RENAL OVERVIEW Flashcards
What is the basic unit of the kidney?
The nephron
How many nephron units are there per kidney?
400 000 – 800 000
What are the different parts of the tubule that starts in the glomerulus and ends with the papillary duct which opens out into the renal papilla?
Proximal convoluted tubule Descending limb of the loop of Henle Thin ascending limb of the loop of Henle Thick ascending limb of the loop of Henle Distal convoluted tubule Collecting duct
Where is the juxtaglomerular apparatus found in the nephron of a kidney?
Between the arterioles entering and leaving the Bowman’s capsule and the macula densa which is found on the distal convoluted tubule.
Where does secretion into the nephron tubule occur?
In the glomerulus and in the proximal convoluted tubule.
What are the three layers of the filtration in the glomerulus of the nephron?
Endothelial cells of the capillary
Glomerular basement membrane
Epithelial cells of the Bowman’s capsule
What size are the pores in the endothelial wall of the capillaries in the glomerulus of the nephron?
70 nm
What are the main functions of the kidney?
Control extracellular environment (eg sodium, potassium, calcium etc)
Secrete products of metabolism
Fluid volume regulation
Secrete EPO
What is actively reabsorbed in the proximal convoluted tubule of the nephron?
Sodium Potassium Calcium Phosphate Glucose Amino acids Proteins (via endocytic receptors)
Is the filtrate hypo-, hyper- or iso-osmotic by the time it reaches the end of the proximal convoluted tubule in the nephron?
Iso-osmotic
What are the five main hormones that work on the kidney?
Vasopressin (ADH) Aldosterone Natriuretic peptides Parathyroid hormone Angiotensin II
What is the role of ADH in the kidney?
Promotes water reabsorption in the collecting duct
Where is ADH produced?
Posterior pituitary gland
What is the role of aldosterone in the kidney?
Promotes sodium reabsorption in exchange for potassium in the collecting ducts.
Where is aldosterone produced?
Adrenal glands
What is the role of natriuretic peptide hormone in the kidney?
Promote sodium excretion in the collecting ducts by inhibiting ENaC channels
Where are natriuretic peptides produced?
Cardiac cells