urinary system lab 7. announcements urinary system lab practical week after spring break practical...
TRANSCRIPT
Urinary system
Lab 7
Announcements
• Urinary system
• Lab Practical Week after Spring Break
• Practical Review this Sunday 23rd at 3-5 pm
Functions of Urinary System
• 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.
Urinary System
• Two Kidneys– Perform all functions except actual excretion.
• Two Ureters– Convey urine from Kidneys to Urinary Bladder
• Urinary Bladder– Holds Urine until excretion
• Urethra– Conveys urine from bladder to outside of body
Complete System
Kidney general info
• Lie against posterior abdominal wall at level of T12-L3.
• Right kidney is lower than left kidney due to the shape of the liver.
• Lateral surface of kidney is convex while medial is concave.– Concave side has a cleft – Renal Hilus
– Inside hilus is Renal sinus• Where kidneys receive renal vessels and nerves.
Kidney External Anatomy
• Average size – 12cm x 6cm x 3 cm• Weights 150 grams or 5 oz• Surrounded by three membranes (deep to
superficial)– Renal capsule – fibrous barrier for kidneys.
– Adipose capsule – fatty tissue designed for protection / stability.
– Renal fascia – dense fibrous CTP anchors kidneys/ adrenals/ membrane 1 and 2 to surroundings.
Kidney Anatomy• Renal arteries and veins• Renal cortex• Renal medulla• Nephron• Renal pyramids (6-10)• Renal papilla• Calyx (ces)• Renal pelvis• Ureter
Kidney- External Anatomy
• Lateral surface- convex
• Medial is concave-– Renal Hilum
• Opening to Kidney
– Renal Sinus• Space within hilus
• Kidneys receive blood vessels and nerves.
Kidney Internal Anatomy I• Renal arteries and veins
– Bring blood in and out of kidney
• Renal cortex– Outer layer of Kidney
• Renal medulla– Inner layer of Kidney
• Nephron
Kidney Internal Anatomy II
• Renal Pyramids• Renal Columns
– Space between pyramids within the medula
• Renal Papilla– Narrow end of pyramid
• Calyx (ces)– Collecting tubes
• Renal Pelvis– Collecting vessel prior to ureter
Human Kidney
Nephron
• Blood processing unit which serves to produce urine
• 1 million per kidney
• Consists of a glomerulus and tubules
Nephron: Vascular System
• Afferent arteriole• Glomerulus• Efferent arteriole• Peritubular capillaries
– Capillary beds reabsorb in cortex
• Vasa recta– Capillary beds
reabsorb in medulla
Nephron• Tubular system
– Glomerular Capsule– Proximal convoluted tubule– Loop of Henle (nephron loop)
• Descending limb
• Ascending limb
– Distal convoluted tubule– Collecting duct
Nephron
Dynamic Human
Gross Anatomy
Urinary system
Kidney
Nephron
Urine Formation I
• Glomerular filtration• Water, ions, amino
acids, and glucose get into capsular space from blood
• Proteins stay in blood – too big to leave capillaries.
Urine Formation II
• Proximal convoluted tubule and Peritubular capillary
• Na+ goes down gradient and brings glucose, amino acids, etc. back into blood stream (cotransport).
• Reabsorbs about 65% of filtrate.
Urine Formation III
• Descending limb
• Goes into medulla - increasing salt gradient
• Water leaves• Fluid concentrates
• Ascending limb
• Goes up toward cortex - decreasing salt gradient
• Na+ pumped out• Fluid relatively diluted
Countercurrent Multiplicationin the Nephron Loop
Nephron Loop
Urine Formation IV
• Collecting duct
• Travels down into medulla
• Water leaves tubule and enters blood
• Urine becomes concentrated and enters renal papilla
• ADH controls water channel
• ADH – Antidiuretic hormone
Collecting duct
Dynamic Human
Urine Formation
Micturition
• Ureters– 25 cm long– Enters on the floor of bladder
• Urinary Bladder– Muscular sac on floor of pelvic cavity– Muscle layer formed by detrusor muscle– Average bladder volume is 500 ml– Max capacity is 700-800 ml
Micturition
• Urethra– Conveys urine out of body– Female urethra – 3 - 4 cm– Opens into external urethral oriface– Lies between vaginal oriface and clitoris– Male urethra – 18 cm– 3 regions
• Prostatic urethra – 2.5 cm• Membranous urethra – 0.5 cm• Penile urethra – 15 cm
Micturition Reflex
Bladder with >= 200 ml of urine
Sensory input to parasympathetic system
Contraction of detrusor muscle and relaxation of internal urethral sphincter
Relaxation of external urethral sphincter
Micturition
Kidney stones
• A hard granule of calcium, phosphate, uric acid and protein.
• Form in renal pelvis and get lodged in pelvis or ureter.
• Caused by urinary tract infections, dehydration, pH imbalances, or an enlarged prostate gland.
• Treated with stone dissolving drugs, surgical removal, or lithotripsy (ultrasonic vibrations)
Dynamic Human
Visualizing the Urinary System
Intravenous pyelography
Ultrasound
Dissection
• Be able to identify layers of the kidney on human material
• Be able to locate kidneys, ureters, urinary bladder, and urethra on cat.
Next Week – Spring BreakWeek After - Practical II
• Material over lymphatic, respiratory, and urinary systems
• Review Sunday (end of break) at 3-5pm
• Remember – some questions will be based on identifying structures on the cats.