RAT 18 Flashcards
what is the primary function of the countercurrent mechanism system?
to conserve water for the body when needed
what two things must be in place for water to be reabsorbed in the collecting ducts?
- ADH
- osmotic gradient
what are the three main components of the countercurrent mechanism?
- counter multiplier of the thick ascending limb establishes the medullary interstitial gradient by pumping NaCl into the interstitial fluid
- continued solute reabsorption, including urea cycling, from the filtrate in the medullary collecting ducts adds to the gradient
- the countercurrent exchanger of the vasa recta allows perfusion of the inner medulla while maintaining the medullary interstitial gradient
urine contains water, electrolytes, and metabolic wastes. list four metabolic wastes found in urine.
- urea
- creatine
- ammonia
- uric acid
list and briefly describe 5 factors typically included in a urinalysis
- color: more urochrome (darker yellow) more concentrated
- translucency: cloudy urine indicates an infection and high number of proteins
- odor: if urine sits out, bacteria metabolizes the urea and produces ammonia, normal urine has a mild odor
- Ph: normal ~6, range = 4.5 - 8
- specific gravity: deionized water = 1.0 range = 1.001 (very hydrated) - 1.035 (very concentrated)
name four substances that are commonly tested for that should not be present in the urine in any significant amount.
- blood
- protein
- leukocytes
- glucose
what is renal clearance?
measure of the rate at which the kidneys remove a substance from the blood
explain why a substance should be completely filtered and neither reabsorbed nor secreted to provide an accurate measure of renal clearance and the GFR
- substance secreted by renal tubules have a renal clean > their GFR
- substances that are reabsorbed have a renal clearance < their GFR
what is creatine?
a waste product of the metabolism of muscle and other cells
creatine is often used to check for renal clearance. how could this potentially provide inaccurate results?
between 15-50% of creatine in the urine arrived via secretion not filtration
what is insulin? why can it be used to measure GFR?
complex carbohydrate found in plants that is filtered by the glomerulus but neither reabsorbed nor secreted by the renal tubule or collecting system
list all organs in the urinary tract
- 2 ureters
- urinary bladder
- urethra
what organs are connected by the ureters?
kidneys to urinary bladder
are the ureters retroperitoneal?
yes
list the three layers of the ureter.
- adventitia
- muscularis
- mucosa
what tissue type composes the muscularis?
smooth muscle
what is the function of the muscularis?
propel urine toward the urinary bladder
what tissue type lines the lumen of the ureter?
transitional epithelium
what is the benefit of transitional epithelium?
allows epithelium to expand and recoil
where in the bladder does the ureter connect?
bladder wall at the urethral openings
list the three layers of the urinary bladder.
- adventitia
- detrusor muscle
- mucosa
what is the name of the muscle in the urinary bladder?
detrusor muscle
how many layers of muscles are in the urinary bladder?
3
what is the name of the muscle found around the urethra opening?
internal urethral spincter
what epithelium lines the urinary bladder?
transitional epithelium
what are rugae?
folds of mucosa
what marks the three corners of the trigone?
- 2 ureteral orifices
- internal urethral orifice
what is the function of the urethra?
drains urine from the urinary bladder to the outside of the body
what is the additional function that the urethra has in males?
production of semen
name the two openings of the urethra.
- internal urethral orifice
- external urethral orifice (between vagina and clitoris)
what are the two sphincters of the urinary bladder? which is voluntary?
- internal urethral sphincter
- external urethral sphincter (voluntary)
what are the three regions of the male urethra?
- prostatic urethra
- membranous urethra
- spongy urethra
define micturition
discharge of urine from the urinary bladder to the outside of the body
describe the sphincters involved in micturition
- external urethral sphincter - as children mature, the brain gains control over this sphincter
- when not appropriate internal and external sphincters remain closed
what is the function of the oral cavity?
- ingestion
- mechanical digestion
- propulsion
- secretion
what is the function of the pharynx?
propulsion
what is the function of the esophagus?
- propulsion
- limited secretion
what is the function of the stomach?
- propulsion
- chemical digestion
- mechanical digestion
- secretion
- limited absorption
what is the function of the small intestine?
- chemical digestion
- mechanical digestion
- absorption
- secretion
- propulsion
what is the function of the large intestine?
- absorption of water, electrolytes, and vitamins
- propulsion
- limited secretion
- defecation
what is the function of the teeth?
mechanical digestion (mastification)
what is the function of the tongue?
- mechanical digestion
- propulsion
- sense of taste
what is the function of the salivary glands?
- secrete saliva
- chemical digestion of carbohydrates
what is the function of the pancreas?
- secretes enzymes that catalyze chemical digestion of lipids, carbs, proteins, and nucleic acids
- secretes bicarbonate ions to neutralize acidic chyme
what is the function of the liver?
- mechanical digestion
- excretion
what is the function of the gallbladder?
- mechanical digestion
