Histology of Kidney Tissue Flashcards
What does the urinary system consist of?
- two kidneys
- two ureters
- one bladder
- one urethra
Explain what happens to urine after it is produced in the kidney
It is conducted by the ureters to the bladder where it is stored and leaves the body via the urethra.
Explain the blood supply and drainage to and from the kidney
Renal arteries arise from the abdominal aorta. One of more renal veins drain each kidney to the inferior vena cava.
Give and explain the 4 functions of the kidney
- Homeostasis (of water, electrolytes, acid/base)
- Excretion (of soluble toxic metabolic waste products, particularly nitrogenous urea and creatinine
- Hormonal (synthesis of renin, synthesis of erythropoietin)
- Metabolic (vitamin D is converted to active form in kidney)
What are the 3 parts to kidney function?
- Filtration (of most small molecules from blood plasma to form ultra filtrate of plasma - most negative molecules repelled and do not enter filtrate)
- Selective reabsorption (of most water and some molecules from ultra filtrate, leaving behind excess and waste to be excreted)
- Secretion (of soluble waste products from blood, and of H+ ions for acid/base balance
Is the filtrate further processed after the kidney?
No
Give details on kidney structure
- consists of outer cortex and inner medulla
- medullary pyramids project into subdivisions of the renal pelvis
- the renal pelvis narrows as it leaves the kidney to give the ureter
- the hilum: site of entry and exit of renal blood vessels and ureter
- the whole kidney is surrounded by a fibrous capsule, which also surrounds the attached adrenal gland (sits ontop of the kidney), also surrounded by a thick layer of fat
How is the kidney organised?
A medullary pyramid and its associated cortex forms a lobe.
A human kidney has 10-18 lobes.
The functional unit of a kidney is the nephron.
Kidney donation reflects the way the 10^6 nephrons are arranged.
Accurate and interlobular vessels. The renal artery brings the blood in and then then divides to form the individual filtration units.
What does a nephron consist of?
A renal corpuscle and a renal tubule.
What happens in a nephron when the cortex is met again?
blood flows into the distal convoluted tubule
What is most of the cortex formed of?
The proximal convoluted tubule
Give details on each of these Renal corpuscle Bowmans capsule Glomerulus Renal tubule
rc - plasma filtration, consists of 2 structures
bc - distended, blind end of the renal tubule
g - packed capillaries that invaginate Bowmans capsule derive from the afferent arteriole
rt - reabsorption, extends from Bowmans capsule to the collecting duct, convoluted in shape and has 4 zones (proximal convolutes tubule, loop of henle, distal convoluted tubule, collecting tubule
What does the renal cortex contain?
Tubules make up the vast bulk of the —– between the ——.
What is parenchyma?
Renal corpuscles
parenchyma, corpuscles
Surrounding tissue of the tubules
Explain the movement of the afferent and efferent arterioles
Wide afferent arteriole enters the Bowmans Capsule at the vascular pole, branches to form a network of capillaries.
Efferent arterioles is smaller in diameter, so to maintain a pressure gradient that drives filtration of plasma into Bowmans space
What do parietal cells do?
Where do podocytes sit?
Surround the Bowmans capsule
On the outside of the Bowmans capsule
What is the purpose of a mesangial cell?
They are phagocytic. They pick up dead matter such as if you had kidney damage or an infection.
What are the 3 layers which the filtrate must pass through before entering the renal tubule? Give some details
- Capillary endothelium (fenestrated)
- Glomerular basement membrane (thick as formed by 2 basal laminae of podocytes and endothelia. contains type 4 collagen
- Between the podocytes lining the capsule (indigitating pedicels). Gaps between pedicles are filtration slits