Lecture 16 - Cardiovascular Regulation

Question 1

Protein gradient?

Answer 1

from higher conc. in plasma, across capillary to essentially nil conc. in interstitial fluid

Question 2

Water movement between cells and interstitial space?

Answer 2

water movement between cells and interstitial space is driven by osmotic gradients; cell volume is determined by Na and water balance in extracellular compartment

Question 3

Osmoreceptors?

Answer 3

cells in supraoptic and paraventricular nuclei of hypo. sensing changes in effective osmolality by altering volume, modulating synth. and release of AH from PPG; increased plasma osmolality also stimulates thirst receptors in hypo

Question 4

ECF volume affecting cardiac function?

Answer 4

increased ISF and plasma volume increase total ECF, increasing filling pressure of heart -> cardiac output -> arterial pressure (affect on peripheral R also)

Question 5

Cardiac receptors?

Answer 5

myelinated and unmyelinated neurons sensitive to small changes in pressure

Question 6

Loss of blood volume?

Answer 6

cardiac filing decreased, reduced cardiac receptor activity but maintained arterial baroreceptor firing until >10% BV loss reduces arterial pressure and arterial baroreceptor firing

Question 7

Neuro-humoral response to reduction in ECF volume?

Answer 7

DRAW IT; ADH fast RAAS slow,

Question 8

Restoration of blood constituents?

Answer 8

RCV and other constituents restores over day to weeks, preformed albumin transferred into circulation immediately after acute blood loss but other proteins produced by liver over 3-4days, red cell synthesis complete after 4-8wk

Question 9

Acute blood loss?

Answer 9

nonhypotensive haemorrhage (<10%, MAP maintained, pulse pressure reduced), hypotensive haemorrhage (>10%, fall in systemic BP), haemorrhagic shock (extreme, not compensated for long time, replacement of volume but maybe no CV homeostasis restoration)

Question 10

Response to altered pressure?

Answer 10

changes in hydrostatic pressure causes more blood to be stored in the lower extremities singificantly decreasing ventricular filling - NOT GRAVITY

Question 11

Systemic arterial baroreceptor resetting?

Answer 11

maintaining higher level of firing causes rightward shift, therefore long term maintenance of average pressure is maintained by multiple systems e.g. cardiac receptors, RAAS, renal function