L26 Fundamentals of Cardiovascular and Renal Physiology Flashcards

1
Q

what is important to note after deoxygenated blood has exited alveoli capillaries?

A

it is still relatively high in oxygen

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2
Q

what happens blood flow in increased temperatures?

A

blood flow increases, loses heat at skin surface, sweating

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3
Q

how is blood flow physically regulated?

A

vasodialation(encourages flow) and constriction(limits flow) of arterioles (away from heart)

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4
Q

what are sphincters?

A

present in capillaries, when relaxed blood flows easily through all capillaries

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5
Q

when are sphinchters contracted?

A

when we don’t require as much blood flow to our tissues example sitting down

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6
Q

where is water found in the body?

A

2/3 within cells, 1/3 outside in plasma and interstitial fluid

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7
Q

what 2 systems compose the circulatory system?

A

cardiovascular system(heart and blood vessels) and lymphatic system

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8
Q

where are lympathic capillaries?

A

surrounding blood/ cardiovascular capillaries

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9
Q

why are lympathic vessels and capillaries ‘blind ending’?

A

they bring lymph fluid to subclavian vein which joins with vena cava - returning it to cardiovascular system

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10
Q

what does the lymphatic system do?

A

drains fluid from tissue and returns leaked plasma to blood vessels, also absorbs digested fats and acts as immune defence via lymph nodes

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11
Q

what would happen without lymphatic system?

A

20L of blood loss a day by capillaries, lymphatic system returns 3L a day

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12
Q

how does fluid leak from capillaries?

A

Starling Law/ Forces

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13
Q

what is the Starling Law?

A

narrow thin walled capillary - blood pressure exerts against walls causing leakiness

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14
Q

20L of blood lost a day due to Starling Law, 3L returned by lymphatic system, what about the rest?

A

17L returned by plasma proteins and osmotic pressure

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15
Q

what is oedema?

A

build up of fluid in tissues
known as hypoxia if it occurs in lungs
-can occur from lack of plasma proteins (dysfunctional kidney and liver)
or by increased capillary permeability caused by histamine

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16
Q

how are kidneys involved in osmoregulation?

A

regulate composition of plasma

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17
Q

what is urine?

A

filtered plasma?

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18
Q

what is the kidney’s primary function

A

filtering blood, urine is just a by-product

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19
Q

Describe how Kidneys filter the blood

A

1) Filtration - blood is filtered, filtrate is formed
2) filtrate undergoes reabsorption
3) filtrate undergoes secretion (non-essential solutes and wastes added)
4) excretion - exits body as urine

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20
Q

what does the kidney consist of?

A

cortex(outer), medulla(inner), renal artery and vein

21
Q

what are nephrons?

A

individual functional units within the kidney that allow filtration of blood

22
Q

what is Bowman’s capsule?

A

it contains a network of capillaries known as glomerulus which allows filtration

23
Q

where does blood enter kidney’s nephrons?

A

it enters via renal arter into afferent arteriole into the glomerulus

24
Q

Describe the process of blood filtration

A

1) blood enters glomerulus capillary network and undergoes filtration
2) efferent arteriole leaves glomerulus, filtrate goes through nephron’s proximal convoluted tubule
3) filtrate goes through loop of Henle (descending followed by ascending limb)
4) filtrate goes through distal tubule and into collecting duct

25
is the capillary system containing blood, separate from filtrate system in nephron?
YES, diffusion between pathways takes place
26
what does the filtrate contain in Bowman's capsule?
water, salts, glucose, amino acids, nitrogenous waste, vitamins
27
what does the proximal tubule reabsorb?
ions, water and nutrients
28
what does descending loop of henle absorb?
water through aquaporin channels
29
what happens in ascending loop of henle?
salt diffusion/ reabsorption - filtrate is v dilute
30
what happens in distal tubule?
K+ and NaCl, H+ and HCO3- concentrations are regulated, pH regulation of blood
31
what happens in collecting duct?
filtrate is carried through medulla to renal pelvis and reabsorption of solutes and water occurs
32
urine is hyperosmotic to body fluids what does this mean?
there is less water in it compared to blood plasma
33
what are aquaporins?
water holes
34
what regulates the kidney function?
endocrine and nervous system
35
what part of blood filtration in kidney requires active transport?
1) proximal tubule (H+, HCO3-, K+) 2) ascending loop of henle (NaCl) 3) distal tubule (NaCl, K+, H+, HCO3-) 4) collecting duct (NaCl)
36
what molecule/fluid only requires pasisve transport during blood filtration in the kidneys nephrons?
H2O and urea
37
what hormones from endocrine system effect blood filtration in kidneys?
ADH/ vasopressin
38
where is ADH secreted?
posterior pituitary gland
39
what effect does ADH have on blood filtration?
modifies water absorption, increases presence of aquaporins in collecting duct - reduces water urine volume
40
what happens when ADH is inhibited by alcohol?
increased volume of dilute urine - dehydration
41
what happens when there is too much water being reabsorped into blood?
posterior gland inhibits production of ADH
42
how does ADH activate aquaporin formation?
1) ADH binds to receptor of collecting duct cell membrane 2) cAMP secondary messenger is activated 3) cAMP activates PKA 4) PKA activates storage vesicles containing aquaporins to bind with membrane via exocytosis
43
what happens when osmolarity increases above a set point?
positive negative feedback - osmoreceptors in hypothalamus detect change and ADH secretion increases
44
what is high blood osmolarity?
blood has higher solute content - not as dilute
45
when does the blood have high osmolarity?
after profuse sweating
46
when does the blood have low osmolarity?
after drinking a lot of water
47
what are major contributors to blood pressure?
blood osmolarity and blood volume
48
when monitoring blood pressure when do you recieve lowest pressure?
when the sound is no longer audible in stethoscope - pressure in cuff is below 70mmHg
49
when monitoring blood pressure when do you recieve highest pressure?
when you can hear audible stethoscope, pressure in cuff drops just below 120mmHg