Homeostasis Flashcards
what percentage of our body is water
60%
ICF is what percent of total body water
2/3
ECF is what percent of total body water
1/3
what is ICF
anything inside cell
what is ECF
anything outside cell
what two compartments are in ECF?
plasma, interstitial fluid
plasma
blood cells, plasma proteins
interstitial fluid is what
ultrafiltrate of plasma
difference b/w females and males in total body water
60% for males
55% females
what percentage is interstitial fluid and plasma
80% interstital fluid
20% plasma
4 important constitutents of ECF
Na+
K+
Ca++
Cl-
Na+ in ECF amount
142 mEq/L
K+ ECF
4 mEq/L
Ca++ ECF
2.4 mEq/L
Cl- ECF
103 mEq/L
Na+ ICF
10 mEq/L
K+ ICF
140 mEq/L
Ca++ ICF
.0001 mEq/L
Cl- ICF
4 mEq/L
phosphates ICF
75 mEq/L
sodium potasium ATPase does what
3 sodiums out for every two potassiums in
if sodium is 142 on inside of cell
you will die
as many potassium ions go out (postiive charge goes out) what happens to keep homeostasis
as many leave, that many go back in cell
what is the unit to describve ion quantitites
miliequivalent per liter
what is a concentration gradient
different concentrations for sodium to go into cell
when an ion is going to move, how does it move
toward the lower concentration gradient
if only concentration gradient is there, where will ion go
“downhill” so Na+ would go from 142 to 10, so it would go inside cell
the bigger the concentration gradient
the faster the ion will move
what is major anion and cation inside cell
cation: potassium
anion: phosphates
what is major anion and cation outside cell
cation: sodium
anion: chlorine
Draw graph of major anions and cations inside extracellular and intracelluar
slide 6 homeostasis
osmolality is:
whatever is in the compartment, like beaker of water. add sodium chloride. add 142 mE/L ,all the solutes impart osmotic pressure and would impart it on a cell if the cell goes inside beaker, they would put pressure on cell membrane. it is the number of solute molecules at concentration x number of solute molecules that can be disassociated
osmolality vs osmolarity
osmolarity is expressed as mOsm/L
osmolality is mOsm/kg
osmolarity is volume, osmolality is weighing it. they are very similar to each other
what is ECF and ICF osmolality
290 mOsm/kg
osmotic pressure
difference in solute concentration
osmotic pressure does what to water
causes it move if there is osmotic gradient
what is normal osmolarity
285 mOsM
what is the osmolarity in ECF and ICF
285 mOsM for both
what are the five components of homeostatic control system
- stimulus
- change detected by receptor
- input
- output
- response
variable example for homeostatic control
blood pressure
as soon as variable deviates enough from set point what happens
sensor notices and sends information to control sensor
describe negative feedback control system
some variable is off balance, like it being 80 degrees in apartment, it brings it back down to normal range, like air condition turning on and cooling off apartment to 75
a person eats, causes raise in blood glucose level, this does what to sensors
stimulates
what cells are stimulated as results of increased blood glucose lvels
beta cells of pancreas - they release insulin into blood
what is the result of negative feedback mechanism after eating
blood glucose levels go back down
if diabetic person is not eating, person is drinking too much, hepatitis or kideny disorders, they would all result in
lowered blood glucose levels
deviation from normal blood glucose - lower blood glucose, stimulates what sensors
alpha cells in pancreas
alpha cells in pancreas release what
glucagon
what is restult of negative feedback of low blood glucose
blood levels go back to normal
if blood pressure is increased, ex: 140/90, it stimluates what sensors
baroreceptors in carotid sinuses and aortic arch
what do baroreceptors respond to
stretch due to increase bp
how does brain interrpret barorecptors
electircal activity - increase firing rate of AP going to brain
centers in brain integrate info in brain, and do what in responde to high BP
decrease sympathetic impulses to heart → decrease HR
Decrease contractility and decrease CO (cardiac output)
increase parasympathetic
acetylcholine binds to receptors in heart and does what
decreases heart rate
when norepinephrine is realeased from sympathetic nervous system it goes to what receptors
alpha echo
list steps of negative feedback to decrease BP
pg 14
decrease in BP, acts on baroreceptors and electrical activity does what
decrease impulse/frequency to brain
if low BP, what happens to baroreceptors
less stretch/pressure
list steps for negative feedback of low BP
pg 15
go through thermoregulation - increase in temp. negative feedback steps
pg 17
go through thermoregulation - decrease in body temp. negative feedback steps
pg 18
negative feedback purpose:
stabilize system
positive feedback purpose:
destabilize system
what happens in positive feedback
initial deviation, initial parameter (ex: increase) is amplified, and is continued to be amplified. for positive feedback you want to reach a certain endpoint
Ex: of positive feedback
giving birth
go through steps of positive feedback of childbirth
pg 20
voltage-gated sodium current is an example of what feedback
positive
go through positive feedback of voltage-gated sodium channels
pg 21
ECF osmolality is roughly
300 mOsm/kg H2O
