Renal Lecture 2

What are the basement membrane negatively charged proteins?

*The basement membrane is composed of negatively charged proteins such as Collagen Type IV, Laminin, and Proteoglycans (Agrin) and Nidoge

What does an increase amount of Ca in the JG cells cause?

-Also the macula densa cells have gap junctions that alllow the flow of calcium to go to JG cells that cause the decrease secretion of renin. -efferent have more angiotensin II receptors than afferent

What is nephrotic syndrome?

-Nephrotic Syndrome: Multi-focal glomerular disease resulting in Proteinuria. -Other indicators include: Hypoalbuminemia, Edema, and Hyperlipidemia/ hyperlipiduria. breakdown of the basement glomerular membrane lipoproteins are big due to the liver protein making more proteins Examples: -Minimal Change Disease: Unknown etiology, possibly related to T-cell dysfunction and production of glomerular permeability factor. Most common example of nephrotic syndrome in children. -Diabetic nephropathy: Both metabolic cellular damage and glomerular hyperfiltration may result from elevated blood glucose. -Focal Segmental Glomerulosclerosis: Can have a genetic origin (mutation of Nephrin or Podocin) or due to infection (most common in patients with HIV).

What is starling forces drive and glomerular filtration?

-bulk flow is driven by starling forces. filtration forces push fluid out of the capillaries into bowman space, which would be hydrostatic pressure. -

WHat does adenosine cause in most systemic vascular beds that different in the tubuloglomerular feedback?

-vasodilation by binding to A2a subtype receptor, but vasoconstriction by A1

What regulates glomerular filtration?

1) Filtration decreases with increasing size 2) Filtration is decreased for negatively charged molecules if the negative charges of the basement membrane for some reason are not in position, then the filtration through the glomerulus would be dependent only on size and it will have a greater filtration than the normal.

What has the greatest effect on the autoregulation in vascular resistance?

Branching of the renal artery eventually gives rise to the afferent arterioles, the glomerular capillaries, and the efferent arterioles. Changes in renal artery pressure have a larger effect on the regulation of afferent arteriolar resistance caused by the tubuloglomrular feeback and myogenic feedback

What are the components of the slit diaphragm?

Filtration slits between podocyte foot processes are traversed by a thin diaphragm known as the filtration slit diaphragm with pores of 40 - 140 Angstroms. Nephrin, NEPH1, and NEPH2 have large extracellular domains that interact. Membrane spanning proteins are also linked with intracellular "adaptor" proteins that link with extracellular proteins of The filtration diaphragm and the glomerular basement membrane

What is the tubuloglomerular feedback mechanism?

GFR feedback to talk to RBF. GFR increase independent of blood flow, which causes an increase in NaCl filtering and being sensed by the macula densa that delivers a message that is sent to the smooth muscle cells to tell them to contract.

What is the cellular control of the tubuloglomerular feedback?

NKCC2 pump transports the electrolytes inside the macula densa cells that stimulates Na/K ATPase which cause an increase amount of ATP formation into ADP which is converted into adenosine that binds to a adenosine A1 receptor on a smooth muscle cell cause an increase in Ca causing the muscle to contract causeing vasoconstiction.. -elevating Na inhibits the Ca/Na antitransporter and the increase intracellular Ca and causes a stimulation in ATP synthesis and in the mitochondria and being released that binds to P2X causing elevation of ca causing contraction of the afferent arterioles that do not have many angiotensin II receptors reducing renal blood flow and reducing GFR

What can cause local control of RBF and GFR?

Prostaglandins: Produced following a hemmorhage to attenuate effects of systemic vascoconstrictors and prevent renal ischemia. Therefore, NSAIDS are contra-indicated with hemmorhagic shock . Nitric Oxide: A vasodilator that will locally increase RBF and GFR in response to increased sheer stress. Also counteracts systemic vasocon- strictors. Endothelin: Elevated levels cause decrease in RBF and GFR. Elevated in diabetes mellitus. Atrial Natriuretic Peptide (circulating, not local): Antagonizes Angiotensin II and produces vasodilation

What must a filtered substance pass in the glomerulus?

To be filtered a substance must pass: 1) The pores in fenestrated endothelium of the glomerular capillaries 2) The acellular basement membrane 3) The filtration slits between the foot processes of podocytes

What happens during the myogenic mechanism in autoregulation?

autoregulated keeps the kidney within the functional capacity. an increase in pressure will cause an increase in the amount resistance to help maintain the pressure allows the afferent arterioles to respond to any change in pressure

What renal arteriole does the sympathatetic system innervate?

baroreceptor response afferent causes decrease in RBF and GFR do not want to completely shut down GFR. -do not take asprin with hemorrage because it blocks prostaglandins

WHat is the relationship between GRF and Renal blood flow? Whats autoregulation

both directly proportional control mechanism to maintain GFR by myogenic or tuberloglomerular echanism ` 1) Renal blood flow determines Starling Forces and therefore indirectly determines GFR 2) RBF and GFR are autoregulated over a wide range of physiologic pressures. 3) Autoregulation: Myogenic or Tubuloglomerular Feedback (allows GFR to also affect RBF)

How is the constriction and dilation of the afferent and efferent arterioles affect GFR, resistance and RBF?

constriction of the afferent arteriole decreases the amount of blood that enters the glomerulus which decreases the amount of GFR, increased resistance and renal blood flow. -Constriction of the efferent arteriole causes an buildup in the glomerulus which causes an increase GFR, increase resistance, and decreased RBF. -Constriction of the afferent end and dilation of the efferent end causes due to the dilation an increase in RBF, decrease GFR, and decrease the resistance thats why blood flow goes up. -Dilation of the afferent and constriction of the efferent end causes an increase in RBF, GFR and resistance.

WHat does angiotensin II constrict?

efferent arterioles that decreases RBF but doesnt really effect the GFR

What is nephritic syndrome?

usually happen due to inflammatory responses. less protein but the inflammation causes a decrease the GFR, which causes the amount the amount of protein loss, but some of the blood will leak. less urine being produced causes an increase in the BUN