Kidneys Flashcards
What species have unilobar kidneys?
- Dog
- Cat
- Horse
- Small ruminant
Structure of unilobar kidney
- Single lobe formed by fusion of several lobes
- No obvious pyramid
- Renal crest
- Collecting ducts feed into renal pelvis
What species have multilobar kidney?
- Cow
- Pig
- Primate
Structure of multilobar kidney
- Apex of each lobe directed toward sinus → forms papilla
2. Major and minor calices
Kidney surface in pigs and primates
Smooth
Bovine kidney surface
Has fissures
2 parts of each renal lob
- Outer cortex
2. Inner medulla
2 parts of outer renal cortex
- Cortical labyrinth (pars convoluta)
2. Medullary rays (pars radiata)
Cortical labyrinth aka?
Pars convoluta
Medullary rays aka?
Pars radiata
2 parts of inner renal medulla
- Loops of Henle
2. Collecting dugs
What are area cribosa?
Tiny opening in papilla which collecting ducts open through
After opening through area cribusa, how does urine drain?
Into minor calyx →
Major calyx (multilobar) OR Renal pelvis (unilobar)
What is pars convoluta?
Part of renal cortex which contains renal corpuscles and convoluted tubules
What is pars radiata?
Part of renal cortex alternating with pars convoluta consisting of collecting tubules and straight portions of nephrons
What is a renal lobule?
1 medullary ray + 1/2 of pars convoluta on either side, bordered by interlobular aa.
Arterial renal blood supply
- Renal a. →
- Segmental a. →
- Interlobar a. →
- Arcuate a. →
- Interlobular a. →
- Afferent arteriole →
- Glomerulus →
- Efferent arteriole
Blood in efferent arteriole enters?
- Peritubular capillaries
2. Vasa recta
Peritubular capillaries are associated with?
Convoluted tubules
Vasa recta are associated with?
Loop of Henle
Glomerulus may also be called?
Renal corpuscle
Venous renal blood supply
- Interlobular v. →
- Arcuate v. →
- Interlobar v. →
- Renal v.
What is the functional unit of the kidney?
Uriniferous tubule
2 parts of uriniferous tubule
- Nephron
2. Collecting duct
Function of nephron
Produces urine
2 parts of nephron
- Renal corpuscle
2. Renal tubules
Collecting duct function
Collects, concentrates and transports urine
Is collecting duct part of a nephron?
Most definitely not. Absolutely not. Not at all.
Parts of renal corpuscle
- Glomerulus
2. Glomerular capsule
Layers of glomerular capsule
- Visceral layer
- Parietal layer
- Capsule space
Parts of renal tubule
- Proximal convoluted tubule
- Loop of Henle
- Distal convoluted tubule 4. Connecting tubule → empties into collected duct
Parts of loop of Henle
- Proximal straight tubule
- Thin descending limb
- Thin ascending limb
- Thick ascending limb
Bowman’s capsule aka?
Glomerular capsule
Glomerulus connects?
Afferent and efferent arterioles
Visceral layer of renal corpuscle lines?
Arterioles
Parietal layer of capsule lines?
External capsule
Parietal layer is lined by what cells?
Simple squamous epithelium
Visceral layer is lined by what cells?
Podocytes
What is the vascular pole?
Where afferent and efferent arterioles enter/leave
What is the urinary pole?
Where proximal tubule originates
What are podocytes?
Epithelial cells lining visceral layer of Bowman’s capsule
What are pedicels?
Long cytoplasmic processes of podocytes which interdigitate to form filtration slits
Pedicels are also known as?
Foot processes
What are mesangial cells?
Phagocytic cells found between capillaries of glomerulus which have cytoplasmic processes between endothelial cells → cleans GBM of particulate matter
Filtration barrier is formed by?
- Fenestrated capillary epithelium
- Glomerular basement membrane (GBM)
- Filtration slit between podocytes
GBM is formed by?
Fused basal lamina of endothelial cells and podocytes
GBM blocks what from draining into the filtrate?
Large proteins
Filtration slits block what from draining into the filtrate?
Small proteins
Filtrate includes?
- Water
- Glucose
- AAs
- Ions
- Urea
- Hormones
- Vitamins B and C
- Ketones
- Small amount of protein
How is GBM diffderent than other basement membranes?
Thicker
3 layers of GBM
- Lamina rara interna
- Lamina densa
- Lamina rara externa
The lamina rara layers of GBM are made of?
Heparan sulfate
Lamina densa of GBM is made of?
Type IV collagen
GBM filters substances by?
Size and charge
How does GBM filter substance by size?
Type IV collagen
How does GBM filter substance by charge?
Negatively charged heparan sulfate
3 activities of renal function
- Filtration
- Tubular reabsorption
- Tubular secretion
Major hormone which influences reabsorption process
Antidiuretic hormone (ADH)
Which substances are active transported into the uriniferous tubules?
- Glucose
- AAs
- Na
Sodium is mainly reabsorbed where?
PCT and Loop of Henle
What influences amount of urea in urine?
Extent of water reabsorption
3 secreted substances
- Endogenous compounds
- Exogenous compounds (drugs)
- Water and ions
Function of tubular epithelium is determined by?
- Asymmetric distribution of channels and transporters
2. Permeability of zona occludens (paracellular transport)
Epithelium of PCT (proximal convoluted tubule)
Simple cuboidal with brush boder
Longest part of the nephron
PCT (fill up most of cortex)
Epithelium of thin Loop of Henle
Simple squamous
Function of thin Loop of Henle
Passive reabsorption of Na and Cl
Loop of Henle is located in?
Medulla
Epithelium of thick Loop of Henle
Simple cuboidal
Function of thick Loop of Henle
Active electrolyte reabsorption
DCT epithelium
Simple cuboidal with short microvilli
Emptier lumen
2 types of cells in collecting ducts
Principal and intercalated cels
Functions of principal cells
Reabsorption of water and electrolytes
K secretion
Functions of principal cells
K reabsorption
JG apparatus
Found between vascular pole and returning DCT of same nephron → regulates blood pressure
3 types of cells in JG apparatus
- Macula densa of DCT
- Juztaglomerular cells
- Mesangial cells
Juxtaglomerular cells
Located in wall of afferent arteriole → secrete renin
Macula densa
Chemorecptors for Na and Cl