Intro to Neph Flashcards
True/False
The amount of sodium you intake on a single day will alter what the normal homeostatic function of the kidney is.
False, regardless of how much or how little the sodium, water, or potassium in take is, the kidney will still maintain it’s “single” homeostatic state.
What is the homeostatic value of sodium that the kidney tries to maintain?
140
What is the homeostatic value of potassium that the kidney tries to maintain?
4
What is the homeostatic pH that the kidney tries to maintain?
7.4
What is the functional unit of the kidney?
Nephron
What is a nephron comprised of?
Glomerulus and Tubule
Where is the afferent arterioles of the kidney coming from? Where is it going?
From the heart/outside the kidney; Going to the glomerulus.
Where is the afferent arterioles of the kidney coming from? Where is it going?
From the glomerulus; Going to the heart/outside the kidney
What are the important cells that surround the afferent arterioles?
JG cells
What is the function of the JG cells?
To make renin
What is the function of the macula densa? Where is this located?
Senses NaCl; Located in the distal convoluted tubule that comes into contact with the afferent arteriole
What do the JG cells contain?
Mechanoreceptors that sense changes in blood pressure (stretch receptors)
If blood pressure drops, what will cause your body to naturally increase BP?
Renin-Angiotensin System
Simplified Breakdown of the RAAA system?
Renin –> Angio I –> ACE –> Angio II –> Vasoconstriction/Na Reabsorption –> Inc. BP
What sensory receptors do the macula densa cells have?
Chemoreceptors
What do the chemoreceptors in the macula densa cells do?
Sense changes in the concentration of the ultrafiltrate before it goes into the DCT.
What happens when there is a DROP in Na+ concentration?
- Leads to vasodilation of the afferent arteriole –> Inc GFR and NaCL reabsorption
- Lead to renin release from the JG cells by the shrinking of the MD cells
Drop in Na+ concentration similar to drop in BP?
A drop in NaCl will leave to the constriction of which vessels?
Efferent Arterioles that will force blood to build up in the glomerulus, and causes peripheral vasoconstriction that will increase BP
The tubuloglomerular feedback mechanism is considered?
A. Autoregulated
B. Regulated based on parasympathethic activity
C. Regulated based on sympathetic activity
D. No regulatory control, extrinsic or intrinsic, it is a fixed system.
A. Autoregulated
Structure of the Glomerulus includes:
Afferent Capillary Efferent Capillary Glomerular Tuft Bowman's Capsule Endothelial Cells Glomerular Basesment Membrane Podocytes Mesangial Cell
What is the function of the glomerular tuft?
Filtering element that consists of an enclosed capillary network
Glomerulus is enclosed in what structure?
Bowman’s capsule
What IS a glomerular tuft?
Lobular structures of capillaries that are lined by endothelial cells.
What is the glomerular basement membrane made of?
Hydrated gel composed of glycoproteins that contain interwoven Collagen Type IV
This lines the inside of the capillary walls and is perforated with small fenestra (windows) that let only plasma through but retains the formed elements such as RBCs.
Endothelial Cells
What is the function of the fenestrated endothelial cells?
- Regulate coagulation, inflammation, and vasomotor tone.
- Make surface antigens, express adhesion molecules for leukocytes, and release vasodilator substances like nitric oxide.
This is an important determinant of the charged porous nature of GBM.
Glomerular Basement Membrane
If the layers of the glomerulus were compared to a PB & J sandwich the GBM would be the ________.
Jelly
True/False:
Most substances can cross the GBM
FALSE!
Most substances are too big to cross the GBM.