Glomerular filtration (YT video) Flashcards
(34 cards)
What is the renal Corpuscle?
1) Glomerulus
2) Bowman’s Capsule
What is the Glomerulus?
Tuft of Capillaries
Afferent arteriole feeds into it
Efferent Arteriole
(E for exit)
what type of capillaries are in the glomerulus?
Fenestrated capillaries
Approx 50-100 nanometres in diameter
What can filter through the fenestrations?
Small proteins
water
electrolytes (na, K, Ca)
Nutrients
waste products
What is the glomerular basement membrane?
Has 3 sub layers
What are the three layers of the basement membrane
Lamina Denza-Type 4 collagen and laminins> very dense
Endothelial slide-closest to the endothelial cells
Podocyte layer
Endothelial Layer (Lamina rara interna) and podocyte layer (Lamina rara externa)
Thinner layer
Negatively charged Heparin sulfate
Why is it important for the layers to be negatively charged?
Most plasma proteins are negatively charged (e.g albumin, Immunoglobulin g)
So they repel each other, and protein cannot pass through the filter
Positive charge particles (electrolytes) can easily move through
Glomerulus consists of :
Endothelial lining, Glomerular basememnt membrane
What is in the bowman’s capsule?
Parietal and Visceral (Podocytes)
What is inbetween the podocytes
Specific type of protein molecule interconnecting with each other
Called Nephrin
Why are mutations in nephrin significant
Very important to control what’s going through the layers
The space between podocytes?
Filtration slit
25-30 nanometres in diameter
Nephrin only allows ______ size through
7-9 nanometres or less through
What is nephrin called?
The slit diaphragm
What is the pareital layer of the bowman’s capsule
Collects everything filtered into the bowman’s space
Connected to visceral layer
Where do they (substances) move into after being filtered?
Proximal Convolated tubule
What happens if a macromolecule slips through?
Mesangial Cells phagocytose anything stuck on the slit diaphragm
He can contract the amount of blood flowing through afferent arteriole
what else does the mesangial cell have?
Gap junctions that connect him to the Juxtaglomerular cells (these produce renin, baroreceptors)
Allows positively charged cells to flow and act upon the JG cells
Net filtration pressure
Happens over a given period of time
Pressures forcing out - (minus) pressures pulling things in
Glomerular Filtration rate
amount of plasma being filtered per minute
125ml/min
Around 1200ml of plasma flowing through glomerulus only 625 per minute are used in filtration process
575 leaving via efferent arteriole
Factors affecting GFR
Glomerular hydrostatic pressure (GHP) -tries to push things out of capillary into bowman’s space- about 55mmHg
Colloid osmotic pressure (oncotic pressure) (COP)- exerted by plasma proteins trying to keep water in the blood- avg. 30mmHg
Capsular hydrostatic pressure (CHP)- pressure being exerted by the back pressure in the bowman’s capsule, pushing fluid out of it-15mmHg
Total of pressure forcing out- total of pressure pulling in
(GHP)-(COP+CHP)
(55)-(30+15)
Net filtration pressure= 10 mmHg
Net filtration pressure is directly proprotional to GFR
