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FS Exam 4 > Special Circulations > Flashcards

Special Circulations Flashcards

1
Q

Where do you see Active VD response

A

skin muscle = high

kidney = low - at rest is already maximally dilated

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2
Q

Muscle - What happens to CO with exercise

A

increases

20-25 L/min with exercise

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3
Q

Muscle - Where is most of CO going with exercise

A

to muscle - 80 to 85% of it
As inc exercise intensity - CO to viscera diminishes
As inc exercise intensity - CO to heart and brain stays the same
As inc exercise intensity - CO to skin increases and then kind of narrows off

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4
Q

Muscle - Weight

A

30kg

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5
Q

Muscle - At rest receives how much blood flow? and with exercise?

A 
Rest = 2-4 ml/min or 15-20% of CO
Exercise = 400 ml/min or 85% of CO
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6
Q

Maximal amount of flow that muscle can receive in limited buy

A

Cardiac Output

If didn’t matter, would want CO of 90L/min - this would rupture aorta

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7
Q

If we activate sympathetic NS

A

Decrease in blood flow of about 70-80%

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8
Q

If block sympathetic NS

A

Would see double or tripling in BF from rest

Inc 200-300%

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9
Q

Fibers types and blood flow

A

The more oxidative the tissue, the more flow that it will get

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10
Q

Capillaries with muscle

A

Very dense capillary unit, only heart has mroe
density of this matches the oxidative potential of the fiber
with exercise training = inc in number of capillaries per muscle fiber and inc mitochondria

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11
Q

Blood flow control has both neural and local component in skeletal muscle

A

Contains both alpha and beta ARs (alpha= constrict, beta = dilate) and with this alpha wins

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12
Q

Blood flow control has both neural and local component in skeletal muscle - Neural

A

EPI and NE = cause VD of muscle by binding to beta

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13
Q

Blood flow control has both neural and local component in skeletal muscle - Local

A

Metabolic vasodilation

And shear stress and muscle pump

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14
Q

How does blood flow to muscle increase during exercise

A

Muscle has greatest absolute increase in total NE spillover - we have overshadowed the inc in SNA during exercise, as you inc exercise you are inc spill over
Functional Sympatholysis - overshadow SNA during exercise

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15
Q

Splanchnic weight

A

Weight = 1.5 kg

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16
Q

Liver receives blood from

A

Hepatic Artery

Portal Vein

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17
Q

Haptic Artery vs. Portal Vain

A

Hepatic artery has autoregulatory mechs

Portal vein does not (more ANS)

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18
Q

Splanchnic Circulation - Extrinsic

A

Highest density of Alpha - can constrict down very well
Highest density of Beta too - during stress will VD
NO PARASYMP HERE

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19
Q

Splanchnic - Redistribution of flow

A

Splanchnic circulation is a huge resdistributor of blood flow

  • it receives high BF
  • has little metabolic activity - doesnt really need the flow so is the best place to take it away from
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20
Q

Splanchnic circulation and compliance

A

It is very compliant
Compliance primarily impacts venous circulation
27% of CO
Max flow = 2.5L/mn

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21
Q

Other that is very compliant?

A

Skin
9% of CO
Max flow = 8 L/min

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22
Q

Splanchnic and Skin

A

Will accommodate large change in volume with a very small pressure

23
Q

If you constrict Splanchnic or Skin

A

Upstream pressure will inc
Downstream pressure will dec - this drop in pressure will mobilize a large amount of flow - this is what initially happens during exercise

24
Q

If you constrict muscle

A

You aren’t mobilizing hardly any flow - it is not as compliant

25
Q

Compliant circulation - if you dilate a compliant circulation you will

A

dec SV and venous return back to the heart

26
Q

Compliant circulation - if you constrict a compliant circulation you will

A

you are liberating more volume back to heart - it inc venous return, SV and CO
When flow goes back through circulation again (from heart) will go to where least resistance - the muscle

27
Q

Constriction of compliant vessels

Dilation of noncompliant vessels

A

VC of compliant –> inc flow back to heart
After you will get less flow back to the constricted area and more flow back to the dilated - noncompliant area - more flow and more pressure here

28
Q

Constriction of noncompliant vessels

Dilation of compliant vessels

A

Flow gets caught up in the dilated compliant vessel and less will go back to the heart

29
Q

Basic Renal Process

A

Filters
Secretes
Reabsorbs

30
Q

Renal Circulation: Blood Flow -

A

Highly overperfused

31
Q

Renal Circulation - Resting Blood Flow, Max Blood Flow

A

Resting = 1.2 L/min = 22% CO

Max blood flow = 1.2 L/min

32
Q

Renal Weight

A

0.3 kg

33
Q

Flow Control - Renal

A

Does not have alpha but does have beta Ars
Dec 20-30% with SNA
Regulated by autoregulatory control - myogenic and metabolic

34
Q

Cerebral Circulation -

A

Comes through carotid and basilar to circle of willis

Enclosed in cranial vault - so is non compressible

35
Q

Cerebral - Resting Blood Flow and CO

A

750 mL/min

12-15% CO

36
Q

Cerebral - Max blood flow

A

about 2 L/min

Constant blood flow sure to incompressibilty - vault prevents tissue from

37
Q

Cerbral Flow Control

A

Unaffected by ANS
Controlled exclusively by autoregulation
Myogenic, metabolic and starling resistor

38
Q

Cerebral - Starling Resistor

A

As tissue pressure increases, transmural pressure of vessels will decrease
Autoregulatory resistors are subject to this
If tissue pressure inc too much, you will not get flow to the brain

39
Q

Cerebral and gases

A

Sensitive to changes in blood gases

Small changes in PCO2 will have large changes in cerebral blood flow

40
Q

Cerebral - Cushing Reflex

A

Cerebral ischemia activates the cushing reflex

Inc in intracranial press –> dec in blood flow –> hige SNS –> inc in MAP –> inc CNS flow

41
Q

Coronary Blood Flow -

A

Receives 250mL/min (5% of CO)

42
Q

Coronary - Capillary

A

Has very dense capillary network (10x as many as skeletal muscle)

43
Q

During exercise - what happens to coronary BF

A

increases as HR increases - up to 1200 mL/min

Coronary BF can inc to 1L/min during max exercise

44
Q

Control of Coronary Blood Flow

A

Powerfully regulated by autoregulation
- metabolic control
Increased O2 will math increased flow
Little to no influence of symp NS

45
Q

Atherosclerosis starts with

A

Endothelial dysfunction

and ends with plaque - thickening of intima space and change ind diameter of the vessel

46
Q

Why are plaques dangerous

A

Unstable, can rupture and cause MI or stroke

Plaque will compromise flow to areas downstream from it and tissues will become ischemic

47
Q

Thrombus

A

platelets held together with fibrin strands

48
Q

Emobolus

A

when thrombus separates from wall and floats in circulation

49
Q

Results of plaque –>

A

Will weaken the vascular wall and an aneurysm can develop

50
Q

Myocardial Infarction

A

Death of myocardial cells due to O2 deprivation

Disrupts the depolarization and can lead to Vtach or Vfib

51
Q

Causes of MI

A 
Coronary Artery Disease
- plaque formation
- thormbus
Will see drop in CO and MAP
Compensate with baroreflex --> SNA will inc to bring CO back up --> it iwll vasoconstrict --> you are now inc workload of already damaged heart though --> not good
52
Q

Left Heart Failure

A 
Dam = jxn LV and aorta
Upstream = pulmonary circulation
Downstream = systemic circulation
53
Q

Right Heart Failure

A 
Dam = lung or jxn RV and pulmonary aorta
Upstream = venous return in RA
Downstream = left heart
54
Q

Etiology of Heart Failure

A 
Drop in CO
Baroreflex kicks in to bring pressure up
SNA - contractillity, inc HR
Stressing an already damaged heart
vasoconstriction --> inc afterload --> working heart too hard

FS Exam 4 (6 decks)

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