Trans - Concepts in Regulation Flashcards
components of feedback system
- receptor
- control center
- effector
negative feedback - define
feedback that tends to stabilize a process
baroreflex - what is the receptor
stretch receptors in arteries
baroreflex - what is the control center
vasomotor center in medulla
baroreflex - what is the effector
vagal parasympathetic center and fibers
baroreflex - what is the stimuli, and what is the goal
decrease in heart rate in response to increase in blood pressure, to maintain BP
what type of system is the extracellular fluid
open
what type of system is the intracellular fluid
closed
plasma - define
effective circulation volume of ECF,
which is the smallest compartment of bodily fluid
plasma
interstitial fluid - define
surrounds the cell, access from plasma to cell
structure that regulates excretion of fluids and electrolytes from the ECF
kidney
what sex has higher % body water? why?
male, because females have more body fat (fat is water-deficient)
electrolyte composition of plasma is similar to electrolyte composition of what other compartment
interstitial fluid
electrolyte composition of ICF is similar to electrolyte composition of what other compartment
none
what determines osmolarity outside cells
Na, Cl
osmosis - define
net movement of water across semipermeable membrane according to concentration gradient
water channels that facilitate osmosis in nonpermeable membranes
aquaporins
amount of pressure required to stop movement of pure water into the solution
osmotic pressure
what counteracts osmotic pressure
hydrostatic pressure
steady state - relationship of osmotic pressure and hydrostatic pressure
equal
steady state - relationship of osmotic concentration of cytoplasmic compartment and osmotic concentration of extracellular fluid
equal
regulation of ECF volume - effector
modification of Na secretion in kidney
regulation of ECF volume - sensor
detect changes in volume and vascular capacity
major osmotically active particles in ECF
Na, Cl, bicarbonate
low pressure baroreceptors - detect pressure in what part of circulation
venous
low pressure baroreceptors - detect pressure in which chambers of the heart
all except LV
low pressure baroreceptors - function
assess filling of central venous circulation
cardiac atria receptors - what type of receptor
stretch receptors
cardiac atria receptors - secrete what substance
atrial natriuretic factor (ANF)
end result of stimulating cardiac atria receptors
natriuresis and diuresis
part of ECF in arterial system and effectively perforating all tissues
effective circulation volume
cardiac atrial receptors - send impulse to where?
hypothalamus and medulla
how do the hypothalamus and medulla help in cardiac atrial receptor function
- reduce sympathetic muscle discharge to kidney
2. reduce ADH secretion by pituitary
2 types of low pressure baroreceptors
- cardiac atrial receptors
2. cardiopulmonary receptors
sympathetic stimulation - effect on kidney
reduce function
high pressure baroreceptors - detect pressure in what part of the circulation
arterial circulation
high pressure baroreceptors - where located?
- bifurcation of common carotid artery (carotid sinus)
2. aorta (aortic body)
high pressure baroreceptors - function
detect changes in mean arterial pressure to maintain it, and thereby protect the brain
intrarenal baroreceptor - example
juxtaglomerular apparatus (JGA)
JGA - stimulated by
- sympathetic signals
- hypotension
- decreased sodium delivery
JGA - release what substance
renin
aldosterone - function
main regulator of sodium excretion
lack of adosterone causes uncontrolled secretion of Na (and H2O waste)
what is the end result of the RAS
increase blood volume by decreasing natriuresis and therefore diuresis
what is the end result of the stimulation of low pressure and high pressure baroreceptors
decrease/maintain BP by increasing natriuresis and therefore diuresis
renin activates (1)_______ to become (2)_______
- angiotensinogen
2. angiotensin I
angiotensin I is acted upon by (1)_______ to produce (2)_______
- angiotensin converting enzyme
2. angiotensin II
angiotensin II production occurs in what organ
lungs
important functions of angiotensin II
- stimulation of thirst –> increase in blood volume
- stimulation of pituitary –> release of ADH –> decrease diuresis –> increase blood volume
- stimulation of adrenal cortex –> release aldosterone –> decrease in Na secretion/natriuresis –> increase in blood volume
from where is aldosterone released
adrenal cortex
from where is ADH released
posterior pituitary
4 components of effector limb in maintaining ECF
- glomerular filtration rate
- Na resorption in tubules
- humeral effectors (RAS)
- renal sympathetic nerves
increased ECF osmolarity causes release of (1)________ and therefore (2)_______
- ADH
2. water and salt retention
ADH - function
prevent diuresis and therefore act in fluid retention
where is ADH produced
supraoptic and paraventricular hypothalamic nuclei
from where is thirst controlled
hypothalamic thirst center
threshold for thirst
plasma osmolarity of 295 mOsm/L
(1)__________ mechanism dominates over (2)______ mechanism
- baro(mechanism)
2. osmotic
osmometers in regulation of ICF
RBC
major cell membrane impermeant solutes
Na, K, Cl
major cell membrane permeant solutes
glycerol, urea
determines steady state volume of ICF
concentration of impermeant solutes in ECF
effect of permeant solutes in concentration
transient changes
[T/F] the more permeable the membrane is to a certain permeable solute, the longer the duration of any transient change in concentration this solute might produce
F
types of solute
- perturbing
2. nonperturbing
perturbing solute - define
solute that can harm cells and disrupt mechanism in excess of concentrations or rate of change
perturbing solute - example
electrolytes, urea
nonperturbing solute - define
solute that may be accumulated within the cytosol without detrimental effects, used in adaptation to chronic changes
type of cell volume change
- anisoosmotic
2. isoosmotic
anisoosmotic volume change - cause
alterations in cellular osmolarity
isoosmotic volume change - cause
alterations in cell content and membrane permeability
differentiate anisoosmotic and isoosmotic volume change
anisoosmotic - change in volume with change in ICF solute concentration
isoosmotic - change in volume without change in ICF solute concentration
how does a cell regulate its ICF
through metabolic production and removal of osmotically active substances
most vulnerable organ to intracellular volume changes
brain
only place/space where brain can expand
foramen magnum
effect on volume of cellular solute gain
increase
effect on volume of cellular solute loss
decrease
hypovolemic hypernatremic state - what solution to give to correct volume deficit? why?
isoosmotic solution, to prevent brain edema
hypovolemic hypernatremic state - what solution to give to correct concentration anomaly
hypoosmotic solution
low plasma volume - effects:
- low BP
2. rapid pulse
low interstitial fluid volume - effects
- poor skin turgor
- dry tongue
- sunken eyes
ICF depletion - effects
- hallucination
2. loss of many functions
[T/F] drinking urine results in net water loss
T
drinking urine - effects
increase in effective circulating volume
increase in osmolarity
cell shrinkage
effect of dehydration on body fluid compartments
decrease in volume of both ECF and ICF
