Urinary system Flashcards
kidney+function
12cm, 6, 2,5 thick w hilum ( a concave medial border-vessels enter)+ convex lat border. covered by fibrous capsule.
- medulla has 8-15 renal pyramids base= corticomedullary junction; separated by renal columns. tip of pyramid=renal papillae collects urine from tubule-> minor calyx. nephrons functional unit of kidney decreases in age-accelerated by b.p
- balance +reg of ions, water+ electrolytes, acid base balance
- excretion of metabolic waste + excess water+ions pass ureter for temporary storage into bladder.
- excretion of bioactive substance =drugs
- excrete RENIN which cleaves angiotensin I+II=reg b.p
- secrete ERYTHROPOITIN which stimulate production rbc when O2 level low
-produce active form of vit D (initially made in skin) = 1,25 dihydroxyvitamin D3=CALCITROL - GLUCOGENESIS converts aa-> glucose in periods of prolonged fasting
blood circulation
filtration
renal a+v-> interlobular (at renal pelvis)-> arcuate along base of pyramid-> smaller interlobular extend to cortex-> afferent a divide to form capillary plexus= globular a
blood leaves via efferent a -> branch to peritubular capillaries in cortex and vasa recta in medulla (cortex receive 10X more blood than medulla)
filtration where water+ solutes leave vascular pole-> nephron lumen-> tubular secretion: substances epi cells of tubules to lumen-> tubular reabsorption: substance move from tubular lumen -> intertitium+ capillaries
Renal corpuscle
200um=d, has vascular (vessels)+urinary (recieve fluid filtered through cap wall) + tubular pole (PCT begins)
corpuscle has parietal (SIMPLE SQ epi)+ visceral (stellate=PODOCYTE- large ovoid nuclei, cover glomerular capillary; has primary process-> parallel interdigitating secondary processes= PEDICLES- cover endothelial surface +basal lamina)
urinary/bowmen’s space between both: receive ultrafiltrate
interdigitating pedicles have pores 25-30nm w bridging SLIT DIAPHRAGMS (modified tight junctions made of nephrins, protein, glycop+ proteogly)
Glomerulus: ultrafiltrate: slit together w endothelium of capillary=narrow filtration
- glomerular basement membrane: joint product of ENDOTHELIUM+PODOCYTES, thick, PAS+
mesangial cells: stains darker than podocytes
support+ receptors for angiotensin
contraction to maintain optimal filtration rate, phagocytose antigen-antibody complex, secrete cytokine+ prostaglandins (immune def+repair)
filtration: rate 180L/d
1) fenestration of capillary endothelium
2) glomerular basement membrane (300-360um)- laminin+fibronectin bind to Iv vollagen+ podocyte +endothelial cell membrane: restrict large mol, smaller pass and degrade reabsorbed by PCT, abundant gag anionic also restrict
3) diaphragms of filtration slits between pedicles
filtration affects blood pressure ↑ b.p: ↑ arteriorle p-> ↑ glomerular p -> ↑ filtration (↑ na+cl, monitored by cells of macula densa) ↑ ions release ATP for contraction of afferent arteriole
decreasing b.p: stimulate autonomous inn of JGA due to baroreceptors on afferent/ JC cells release renin, cleaves angiotensin I +II, rasininf blood pressure + stimulate release of aldosterone
juxtamedullary nephrons =in medulla w long loops henle +long asc thin segments -> inner region of pyramid
macula densa: COLUMNAR cells of DT in contact w vascular pole of renal corpuscle
juxtaglomerular granular cells: modified smooth cells of afferent arteriole tunica media
RER+GA+ ZYMOGEN GRANULES- w renin
kidney cortex+medulla
cortex:
RENAL CORPUSCLE: glomerulus+ bowmans
CORTICAL LABYRINTH: convoluted portion of PTC+DTC
MEDULLARY RAYS: medullary tissue, straight portion of PT,DT and collecting tubule
medulla:
has interstitium w sparse myofibroblasts+ hyaluronate (for ref of osmolarity gradient)
RENAL PYRAMIDS (thick+thin loops of Henle)
RENAL PAPILLAE (papillary duct PD- distal part of collecting duct)
RENAL COLUMN (cortical tissue)
renal corpuscle-> PT (convoluted in cortex and straight in medulla)-> loop of henle (thin desc+thin asc)-> Distal tubule (thick straight part that asc+ convoluted part) -> connecting tubule (link nephron to collectin ducts) merge-> collecting tubule merge= collecting duct
medullary rays (tubules)-> collecting duct-> (distal portion of CD) papillary duct -> renal papillae-> calyx -> renal pelvis
PCT
Loop
DCT
Collecting duct
papillar duct
PCT: SIMPLE CUB TO SIMPLE COLUMNAR+ EOSINOPHILIC (mito)
- 50-60um, BRUSH BORDER (irreg lumen)+ BASAL STRIATION (na/K) - mito in infolding of basal labyrinth (deep invagination of plasmolemma)
- indistinct lateral cell boundaries+ irreg lumen
- low # of nuclei
- on apical surface has vesicles= active ENDOCYTOSIS+ PINOCYTOSIS
- Large mol (organic ions+cations, creatine, bile salts)-> peritubular a, now filtrate-> efferent
- PAS (due to glycocalyx of microvilli)+ALKALINE PHOSPHATASE ACTIVITY (9 pH, dephosphorylation)
azo dye coupling method: ALFA NAPHTOL PHOSPHATE, FAST RED TR
- enzyme hydrolyses substrate into phosphate+naphtol: released naphtol is coupled w DIAZONIUM SALT forming= insoluble coloured azo dye
- F: 1) reabsorption 60-65% glomerular filtrate=primary urine+ glucosa+ aa+ Na+ H2O. 2) has lysosomal- endocytosis of large proteins. 3) tubular secretion: sulfates+steroid+ glucuronids+ kreatinin foreign subs (penicillin+ iodinated compounds for diagnosis)
P STRAIGHT TUBULE: descent from cortex-medulla.
similar to PCT
Loop of Henle
U shaped, desc+asc limb
thin: 15um, SIMPLE SQ epi
thick 30um, SIMPLE CUBOIDAL epi
f: cuboidal cells transport Na+ Cl out of tubule against conc gradient become hyperosmotic, so water taken out of descending tubule.
DTC:
50-60um, SIMPLE CUBOIDAL epi. More nuclei on section bc NO BRUSH BORDER; has BASAL STRIATION (unfolding of p.m+ mito). less eosinophilic. visible cell boundaries.
- F: ion transportation (water+ Na reg aldosterone+ ammonium and hydrogen)
Collecting duct
40um, SIMPLE CUBOIDAL/COLUMNAR epi
pale staining cells, prominent cell borders
bulged apical surface, have PRINCIPAL cells- on basal membrane infoldings (ion transport =primary cilium; have aquaporin in vesicles which go apical (due to ADH)
to increase water channels
- intercalated cells IC (abundant mito+apical folds) maintain acid-base conc by secreting H or HCO3
Papillary duct
200-300um+ SIMPLE COLUMNAR epi. involved in final water reabsorption under ADH
Ureter
excretory urinary ways: intrarenal (collecting tubules+papillary ducts)+ extrarenal (calyxes, renal pelvis, ureter, bladder urethra f/m)
T mucosa: transitional epi (urothelium-between strat sq non kera+pseudo ) for extrarenal (calyxes, renal pelvis, ureter, cranial part female urethra, intramural+ prostatic part of male urethra); caudal part of female urethra= STRAT SQ epi; membranous+spongy part of male urethra STRAT COLUMNAR epi (some parts pseudo; fossa navicularis=STRAT SQ
LP- FIBROELASTIC (denser) + longitudinal folds (NO GLANDS)
T muscularis: irreg arrangement of smooth m (inner circular+ outer long)=thick. caudal part of ureter= has 3 layers (outer long, middle circular, outer long)
T adventitia- loose CT, vessels, nerves+ adipocytes
transitional epi- basemen membrane has basal cells+intermediate region w columnar cells. superficially UMBRELLA CELLS (bulbous/elliptical) can be binucleated: protect against cytotoxic effects of urine (very well developed in urinary bladder)
urinary bladder
bladder holds 400-600mL urine, urge to empty 150-200mL. carry urine from ureter and stores it.
T mucosa: same as ureter (urothelium, basal+columnar cells) but more developed+abundant? umbrella cells (100um+ intracellular JUNCTIONS form from apical plaque = UROPLANKIN- asymmetric unit membrane outer layer-thicker lipid > inner).
LP-loose CT (collagen) +elastic
T submucosa (thin): dense irreg CT highly vasc (more elastic fibres in a to remain open when full)
T muscularis =DETRUSOR MUSCLE (inner long, middle circ, outer long)-adipose tissue in between (3 layers most distinct at neck of bladder- near urethra)
T serosa: upper part (above trigone)
T. adventitia (loose CT+ elastic fibers)
relaxed: more folds in mucosa; full: mucosa pulled smooth, urothelium is smoother+ umbrella cells flatter.
urine moved through peristatic contractions.
urethra
tube carry urine from bladder-> exterior
Male- 4 seg:
- intramural (wall of bladder): transitional epi
- prostatic: transitional, 3-4cm
- diaphragmic (urogenital diaphragm): STRAT COLUMNAR epi
- spongy (corpus spongiosum): STRAT COLUMNAR epi
navicular fossa has STRAT SQ epi
T mucosa: longitudinal folds
LPM=loose CT+ elastic f+ LACUNAE URETHRAL GLANDS (MORGAGNI)= endoepi mucous glands; PARAURETHRAL GLANDS (LITTREI)= branced tubular mucous glands+ venous plexus mainly in spongiosa part
T muscularis
inner circ+ outer long.
reduced in pars spongiosa=only bundles
pars diaphragmatica= STRIATED M: urethral sphincter m (external?)
Female- 3-5cm
T mucosa: transitional at cranial; becomes STRAT SQ non-keratinized (bc continuous w labia minora of skin)+ longitudinal folds; endothelial mucous glands+ branched tubular mucous glands
LPM: loose CT+ venous plexus
T muscularis: inner circ+outer long+ outer striated= urethral sphincter m
T adventitia -loose CT
