Urinary systems and electrolyte balance Flashcards
What are the functions of the urinary system?
- removal of waste products
- regulation of volume and solute concentration of blood plasma
- elimination of waste products into the environment
What are the components of the urinary system?
- kidneys
- ureters
- bladder
- urethra
Describe the anatomical location of the kidneys
- located on either side of the midline, on the posterior abdominal wall
- T12 - L3 (T= thoracic vertebra and L= lumbar vertebra)
- left kidney is located slightly higher than the right kidney
- lie behind the parietal peritoneum = retroperitoneal organs and are surrounded by adipose tissue
Describe the anatomical location of the adrenal glands
not part of the urinary system and located on the superior pole of the kidneys
What is the function of the cortex
- corticosteroids
- aldosterone
- sodium and water retention
- increases blood pressure and volume
What is the function of the medulla
- secretes adrenaline and noradrenaline
- involved in fight or flight response
Describe the size and shape of the kidneys
- 150g, 10cm long, 5 cm wide, 2.5cm thick
- indented ovoid - bean shaped
Describe the components of the renal lobe
renal cortex –> proximal and distal parts of the nephron and collecting ducts (medullary rays)
renal medulla (pyramids) –> loop of henle and collecting ducts (collection and delivery of urine)
Describe the ureters
- hollow muscular tubes, propel urine from the kidneys to the bladder
- located in both the abdomen and pelvis
- retroperitoneal
- congenital anomalies - duplex ureter
- enter bladder obliquely
- when bladder is full - prevent backflow of urine into the ureters, compression closes off the ureters acting as valves
Describe the urinary bladder
- apex - points toward the pubic symphysis
- fundus - opposite the apex and formed by the posterior wall
- usual capacity of 0.75 liters- obstruction to outflow leads to enlargement of 6-7 liters
- world record of 21 liters
Describe the female urethra
- 4-5cm long - urinary tract infection much more common
- passes through pelvic floor and opens anterior to vagina
Describe the female urethra sphincters
- internal urethral sphincter - junction between bladder and urethra
- external urethral sphincter - immediately inferior to the internal urethral sphincter
Describe the male urethra
- 20cm in length
- S- shaped
- 4 parts
- pre-prostatic
- prostatic
- membranous
- penile
Describe the male urethral sphincter
- internal urethral sphincter - junction between the bladder and urethra
- prevents reflux of semen into the bladder
- external urethral sphincter - inferior to the prostate
What are the two body fluid compartments?
- intracellular fluid
- extracellular fluid = interstitial fluid + blood plasma
What are the major sites of ions and water exchange
- skin
- respiratory systems
- digestive systems
- excretory systems
Describe osmoregulation in freshwater fish
- uptake of water and some ions in food
- osmotic water gain through gills and other parts of the body surface
- uptake of slat ions by gills
- excretion of large amounts of water in dilute urine from kidneys
- must continually use energy to expel water
Where are aquaporins found?
prominent in brain, RBCs, kidney and skin and bladder of amphibians
