WEEK 2- REGULATION OF URINARY SYSTEM Flashcards
describe the theoretical description of a negative feedback loop and include terms stimulus, receptor, control centre, effector and response.
-a negative feedback loop is usually what brings the system back to normal and regulates it by solving the problem directly.
terms;
stimulus; is a change in regulated variable (like blood pressure, body temp) that moves away from the normal range
receptor; what detects the stimulus and sends it to the control center
control center; processes information in the brain and sends signal to the effectors
effector; the organ that acts to reverse the change
response; the action that restores the variable to its normal range
describe micturition as a negative feedback response
micturition is the process of urine being expelled from the body
feedback response;
stimulus; increased bladder filling and stretching of the bladder walls
receptor; stretch receptors in the bladder wall detect the fullness
control center; the sacral region of the spibal cord sends signals to the brain
effector; detrusor muscle contracts, and internal urethral sphincter relaxes
response; urination which empties the bladder, reducing the stretch and stopping further signals.
ADH release as a negative feedback response
-stimulus; increased plasma osmolarity ( too little water in the blood) low blood volume
-receptor- osmoreceptors in the hypothalamus detect increased osmolarity
-control center; the hypothalamus signals the posterior pituitary to release ADH
-effector; kidneys increase water reabsorption by inserting aquaporins into collecting ducts
-response; increased water retention reduces osmolarity and brings back to normal
-aquaporins; located in the collecting ducts, allowing water reabsorption into the blood.
production of angiotensin II
renin; secreated by juxtglomerular cells in response to low blood pressure
angiotenisinogen; a precursor protein produced by the liver
angiotensin I; formed when renin converts angiotensiogen into angiotensin I
angiontensin II; created when angiotensin-converting enzyme (ACE) converts angiotensis I into angiotensin II in the lungs.
effects of angiotensin II
Increased Sympathetic Activity: Angiotensin II stimulates the sympathetic nervous system, increasing heart rate and vasoconstriction, which raises blood pressure.
Increased Tubular Reabsorption of Na+ and Cl-: Angiotensin II stimulates aldosterone release, promoting Na+ and Cl- reabsorption in the nephron. This increases water retention and blood volume, raising blood pressure.
Increased Arteriolar
Vasoconstriction: Angiotensin II causes the blood vessels to constrict, increasing vascular resistance and raising blood pressure.
Increased ADH Secretion: Angiotensin II stimulates ADH release, increasing water reabsorption in the kidneys, leading to higher blood volume and pressure.
Decreased Difference in Afferent and Efferent Arteriole Diameters: By constricting the efferent arteriole more than the afferent, angiotensin II increases glomerular pressure, enhancing filtration.
define aldosterone mechanism
Stimulus: Low Na+ levels or high K+ levels.
Effect: Aldosterone increases Na+ reabsorption and K+ excretion by upregulating sodium-potassium pumps in the distal tubule and collecting ducts.
Relation to Facultative Water Reabsorption: Water follows Na+ reabsorption, which increases blood volume and pressure.
define diuretics and the following types; osmotic, thiazide-type, loop and potassium-sparing
Osmotic Diuretics: Increase solute concentration in the nephron, preventing water reabsorption (e.g., mannitol).
Thiazide-Type Diuretics: Inhibit Na+ reabsorption in the distal convoluted tubule, increasing urine output.
Loop Diuretics: Inhibit Na+, K+, and Cl- reabsorption in the loop of Henle, leading to significant water loss.
Potassium-Sparing Diuretics: Inhibit Na+ reabsorption while preventing K+ excretion in the distal nephron.
describe the fluid compartments and what separates them
Intracellular Fluid (ICF): Inside cells.
Extracellular Fluid (ECF): Outside cells, including:
Interstitial Fluid: Between cells.
Plasma: In blood vessels.
