Final: Circulation 7 Flashcards

1
Q

net filtration pressure (NFP) (3)

A
  • based on the Starling principle
  • may result in net filtration or net reabsorption across capillary membrane
  • creates a micro-circulation to mix interstitial fluids around the capillaries
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2
Q

NFP formula

A

NFP = (Pcap - Pif) - (πcap - πif)

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3
Q

NFP formula: Pcap

A
  • hydrostatic pressure of blood in capillary
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4
Q

NFP formula: Pif

A
  • hydrostatic pressure of interstitial fluid
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5
Q

NFP formula: πcap

A
  • osmotic pressure in the capillary
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6
Q

NFP formula: πif

A
  • osmotic pressure of interstitial fluid
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7
Q

what determines osmotic pressure (2)

A
  • determines by concentration of salts and proteins in a solution
  • water will move to solution with higher concentration of salts + proteins
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8
Q

hydrostatic pressure (2)

A
  • pressure of a column of fluid due to gravity
  • the area with high hydrostatic pressure will force fluid to the area of lower hydrostatic pressure
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9
Q

NFP: arterial side of capillary (3)

A
  • Pcap > πcap
  • NFP is positive
  • net filtration occurs
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10
Q

NFP: middle of capillary (3)

A
  • Pcap = πcap
  • NFP is ~0
  • net movement is zero
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11
Q

NFP: venous side of capillary (3)

A
  • Pcap < πcap
  • NFP is negative
  • net reabsorption occurs
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12
Q

lymphatic system: functions (2)

A
  • collects excess filtered fluid and returns it to the circulatory system
  • lymph nodes filter lymph to remove and kill pathogens
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13
Q

how does fluid move through the lymphatic system (2)

A
  • net water pressures and body movement drive fluid movement
  • lymphatic veins and ducts contains valves to prevent backflow
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14
Q

edema (2)

A
  • accumulation of interstitial fluid
  • can be due to ineffective lymphatic system
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15
Q

gravity on blood pressure: formula

A

ΔP = p * g * Δh

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16
Q

gravity on blood pressure: ΔP

A
  • pressure difference between two points
17
Q

gravity on blood pressure: Δh

A
  • height of the fluid column
18
Q

gravity on blood pressure: p

A
  • density of the fluid
19
Q

gravity on blood pressure: g

A
  • acceleration due to gravity
20
Q

what are the arterial and venous pressures at our heart due to gravity (standing) (2)

A
  • arterial: 100 mmHg
  • venous: 10 mmHg
21
Q

how much lower are venous pressures than arterial pressures due to gravity

A
  • venous pressure at each height are ~100 mmHg lower to permit blood flow
22
Q

how does body position affect blood pressure

A
  • changes in body position can alter blood pressure and flow
  • changes relative to gravity, such as standing up
23
Q

body positions and blood pressure: standing up (2)

A
  • causes pooling of blood in lower body
  • due to low venous return, low SV, and low MAP
24
Q

how does our body regulate MAP when we stand up (2)

A
  • baroreceptor reflex brings MAP back to normal
  • increases HR and SV to raise MAP
25
orthostatic hypotension (2)
- low blood pressure upon standing - occurs when baroreceptor reflex is too slow and not enough blood flows to the head
26
in what animals are the effects of gravity more important (2)
- snakes - giraffe
27
how do snakes deal with gravity
- heart is close to the brain so that it is guaranteed blood flow regardless of body position
28
how do giraffes deal with body position changes (2)
- vasoconstriction occurs in vessels of lower body when the head is upright and aortic pressure increases - vasodilation occurs in the vessels of the lower body when the head is feeding on ground and aortic pressure decreases
29
giraffes and gravity: head problem
- heart must generate sufficient pressure to overcome hydrostatic pressure
30
giraffes and gravity: head solution (2)
- thick-walled heart with low stroke volume & fast heartbeat - generate very high MAP
31
giraffes and gravity: feet problem
- giraffe must have solution to counter blood pooling in their legs and feet
32
giraffes and gravity: feet solution (4)
- giraffe arteries are usually muscular - skin on legs is very tight, acting as a compression stocking - tight endothelium to prevent H20 loss - venous valves
33
gravitational effects on cardiovascular function in air
- pressure increases with height of the water column, causing pooling/high pressure at the bottom
34
gravitational effects on cardiovascular function in water (2)
- blood and water have similar density and hydrostatic pressure - effects outside the animal cancel out gravitational effect, acting as a large "compression stocking"