? (6)

A
  1. ventricular systole:
    - ventricles contract, incr b.p. within
    - this forces AV valves to close -> prevent backflow of blood -> ‘lub’
    - forces semilunar valves in pulmonary artery and aorta to open
    - blood flows to the lungs + rest of e body respectively
  2. atrial diastole:
    - atria relax
    - atria is refilled by ox and deox blood from pulmonary veins and vena cava respectively
51
Q

what happens during ventricular diastole? (4)

A
  • ventricles relax -> reduces pressure within
  • semilunar valves close -> prevent backflow of blood into ventricles -> ‘dub’
  • when pressure in ventricles drops to a lvl lower than atrial pressure, AV valves open
  • blood passes passively into ventricles
52
Q

what happens during atrial systole? (3)

A
  • atria contracts
  • remaining blood is pumped into ventricles
  • ventricles filled w blood
53
Q

what causes the ‘lub’ sound?

A

closing of AV valves

54
Q

what causes the ‘dub’ sound?

A

closing of semilunar valves

55
Q

what is the hardening and narrowing of the arteries due to cholesterol deposits called?

A

atherosclerosis

56
Q

how can atherosclerosis lead to a heart attack? (6)

A
  1. atheromas develop in arteries -> significantly reduce diameter of e lumen
  2. restricted blood flow -> incr pressure -> damage to arterial wall fr shear stress
  3. damaged region is repaired w fibrous tissue -> significantly reduces elasticity of vessel wall
  4. smooth lining of artery is progressively degraded -> atherosclerotic plaques form
  5. if plaque ruptures -> blood clotting triggered -> forms a thrombus
  6. thrombus occludes coronary artery -> O2 and glucose cannot be transported to heart muscle cells -> heart attack
57
Q
A

HL Bio (52 decks)

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