Lec 30 Flashcards
why Na and water are important
ECF volume and osmolarity
why k is important
cardiac and muscle function
why Ca is important
exocytosis, muscle contraction, bone formation
why h and hco3 are important
ph balance
body must maintain
mass balance
input + cellular respiration = cellular consumption + excretion
excretion route is via
kidney
what come in body in excess of needs musy
excrete
fluid and electrolyte balance involve
integration of respiratory, renal, cardiovascular system
most abundant compound of body
water
water gain by
food and drink
metabolism
water loss by
skin
lungs
urine
feces
water in male
30 L
water in female
42 L
kidney remove or conserve body fluid b y
regulate amount of H2O reabsorb
final osmolarity of urine depend on
hormona regualtion of H2O reabsorption in distal nephron
descending limp absorbtion
water
ascending limb absorption
ions but no water
creating hyposmotic fluid
distal tubule reabsorption
variable water and solutes
collecting duct reabsorption
water by aquaporin/vasopressin
vassopressin (ADH) is
neurohormone
ADH released by
posterior pituitary gland
stimuli for ADH release
1- high plasma osmolarity
2- low blood volume
3- low blood pressure
ADH control
additon of water poles (aquaporines) into apical membrane of collecting duct
result ADH
increased water reabsorption
more concentrated urine
response may be — and depend on amount of hormone released
graded
low BP
1- sense by carotid and aortic baroreceptors
2- sensory to hypothalamus
3- hypothalamic neuron synthesize ADH
4- ADH release from posterior pituitary
5- collecting duct epithelium
6- insertion water pores
7- increased water reabsorption
low blood volume
1- decrease arterial stretch
2- arterial stretch receptor
3- sensory to hypothalamus
3- hypothalamic neuron synthesize ADH
4- ADH release from posterior pituitary
5- collecting duct epithelium
6- insertion water pores
7- increased water reabsorption
high osmolarity
1- hypothalamic osmoreceptors
2- interneurons to hypothalamus
3- hypothalamic neuron synthesize ADH
4- ADH release from posterior pituitary
5- collecting duct epithelium
6- insertion water pores
7- increased water reabsorption
ADH production has – feedback
negative
Aldosterone regulate
Na reabsorption
Aldosterone properties:
1- steroid hormone
2- synthesis and released from adrenal cortex
3- act on principal cells of distal tubule and collecting duct
stimuli aldosterone release
1- angiotensin II (low BP and RAS)
2- hyperkalemia (high K in plasma)
aldosterone result
1- Na reabsorption
2- K secretion
very high osmolarity has — impact on adrenal cortex aldosterone release
negative
low Bp stimulate
renin secretion
renin is a
enzyme
renin secretion pathway
1- low bP
2- low GFR–low flow–macula densa sense–paracrine–granullar cells afferent arteriole
3-direct effect stretch receptor on granular cells
4- cardio vascular control center–increase sympathetic activity–granullar cells afferent arteriole
all result in renin secretion
renin will activate –
angiotensiogen to ANG I
then ANG i will convert to ANG ii by ACE
ACE
angiotensin-converting enzyme
ACE located on
all vascular endothelial cells
ANG ii will effect on
aldosterone release from adrenal cortex
aldosterone will
increase Na reabsorption
water will follow
ANG ii has other targets as well
1- cardiovascular control center: increaase CO
2- arterioles: powerful directly vasoconstrictor
3-hypothalamus: increase vasopressin release/salt apetite/ thirst
H+ input
diet
metabolism
H+ output
ventilation primary
renal second if ventilation doesn’t work
Maintain PH homeostasis mechanism
1- buffers: Hb, HCO3-,proteins
2- regulation of ventilation (rate & depth) :pCO2 and carbonic acid
3- kidneys: secretion/absorption H+
regualtion of ventilation stimuli
1- increase H+
2- increase CO2
happens immediately
low PCO2 is sensed by
carotid amd aortic and central chemoreceptors
regulation of ventilation pathway
1- sensed by chemoreceptor
–carotid/aortic by **sensory neuron **
–central chemoreceptors by interneuron
2-respiratory center in medulla
3- increase Ap in somatic motor neuron
4- muscle ventilation
5- increase rate and depth of breathing
6- decrease plasma PCO2
7- increase PH
regulation of ventilation negative feedbacks
1- high Ph effect on carotid/aortic chemoreceptors
2- low PCO2 effect on central chemoreceptors
Renal compensation
regulation of acid-base balance in collecting duct
– intercalated (I) cells between P cells:
1- high level of carbonic anhydrase
2-type A I cells secrete H+ and reabsorb HCO3-
3-type A II cells secrete HCO3- and reabsorb H
type A I cells respond to
acidosis
type A II cells respond to
alkalosis
CA in body is in:
1- ECM
2- EX fluid
3- intracellular Ca
CA in ECM
calcified matrix in bone and teath
Ca in ECF
1- Nt
2- role in myocaridal and smooth muscle contraction
3- cofactor in coagulation
4- influence excitability
Ca in intracellular
1- skeletal muscle contraction
2- secondary message signal (Gq)
structure of bone
connective tissue
remodeled throughout of life
calcified ECM
Calcified ECM is called
hydroxyapatite
what synthesize bone
osteoblast
what resorb bone
osteoclast
drug for osteoprosis prevent –
osteoclast
mechaism regulate calcium homeostais in body
1- parathyroid hormone (PTH)
2-Calcitriol (vit D3)
3-Calcitonin
PTh will
increase Ca resorption from bone
increase CA reabsorption by kidney
increase Ca absorption by GI
calcitriol will
increase Ca absorption by GI
calcitonin will
increase depostion of Ca in bone
(bone formation)
decrease Ca level in (aq)
PTH origin
parathyroid gland
PTH steroid or peptide
peptide
PTH biosynthesis
continuous production, little storage
PTH half time
short half time
PTH stimulus
low plasma Ca
PTH target cell
kidney, bone, intestine
PTH target receptor
membrane receptor via cAMP
Calcitriol origin
skin, kidney, liver change light to D3
calcitriol peptide or steroid
steroid
calcitriol transport in circulation
via bounding to plasma protein
calcitriol target cell
intestine, bone, kidney
calcitriol target receptor
nuclear
Calcitonin origin
C cells thyroid gland
Calcitonin peptide or steroid
peptide
Calcitonin half life
short half life
Calcitonin target cell
bone and kidney
Calcitonin target receptor
G protein coupled membrane receptor
Calcitonin major role in
child/adolescent
Calcitonin stimulus
high Ca in plasma
Calcitonin function
inhibit osteoclast
decrease renal absorption