Kidney Flashcards
(18 cards)
What is the diameter comparison between the afferent and efferent arterioles?
Afferent arteriole has a larger diameter than the efferent arterioles.
What pressure is created in the glomerulus due to the afferent arteriole?
Creates a high intraglomerular pressure.
What type of pressure does Bowman’s/renal capsule have?
Has hydrostatic pressure.
What is the process that forces fluid through into the renal tubule?
Fluid is forced through into the tubular system.
What components are included in the filtrate?
Filtrate includes:
* amino acids
* glucose
* water
* urea
* Na+
* Cl-
* K+ ions.
What is too big to pass through the filtration barrier?
Proteins and erythrocytes are too big to pass through.
What anatomical feature allows for filtration in the glomerulus?
Gaps between endothelial cells/fenestrations allow for filtration.
What is the composition of the basement membrane in the filtration barrier?
The basement membrane is composed of collagen and glycoproteins.
What is the major structural component that interacts with the filtration barrier?
The gaps between podocytes/pedicels are major structural components.
Describe in detail the mechanism of selective reabsorption in the proximal convoluted tubule.
Cuboidal epithelium cells;
microvilli to increase surface area for absorption; Sodium ions enter cell with glucose/amino acids;
Through co transport proteins; facillitated diffusion;
Glucose/amino acids leave cell and enter the blood through
Protein carrier facilitated diffusion/active transport
Sodium/Potassium pump uses ATP to move 3Na+ out (of cell) and 2K+ into the cell;
Movement of glucose, amino acids and Na+ into cell then into blood…
Causes water potential to lower
Water moves into cell and into the blood by osmosis down a water potential gradient;
Loop Of Henle
To establish a water potential gradient down the medulla
Urea conc rises as water leaves tubule by osmosis
K+ excess ions added in the DCT
Water lost from collecting ducts so conc here increases
Na+ ions conc decrease in the PCT through co transport and Na+/K+ pump increases due to water loss in descending limb
Decrease as actively removed from ascending limb
Water lost in collecting duct
All glucose and amino acids selectively reabsorbed by co transport mechanism and facilitated diffusion or active transport
Aquaporin
Aquaporins only allow passage of water NOT ions;
lons are too large to pass through the channel;
Shape of ion is not complimentary to aquaporin;
+ive charge in aquaporin repels +ive charged ions;
Ultrafiltration
Basement membrane (collagen fibres and glycoprotein fibres)
Stop erythrocytes and large molecules passing through
Fenestratiins between endothelial cells of capillary wall allow small substances through (stops erythrocytes)
Podocyte cells (epithelial cells of bowman’s capsule)
Has extensions called pedicels (major processes) these ensure gaps to allow some substances through but not cells, platelets and large plasma proteins
How the pituitary gland regulates ADH conc
Special nerve cells called NEUROSECRETORY cells in hypothalamus produce ADH down their AXONS;
The ADH passed down the AXON of the neurosecretory cells and is stored in the Posterior pituitary until an action potential causes the release into the blood;
If water potential of blood drops, Osmoreceptors in hypothalamus lose water and shrink (water moves from these cells by osmosis) These receptors then cause ADH to be released from the posterior pituitary cells (hormone storage area)
ADH bind to complimentary specific shaped receptors on the plasma membrane of collecting duct cells (also cells of DCT).
What cells make up the proximal convoluted tubule
Cuboidal epithelium tissue
Many microvilli
Many mitochondria
What happens to molecules in the kidney
Small molecules - can leave blood and enter filtrate
Amino acid/ Glucose- selectively reabsorbed back into blood at the PCT using co transport and facilitated diffusion
Water follows glucose and amino acids into the blood by osmosis from high water potential to low so ion and urea concentration increase (less dilute)
Proteins - are too large to leave the blood
How pregnancy test kits detects the pregnancy hormone
Testing for human chorionic gonadotrophin (hcG)
Hormone small so past into filtrate of the bowman’s capsule
Monoclonal antibodies on test stick (immobolised)
Antibodies have dye/marker attached
hcG binds to complementary antibodies
Immobilised antibodies bind to antibody hormone complex
Gives coloured line in test window
Ovulation tests are the same expect it is LH not hcG
How does the control window work
There are more immobilised monoclonal antibodies in the control window
These only bind to the antibody with the dye that is not bound to the hcG
This shows the test is working
If test performed correctly the control window will show a line whether hcG is present in the urine
