fisiology renal system
DESCRIPTION
bahan pembelajaran tentang fisiologis perkemihanTRANSCRIPT
LELI MULYATI,SKp,M.Kep.Sp.MB
Renal system summary
Functions:1. Remove wastes from the body (urine)2. Regulates fluid balance, maintains
homeostasis
Structures: 2 kidneys - filter blood, produce urine 2 ureters - transport urine (kidneys to
bladder) bladder - reservoir for urine urethra - transport of urine
FUNGSI GINJAL Kidneys carry out four functions
Filter nitrogenous wastes, toxins, ions, etc. from blood to be excreted as urine.
Regulate volume and chemical composition of blood (water, salts, acids, bases).
Produce regulatory enzymes.Renin – regulates BP/ kidney function Erthropoeitin – stimulates RBC production from marrow.
Metabolism of Vitamin D to active form.
Vascular component of nephronMade up of blood vessels:
1. Glomerulus - network of capillaries within Bowman’s capsule
2. Afferent arteriole - leading into glomerulus
3. Efferent arteriole - leading out of glomerulus
4. Peritubular capillaries - surrounding tubules
5. Vasa recta - specialised loops of blood vessels around long Loop of Henle (juxtamedullary nephrons)
Blood supply to the kidney:
Renal arteries from abdominal aorta enter hilum and branch:
1. Interlobar arteries - pass through renal columns and reach junction between medulla and cortex
2. Arcuate arteries run parallel with the base of the pyramids
3. Interlobular arteries move up into the cortex and branch to form the afferent arteriole
The peritubular capillaries unite to form the interlobular veins, arcuate vein, interlobar vein, renal vein
The renal vein exits at hilus and joins the IVC
Nephrons: 85% are cortical, 15% are juxtamedullary
Renal corpuscle
III. Renal CorpuscleSecondary processes interdigitate around
glomerular capillaries. The narrow space between processes is the filtration slit. 19-5
Glomerular FiltrationGlomerular Filtration
afferent arteriole
glomerulus
efferent
arteriole
Bowman’s capsule
Filters blood; proteins can’t pass through
Proximal Convoluted Tubule
Reabsorbs: water, glucose, Reabsorbs: water, glucose, amino acids, and sodium.amino acids, and sodium.
•65% of Na+ is reabsorbed•65% of H2O is reabsorbed•90% of filtered bicarbonate
(HCO3-)
•50% of Cl- and K+
Loop of Henle
Creates a gradient of increasing Creates a gradient of increasing sodium ion concentration towards sodium ion concentration towards the end of the loop within the the end of the loop within the interstitial fluid of the renal pyramid.interstitial fluid of the renal pyramid.
•25% Na+ is reabsorbed in the loop
•15% water is reabsorbed in the loop
•40% K is reabsorbed in the loop
Distal Convoluted Tubule
Under the influence of the hormone Under the influence of the hormone aldosterone, reabsorbs sodium and aldosterone, reabsorbs sodium and secretes potassium. Also regulates secretes potassium. Also regulates pH by secreting hydrogen ion when pH by secreting hydrogen ion when pH of the plasma is low.pH of the plasma is low.
• only 10% of the filtered NaCl and 20% of water remains
Collecting Duct
Allows for the osmotic Allows for the osmotic reabsorption of water.reabsorption of water.
ADH (antidiuretic hormone)- makes collecting ducts more permeable to water-- produce concentrated urine
From the original 1800 g NaCl, only 10 g appears in the urine
Urine
Water- 95%Nitrogenous waste:
• urea• uric acid• creatinine
Ions:• sodium• potassium• sulfate• phosphate
vein
artery
afferent
arteriole
efferent arteriol
e
glomerulus
peritubular
capillaries
Bowman’s capsule
proximal convoluted tubuledistal convoluted tubule
loop of
Henle
collecting duct
Regulation of Water BalanceRegulation of Water Balance
Brain monitors water content of bloodBrain monitors water content of blood
If low water content, pituitary releases ADHIf low water content, pituitary releases ADH
ADH travels in blood to nephronADH travels in blood to nephron
ADH causes more water to move from urine back ADH causes more water to move from urine back into bloodinto blood
Ureters Pyelogram (colour-enhanced)
tubes that transport urine from renal pelvis to bladder
20-30 cm long
muscular walls - peristaltic waves force urine down to bladder
retroperitoneal
pressure in the bladder compresses ureter, helps prevent backflow of urine
(physiological valve) - still allows urine to flow into the bladder
Bladder
hollow muscular organ retroperitoneal, posterior
to pubic symphysis
Capacity ~ 300-400 ml (max = 1000 ml)
empty: looks like a deflated balloon, rugae
full spherical rises above abdominal cavity
Males: anterior to rectum, above prostate
Females: inferior to uterus, anterior to vagina
Martini p983
Support of bladder Martini p983
superior surfaces - peritoneum
middle umbilical ligament - superior border to umbilicus
lateral umbilical ligaments - sides of bladder to umbilicus
At base, tough ligamentous bands anchor bladder to pelvic and pubic bones
Trigone : triangular area bounded by openings of ureters and exit to urethra
cystitis - inflammation of the bladder wall
Urethra Martini p983
Female ~ 4cm long opens to exterior between
clitoris and vaginal opening
Male ~ 20 cm long passes through prostate
gland
pierces urogenital diaphragm
enters penis and extends throughout length
opens at urethral orifice
Micturition reflex:Stretch receptors stimulated when filled to
~ 200 ml afferent fibres to spinal cord motor neurons to sm in bladder wall contracts m. detrusor and increases
pressure
need to relax both internal and external sphincter - external under voluntary control
if external sphincter does not relax, internal sphincter remains closed & sm in bladder wall relaxes again
Once volume exceeds 500 ml, micturition reflex may generate enough P to open internal sphincter
leads to reflexive relaxation of external sphincter