Lecture Outline #25: Urinary System Flashcards
urinary system functions (3)
homeostatic functions
complicated filter mechanism
filtrate urine from kidneys to ureters
urinary function: homeostasis
maintain correct balance of Na, K, Cl, and Ca ions (create the pH level)
assist in pH balance (urine should be acidic)
regulates blood pressure by adjusting blood volume which needs a certain osmotic pressure.
urinary function: filter mechanism
retain valuable nutrients
excrete nitrogenous wastes
urinary function: filtrate urine
ureters transfer urine into urinary bladder
kidney location
paired organs on posterior wall of abdominal cavity
outside of peritoneal cavity: retroperitoneal
surrounded by pararenal adipose and renal capsule
kidney structure: renal cortex
outer-most layer
primary function: filtration
kidney structure: renal medulla
inner-most layer
primary function: contain BVs and drainage
contains: renal columns (blood supply to nephron) and renal pyramids (drainage)
kidney structure: renal pelvis - cavity
tapers to form the ureter
contains minor calyces (right after renal papilla), major calyces (where minor calyces meet), and the actual renal pelvis (where major calyces meet)
kidney structure: renal hilus
entrance for renal a.s and ANS n.s and exit for renal v., lymphatic vessels, and ureters.
contain the renal sinus located outside the kiney and surrounds renal pelvis and calyces, is a fat-filled depression
kidney structure: lobes
renal pyramid + renal papilla + minor calyx = lobe
pyramid pokes into minor calyx via papilla
lobes are separated by renal columns which are composed of cortical tissue and act as a path for renal BVs from hilus to cortex
renal BVs: arteries
renal a.s off abdominal aorta @ hilus outside major/minor calyces
- segmental a.s (where renal a.s separate, come up to renal columns
- interlobar a.s (go through renal columns)
- arcurate a.s (bend towards the merge of cortex & medulla)
- cortical a.s (extend through cortex)
- afferent arterioles
- glomerulus (capillary bed)
glomerular/bowman’s capsule
surrounds glomerulus where blood filtrate (completely plasma) is and is pushed to proximal convoluted tubule
glomerulus drained by
efferent arterioles - where blood plasma is leaked to maintain osmotic pressure, controlled by ANS
- this plasma is sent to nephron
blood plasma/filtrate passes to peritubular capillaries - recover 99% of blood/plasma/H2O
kidneys drained by
peritubular capillaries
venules
interlobular v.s
arcurate v.s
interlobar v.s
renal v.s
nephron
function unit kidney
1 million per kidney
complex plumbing
majority located in cortex = cortical nephrons
some in both cortex and medulla = juxtamedullary nephrons
nephron - renal corpuscle (malphighain)
consists:
1. glomerular capsule
2. afferent arteriole
3. efferent arteriole
4. glomerular capillary bed
glomerulus
covered by podocytes - regulate interdigitated pedicles to open/close
interdigital pedicles - course filter, secondary BP control (when hydrated, plasma leaks more but still don’t allow RBCs and big proteins past - if they do = problems)
nephron - proximal convoluted tubule
collects filtrate from glomerular capsule
reclamation of water, all organic nutrients
1 tube per nephron
nephron - loop of henle
descending limb - travels down to medullar
ascending limb - travels back to cortex
1 per nephron
reclamation of sodium, chloride, and water
nephron - distal convoluted tubule
secretion of durgs, toxins
1 per nephron
nephron - collecting duct
multiple nephrons dump into this
gathers the filtrate from many distal convoluted tubules
further reclamation of water
they combine/terminate to form renal papilla, where the filtrate is now urine
kidney (through nephron) filtrate flow
renal corpuscle
proximal convoluted tubule
descending limb
ascending limb
distal convoluted tubule
collecting duct
renal papilla
minor calyx
major calyx
renal pelvis
ureter
urinary bladder
urethra
urethral orifice
ureters
transfer via peristalsis urine from renal pelvis to urinary bladder
urine only retains cells from here
retroperitoneal location
made up of
- mucosa (epithelium) on inside
- muscularis (2 layers, active peristalsis) in middle
- adventitia (CT, serosa) on outside
urinary bladder
hollow organ to store urine
walls made of 2 layers of m. - detrusor m. (involuntary smooth m., when contracts = urinate)
rugae on inner surface, increased SA when expands/flattens which stretches baroreceptors = urge to urinate)
retroperitoneal location - posterior to pubic symphysis
male - anterior to rectum
female - anterior to uterus
urinary bladder - urethra, ureters, trigone
ureters enter posterolateral corners of bladder and open at the ureteral openings on trigone of bladder floor
trigone is the region of bladder floor that also has 1 urethral opening
urethra drains via internal urethral sphincter (internal smooth m.)
urethra
transfers urine from bladder to outside body
passes through pelvis diaphragm via external urethral sphincter (voluntary skeletal m.)
urethra - male division
- prostatic urethra - passes through prostate gland
- membranous urethra - goes through pelvis flood via external urethral sphincter
- penile urethra
UTIs
urinary tract infections, occur because bacteria more readily colonize bladder, ureters, and kidneys
urogenital system
urinary + reproductive systems
- have a shared development and predictable malformation
kidney malformations
fine as long as they work
ex - horseshoe kidneys, 4 of them
urine comp
93-97% water
sterile
pH: 4.5-8
urinalysis
physical and chemical assessment of urine
pregnancy detection
pyelogram
x-ray image of kidneys and urine after injection of a radiopaque dye
nephrolithiasis
renal calculi - kidney stones (not smooth or circular)
made of Ca/Mg salts and uric acid crystals that cause blockage of ureters
diuretics
drugs that promote fluid loss in the urine (mainly to get alcohol out)
hematuria
blood loss in urine
(blood in urine = problem)
proteinuria
protein loss in urine
dysuria
painful urination often associated with STDs
