Ch 19 Flashcards
What part of the loop of Henle is permeable to water and solutes?
Proximal tubule
What part of the loop of Henle is permeable to water only? Does it secrete or resorb water? Why?
Descending loop of Henle resorbs water because the medullary OsM is super high
What is the OsM of the filtrate at the bottom of the loop of Henle?
1200 mOsM
What part of the loop of Henle is permeable to solutes only? Does it secrete or resorb? Why?
The ascending loop of Henle resorbs solutes to get back as many nutrients as possible. This partially happens because the OsM of the blood around the tubule is lower than the tubule, but also because of lots transporters
How much blood is filtered by the glomerulus a day?
180 L
How much blood passes through the descending loop of Henle a day?
54 L
How much blood passes through the ascending loop of Henle a day?
18 L
How much blood passes through the collecting duct and into the bladder a day?
1.5 L
What percentage of the blood leaves the capillaries at the glomerulus?
20%
What are the contractile cells that alter blood flow in the glomerulus?
Mesangial cells
What two factors influence glomerular filatration rate?
Net filtration pressure and filtration coefficient
How is net filtration pressure calculated?
blood hydrostatic pressure - colloid osmotic pressure - hydrostatic pressure of filtrate
What is the filtration coefficient?
Surface area of glomerular capillaries available for filtration
Permeability of interface between the capillary and Bowman’s capsule
What does the sympathetic nervous system do to decrease GFR?
Constrict afferent artioles leading to the glomerulus
How do the macula densa cells elicit change and what change occurs?
Too much blood flow causes the macula densa cells to secrete paracrines that signal to the juxtaglomerular cells. The JG cells constrict the afferent arteriole while dilating the efferent.
The opposite pathway is true
What is the ENaC? Where is it located?
The epithelial sodium channel is a passive transport protein on the luminal side of the proximal tubule in the kidney
What is the action of the SGLT transporter? Where is it located? What transporters succeed the SGLT in the pathway?
It uses the Na+ gradient in the lumen of the nephron to perform secondary active transport and resorb glucose back into the body. It is located on the luminal side of the nephron. The GLUT transporters move the glucose. The Na+/K+/ATPase moves the Na+
