Upgrade to remove ads
Only $35.99/year

Chapter 20 -Integrative Physiology II

Terms in this set (54)

kidneys, respiratory, and cardiovascular system
homeostasis of water and electrolytes depends on the integration of
behavioral mechanisms
thirst and craving for salt are examples of ________________ _____________
replenish; conserve
the kidneys cannot __________ lost water, but they can ___________ it
GFR
how well blood is filtered by the kidneys
high medullary interstitial osmolarity
allows urine to be concentrated
descending loop of Henle
fluid in the _________________ loses water by osmosis to the interstitial tissue of the medulla
impermeable to water and active transport of ions out of the lumen into the medulla is not followed by water
cells in the thick portion of the ascending limb of the loop are:
distal nephron
water permeability is variable and under control of hormones; if the body needs water it becomes permeable to water and water leaves by osmosis
diuresis
the removal of excess water in urine
diuretics
drugs that promote urine excretion
vasopressin (ADH or AVP)
initiates membrane recycling which controls which parts of the cell membrane are permeable to water in the distal tubule collecting duct
aquaporins
water pores are inserted into the apical membrane of the collecting duct cells
plasma osmolarity, blood volume, and blood pressure
three stimuli that affect vasopressing release
nocturnal enuresis
bed wetting (developmental delay in elevated nocturnal vasopressin release)
vasopressin
with maximal ______________, the collecting duct is freely permeable to water
vasa recta capillaries
water leaves by osmosis and is carried away by the ______________________
apical membrane
vasopressin causes insertion of water pores into the ______________ ____________
countercurrent
high medullary interstitial osmolarity is maintained by a ________________ system
renal countercurrent exchange system
consists of closely associated tubules and capillaries of the vasa recta
active
countercurrent multiplier transfers solutes by ____________ transport into the medulla
interstitium
vasa recta (capillaries) removes water from _____________ and prevents dilution of the medulla interstitial fluid
urea
___________ is concentrated in the medulla which helps increase the osmolarity of the medullary interstitium
collecting tubules
urine is concentrated passing through the ___________ _____________
NaCl
extra _______ raises osmolarity
decrease; increase
vasopressin release (conserves water) and thirst prompts drinking causing a _________ in osmolarity but an _________ in ECF volume and blood pressure
aldosterone
controls reabsorption of Na+ in the distal tubules and collecting ducts (Na+-K+-ATPase) and targets P cells in the distal tubule
low blood pressure and high extracellular K+ concentration
stimulate aldosterone secretion
renin-angiotensin system (RAS)
juxtaglomerular cells secrete renin if blood pressure drops
renin
converts angiotensionegen to angiotensin I
angiotensin converting enzyme (ACE)
converts angiotensin I to angiotensin II
synthesis of aldosterone, increase in vasopressin release, increased thirst, increased sympathetic cardiac output, vasoconstrictor, and Na+-H+ exchanger
angiotensin II increases blood pressure by:
high blood pressure drugs
ACE inhibitors preventing conversion of angiotensin I to II
aldosterone
plays a critical role in the regulatory mechanisms that keep plasma potassium in narrow range
hypokalemia
less K+ in cells (hyperpolarized) and less likely to fire an action potential; can lead to muscle weakness and failure of respiratory muscles and the heart
hyperkalemia
more K+ so cells depolarize and reach the action potential threshold easier; can lead to cardiac arrhythmias
decreases; increases
dehydration ______________ blood volume/pressure and ____________ osmolarity
7.38-7.42
normal pH of plasma
H+ concentration
changes in concentration of _____ can alter the three-dimensional structure of proteins
acidosis
neurons become less excitable; CNS depression, confusion, coma, and breathing stops
alkalosis
hyperexcitable, tetanus of respiratory muscles
K+
pH disturbances are associated with ______ disturbances
organic acids
diet; fatty acids, amino acids, and metabolic intermediates (lactic acid)
ketoacids
strong acids causing a state of metabolic acidosis known as ketoacidosis
CO2
production of ______ is the biggest source of H+
buffers
first line of defense that handle moderate changes in pH; combine with or release H+; examples: cellular proteins, phosphate ions, hemoglobin, and bicarbonate (plasma)
hypoventilation
decreases pH
ventilation
second line of defense that provides a rapid response triggered by H+ and CO2; corrects 75% of disturbances
hyperventilation
increases pH
renal regulation
last line of defense directly altering pH homeostasis by excreting or reabsorbing H+ and indirectly by changing the rate at which HCO3- buffer is reabsorbed or excreted
apical Na+-H+ exchanger (NHE), basolateral Na+-HCO3-symport, H+-ATPases, H+-K+-ATPase, Na+-NH4+ antiport
membrane transporters for handling H+ and HCO3-
acid-base disturbances
can be respiratory or metabolic
respiratory acid-base disturbances
hyperventilation or hypoventilation cause pH to shift when PCO2 changes
metabolic acidosis
dietary and metabolic input of H+ exceeds excretion
metabolic alkalosis
loss of H+ through excessive vomiting or excessive ingestion of bicarbonate-containing antacids
Other sets by this creator