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
Lining of bladder
Transitional epithelium
Shape of bladder in relaxed or empty state
Cuboidal
Shape of bladder in full or stretched state
Squamous
High NaCl concentration in DCT = afferent arterioles ____
High NaCl concentration in DCT = afferent arterioles CONSTRICT
Low NaCl concentration in DCT = afferent arterioles ____
LOW NaCl concentration in DCT = afferent arterioles DILATE
Signals Juxtaglomerular cells to release RENIN
Low NaCl concentration in DCT
Cells found along afferent arterioles that secretes RENIN which is important for RAAS
Juxtaglomerular cells
BQ: GFR measures: 3
“CrIB”
Creatinine - most important
Inulin
Blood urea nitrogen (Bun)
BQ: What is the average daily urine output?
- 5L/day
1. 5-2.0L/day
Most specific in determining GFR
Creatinine
⬆️ creatinine = problem in
Problem in kidney
Are almost completely reabsorbed in the PCT
Glucose and amino acid
99% of filtered water is reabsorbed: Only 1% of water forms the _
1% of water = urine
RAAS:
Na and water =
K =
RAAS:
Na and water = reabsorption ⬆️
K = excretion ⬆️
Urine pigment
Urobilin
Uric acid crystals are from what Bases
Purine (adenine and guanine)
BQ: Renal threshold for Glucosuria
160*-180mg/dl
BQ: How many nephrons per kidney?
1 million nephrons per kidney
Inner part of kidney
Renal medulla
Outer part of kidney
Renal cortex
Which is lower: Left or right kidney?
Right kidney is lower - because of the LIVER
What does the kidney filter?
Kidney filters BLOOD
Blood vessel towards a nephron
Afferent arteriole
Blood vessel away from a nephron
Efferent arteriole
Loop of Henle is located in which part of the kidney
Renal medulla
Other name for Renal corpuscle
Malphigian corpuscle
Can RBCs cross or enter the proximal convoluted tubules?
No.
*If yes = HEMATURIA (Blood in the urine)
Filtrate is composed of (4)
Water
Electrolytes (Na,K,Cl)
Amino acids
Glucose
BQ: Water comes out from the Thin descending segment of loop of henle because of
Hyperosmotic renal medulla
Water and electrolytes that go out from the loop of henle goes to the
Vasa recta - then towards the circulatory system
What is the blood vessel adjacent to a nephron?
Vasa recta
Hormones that affect function of DCT
“PAA”
Pth
Aldosterone
Adh
blood volume is how many % in relation to the body weight
8% of body weight
What happens when Macula densa cells detect HIGH NaCl concentration in the DCT?
⬆️NaCl concentration
- Macula densa cells signals afferent arterioles to?
- Blood volume?
- GFR?
- Urine output?
⬆️NaCl conc(iisipin ng macula densa cells: maalat = kulang sa water/blood volume)
- signals afferent arterioles to CONSTRICT
- ⬇️ Blood volume towards glomerulus
- ⬇️ GFR
- ⬇️ Urine output
2 important cells present in the juxtaglomerular apparatus
Macula densa cells of DCT and Juxtaglomerular cells
What happens when Macula densa cells detect LOW NaCl concentration in the DCT?
⬇️NaCl concentration
- Macula densa cells signals afferent arterioles to?
- Blood volume?
- GFR?
- Urine output?
⬇️NaCl conc (iisipin ng macula densa cells: matabang = sobra sa water/blood volume)
- signals afferent arterioles to DILATE
- ⬆️ Blood volume towards glomerulus
- ⬆️ GFR
- ⬆️ Urine output
IMPORTANT: Macula densa cells send signals to 2 cells when there is LOW NaCl concentration
- Afferent arterioles to DILATE = ⬆️Vol
- Juxtaglomerular cells to secrete RENIN (RAAS: Aldosterone - end product)
Aldosterone = Na reabsorption
– Ayaw ni macula densa itapon mga solutes, so babalik sa VASA RECTA to blood
– Aldosterone - Sodium reabsorption ❤️ H20 follows: pakonti konti lang para di agad babagsak yung katawan
Cells found along the afferent arterioles that secretes renin which is important in RAAS
Juxtaglomerular cells
RAAS EFFECT:
Bv -
BP -
GFR -
RAAS EFFECT: Aldosterone :Na reabsorption
Bv - vasodilation
BP - increase BP
GFR - increase GFR
BQ: Location of Baroreceptors
Carotid and aortic SINUS
Stimulus for RENIN secretion (4)
Low NaCl concentration in DCT
Low BP
Decrease renal blood flow = Dec GFR
Sympathetic activation
What detects pressure in the blood?
Baroreceptors
BQ: Lining of urinary bladder
Transitional epithelium
Suffix for ACE inhibitors
ACE-pril
- Captopril: dont convert angiotensin I to II
Example of A2 antagonist drug
Losartan