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MCDB 1B > Circulatory System > Flashcards

Circulatory System Flashcards

1
Q

advantage of a closed circulatory system

A

fluid flows faster, direct blood to specific tissues, special cells and large molecules can be kept within the blood vessels

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2
Q

what is the circulation type of a fish

A

fish have a single circuit (closed system)

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3
Q

what does a single circuit have

A

a single atria, single ventricle all in one circuit

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4
Q

what is the double circulation system

A

2 atria and one ventricles

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5
Q

what is the benefit of double circulation

A

increased number of circuits: pulmocutaneous and systemic; double circulation maintains higher blood pressure in the organs than single circulation

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6
Q

what are the characteristics of having 2 atria and 1 ventricle

A

because the ventricle only goes a partial way up, there is mixed blood that occurs, the oxygenated blood mixes with deoxygenated blood

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7
Q

what does an increased number of heart chambers do

A

it increases the separation of blood flow to the gas exchanged organs and to the rest of the body

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8
Q

how is the blood flow separated

A

deoxygenated blood flows to gas exchange organ (gills, skin, or lungs), while oxygenated blood flows to rest of the body (systemic)

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9
Q

what does an increased number of heart chambers permit

A

increased separation of blood flow to the gas exchange organs and to the rest of the body

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10
Q

what is gas exchange driven by

A

driven completely by diffusion

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11
Q

why are the walls of the left side of the heart thicker than the right side

A

the left side pumps blood throughout the whole body, the right side only pumps to the lungs

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12
Q

what is the lup sound of the heart

A

the AV valves shutting

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13
Q

what is the dup sound

A

the semilunar valves closing

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14
Q

what are the two phases of the cardiac cycle

A

diastole and systole

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15
Q

what is the diastole phase

A

the relaxation phase

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16
Q

what is the systole phase

A

the contraction phase

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17
Q

are the contractions and relaxations of the atria and ventricles synchronized or sequential

A

they are sequential. the atria contracts first then the ventricle

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18
Q

what does effective pumping of the heart require

A
  1. sequential contraction of chambers
  2. coordinated contractions muscle cells within chamber
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19
Q

what are the specialized cells that initiate action potentials and contractions

A

the sinoatrial node, atrioventricular node, bundle of his and purkinje fibers

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20
Q

what is the sinoatrial node/ what does it do

A

its the pacemaker of the heart. it controls the rate of heart contractions. no stimulus is required, it generates its own action potentials

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21
Q

what is the atrioventricular node/ what does it do

A

it delays the start of ventricular contractions (~0.1 seconds) controls the rate of atrial contraction

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22
Q

where is the SA node located

A

in the right atrium

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23
Q

where is the AV node located

A

top of atrial sphincter

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24
Q

what do the bundle of his and purkinje fibers do

A

they transmit action potentials to ventricle walls

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25
Q

does the contraction of the heart go from top down or bottom up

A

contractions take place bottom up in order to push the blood out of the heart

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26
Q

how do actin potentials in cardiac cells differ from those in neurons or skeletal muscles

A

in terms of kinetics and ion channels involved; cardiac muscle action potentials last 100x longer than regular muscles

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27
Q

what causes the plateau of the action potential in cardiac muscle

A

the calcium channels open

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28
Q

how does contraction end

A

it ends when Ca2+ is taken up by the sarcoplasmic reticulum

29
Q

how are contractions of muscle cells coordinated within chambers

A
  1. cardiac muscle cells are connected by gap junctions
  2. electrical continuity allows rapid spread of action potentials
  3. no gap junctions between atria and ventricles
30
Q

why are the atria and the ventricles able to synchronize their contractions

A

cell communication via gap junctions

31
Q

EKG waves reflect specific electrical events what do the letters mean on the graph

A

p: corresponds to depolarization and contraction of atria (SA node)

Q,R,S: corresponds to depolarization of ventricles (bundle of his and purkinje fibers)

T: corresponds to relaxation and repolarization of ventricles

32
Q

how does the nervous system control the heart rate

A

sympathetically and parasympathetically

33
Q

what is the sympathetic system

A

sympathetic nerves release (nor)epinephrine (adrenaline) which increases heart rate (fight or flight response)

34
Q

what is the parasympathetic system

A

parasympathetic nerves release acetylcholine. which decrease pacemaker activity, and slows the heart rate (rest and digest)

35
Q

how does the sympathetic system affect action potentials

A

norepinephrine increase permeability of Na+ and Ca2+ channels. the resting potential rises more quickly and action potentials are closer together

36
Q

how does the parasympathetic system affect action potentials

A

acetylcholine increase permeability of K+ and decreases the permeability of Ca2+ channels
the resting potential rises more slower and action potential are farther apart

37
Q

what are the 5 types of vessels

A

arteries, arterioles, capillaries, venules, veins

38
Q

function of arteries

A

carry blood away from heart

39
Q

function of arterioles

A

control distribution to specific capillary beds

40
Q

function of capillaries

A

site of exchange between blood and interstitial fluid

41
Q

function of venules

A

return blood to veins

42
Q

function of veins

A

returns blood to the heart

43
Q

why are is the smooth muscle and connective tissue thicker on the arteries than on the vein

A

a lot thicker on the artery due to pressure form the heart. most has the pressure has decreased by the time the blood gets to the veins

44
Q

how thick are the capillaries

A

one endothelial cell thick

45
Q

what occurs in the capillaries

A

the site where exchange of blood and surrounding fluid is occurring

46
Q

what is the structure of the arteries and arterioles

A

they have elastic fibers, enabling them to withstand high pressures

have smooth muscle cells allowing them to contract and expand, alter their resistance and thus blood flow

47
Q

what is the structure of veins

A

veins have valves to prevent backflow of blood

48
Q

what is the local regulation of blood pressure

A

metabolite and waste affect flow to specific tissues

49
Q

what is the systemic regulation of blood pressure

A

responses to changes in central blood pressure and is medicated by hormonal signals

50
Q

systemic control of blood pressure gives rise to the sympathetic and parasympathetic nervous system. what does it do in terms of the sympathetic system

A

smooth muscles contract, constrict vessels, increases blood pressure and decreases blood flow. (exception = skeletal muscle)

51
Q

systemic control of blood pressure gives rise to the sympathetic and parasympathetic nervous system. what does it do in terms of the parasympathetic system

A

it relaxes smooth muscle, increase blood flow and decreases blood pressure

52
Q

what controls the direction and identify of material movement between blood and interstitial fluid

A

direction of fluid movement is controlled by balance between blood pressure and osmotic pressure

53
Q

is osmotic pressure higher or lower than blood pressure when approaching the veins

A

osmotic pressure stays constant throughout. it becomes higher than the blood pressure when blood pressure decreases below the constant osmotic pressure

54
Q

does blood pressure increase or decrease as it flows from arteries to veins

A

blood pressure decreases as it flows from the arteries to the veins

55
Q

what are the capillaries permeable to

A

O2, CO2, glucose, lactate and small ions

56
Q

how are veins able to get blood back to the heart

A

skeletal muscle contractions and gravity help veins and lymphatic vessels carry blood and fluid back to the heart

valves prevent back flow

57
Q

when moving from the arteriole toward the venule end of the capillary beds what happens to the fluid

A

net fluid loss at the arterial side exceeds fluid uptake at the venous side

58
Q

what is happening with the blood and osmotic pressure on the venous side

A

osmotic pressure is higher than the blood pressure on the venous side, so that creates a net pressure that sucks fluid back into the vein

59
Q

what is happening with the blood and osmotic pressure on the arteriole side

A

blood pressure is higher than the osmotic pressure on the arteriole side therefore that creates a net pressure of pushing fluid out of the artery.

60
Q

does fluid flow in or out on the venous side

A

fluid flow in

61
Q

does fluid flow in or out on the arteriole side

A

fluid flows out

62
Q

does osmotic pressure decrease as it flows down

A

no, osmotic pressure stays constant

63
Q

does blood pressure increase as it flows down

A

no, blood pressure deceases as it goes down

64
Q

what is the challenge of the circulatory system

A

transport gases efficiently via liquid medium despite low solubility of gas in liquid

65
Q

what are the mechanisms for increasing efficiency of circulatory system

A
  1. gas exchange surfaces in lungs (alveoli- large surface areas)
  2. increase o2 capacity of blood by specializing red blood cells (large surface area due to biconcave shape)
  3. efficient removal of co2 from tissues
66
Q

why is hemoglobin important for efficiency of o2

A

it allows 60 times more o2 to be carried

67
Q

how much oxygen is release during normal metabolism

A

only 25% of O2 is released during rest, 75% is reserved. the rest of it gets released during exercise

68
Q

what is the process for red blood cells to be produced when oxygen levels are low

A

If too low, HIF-1 is introduced. that induces the kidney to produce erythropoietin which stimulates stem cells in the bone marrow to produce red blood cells. which increases oxygen supply in tissues

MCDB 1B (9 decks)

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