physiology Flashcards
what is the cell membrane primarily composed of
phospholipids
phospholipid head and tail
head - hydrophobic
tail hydrophilic
what does cholesterol do to the membrane
stiffens/hardens it
what substances can cross the phospholipid bilayer easily
uncharged polar molecules e.g. O2, CO2, water and NH3
what is response for the fluidity of the membrane
lipid bilayer
name a ligand binding receptor
hormone receptor
what are adhesion molecules important in
regulating cell shape, growth and differentiation - allowing cell to adapt to its immediate surrounding
what is a glycocalyx
carbohydrate and lipid layer that surrounds some cells
what serves as self identity markers in cells
membrane carbohydrates
what are aquaporins
water channels
define tonicity
the effect a solution has on cell volume
what effect does overheating have
protein denaturation, nerve malfunction, convulsion
what effect does dec body temp have
slow down cellular reactions and metabolism
normal ear drum temp range
35.5 - 37.5
normal rectal temp range
36.7-37.5
when will you have your lowest body temperature
morning
what effect does menstruating have on your temp
higher during the 2nd half cycle
BMR
minimum amount of energy needed to sustain vital body functions
what effect do adrenaline and thyroxine etc have on BMR
inc it
what fat do children and hibernating animals have high level of
brown
what does brown adipose tissue contain
UCP
what does brown adipose tissue do
generate heat by short circuiting the mitochondrial battery - non shivering thermogenesis
which part of the hypothalamic centre is activated by cold
posterior
which part of the hypothalamic centre is activated by warmth
anterior
what is a pyrogen
a substance that produces fever
define fever
temp > 38 C
define hyperthermia
temp >40
define hypothermia
temp <35
what does heat exposure do to muscle tone
decrease it
what is the resting membrane potential of a typical nerve cell
-70mV
what equation can be used to calculate the equilibrium potential
Nernst
what equation can be used to calculate the membrane potential
goldman hodgkin katz
which type of diabetes is ketosis common in
type 1
what hormones are released from the adrenal gland is response to stress
adrenaline and cortisol
define MAP
the average arterial blood pressure during a single cardiac cycle
length of diastolic portion in comparison to systolic
diastolic is twice as long
normal MAP range
70-105mmHg
lower MABP needs to perfuse organs
60mmHg
where are the baroreceptors locate
aortic arch and carotid sinus
what are baroreceptors responsive to
stretch
what happens when baroreceptors are stimulated
parasympathetic stimulation the heart
MABP equation
MABP = CO x TPR
CO =
HR x SV
define SV
vol of blood pumped by each ventricle of the heart per heart beat
define TPR
sum of resistance of all peripheral vasculature in the systemic circulation
define AUTORHYTHMICITY
heart able to beat in the absence of external stimuli
how is intrinsic control of SV controlled
frank starling mechanisms
what are the main resistance vessels
arterioles
what is vasomotor tone
vascular smooth muscles partially constricted at rest
what is the vasomotor tone caused by
tonic discharge of sympa nerves resulting in continuous release of noradrenaline
what are the only smooth muscles that have parasympathetic innervation
penis and clitoris
what type of changes do baroreceptors only respond to and why
acute changes in BP
they reset and will only fire again if there is a new acute change in MAP above the new steady state level
