1001NSC Lecture Notes - Lecture 12: Creatinine, Small Intestine, Helicobacter Pylori
20 Jun 2018
School
Department
Course
Professor
The Urinary System
Anatomy:
Kidneys: contain nephrons
Ureters: tubes from kidneys to bladder
Bladder: urine storage
Urethra: tube by which urine leaves the body
Physiology:
Conservation of water/salts
Some glucose supply used during prolonged fasting
Excretion of wastes (creatinine, urea etc)
Hormone production (erythropoietin - stimulates RBC production)
Enzyme production (renin - regulates blood pressure)
Vitamin activation (vitamin D3)
Horseshoe kidney
Congenital abnormality affecting 1 in 500 people
Kidneys fuse together to form horseshoe shape during development in womb
Most common renal fusion anomaly
Mel Gisbon has this!
Most cases are asymptomatic and are only discovered upon autopsy
May increase risk for kidney obstruction, infection, kidney stones, kidney cancer
Kidneys:
Protected and insulate by
Renal fascia: outer, dense, fibrous tissue
Adipose layer: middle layer of fat
Renal capsule: inner, thin, shiny membrane on kidney surface
Structure of Kidney:
Outer cortex: site of filtration, light-coloured, granular appearance
Inner medulla: site of reabsorption and excretion, dark red-brown colour, arranged into
series of pyramids, point of each pyramid is the papilla, papilla points inwards, towards
calyces
The Renal Pelvis
A central junction close to where renal artery enters and renal vein exits kidney
large funnel-shaped collecting tubule
Calyces: branching extensions of renal pelvis, collect urine draining from pyramids
Walls of calyces, renal pelvis and ureter contain smooth muscle
Propels urine along peristalsis
Nephron:
consists of glomerulus, Bowman’s capsule, proximal and distal convoluted tubules, look of
Henle, collecting duct
Glomerulus: pin head sized gift of arterioles
Bowman’s Capsule:
up like structure that holds glomerulus
Allows fluid to pass from blood into collecting tubules
Glomerulus and bowman’s capsule make up the renal corpuscle
Arteriole endothelial wall has tiny holes allowing fluid, solutes, wastes to leak out of blood but does
not allow blood cells out
Urine formation:
1. Glomeral Filtration: filtration membrane, endothelial cell membrane, podocytes, filtrate
collected by bowman’s capsule
find more resources at oneclass.com
find more resources at oneclass.com
2. Tubular reabsorption: following are reabsorbed - glucose, lactate, amino acids, Na+ ions,
water
Descending look of Henle: freely permeable to water therefore water moves by
osmosis out of look into extracellular place within tubule wall
Ascending loop of Henle impermeable water, actively reabsorbs salts back into blood
Distal consulted tubule and collecting duct: hormone-dependant permeability to water by
ADH (Anti-diuretic hormone) and Aldosterone
3. Aldosterone: released by adrenal glands
Enhances Na+ reabsorption in distal convoluted tubule
Water follows Na+ ions back into the blood
Urine becomes more concentrated
4. Tubular secretion:
Occurs within proximal convoluted tubule, late regions of distal convoluted tubule and
collecting duct
Tubular secretion important for: disposal of certain substances (drugs, penicillin), controlling
body pH, ridding body of excess potassium and toxic end-products (urea, uric acid)
ADH: assists with water reabsorption back into the body
Urine output
Polycystic kidney disease:
Cysts are non-cancerous sacs containing watery fluid
Cysts vary in size
Urinary bladder:
Collapsable, smooth muscular sac, temporarily stores urine
Three layers: inner mucosa, middle, smooth layer and outer, fibrous connective tissue
Ureters:
Slender tubes lined with smooth muscle, convey urine from kidney to bladder
Urethra:
thin-walled, muscular tube, drains urine from bladder during urination, has internal and
external sphincter
Trigone:
Smooth, triangular region in bladder floor, outlined by three tubes (two ureter’s from kidney,
and urethra)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Urethra: tube by which urine leaves the body. Kidneys fuse together to form horseshoe shape during development in womb. Most cases are asymptomatic and are only discovered upon autopsy. May increase risk for kidney obstruction, infection, kidney stones, kidney cancer. Renal capsule: inner, thin, shiny membrane on kidney surface. Outer cortex: site of ltration, light-coloured, granular appearance. Inner medulla: site of reabsorption and excretion, dark red-brown colour, arranged into series of pyramids, point of each pyramid is the papilla, papilla points inwards, towards calyces. A central junction close to where renal artery enters and renal vein exits kidney large funnel-shaped collecting tubule. Calyces: branching extensions of renal pelvis, collect urine draining from pyramids. Walls of calyces, renal pelvis and ureter contain smooth muscle. Nephron: consists of glomerulus, bowman"s capsule, proximal and distal convoluted tubules, look of. Bowman"s capsule: up like structure that holds glomerulus. Allows uid to pass from blood into collecting tubules.
