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renal
n/a
36
Physiology
Graduate
02/11/2013

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Term
what is the gross anatomical and physiological makeup of a renal lobule?
Definition
Gross - a medullary ray
phys - the area drained by a collecting duct
Term
What is the difference between juxtamedullary and cortical nephrons?
Definition
Juxtamedullary = long loop, vasa recta
cortical = short loop, lots of peritubular capillary
Term
What sorts of cells create the filter of the glomerulus?
Definition
The podocytes, with their pedicles
Term
Name the layers that filtrate has to pass through to go from glomerulus to proximal convoluted tubule
Definition
1) glomerular endothelium 2) basement membrane 3) filtration slits of podocytes
Term
what is the type of collagen that the GBM is made of? What is its net charge (combined with other GBM substances)
Definition
type IV collagen -> negative charge
Term
what type of epithelia are in the kidneys?
Definition
fenestrated
Term
What is the support cell of the glomerulus?
Definition
the mesangium - phagocytosis, growth factor, physical support
Term
What are the specializations of the proximal conv. tubule cells?
Definition
Apical absorptive (long microvilli, glycocalyx w/ digestive enzymes), active transport (lots of mitochondria, basal foldings, tight junctions)
Term
What is histological difference between proximal/distal conv. tubule cells?
Definition
apical nuc -> distal
shorter microvilli -> distal
no glycocalyx -> distal
Term
What are the histological features of collecting duct cells?
Definition
Intercalated - dark (lots of mitochondria), secretes H+, reabsorb HCO3-
Principle cells - lighter, aquaporins (ADH) and Na+ channels (aldosterone)
Term
What is the location of the dural venous sinuses relative to the meninges?
Definition
They are located in the middle of the meningeal (central) layer of the dura mater.
Term
What is the nerve supply to the dura mater?
Definition
Supratentorial -> CN V
Infratentorial -> Upper cervicals
Term
What is the source of bleed for a subdural hemotoma?
Definition
bridging veins (between brain and dural v. sinsuses) are torn at plane of dural border cells
Term
what are arachnoid villi?
Definition
Projections from arachnoid barrier cell layer (contain trabecuale too!) -> dural v. sinuses
Transmits CSF -> DVS's
Term
What is source of bleed of subarachnoid hemotoma?
Definition
arteries in sub arachnoid space
Term
how do toxins drain from the brain?
Definition
the CSF especially (takes place of lymph)
Term
where is the choroid plexus located?
What else secretes CSF?
Definition
1.All 4 ventricles (only roofs of 3+4)
2. Ependyma
Term
What is the characteristic of the endothelium in most of the brain? What sort of structures form exceptions to this characteristic?
Definition
Most - tight junctions, no/little pinocytosis
Body-monitoring nuclei (circumventricular: around 3+4 ventricles) = fenestrated, pinocytosis
Term
What are the arteries that supply the spinal chord?
Definition
The anterior (single) and posterior (paired), and the artery of adamkiewicz
Term
How many posterior communicating arteries are there? Anterior ""?
Definition
posterior -2
anterior -1
Term
What is the
Definition
Term
What is the site of action of ADH? Aldosterone?
Definition
ADH -> CD
Aldosterone -> CD, DCT
Term
Where in the kidney would there be most damage if there was a toxic substance secreted in the urine?
Definition
tubular cells in the (deep) medulla - because there would be highest [solute]
Term
What layers are present in the ureters and bladder?
Definition
Epithelium, L.P. with lot of collaginous CT, 2-3 layers of muscle (more distally). Adventitia (well vascularized, innervated, continuous with pelvic fascia.)
Term
What type of cells/where are the JG cells?
Definition
These are specialized renin-filled myoepithelioid cells in the afferent arteriole.
Term
What are macula densa cells?
Definition
These are cells that maintain contact with the JG cells (no basement membrane). They are part of the very proximal distal convoluted tubule, and are tall and crowded.
Term
What are the cells between the macula densa and the glomerulus?
Definition
the extraglomerular mesangial cells
Term
What is the net effect on blood pressure during partial kidney loss?
Definition
Increase -
1) less Na+ excretion -> greater extracellular fluid volume
2) greater renin secretion (mechanism unknown - but renin secretion does increase in partial kidney loss)
Term
What is uremia? Sympotms?
Definition
Uremia is kidney failure, characterized systemic buildup of substances (eg urea) the kidney was supposed to excrete. Symptoms include edema (Na retention, low plasma [protein] 2ndary to proteinuria), itching, anemia (low [EPO]), fatigue (2ndary to anemia), dyspnea (2ndary to pulmonary edema), myalgia ("") (muscle pain), nocturia, protein in urine
Term
what is nephrin?
Definition
A protein found in the diaphragms between podocyte pedicles
Term
can proteins be filtered across the glomerulus/bowman's capsule barrier?
Definition
Yes - but only if they're quite small, like myoglobin
typically, the net filtration is zero, because of the constant pinocytotic activity of the proximal tubule.
Term
which three forces determine the starling forces that affect glomerular filtration?
Definition
colloid osmotic pressure of plasma, capillary hydrostatic pressure, bowman's space hydrostatic pressure
Term
why is the renal medulla nearly hypoxic?
Definition
All blood supply to the renal medulla is indirect, passing through glomerulus first (vasa recta).
Term
what are the greatest sites of vascular resistance (and thus regulation) in the kidney?
Definition
the afferent and efferent arterioles
Term
why is it that the peritubular capillaries are mostly absorptive, while the glomerular capillaries are mostly secretive?
Definition
The efferent arteriole is high resistance, so there is a large pressure drop over its length, so that for the peritubular capillaries, the net starling forces (sum of hydrostatic + colloid osmotic pressures) favor absorption
Term
is the glomerulus a high-resistance vascular system?
Definition
No! Very little observable pressure drop over the glomerulus (also, remember that only ~1% of incoming plasma is being filtered, so there is no pressure difference across glomerulus due to change in capillary wall tension)
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