Urinary System Flashcards
Describe the position of the kidneys and how they are protected
- Retroperitoneal - behind the peritoneum
- Protected by layers of fascia and firm renal fat
Describe the structure of the kidney
Renal cortex Renal column Renal Pyramid in Renal Medulla Renal Papilla (opening) Minor calyx (pl calyces) Major calyx Renal pelvis Ureter
Function of the renal pyramids
They house the nephrons, which filtrate and reabsorb
What does the nephron consist of?
Renal corpuscle (glomerulus) Proximal convulated tubule (PCT) Loop of Henlé Distal convulated tubule (DCT) Collecting duct
Differentiate between the two types of nephrons
Juxtamedullary
- Receives 10% of renal supply
- Concentrates urine
- Its glomeruli are found in the inner cortical regions, and it has a long nephron loop
- Associated with vesa recta
Superficial
- Receives 90% of renal supply
- Reabsorbs large % of fluid that filters from vasculature
- Its glomeruli are found in the outer cortical regions, and it has a short nephron loop
Position of Ureter and Urethra in male and female bodies
In females:
- Ureter passes posterior to the ovary, lateral to the cervix and vagina
In males:
- Urethra passes through the prostate and into penis
What’s the name of the muscular wall of the bladder?
Detrusor muscle
What epithelium lines the bladder?
Transitional
What is the muscle of the bladder like?
Smooth and involuntary
What division of nervous system controls the bladder?
Autonomic, PSNS;
The external sphincter around the urethra however is striated and is under voluntary control
What is the blood supply/drainage of the bladder?
Common iliac artery
Internal iliac artery
Superior vesical artery
Inferior vesical artery
Describe the filtration process
The glomerulos is compromised of capillaries with densely fenestrated walls
Hydrostatic pressure forces plasma through the filtration barrier, separating it from cells and proteins - these leave through the vasa recta
The leftover filtrate is then sent along the proximal convulated tubule
What is the blood supply/drainage of the kidneys?
Renal artery and Renal veins
List the processes of urine production
Filtration
Reabsorption
Secretion
Describe the function of the kidney
Cleanses blood of metabolic end products, toxins, water, and ions
It is also an endocrine and homeostatic organ controlling blood pressure, tissue osmolality and electrolyte levels
Describe the reabsorption process
Na+ ions are transported through the cuboidal epithelial cells by Na-K-ATPase through active/co-transport in PCT
Water passively flows out after Na+ by osmosis and is reabsorped because of the salty nature of the intestitial space
The remaining filtrate is full of urea, and runs back through the medulla - some urea is reabsorped and makes the intertitial space even more salty, allowing even more water to be reabsorped - urea then returns to the collecting duct and is finally released into the urethra
Secretion - sneaking out extra waste like potassium and hydrogen - wastes that have already made their way into the blood in the capillaries, ready to leave the kidneys
Describe the process of micturition
Bladder stores urine until micturition
Valves prevent urinary reflux into the ureters
Inner and outer sphincters control outflow via the urethra
Inner sphincter (and bladder contraction) is controlled by spinal reflexes and the CNS
Outer sphincter is under voluntary control
Bladder filling stretches its muscular wall and initiates a spinal micturition reflex - the reflex causes PS motor efferents to stimular bladder contraction
Emptying is prevented by the CNS until the outer sphincter is relaxed voluntarily
