Vascular Physiology Flashcards

1
Q

blood

A

-mostly made of water
-if you were to put blood in a test tube and let it sit, you would see the blood cells fall to the bottom that are called the hematocrit
-above it is the water which makes up a large % of the plasma as well as proteins like albumin, globulin, and fibrinogen
-RBC, WBC, and platelets

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2
Q

hemodynamics

A

-pressure = flow x resistance or delta P = Q x R where Q is the heart when it squeezes (cardiac output), R is the vessels constricting or dilating, and P is the blood pressure

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3
Q

cardiac ouput

A

stroke volume x heart rate and it defines the heart squeezing or relaxing

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4
Q

anatomy of the cardiovascular system

A

comprised of the heart, pulmonary circulation, and systemic circulation

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5
Q

pulmonary circulation

A

-heart pumps blood —> lungs —> comes back oxygenated
-heart pumps red blood —> body —> comes back deoxygenated
-blood flow, gas exchange, and one of the carriers of gas exchange is the hepatic vein

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6
Q

what is gas exchange and where does gas exchange occur?

A

occurs across capillaries and it is when blue blood loses CO2 and gains O2 in the lungs

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7
Q

gas exchange

A

-oxygen enters the lung into grape-like structures called alveolus
-oxygen diffuses across the alveoli and goes into the blood

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8
Q

oxygen and hemoglobin

A

oxygen gets dissolved in water at low level but combines with hemoglobin at higher level —> RBCs diffuse

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9
Q

systemic circulation

A

-blood flow of oxygenated blood
-LV pumps oxygenated blood to the tissues of the body
-O2 is unloaded by the RBCs

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10
Q

oxygen transport

A

oxygen in air —> lungs —> blood —> peripheral tissues

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11
Q

vascular histology

A

blood vessels all have the same 3 layers but depending on where you are in body, some may have more of one layer compared to another

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12
Q

3 layers of vessels

A
  1. adventitia
  2. media
  3. intima
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13
Q

intima

A

endothelial cells with internal elastic lamina

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14
Q

media

A

-in the middle of the vessel walls
-smooth muscle cells with external elastic lamina

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15
Q

adventitia

A

-outside of the vessel
-composed of smooth muscle cells and connective tissue
Ex. strong, powerful arteries have a lot of smooth muscles where the media is big but weak veins have only a little bit of smooth muscle

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16
Q

different types of vessels

A

arteries, capillaries, and veins

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17
Q

arteries

A

-deliver blood to the periphery
-on a graph showing the bp vs the different types of vessels, you see the biggest drop in BP across the arterioles
-arteries, particulary arterioles, regulate blood flow into the capillaries

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18
Q

arterioles

A

very small blood vessels that branch off of arteries and carry blood from heart to peripheral tissues

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19
Q

capillaries

A

-thin-walled vessels with pores
-diffusion and gas exchange occurs across them
-red blood from heart and blue blood to heart with the connection being the capillaries
-BP is continuing to drop as you go from left to right

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20
Q

what happens as you go from left to right in capillaries?

A

-from left, you have the fluid being pushed out like water and the ions go with it
-as the blood gets closer to the venuoles the fluid and waste products come in

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21
Q

what two principles does fluid move across the capillaries?

A

hydrostatic pressure and oncotic pressure

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22
Q

hydrostatic pressure

A

pressure pushing the fluid out

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23
Q

oncotic pressure

A

when water gets drawn out against the concentration gradient, a lot of the proteins are left in the capillary with less water so this pressure causes the water to get sucked back in

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24
Q

what type of movement of fluid do you have at the start of the capillary and at the end?

A

net movement

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25
Q

starling’s law

A

-the heart stroke’s volume increases as the volume of blood in the ventricles increases
-the hydrostatic and oncotic pressure gradients must be equal and opposed

26
Q

what happens as we travel left to right in capillaries?

A

O2 is going to tissues because you have a lot of oxygen in the beginning and flows down the gradient then at the end there is a lot of CO2 in the tissues

27
Q

peripheral arterial disease

A

-this occurs when the blood vessels narrow
-less blood gets delivered to the leg —> less O2, glucose, and nutrients and you have waste buildup
-must have an operation to deliver the blood

28
Q

veins

A

-transport blood from the periphery back to the heart
-venuoles converge to become veins, which becomes one large vena cava
-2/3 of blood supply sit in veins and move back

29
Q

venous disease

A

if the veins do not work, the blood builds up in the legs and backs up the capillaries —> skin in legs starts to slowly break down

30
Q

lymphatic system

A

-collects waste
-when fluid flows out of capillaries to tissues, it has to go somewhere and it goes to this sewage system
-vessels that drain out of tissues and empty to bloodstream
-thin-walled, easily damaged vessels

31
Q

how does the lymphatic system work?

A

-as the heart pumps blood out and the fluid leaks out of capillaries, it gets picked up by lymph nodes
-while the nodes are collecting waste and water, they’re also collecting pathogens and viruses

32
Q

filaraisis

A

-small worm can infect people through a mosquito bite
-goes into the lymphatic system and blocks it —> if you get it in your leg, it can swell from backup

33
Q

regulation of blood flow

A

-blood vessels are always relaxing and dilating at the same time
-forces that are vasodilating and vasoconstricting are opposing each other

34
Q

what are the three parts of regulating blood flow?

A
  1. brain- neuronal
  2. kidney- hormonal
  3. arterioles- local
35
Q

integrated regulation of blood flow

A
  1. sensors —> brain —> nerves —> heart and blood vessels
  2. sensors —> kidney —> hormones —> heart and blood vessels
  3. sensors —> tissues —> local factors —> heart and blood vessels
36
Q

blood flow for brain

A

receptors —> afferent nerves —> brainstem —> efferent nerves —> vascular response

37
Q

how does the brain control blood flow?

A

-does this through the autonomic nervous system — > involuntary control
-autonomic is divided between the sympathetic and parasympathetic nervous systems
-driven by brain sending out nerves to body
-center in the brainstem called the vasomotor center, which sends out messages to all parts of the body
-brain gets messages from the body about blood pressure and other sensors to control blood flow

38
Q

baroreceptor regulation of blood flow

A

-baroreceptors sense pressure
-BP goes up —> carotid sinus baroreceptor senses it —> afferent nerves —> brain —> autonomic nervous system —> efferent nerves —> decrease the vasoconstriction and HR and contractility —> decrease in BP

39
Q

patient in ER with high BP

A

touch the carotid arteries to fool them into thinking the BP is high and turns on the parasympathetic nervous system and brings down BP

40
Q

chemoreceptor regulation of blood flow

A

aorta, carotid, or medulla —> decreased O2 or increased CO2 —> chemoreceptors —> brain —> ANS —> vasoconstrict, increase the HR, and increase respiration

41
Q

hormonal regulation of blood flow

A

vasoconstrictors and vasodilators

42
Q

vasoconstrictors

A

substances that cause blood vessels to narrow or constrict
Ex. adrenal gland- epinephrine and cortisol, kidneys- renin, and pituitary- vasopressin (ADH)

43
Q

vasodilators

A

open blood vessels and allow blood to flow more easily through the body
Ex. tissues (local regulators) like hypoxia, CO2, adenosine, bradykinin, histamine, and serotonin

44
Q

kidney’s function in regulating blood flow

A

-kidney senses BP is down —> releases hormone
-kidney releases renin —> angiotensinogen —> renin acts on angiotensinogen to create angiotensin I —> angiotensin-converting enzyme from the lungs acts on angiotensin I to form angiotensin II, a potent vasoconstrictor

45
Q

role of angiotensin II

A

acts directly on blood vessels and adrenal gland to stimulate the release of aldosterone, which tells the kidneys to urinate less and save water/salt long-term

46
Q

local mediators of vessel tone

A

-divided between vasodilators and vasoconstrictors
-vasodilators are nitric oxide (NO) and tissues
-vasoconstrictors are peptides like endothelins and angiotensin as well as arachadonic acid like EDHP and thromboxane

47
Q

local regulation of blood flow: vasodilation

A

metabolic demands —> decreased O2, increased CO2, adenosine, and other mediators —> vasodilation

48
Q

local vasodilation

A

-endothelial cells control vasodilation
-NO diffuses out of cells into media and activates mediators that cause relaxation like cGMP
-NO is a free radical, highly reactive with a short half-life and diffuses across membranes

49
Q

what does NO do?

A

binds to other oxygen radicals and is made by the enzyme nitric oxide synthase
-amino acid and oxygen —> another amino acid and NO, which is made by ripping off electrons on NADPH and dumping them
-if you have endothelial cells that don’t work, then you have issues with vasodilation since NO is a vasodilator

50
Q

NO is a vasodilator for the smooth muscle cell

A

-NO enters muscle cells and turns on a signalling cascade
NOS —> NO —> activates guanylate cyclase, which makes cGMP leading to kinases that make the smooth muscle cell relax

51
Q

NO protects vessels

A

-NO is a vasodilator, anti-thrombotic, and anti-inflammatory
-acts on platelets, smooth muscle, and lymphocytes

52
Q

physiological role of NO

A

-produced by blood vessels and drugs
-dilates blood vessels
-protects blood vessels from disease
-loss of NO predisposes to atherosclerosis

53
Q

local regulation of blood flow: vasoconstriction

A

metabolic demands —> endothelin, angiotensin II, superoxide, EDHF, and thromboxane —> vasoconstriction

54
Q

hemorrhage

A

-heart rate is up, BP is down, and your vessels constrict to keep BP up (resistance would increase)
-mechanisms by which body senses BP is down and tries to get it up
-less blood in heart —> cardiac output goes down

55
Q

what do baroreceptors do when the body senses BP is down?

A

they send messages to the brain and the brain tells vessels to constrict (increase resistance) and kidney kicks in and makes angiotensin leading to alderosterone

56
Q

hypotension

A

when the BP is really low and the body can’t compensate

57
Q

what can cause hemorrhages?

A

-loss of blood
-heart not working from heart attack
-issue with brain
-sepsis

58
Q

sepsis and NO

A

-NO kills pathogens like viruses, bacteria, atypical bacteria, fungi, and parasites
-NO acts an immune effector by killing the bacteria
-need tons of NO to kill the bacteria but a large amount can cause vasodilation (decreases resistance) and BP goes down

59
Q

hypertension

A

-brain and kidney have determined that normal BP is 120/80
-in hypertension, the kidney has gone rogue and decided that the BP should be higher than 120/80
-senses that the normal BP is low so kidney releases angiotensin and aldosterone —> kidney holds on to more salt and water then BP goes up

60
Q

atherosclerosis

A

-disease of the arteries
-high cholesterol can lead to this which can lead to heart attacks
-damaging epithelial cells can lead to damaging the blood vessels

61
Q

endothelial disfunction in atherosclerosis

A

endothelium is damaged and becomes inflamed —> white blood cells adhere to it then inflammatory cells come in and suck up the cholesterol —> vessels wall off by scarring —> inside of blood vessels fills up with lipids and if it ruptures the vessels become blocked