URINARY SYSTEM Flashcards
what are the kidneys?
Organs that excrete urine
what do the kidneys look like and where are they located?
Paired, bean-shaped organs located in the posterior abdomen
what is the lateral surface of the kidney?
convex
what is the medial surface of the kidney?
concave
where is the hilum?
medial surface of kidney
is the right kidney lower or higher than the left?
lower due to the liver
what are the kidneys capped by?
adrenal glands
what is found in the urinary tract?
organs that eliminate urine
what organs are found in the urinary tract?
ureters
urinary bladder
urethra
what is the ureter?
paired tubes
what is the urinary bladder?
muscular sac
what is the urethra?
exit tube
what is urination/micturation?
process of eliminating (voiding) urine through urethra and out of body
what is the hilum?
A depression through which ducts, nerves or blood vessels enter and leave the organ
what is excretion?
Removal of waste from body fluids
where does excretion occur?
kidneys – the nephron is the functional unit for this process
what is elimination?
Storage of urine (bladder)
Discharge of waste products (urination/micturition)
what is regulated by homeostasis in the urinary system?
Blood plasma vol & pH
Plasma ion conc
Conservation of nutrients
Elimination of toxins
what is the renal capsule?
Fibrous capsule that encases kidney and prevents infection
what is the adipose capsule?
Perinephric fatty mass, cushions kidney and aids attachment
what is the renal fascia?
Outer layer of dense fibrous CT that anchors the kidney
what is perirenal fat?
External to renal fascia + provides protection to kidneys
where are the points of entry of the kidney?
Renal artery
Renal nerves
where are the points of exit of the kidney?
Renal vein
Ureter
what is the cortex?
Granular superficial region.
Extends into medulla as renal columns
what is the medulla?
Subcortex, composed of 6-8 triangular renal pyramids, separated by renal columns
where is the renal papillae found?
at the base of renal pyramids
what is the renal papillae?
Openings into the minor calyx that channel urine towards the renal pelvis
what is the cortical nephron?
Only just penetrating the medulla
what is the juxtamedullary nephron?
Reaching deep into the medulla
what is the renal corpuscle?
spherical structure
what is the Glomerular (Bowman’s) capsule?
cup-shaped chamber
what is the glomerulus?
a network of capillaries
what is the renal tubule?
long tubular passage
begins at the renal corpuscle
what does the renal corpuscle include?
glomerulus and Bowman’s capsule
what does the outer layer of the renal corpuscles contain?
simple squamous epithelium
what does the inner layer of the renal corpuscles contain?
specialised podocytes
what are podocytes?
Cells with processes adhering to basal lamina over fenestrated capillary endothelium
how much of the systemic cardiac output flows through kidneys?
25%
what is the Proximal convoluted tubule (PCT)?
First segment of renal tubule
what is the PCT made of?
Simple cuboidal cells with microvilli on the luminal surface
what does the nephron loop/ loop of henle contain?
descending limb and ascending limb
what is the descending limb made of and where is it?
(squamous) passes into medulla
what is the ascending limb made of and where is it?
cuboidal) re-enters cortex and transitions into distal convoluted tubule (DCT)
what is the Distal convoluted tube (DCT)?
Empties urine into common collecting duct
where is the DCT?
leading to the papillary duct and renal papillae at the tip of the renal pyramid
where does urine flow?
from renal pelvis through the ureter to the urinary bladder
why is the entrance to the bladder oblique?
prevents backflow of urine and increased pressure within the bladder compresses the distal ends of the ureters shut
what is the function of the ureters?
actively propel urine to bladder via peristalsis, in response to smooth muscle stretch
what does the tri-layered wall of the ureters contain?
internal mucosa
medial muscularis layer
external adventitia
what does the internal mucosa contain?
transitional epithelium called urothelium
what is the external adventitia layer made of?
fibrous CT
what is the urothelium?
transitional epithelium impermeable to salts and water
what are the layers found in the urothelium?
Superficial
Intermediate
Basal
what is the bladder?
Smooth muscle ‘sac’ that stores urine
where is the bladder found?
Rests on pelvic floor (retro-peritoneal)
what happens when urine accumulates in the bladder?
bladder expands
without significant rise in internal pressure
how many layers does the bladder contain?
3
what are the 3 layers in the bladder?
Transitional epithelial layer (urothelium)
Muscle layer (detrusor muscle)
Adventitia
what is the trigone?
Triangular area outlined by openings for the ureters and the urethra
why is the trigone clinically important?
infections tend to persist in this region
what is the urethra?
muscular tube
what is the function of the urethra?
Drains urine from the bladder
Conveys it out of the body
what is the internal urethral sphincter involved in?
involuntary control
where is the internal urethral sphincter located?
bladder-urethra junction
what is the external urethral sphincter involved in?
voluntary control
where is the external urethral sphincter located?
Passes through urogenital diaphragm
what is the external urethral sphincter controlled by?
by levator ani muscle, situated on the side of the pelvis
