Chapter 14: The Urinary System Lesson 14.1 Anatomy of the Kidney

Kidney Location and Size

Anatomy of the Kidney Retroperitoneal and fat covered renal cortex 11 cm X 3cm X 6cm 150 gm renal cortex Outer, light colored renal medulla Middle, darker Renal pyramids renal pelvis Inner, leads to ureter hollow

Anatomy of the Kidney renal medulla Ureter bladder Pyramid Columns Base- out Papilla-in Columns Separate Ureter One for each bladder urethra

Nerve and Blood Supply 20–25% of blood flows to kidneys renal artery renal vein sympathetic nerve system renal nerve fibers Mesh around renal artery Everything connects at the Hilum

The Nephron basic working unit of each kidney two main parts Each kidney has 1 million nephrons Each nephron has a blood supply and creates urine two main parts renal corpuscle Glomerulus (capillaries) Glomerular capsule ( collecting cup) Enters at afferent, exits at efferent (arterioles) Like a cul-de-sac renal tubule processing

The Glomerulus glomerular capsule outer surface Podocytes interlock filtration slits wastes sifted out of blood

Renal Tubule proximal convoluted tubule (PCT) At glomerulus nephron loop (loop of Henle) Descending (thin walls) and ascending distal convoluted tubule (DCT) collecting duct Receives from several nephrons Drains to renal pelvis

Blood Flow through the Kidneys renal artery afferent arteriole Glomerulus Plasma and wastes removed efferent arteriole peritubular capillaries or vasa recta Secondary capillaries Fluid reabsorption Venules renal vein

Urine Formation, Storage, and Excretion Chapter 14: The Urinary System Lesson 14.2 Urine Formation, Storage, and Excretion

Urine Formation filtration reabsorption secretion water and solutes from capillary to glomerular capsular space reabsorption water and solutes move from tubule to capillary secretion wastes in capillary pushed into tubule

Urine Formation

Filtration molecules smaller than 3 nanometers pushed out of blood hydrostatic pressure caused by potential energy (high to low) osmotic pressure from dissolved substances in water (salt sucks) pressure controls constriction of arteries

Reabsorption sodium secondary active transport osmotic pressure actively pumped out by sodium-potassium pump proteins secondary active transport glucose, amino acids, ions, vitamins osmotic pressure aquaporin channels Ion movement

Reabsorption

Secretion maintain arterial blood pH at 7.4 (active) hydrogen ions bicarbonate ions some drugs secreted penicillin aspirin

The Renal Medulla nephron loop descending loop ascending loop reabsorb water ascending loop reabsorb sodium (pump)

The Countercurrent Mechanism Blood flows “down and back”, so does filtrate vasa recta movement of blood nephron loop movement of filtrate

Hormonal Regulation of Urine Volume and Composition aldosterone Response to drop in Na or rise in K= more aldosterone Drop in BP= Renin (hormone) reacts to produce angiotensin to increase pressure Acts on distal tubule to inc sodium in waste= increased osmosis atrial natriuretic peptide Response to increased BP ( atrial stretch) Blocks sodium reabsorption in collecting ducts causes urine volume to increase (drop pressure, release water) antidiuretic hormone causes urine volume to decrease ( hold water, increase pressure) Dehydration=high ADH=less urine, Hydration= Low ADH=more urine

Urine Storage ureter bladder urethra kidney to bladder Smooth muscle stores urine Transitional cells Trigone- ureters and urethra Prostate- men 500-1000 ml urethra bladder to outside body Smooth muscle/ sphincters Male 20 cm, Female 3-4 cm

Urine Storage

Urine Excretion micturition Stretch Internal Realize Voluntary Urination Stretch Internal Realize Voluntary External Release

Diseases and Disorders of the Urinary System Chapter 14: The Urinary System Lesson 14.3 Diseases and Disorders of the Urinary System

Assessing Renal Function physical characteristics of urine pH range 4.5–8.0 spG 1.003 to 1.035 0.5-2 L/day chemical composition of urine 95% water, 5% waste Urea, Nitrogen, ions glomerular filtration rate estimate with creatinine concentration in blood Muscle metabolism byproduct, quickly filtered

Diabetes diabetes mellitus diabetes insipidus glucose in urine- osmosis is the reason! type I, type II Proteinuria, ketoacidosis and renal failure. diabetes insipidus large amount of dilute urine (>12L spG <1.002) ADH not made or not used Common in low Hcg (dwarfism)… Remember?

Normal Blood Glucose and Blood Insulin Levels carbohydrate digestion leads to an increase in blood glucose level increase in blood glucose level causes the pancreas to secrete insulin increase in blood insulin level causes liver glucose uptake liver conversion of glucose to glycogen skeletal muscle glucose uptake skeletal muscle conversion of glucose to glycogen

Chronic Kidney Disease kidney damage glomerular filtration rate less than 60 ml/min for at least 3 months develops slowly Usually diabetes related When GFR drops to <15ml/min= renal failure Waste product accumulation, pH uncontrolled, only dialysis or transplant will keep alive Dialysis becomes more frequent, more health effects. Why?

Renal Dialysis- remove H20, urea and Na hemodialysis Dialyzer- artificial kidney (external) peritoneal dialysis dialysis solution introduced via port to AP cavity peritoneum acts as dialysis membrane

Diseases and Disorders of the Urinary System kidney stones (pelvis) calcium, magnesium, or uric acid <5mm can pass Lithotripsy- US waves to break stones apart Fluids good….. urinary tract infection Bacteria up urethra to bladder cystitis more common in women than men Can go to kidneys if untreated= pyelonephritis+ back pain