Urinary System part 1 Flashcards
What are the functions of the urinary system?
- maintenance of water and electrolyte homeostasis
- regualtion of acid-base balance
- excretion of metabolic waste products
- production of renin and erythropoietin
- conversion of vitamin D
- regulation of calcium balance
What does renin do?
blood pressure control
What does erythropoietin do?
stimulates red blood cell production in the bone marrow
What is the order of blood supply to the kidney?
- 5 segmental lobar arteries per kidney
- interlobar artery
- arcuate artery
- intralobular artery
- Afferent arteriole
What layer of the kidney are the afferent glomerular arterioles found?
cortex
The peritubular capillary network (PCN) arises from ____________ __________
efferent arterioles
__________ _________ drain the glomeruli and form capillary networks
Efferent arterioles
What are the two main components of the nephron?
renal corpuscle
renal tubule
What is the functional unit of the kidney?
nephron
What is the function of the renal corpuscle?
filters blood plasma
What is the function of the renal tubule?
modifies filtrate to form urine
The nephron is composed of…
- renal corpuscle
- proximal convoluted tubule
- loop of henle
- distal convoluted tubule
- collecting tubule/duct
What are the capillaries around the proximal and distal convoluted tubules?
peritubular capillaries
What is the name of the capillary network around the loop of henle?
vasa recta (arterial and venous)
What are the two types of nephrons?
-cortical
— subcapsular (short)
— midcortical (intermediate)
-juxtamedullary (long loops)
What does the difference between nephron types depend on?
location in the cortex and the length of the loop of henle
What is the blood flow to the kidneys from the heart and back again?
- aorta
- renal artery
- afferent arteriole (skipped some steps)
- glomerular capillaries
- efferent arteriole
- peritubular capillaries or to the vasa recta
- venules
- veins
- renal vein
- inferior vena cava
What is the path that filtrate/urine takes through the kidney and out of the body?
- bowman’s space
- proximal convoluted tubule
- loop of henle (desending, thin ascending, thick ascending)
- distal convoluted tubule
- collecting duct
- minor calyces
- major calyces
- renal pelvis
- ureter
- urinary bladder
- sphincter
- urethra
Where are the raw materials gathered in the kidney?
Bowman’s space
Where do the “bulk operations” happen in the kidney?
Proximal convoluted tubule
Where does the “fine tuning” (reabsorbtion) occur in the kidney?
distal convoluted tuble and collecting duct
Where does the “planning ahead” and concentration of the interstitum occur in the kidney?
loop of henle
What cells make up the visceral layer on the glomerulus?
podocytes
What cells make up the parietal layer of the renal corpuscle?
simple squamous epithelium
What separates the visceral layer and parietal layer of the renal corpuscle?
bowman’s space (urinary space)
What makes up a vascular pole in the kidney?
Afferent and Efferent arteriole
What are the functions of the mesangial cells in the kidney?
- secrete the mesangial matrix
- secrete vasoactive factors and cytokines
- remove trappped residues and aggregated protein from BM (keep filter free of debris)
- changing te filtration pressure of glomerulus (contractile properties)
What are the main components of the mesangial matrix?
collagen type IV
laminin
fibronectin
proteoglycans
______________ ________ cells found between the afferent A and Efferent A towards the vascular pole
Extraglomerular mesangial
____________ _______ cells are located inside the glomerulus in between the capillaries
Intraglomerular mesangial
What three things make up the filtration barrier?
(she said this would prolly be on the test)
- fenestrated capillary endothelium
- basal lamina (basement membrane)
- podocytes of the visceral layer of bownman’s capsule
What three things make up the filtration barrier?
(so important it is on here twice!)
- fenestrated capillary endothelium
- basal lamina
- podocytes of the visceral layer
What are the characteristics of glomerular capillaries?
- fenestrated
- large pores
- permeable to water, urea, glucose, and small proteins
- barrier only to formed elements in blood and large macromolecules
What are glomerular capillaries permeable to?
water, urea, glucose, and small proteins
The lamina rarae (basal lamina) contains?
type IV collagen
laminin
fibronectin
negatively-charged proteoglycans
What is the average gap between podocyte foot projections (pedicels)?
25 nm
What molecules pass freely through the podocytes (visceral layer)?
- water, ions, and small organic molecules cross freely
- peptide hormones and small proteins cross reasonably freely
What are the pedicles (foot processes) separated by?
filtration slits
What are the filtration slits between foot processes (pedicles) covered by?
slit diaphragm
What protein makes up the slit diaphragm in the kidney?
nephrin
What is the function of the pedicels and filtration slits?
acts as a barrier to large macromolecules, proteins, negatively charged molecules, and blood cells
What is the filtration process before reaching the proximal convoluted tubule?
- blood enters glomerulus (afferent arterioles)
- arteriole pressure forces fluid through fenestrae
- large molecules are trapped by basal lamina
- negatively charged molecules are stopped by basal lamina and podocytes
- fluid passes thorugh pores in slit diaphragm to enter urinary space (proximal convoluted tubule)
Where are proximal convoluted tubules found in the kidney?
ONLY in cortex
What does the proximal convoluted tubule do?
- primary site of water resorption
- removes 75% of water and ions (Na, Cl)
What does the lumen of the proximal convoluted tubule have?
microvilli and brush border
How do Na, Cl, and H2O move in the proximal convoluted tubule?
Na - active transport
Cl - passive transport
H2O - small transmembrane channel
