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MCDB 1B > Circulatory System > Flashcards

Circulatory System Flashcards

(68 cards)

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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
does the contraction of the heart go from top down or bottom up
contractions take place bottom up in order to push the blood out of the heart
26
how do actin potentials in cardiac cells differ from those in neurons or skeletal muscles
in terms of kinetics and ion channels involved; cardiac muscle action potentials last 100x longer than regular muscles
27
what causes the plateau of the action potential in cardiac muscle
the calcium channels open
28
how does contraction end
it ends when Ca2+ is taken up by the sarcoplasmic reticulum
29
how are contractions of muscle cells coordinated within chambers
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
why are the atria and the ventricles able to synchronize their contractions
cell communication via gap junctions
31
EKG waves reflect specific electrical events what do the letters mean on the graph
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
how does the nervous system control the heart rate
sympathetically and parasympathetically
33
what is the sympathetic system
sympathetic nerves release (nor)epinephrine (adrenaline) which increases heart rate (fight or flight response)
34
what is the parasympathetic system
parasympathetic nerves release acetylcholine. which decrease pacemaker activity, and slows the heart rate (rest and digest)
35
how does the sympathetic system affect action potentials
norepinephrine increase permeability of Na+ and Ca2+ channels. the resting potential rises more quickly and action potentials are closer together
36
how does the parasympathetic system affect action potentials
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
what are the 5 types of vessels
arteries, arterioles, capillaries, venules, veins
38
function of arteries
carry blood away from heart
39
function of arterioles
control distribution to specific capillary beds
40
function of capillaries
site of exchange between blood and interstitial fluid
41
function of venules
return blood to veins
42
function of veins
returns blood to the heart
43
why are is the smooth muscle and connective tissue thicker on the arteries than on the vein
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
how thick are the capillaries
one endothelial cell thick
45
what occurs in the capillaries
the site where exchange of blood and surrounding fluid is occurring
46
what is the structure of the arteries and arterioles
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
what is the structure of veins
veins have valves to prevent backflow of blood
48
what is the local regulation of blood pressure
metabolite and waste affect flow to specific tissues
49
what is the systemic regulation of blood pressure
responses to changes in central blood pressure and is medicated by hormonal signals
50
systemic control of blood pressure gives rise to the sympathetic and parasympathetic nervous system. what does it do in terms of the sympathetic system
smooth muscles contract, constrict vessels, increases blood pressure and decreases blood flow. (exception = skeletal muscle)
51
systemic control of blood pressure gives rise to the sympathetic and parasympathetic nervous system. what does it do in terms of the parasympathetic system
it relaxes smooth muscle, increase blood flow and decreases blood pressure
52
what controls the direction and identify of material movement between blood and interstitial fluid
direction of fluid movement is controlled by balance between blood pressure and osmotic pressure
53
is osmotic pressure higher or lower than blood pressure when approaching the veins
osmotic pressure stays constant throughout. it becomes higher than the blood pressure when blood pressure decreases below the constant osmotic pressure
54
does blood pressure increase or decrease as it flows from arteries to veins
blood pressure decreases as it flows from the arteries to the veins
55
what are the capillaries permeable to
O2, CO2, glucose, lactate and small ions
56
how are veins able to get blood back to the heart
skeletal muscle contractions and gravity help veins and lymphatic vessels carry blood and fluid back to the heart valves prevent back flow
57
when moving from the arteriole toward the venule end of the capillary beds what happens to the fluid
net fluid loss at the arterial side exceeds fluid uptake at the venous side
58
what is happening with the blood and osmotic pressure on the venous side
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
what is happening with the blood and osmotic pressure on the arteriole side
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
does fluid flow in or out on the venous side
fluid flow in
61
does fluid flow in or out on the arteriole side
fluid flows out
62
does osmotic pressure decrease as it flows down
no, osmotic pressure stays constant
63
does blood pressure increase as it flows down
no, blood pressure deceases as it goes down
64
what is the challenge of the circulatory system
transport gases efficiently via liquid medium despite low solubility of gas in liquid
65
what are the mechanisms for increasing efficiency of circulatory system
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
why is hemoglobin important for efficiency of o2
it allows 60 times more o2 to be carried
67
how much oxygen is release during normal metabolism
only 25% of O2 is released during rest, 75% is reserved. the rest of it gets released during exercise
68
what is the process for red blood cells to be produced when oxygen levels are low
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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