Urinary system Flashcards
parts of urinary system:
- kidneys
- ureters
- urinary bladder
- urethra
main general function: kidney, ureters, urinary bladder and urethra
filters 150L water- reabsorbed into blood stream, only 1-2L are expelled as urine
- other reabsorbed products by nephron also back into bloodstream
kidneys: filter blood plasma (remove urea, uric acid, ammonia)
ureters, urinary bladder and urethra serve as passageways and storage of urine
kidney functions:
- excrete waste products
- enzymatic blood pressure regulation (secretes renin)
production of hormones:
- calcitriol (active form of vit D, increases Ca)
- erythropoietin (stimulates production of RBC)
regulates blood:
- blood ionic composition
- pH
- volume
- osmolarity
- glucose levels
location: kidneys
- retroperitoneal organ (only ant surface covered)
- left kidney higher
- posterior abdominal wall btw T12-L3 vertebrae
- renal hilum (on concave border)
layers of tissue surrounding: kidney
- renal capsule (DICT)
- adipose capsule
- renal fascia (DICT)
kidney parts:
- renal cortex (outer)
- renal medulla (inner) -> renal pyramids: apex- renal papillae -> towards hilum
renal column: cortex in btw pyramids
renal lobe: pyramid with cortex and half column each side
- segment
minor calyx:
receives urine from papillary ducts of ONE renal papilla
how many major and minor calyces per kidney:
minor: 8-18
major: 2-3
they are spaces to move filtrate
renal pelvis:
single large cavity in kidney connected ureter
renal sinus:
combo of: renal pelvis, calyces, renal blood vessels and nerves
difference btw filtrate and urine?
filtrate: products filtered in nephron all the way to minor calyx
then is called urine
flow of filtrate/urine:
pyramids -> renal papillae -> minor calyx -> major calyx -> renal pelvis -> ureter
blood supply: kidney
renal arteries (from hilum) -> segmental arteries -> interlobar (around medulla) -> arcuate (base of medulla) -> afferent arterioles -> blood inside kidney
nephron parts:
- renal corpuscle
- glomerulus
- glomerular (Bowman’s capsule)
- renal tubule
- proximal convoluted tubule
- loop of Henle
- distal convoluted tubule
- collecting ducts
types of nephron:
cortical: in cortex
juxtamedullary: sit more inside medulla
cortical nephron features:
80-85% nephrons
- renal corpuscle in outer portion of cortex and
- shorter loops of Henle only into outer region of medulla
- thick ascending limb of Loop of Henle
- tubules receive secretions from peritubular capillaries which reabsorb some filtrate
juxtamedullary nephron features:
15-20% nephrons
- renal corpuscle deep in cortex
- long loops of Henle extend deep into medulla
- ascending limb of LOH has thin and thick portions
- tubules receive secretions from peritubular capillaries and casa recta -> also reabsorb some of the filtrate
- enable kidney to secrete very conc. urine
glomerular capsule layers:
- visceral layer: modified s.s.e -> podocytes (pedicles, filtration slits) allow water and small molecules to filter into corpuscle space
- parietal layer: sse.
- capsular (Bowman’s) space-> blood not filtered passes into efferent arteries
cells: proximal convoluted tubule (PCT)
simple cuboidal epithlium with microvilli brush border
cells: Loop of Henle- thin ascending and thick descending limb
simple squamous epithelium
cells: thick ascending limb
simple cuboidal cells, to low columnar epithelium
cells: most of distal convoluted tubule (DCT)
simple cuboidal epithelium
cells: last part of DCT and all of collecting duct
simple cuboidal epithelium, consisting of principle cells and intercalated cells
macula densa: features and juxtaglomerular cells
macula - final part of LOH, in contact with afferent arteriole
juxtaglomerular- modified smooth muscle cells in afferent arteriole wall
ureters: features
muscular ducts carry urine from kidneys to bladder
- retroperitoneal
- stellate lumen (star shape)
- 3 layered wall: muscosa, muscularis, adventitia
- peristaltic movement
ureters: blood supply
renal, testicular or ovarian arteries
- common iliac arteries
urinary bladder general features/ location:
hollow organ with strong muscular wall,
- distensible
- pelvic cavity posterior to pubic symphysis
ureters: mucosa cells and muscularis layers
transitional epithelium, lamina propria
- inner longitudinal, outer circular layers
urinary bladder in relation to female body location:
inferior to uterus
- anterior to rectum,
- superior to vagina
- posterior to pubic symphysis
urinary bladder in relation to male body location:
anterior to rectum
- posterior to pubic symphysis
urinary bladder: trigone
- floor
- triangular shape
- ureteral openings
- internal urethral orifice
urinary bladder: apex
points to pubic symphysis
urinary bladder: internal urethral sphincter
meeting point of urethra and bladder
urinary bladder: wall
- muscosa: transitional ep. lamina propria (forms rugae for distension)
- muscularis
- adventitia (poster, inferior aspects)
- serosa (superior)
detrusor muscle:
- inner longitudinal
- middle circular
- outer longitudinal
female urethra: wall, ends at
ends in external urethral orifice
mucosa, muscularis (circular layer)
female urethra: mucosa cells
transitional - stratified columnar or pseudostratified columnar -> non keratinised simple squamous
male urethra: parts
- prostatic urethra (btw prostate glands)- also seminal vesicles/ vas deferens openings
- membranous urethra
- spongy/ penile urethra ends in external urethral orifice
micturition:
discharging urine from urinary bladder: combo or involuntary and voluntary muscle contraction
