Physiology 2 - Structure and Function of the Kidneys Flashcards
Roughly how much salt do the kidneys excrete per day?
10g
What are some examples of metabolic waste products which are excreted by the kidneys?
Urea, creatinine, bilirubin
Which hormone is secreted by the kidneys to control arterial blood pressure?
Renin
Which hormone is secreted by the kidneys to stimulate red blood cell production?
Erythropoietin
What is the functional unit of the kidney?
Nephron
What are the three main functions of the nephron?
Filtration, secretion, reabsorption
The initial tubular fluid formed by glomerular filtration passes from the glomerulus into where?
Bowman’s capsule
Describe the flow of tubular fluid once it has exited the Bowman’s capsule?
Proximal tubule - loop of Henle - distal tubule - collecting duct
The collecting ducts empty urine into where?
Renal pelvis
Histologically, the tubules of the nephron are made up of what?
A single layer of epithelial cells
What blood vessel drains blood into the glomerulus?
Afferent arteriole
Blood leaves the glomerulus into which vessel?
Efferent arteriole
In the vast majority of nephrons, where does blood pass into from the efferent arteriole?
Peritubular capillaries
The juxtaglomerular apparatus is a small portion of what part of the nephron, that passes between the afferent and efferent arterioles?
Distal tubule
What is the most common type of nephron in the kidneys?
Cortical
20% of the nephrons in the kidneys are what type?
Juxtamedullary
In which type of nephron is the loop of Henle longer?
Juxtamedullary
Juxtamedullary nephrons do not have peritubular capillaries. What do they have instead?
Vasa recta
The vasa recta follows the route taken by which part of the nephron?
Loop of Henle
What is the purpose of the juxtamedullary nephrons?
To produce a more concentrated urine
Which is larger in diameter- the afferent or efferent arteriole?
Afferent
If the smooth muscle of the afferent arteriole contracts, what happens to the blood supply to the glomerulus?
Decreased
If the smooth muscle of the afferent arteriole relaxes, what happens to the blood supply to the glomerulus?
Increased
Which cells make up the inner layer of the Bowman’s capsule?
Podocytes
What is located between the endothelial cells of the glomerulus capillary and the podocytes of the Bowman’s capsule?
Basement membrane
Does the basement membrane of a nephron contain any cells?
No
What is the purpose of the granular cells in the juxtaglomerular apparatus?
To secrete renin
What is the purpose of the macula densa cells in the juxtaglomerular apparatus?
To sense the salt concentration of the tubular fluid
If there is too much salt in the tubular fluid, what is the action of the macula densa cells in the juxtaglomerular apparatus?
Contract smooth muscle cells in the afferent arteriole
If there is too little salt in the tubular fluid, what is the action of the macula densa cells in the juxtaglomerular apparatus?
Relax smooth muscle cells in the afferent arteriole
What percentage of blood passing through the glomerulus becomes tubular fluid?
20%
What is the normal glomerular filtration rate?
125ml/min
If the rate of filtration of a substance is higher than the rate of excretion of the same substance, what has happened to that substance in the nephron?
Net reabsorption
If the rate of filtration of a substance is lower than the rate of excretion of the same substance, what has happened to that substance in the nephron?
Net secretion
