Formation of filtrate Flashcards Preview

Kidneys and Hormones > Formation of filtrate > Flashcards

Flashcards in Formation of filtrate Deck (24):
1

What is the ultrafiltrate?

Blood filtered as it enters from glomerulus into the Bowman's capsule

2

What is the diameter of the glomerular capillaries?

200 micrometers

3

What is the length of the glomerular capillaries?

19 km in total

1 nephron = 1 cm

4

What is the surface ares of the capillaries?

1 metre squared

5

What is the histology of the filtration barrier on the side of the glomerulus?

Endothelial cells contain endothelial pores

Allow small molecules to move across the filtration barrier

Fenestrae can be plugged with glycocalyx

Glycocalyx is attached to the basal lamina

6

What is the role of the glycocalyx?

Prevent macromolecules from entering Bowman's capsule

7

What is glycocalyx made of?

Glycoprotein - polysaccharide covering

8

What is the basal lamina made up of?

Negatively charged glycoprotein sheets

9

What is the histology of the filtration barrier on the side of the Bowman's space?

Glomerular capillary is surrounded by podocytes

Between the podocytes is a diaphragm made by the protein nephrin

10

How do the podocytes surround the glomerular capillaries?

Podocytes are made up of arm-like structures called primary processes

The primary processes -> secondary processes -> finger-like projections that extend over all capillaried to form a sheet

11

What is the diaphragm of podocytes made up of?

The protein nephrin

12

What disease is caused by a mutation in the protein nephrin?

Congenital nephrotic syndrome

13

How wide is the diaphragm of the podocytes?

4 nm

14

Which factors determine glomerular filterability of molecules?

Electrical charge

Molecular weight

15

How does electrical charge determine filterability of a molecule?

Filtration membrane is made up of negatively charged glycoproteins

Repels negatively charged solutes

Attract positively charged solutes

16

How does molecular weight determine filterability of a molecule?

Small molecules are freely filtered

As molecules increase in size - filtration ratio decreases

17

What is the equation for net ultrafiltration pressure?

Net ultrafiltration pressure = net hydrostatic pressure - net oncotic pressure

18

What creates net hydrostatic pressure in the capillaries?

Heart

19

What creates net oncotic pressure in the capillaries?

Proteins

20

What is the equation for net hydrostatic pressure?

Glomerular hydrostatic pressure - Bowmans space hyrdrostatic pressure

21

What happens to the net hydrostatic pressure as you go from the afferent to the efferent arterioles?

Net hydrostatic pressure = net oncotic pressure

22

What does net hydrostatic pressure do?

Drives filtration of salt, water and other components from the glomerulus to the Bowman's space

23

What happens when net hydrostatic pressure = net oncotic pressure?

No filtration happens

24

What can alter the rate of glomerular filtration?

Change in any pressure can alter ultrafiltrate pressure

Decrease in hydrostatic pressure following haemorrhage

Increase in hydrostatic pressure following kidney stone

Increase in oncotic pressure folowing dehydration