3. urinary systems Flashcards
structures
- 2 kidneys
- 2 ureters
- 1 urinary bladder
- 1 urethra
functions
regulates and eliminates
regulates
blood pressure
blood volume
pH
ion concentrations
eliminates
wastes
eg. urea, uric acid, hormones, drugs
kidneys eternal anatomy
- retroperitoneal
- right lower than left
- supported and protected by 3 layers of CT
- renal hilus (hilium)
3 layers of CT
fibrous capsule
perirenal fat capsule
renal fascia
renal hilus (hilium)
-medial indentation entry point of : renal artery (superior) renal vein (inferior) ureter nerves
internal anatomy
renal cortex (superficial) renal medulla
renal medulla contains
renal pyramids and renal columns
renal pyramids
apex of pyramid = renal pailla
renal columns
separate pyramids
contain blood vessels
Nephron
functional unit of kidney (microscopic)
nephron composed of
renal corpuscle
renal tubules
renal corpuscle
- in cortex
- site of blood filtration (first step in urine formation)
renal corpuscle parts
glomerulus
bowman’s capsule
filtration membrane
glomerulus
=capillary bed
bowman’s capsule
-surrounds glomerulus
-collects filtrate from glomerulus
-2 layers:
outer ( simple squamous epithelium)
inner =podocytes ->wrapped around glomerular capillaries
filtration membrane consists of
- glomerular endothelium (capillaries)
- basement membranes
- podocytes (of bowman’s capsule)
glomerular endothelium
capillaries
-simple squamous with pores (=fenestrations)
-
podocytes (of bowman’s capsule)
- simple epithelium
- projections “cling” to glomerulus)
renel tubules
4 parts: proximal convoluted tubule (PTC) loop of henle distal convoluted tubule (DCT) collecting ducts
proximal convoluted tubule PTC
in cortex
loop of henle
descending and ascending limbs
in medulla
distal convoluted tubule DTC
in cortex
collecting ducts
in cortex and medulla
-connect nephron to ureter by calcyes / renal pelvis)
2 types of nephrons
cortical
juxtamedullary
cortical
85%
- renal corpuscles near kidney surface in cortex
- short loop of Henle in outer medulla
juxtamedullary
15%
- renal corpuscles in cortex near medulla
- long loops - penetrate deep into medulla
- allow concentration of urine, depending on need
kidney and nephron blood supply
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juxtaglomerular complex
- regulates filtrate formation
- point of contact b/w end of ascending limb, afferent and efferent arterioles at the renal corpuscle of the same nephron
juxtaglomerular complex parts
tubular portion
arteriolar portion
tubular portion
modified (tall and narrow) ascending limb cells = macula densa
arteriolar portion
- afferent and efferent arteriolar portion = granular (juxtaglomerular cells)
- monitor blood pressure
- modified smooth muscle cells -> contain renin (enzyme and hormone)
ureters histology
- mucosa
- no submucosa
- muscularis externa
- adventitia/serosa
mucosa
transitional epithelium
no submucosa
lamina propria directly connected to muscularis externa
muscularis externa
smooth muscle approx. three layers
adventitia/seros
retroperitoneal
urinary bladder internally
triangle formed by opening of 2 ureters (posteriorly) and urethra = trigone
*lacks rugae (smooth)-allows openings to remain in fixed position
urethra histology
mucosa
muscularis externa
urethra mucosa
transitional to stratified squamous epithelium
urethra muscularis externa
smooth muscle
urethra
-2 sphincters (both surrounded proximal end of ureter):
internal urethral sphincter
external urethral sphincter
internal urethral sphincter
smooth muscle
-thickening of detrusor muscle at base of bladder
external urethral sphincter
skeletal muscle
-in urogenital diaphragm
urethra in females
transports urine
urethra in males
transports urine and semen
urinary system : filtrate movement
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