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MCAT biology > anatomy and physiology of circulatory system (heart and blood) > Flashcards

anatomy and physiology of circulatory system (heart and blood) Flashcards

1
Q

arteries carry blood?

A

away from the heart at high pressure

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2
Q

veins carry blood?

A

towards the heart at low pressure

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3
Q

arteries branch into?

A

arterioles

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4
Q

arterioles pass into?

A

capillaries which are only wide enough for a single blood cell to pass at a time

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5
Q

after blood passes through capillaries, it passes through?

A

venules

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6
Q

venules pass back into?

A

veins

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7
Q

all exchange of materials in the blood happen where?

A

capillaries

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8
Q

the walls of blood vessels are what type of cell?

A

endothelial cells

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9
Q

vasodilation/vasoconstriction is when?

A

secretion of substances (like nitric acid) and endothelium regulate vessel diameter to maintain blood pressure, tissue oxygenation, and thermoregulation

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10
Q

inflammation is when?

A

release of inflammatory chemicals from injured tissues stimulate endothelial cells to increase their expression of adhesion molecules which allow WBC to adhere to the endothelial cell to enter injured tissue

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11
Q

angiogenesis is?

A

then formation of new blood vessels
ex: many tumors secrete angiogenic growth factors to increase blood supply thus angiogenesis inhibitors are drugs used to restrict blood flow to tumors

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12
Q

thrombosis is?

A

blood clotting

*undamaged endothelial cells secrete substances to inhibit coagulation to prevent life-threatening clots

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13
Q

pulmonary circulation is defined as?

A

flow of blood from the heart to the lungs and back to the heart

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14
Q

systematic circulation is defined as?

A

flow of blood from the heart to the rest of the body and back again

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15
Q

one exception to circulation system is the hepatic portal system, which is when?

A

blood passes first through capillaries in the intestine, the collects in veins to travel to the liver where the vessels branch and blood passes again through capillaries
*important for nutrients directly from intestine to liver

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16
Q

second exception to circulation system is the hypothalamic-hypophysial portal system, which is when?

A

blood passes through capillaries in the hypothalamus to the portal veins, then to capillaries in the pituitary
*important for hormones from hypothalamus directly to pituitary

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17
Q

atrioventricular valves are located?

A

between each atrium and ventricle

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18
Q

the AV valve between the left atrium and left ventricle is the?

A

bicuspid/mitral valve

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19
Q

the AV valve between the right atrium and right ventricle is the?

A

tricuspid valve

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20
Q

the semilunar valve between right ventricle and pulmonary artery is?

A

pulmonary semilunar valve

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21
Q

the semilunar valve between left ventricle and aorta is?

A

aortic semilunar valve

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22
Q

what happens during diastole?

A

ventricles are relaxed and atria contract

blood is able to flow into ventricles from the atria

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23
Q

what happens during systole?

A

ventricles contract and atria relaxed
blood is pushed out of ventricles towards pulmonary artery or aorta
*lub dup sound

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24
Q

heart rate/pulse is the?

A

number of times the “lub-dup” cardiac cycle is repeated per minute

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25
stroke volume is?
the amount of blood pumped with each systole
26
cardiac output is?
the total amount of blood pumped per minute
27
the heart is what type of muscle?
cardiac muscle (involuntary)
28
the cardiac muscle is functional syncytium, meaning?
that the tissues' cytoplasms communicate via gap junctions
29
gap junctions of the cardiac muscle are found in?
intercalated disks which is the connection between cardiac and muscle cells
30
the initiation of each action potential to start each cardiac cycle occurs automatically within the heart itself by?
the SA node located in right atrium
31
the SA (sinoatrial) node acts as a?
pacemaker and is divided into three phases
32
membrane potential in cardiac muscle cell | phase 0 is depolarization, what happens?
AP simulates myocytes to reach threshold causing the fast Na+ channels open Na+ influx
33
membrane potential in cardiac muscle cell | phase 1 is initial repolarization, what happens?
Na+ channels inactivate and K+ channels open causing | K+ efflux
34
membrane potential in cardiac muscle cell | phase 2 is plateau, what happens?
the Na+ influx from phase 0 causes Ca2+ channels to open, so Ca2+ influx K+ channels are still open so K+ efflux are balanced leading the equilibrium
35
membrane potential in cardiac muscle cell | phase 3 is repolarization, what happens?
Ca2+ channels close but K+ remain open for K+ efflux
36
membrane potential in cardiac muscle cell | phase 4 is resting membrane potential, what happens?
inward and outward are equal thus K+ closes
37
the SA node spreads throughout the atria causing them to ?
contract and fill ventricles
38
the SA node triggers the AV node which?
continues electrical impulse to the AV bundle (bundle of His)
39
the AV bundles divided into what two sections?
left bundle branches and purkinje fibers
40
why does the AV bundles divide into left bundle branches and purkinje fibers?
to allow impulse to spread rapidly and evenly over both ventricles
41
what controls the SA node?
the vagnus nerve which the preganglionic axons of it synapose in the ganglia near the SA node
42
what neurotransmitter is released by the vagus nerve to inhibit depolarization by binding to receptors on the cells of the SA node?
acetylcholine
43
hemodynamics is?
the study of blood flow
44
what is the driving force of blood flow?
difference in pressure from arteries to veins
45
blood pressure is systemic arterial pressure is, this is the measurement of?
force per unit area exerted by blood upon the walls of arteries
46
the typical bp is 120/80 where the numbers mean?
120mmHg is the systolic pressure which is the highest pressure that ever occurs in the circulatory system 80mmHg is the diastolic pressure which is the lowest pressure that ever occurs in the circulatory system
47
what measures blood pressure?
sphygmomanometer
48
local auto-regulation is the process known as?
when tissues in need of extra blood flow are able to requisition it themselves
49
blood is composed of?
plasma and formed elements
50
plasma accounts for 54% of blood volume is consists of what items?
electrolytes, buffers, sugars, blood proteins, lipoproteins, co2, o2, and metabolic waste
51
buffers in the blood are there to? what is the primary one?
maintain a constant pH of 7.4 bicarbonate (HCO3-) via the reaction CO2+H2O=H2CO3=HCO3-+H+
52
the electrolytes of the blood are?
sodium, potassium, chloride, calcium, and magnesium
53
the blood protein, albumin is for?
maintenance of oncotic pressure which is the osmotic pressure in capillaries from plasma proteins
54
the blood protein, immunoglobulins are for?
immune system
55
the blood protein, fibrinogen is for?
blood clotting (hemostasis)
56
lipoproteins of the blood are particles consisting of?
fats, cholesterol, and carrier proteins
57
the main metabolic waste product of blood is?
urea which is essentially a carrier of excess nitrogen
58
bilirubin is another blood waste product which is used for?
breakdown product of heme
59
what is another term for RBC?
erythrocytes
60
when centrifuged, the volume of blood that only has RBC is called the? and is what % of whole blood?
hematocrit - 45%
61
what is another term for WBC?
leukocytes
62
leukocytes and platelets make up what % of blood volume?
1%
63
what hormone stimulates RBC production? and where does this production take place?
erythropoeitin (hormone from kidney) | production in the bone marrow
64
RBC lack a mitochondria thus rely on what for ATP synthesis?
glycolysis
65
the purpose of RBC are to?
transport o2 to tissues from the lungs and co2 from tissues back to the lungs
66
what shape are typical RBC? why?
flat and biconcave to increase surface area of hemoglobins to bind to oxygen
67
what is blood type based on?
presence or absence of specific antigens
68
what are the two most important blood antigen groups?
ABO blood group | Rh blood group
69
hemolytic disease of the newborn/erythroblastosis fetalis is when?
mother is Rh- and carrying a Rh+ baby
70
a person with A+ blood will produce what type of antibodies?
anti-B antibodies so that it will clump and destroy B cells
71
granulocytes are class of WBC including?
neutrophils, eosinphil, and basophil
72
lymphocytes are class of WBC including?
T cells and B cells
73
monocytes are class of WBC including?
macrophages
74
what WBC is phagocytic to bacteria and creates pus?
neutrophils
75
what WBC is the most abundant?
neutrophils
76
what WBC destroys parasites and are modulators to allergic reactions?
eosinophils
77
what WBC stores and releases histamine for allergic reactions and attracts other WBC to inflamed sites?
basophils
78
what WBC is the rarest?
basophils
79
what WBC mature into plasma cells that produce antibodies?
B cells
80
what WBC control immunity and attack virus infected cells/tumor cells?
T cells
81
what WBC is phagocytic to debris and microorganisms and activate lymphocytes (T and B cells)?
macrophages
82
what WBC is the largest in size?
macrophages
83
platelets are small fragments of what?
megakaryocytes, which are derived from thrombopoietin
84
the purpose of platelets are to?
aggregate at site of damage to a blood vessel wall to for platelet plug to stop bleeding and activate other clotting factors
85
when none of the four subunits of hemoglobin are bound to, what confirmation happens? and what is the affinity?
tense and has low affinity for o2 | when o2 does bind, it becomes relaxed and affinity increases
86
hemoglobin binds oxygen cooperatively, meaning?
the confirmation change in one subunit, activates the affinity for other subunits to bind
87
bohr effect happens when what factors stabilize tense hemoglobin and reduce oxygen affinity?
decreased pH, increase Pco2, and increased temperature
88
what are the three ways carbon dioxide is transported in the blood?
conversion of co2 to carbonic acid which dissociates into bicarbonate and proton by carbonic anhydrase enzyme (73%) being stuck to hemoglobin by binding to other sites on the protein (20%) co2 is water soluble therefore dissolve in blood more so than o2 does (7%)

MCAT biology (13 decks)

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