18. Urinary System Flashcards
How many segments in a nephron/kidney?
5
Functional unit of kidney
Nephron
Macrophages of kidney
Mesangial cells
Pathway of filtration in a nephron
Afferent BV > Glomerulus > PCT > Loop of henle > DCT > collecting ducts
Made up of bowman’s capsule and glomurular capillaries
Renal corpuscle
Lining of renal tubules (mostly)
Simple cuboidal epithelium
BQ: What are the filtering units of the glomerulus?
Podocytes
Clusters of capillaries where blood is filtered
Glomerular capillaries or glomerulus
Glomerular filtration rate
125mL/min
2/3 (60-70%) of filtrate are reabsorbed here
Proximal convoluted tubule
PCT: Active transport
Glucose, amino acid, Na
PCT: for water reabsorption (facilitated diffusion)
Aquaporins
BQ: Has counter current mechanism
Loop of henle
“Concentrating segment”
- because water goes out here
Thin descending segment of loop of henle
“Diluting segment”
- because solutes or electrolytes go out here
Thick ascending segment of loop of henle
Wall is very permeable to water
- water comes out due to HIGH osmotic pressure in medulla
Thin descending segment
Not permeable to water
Has ion pumps that pumps out (Na, Cl, K) ions out and towards the medulla
Thick ascending segment
Normally not permeable to water
Changes its function depending on the hormone present
(Aldosterone/Adh/Pth)
Distal convoluted tubule
Na reabsorption and K excretion
Aldosterone
H20 reabsorption
Adh
Calcium reabsorption and Phosphate excretion
Pth
Collects the filtered urine
Drains to the minor calyx
Collecting tubules
Receives filtrate from collecting tubules
Minor calyx
Receives filtrate from minor calyx
Major calyx
Receives filtrate from the major calyx
renal pelvis
Brings urine towards ureter going to the bladder
Renal pelvis
Regulates the blood volume
- influences blood pressure and solutes
Juxtaglomerular apparatus
BQ: What are the cells responsible for TGF or tubuloglomerular feedback?
Macula densa cells of DCT
Detects NaCl concentration in DCT = ⬇️Blood volume = ⬇️ Urine output
Macula densa cells of DCT
Maximum capacity of bladder
500ml