urinary system - physiology

Question 1

pressures affecting glomerular filtration rate

Answer 1

glomerular blood hydrostatic pressure
capsular hydrostatic pressure
blood colloid osmotic pressure

Question 2

three steps of glomerular filtration

Answer 2

glomerular filtration,
tubular filtration
tubular secretion

Question 3

name the five hormones effecting renal function, stating causes and effect

Answer 3

• angiotensin II (releases from decreased BP, causes vasoconstriction of afferent and efferent arterioles)
• aldosterone (release from increased K+ in blood or angiotensin II, causes Na+/K+ pumps to open in collecting duct and Na+ & water to be reabsorbed and K+ secreted, thereby increasing BV)
• Antidiuretic hormone (releases from decreased BV, causes aquaporins of DCT and collecting duct to remain open, allowing water reabsorption)
• atrial natriuretic peptide (released due to stretching of aterial walls, causes mesangial cells to relax, increasing salt and water exertion + vasodilates + effectively decreasing BV)
• parathyroid hormone (released from decrease Ca2+ in blood, activates Ca2+ channels to reabsorb calcium

Question 4

effects of aging on urinary system

Answer 4

• decreased number of effective glomeruli
• stretch receptors are weakened
• kidneys shrink with age

Question 5

what are the two innate ways kidneys control BV/BP

Answer 5

• myogenic mechanism (arteries and arterioles detect an increase or decrease in vessel wall stretching, causing vasodilation or vasoconstriction)
• tubuloglomerular feedback (macula densa detects an increased Na+/Cl- in the blood causing juxtaglomerular cells from secreting nitrous oxide(vasodilator)

Question 6

an increased afferent arteriole diameter has what effect on renal blood flow and GFR

Answer 6

decreases Renal blood flow, increasing glomerular blood hydrostatic pressure, therefore, increasing GFR

Question 7

an increased efferent arteriole diameter has what effect on renal blood flow and GFR

Answer 7

decreases the RBF, decreasing glomerular blood hydrostatic pressure, thereby decreasing GFR

Question 8

act of emptying the bladder is called what

Answer 8

voiding

Question 9

the urethra contains an internal and external sphincter made of what muscle

Answer 9

smooth and skeletal respectively