Chapter 18- The Urinary System Flashcards
what organs are included in the urinary system?
two kidneys, two ureters, urinary bladder and urethra.
what are the function of the kidneys?
- regulation of the volume of blood by excretions or conservation of water
- regulation of the electrolyte content of the blood by the excretion or conversation of minerals
- regulation of the acid-base balance of the blood by excretion or conservation of ions,
- regulation of all the above in tissue fluids
- removal of waste: urea, creatinine, ammonium
what fibrous connective tissue membrane help holds the kidneys in place
renal fascia
what is the hilus?
an indentation on its medial side, where the renal artery enters the kidney and the renal vein and ureter emerge.
what is the purpose of the ureter?
carries urine from the kidney to the urinary bladder
what is the name of the 2 layers of the kidneys?
- renal cortex; outter layer tissue,
2. renal medulla, inner tissue layer
what is the renal pelvis
cavity formed by the expansion of the ureter wihtin the kidney at the helius.
Each nephron has two major portions. What are they?
- renal corpuscle
2. renal tubule
what 3 major process are involved in the formation of urine?
1 glomular filtation > in renal corpuscles
- tubular reabsorption > in renal tubules
- tubular secretion > in renal tubules
what is GFR?
glomular filtration rate is the amount of renal filtrate formed by the kidneys in one min.
average 100-125 ml/ min
what is renal failure?
inability of the kidneys to function properly and may be the result of 3 general causes:
- prerenal, (before the kidneys)
- intrinsic renal, (kidney problem) caused 70% of the time by DM or HTN
- postrenal (after kidneys - think urethra block)
what is Rhabdomyolysis
results of damage to skeletal muscle tissues which cayses large molecules to leaf from damaged cells into the blood and may clog the kidney tubules.
what is polycystic kidney diease
when the kidney tubules dilate and become unfunctional.
what is hemodialysis?
use of an artificial kidney machine to do what the patients nephrons can no longer do.
- prolongs life for those with kidney failure
- people usually need a kidney transplant
what percent of the of the filtrate is reabsorbed back into the blood in the peritubular capillaries?
99%, 1% will enter as urine.
where does most reaborsption and secretion take place?
65% in proximal convoluted tubules- those cells have microvilli.
what are the 4 mechanisms of reabsorption?
- active transport >glucose, AA, vit, +ve ions
- passive transport >-ve ions
- osmosis > water
- pinocytosis > small proteins -
what is tubular secretion?
substances are actively secreted from the blood in the peritubular capillaries into the filtrate in the renal tubules
eg. ammonia, creatinine, and metabolic profects of medicaions.
what does the hormone ADH, released by the posterior pituitary gland when the amount of water in the body decreaes, do to the kidneys?
the distal convoluted tubules and collecting tubules are able too reasborb more water from the renal filtrate.
when dehydration has subsited, ADH will diminish.
how does the kidneys react to a change in pH?
if body is too acidic, the kidneys will secrete more H+ ion into the renal filtrate and will return more HCO3- ions to the blood, this will rase the blood pH.
if the body is too alkaline the kidneys will return H+ ions into the blood, and excrete HCO3- ions into the urine.
> kidneys can also use phosphate buffer system
what are 3 other functions of the kidneys that are not related to urine formation?
- secretion of renin
- secretion of erythropoientin
- activation of vit D into vit D3 (calcitriol)
what is renin>
initiates the renin-angiotensin mechanism to raise BP, and produce Angiotensin 2 which causes casoconstriciton and increases the secretion of aldosterone, both help raise BP.
what is erythropoientin
secreted hormone when [O2] decreased. stimulates red bone marrow to increase the rate of RBC production.
what are the 4 steps of renin-angiotensin mechanism?
- decreased BP stimulates the kidneys to secrete renin
- renin splits the plasma protein angiotensinogen (synthesized by liver) to angiotensin 1.
- angiotensin 1 is converted to angiotensin 2, by an enzyme found in lung tissue and vascular endothelium
- angiotensin 2 causes vasoconstriction and stimulates the adrenal cortex to secrete aldosterone.
what is the number of the mucosa layer of the bladder, and why is it unique?
transitional epithelium, permits expansion without tearing the lining.
what are two additional names for urination?
micturition or voiding
- the reflex is a spinal cord reflex overwhich voluntary control may be exerted.
name the following characteristics of urine
- amount
- color
- specific gravity (measures dissolve materials in urine)
- pH
- constituents
- nitrogenous waste
- 1-2 L /24 hours (increase amount is polyuria, and decreased amount is oliguria)
- color (the more amber the more concetration), should be clear not cloudy.
- 1.010 to 1.025
- (4.6-8)
- 95% water, 5% salts and waste
- urea- from AA metaboliosm,
creatmnine- from muscle metabolism
uric acid- from nucleic acid metabolism
where are kidney stones most likely to apprear?
renal pelvis,
d/t decreased fuild, or overingestion of minerals
what is uremia
general term for an elevated blood urea level.
why would BUN be elevated?
as consequence of high protein diet or starvation when body protein is being broken down at a faster rate than normal.
uric acid levels may vary according to what general factor?
diet
what is cystitis
inflammation of the urinary bladder
what is nephritis
is inflammation of the kidneys
