Renal System and Micturition Flashcards

Flashcards generated from lecture notes on renal system and micturition.

What is the primary function of the buffer system in the context of blood?

Regulate blood pH

Name five buffer systems that regulate blood pH.

Bicarbonate, Phosphate, Respiratory, Metabolic, Renal

What will the renal system do if blood pH is too low?

Excrete H+

What will the renal system do if blood pH is too high?

Excrete HCO3-

List two transport mechanisms involved in H+ secretion in the PCT.

Na+/H+ antiport and Vacuolar H+ ATPase

What compound is formed during HCO3- reabsorption in the PCT?

H2CO3 formation

Where is CA located during HCO3- reabsorption in the PCT?

Apical surface of PCT cells

Name two transport mechanisms involved in HCO3- transport across the basolateral membrane of PCT cells.

HCO3- / Cl- antiport and HCO3- / Na+ symport

List two types of ATPase found on the apical membrane of H+ secreting intercalated cells in the collecting duct.

Vacuolar H+ ATPase and H+/K+ ATPase

Which antiporter is located on the basolateral membrane of H+ secreting intercalated cells in the collecting duct?

HCO3- / Cl- antiport

Which antiporter is located on the apical membrane of HCO3- secreting intercalated cells?

HCO3- / Cl- antiport

What type of ATPase is found on the basolateral membrane of HCO3- secreting intercalated cells?

H+ ATPase

What is titratable acid (TA) excretion?

Excretion of H+ with a buffer

Name two buffers found in the tubular lumen that contribute to titratable acid.

Phosphate and Bicarbonate

How does buffering H+ in the tubular lumen affect filtrate acidity?

Reduces free H+ in filtrate, reducing acidity

What type of epithelium lines the bladder?

Transitional epithelium (urothelium)

What is the primary function of umbrella cells in the bladder lining?

Protective

What conditions do umbrella cells protect against?

Hypertonicity and Acidity

What is the name of the muscle in the bladder wall?

Detrusor muscle

How thick is the mucosa of the bladder when empty (with rugae)?

5-6 cell thick

How thick is the mucosa of the bladder when full (flat)?

2-3 cell thick

How long is the female urethra?

3 to 4 cm long

What is the anatomical location of the female urethra relative to the vaginal tract?

Anterior to the vaginal tract

How long is the male urethra?

~18 cm long

Which anatomical structures does the prostatic urethra connect?

Bladder to prostate

The membranous urethra passes through which cavity?

Pelvic cavity

Where does the spongy urethra run?

Through penis

What are the three main targets of the neural circuits controlling micturition?

Detrusor muscles, Internal sphincter muscle, External sphincter muscle

Which pathway causes the detrusor muscles to relax between voiding acts?

Sympathetic pathway

Which pathway causes the internal sphincter muscle to contract between voiding acts?

Sympathetic pathway

What type of fibers cause the external sphincter muscle to contract between voiding acts?

Somatic motor fibers

What is the initial stimulus for the involuntary micturition reflex?

Stimulates stretch receptors

Where do the stretch receptor signals go during the micturition reflex?

Signals to SC

Through which nerve do efferent parasympathetic signals travel during involuntary micturition?

Pelvic nerve

What happens to the internal urethral sphincter (IUS) when the detrusor muscles are excited during involuntary micturition?

Relaxation

Where is the micturition center located that is involved in voluntary micturition?

Micturition center in pons

Through which tracts does the pons return signals to interneurons to cause detrusor contraction and IUS relaxation?

Reticulospinal tracts

Through which tracts do efferent cerebral signals travel to relax the external sphincter during timely voiding?

Corticospinal tracts

Which muscle in males forces out the last milliliters of urine?

Bulbocavernosus muscle

What do females rely on to help with urinary continence since they lack an internal urethral sphincter?

Pelvic floor muscles