Renal Physiology Flashcards
What are the components of the urinary system?
- Kidneys (2).
- Ureter (2).
- Bladder.
- Urethra.
Describe the kidneys?
- Right kidney lower than left.
- Remove urea from blood –> expel it in urine.
What is urea?
Waste product of protein metabolism.
What does the kidneys help maintain a balance of?
- Fluids.
- Salts.
- Other substances in the blood.
What do kidneys produce?
Erythropoietin =
- a hormone that aids red blood cell formation.
What is the purpose of the ureters?
Carry urine from kidneys to bladder.
What type of muscle does the ureter walls contain?
Smooth muscle.
How do the ureters force urine down to the bladder?
Smooth muscle walls contract and relax forcing urine downwards, away from the kidneys.
Why do the ureters enter the bladder posteriorly and horizontally?
To prevent urine backflow (during increased pressure in bladder).
Where is the bladder located?
Lower abdomen.
How much urine can your bladder hold?
500ml –> but can hold up to 1L.
What does the bladder use to help it empty urine?
The urethra.
What is the urethra?
The rube that allows urine to be excreted from the body.
What is the size of the male/female urethra?
Male = 20cm.
Female = 3-4cm.
What do the kidneys do?
1) . Filter blood.
2) . Regulate blood volume + pressure.
3) . Eliminate waste.
4) . Control osmolarity.
5) . Contribute to calcium homeostasis.
6) . Secrete erythropoietin (EPO).
What is the structure of the kidneys?
- Renal vein.
- Renal artery.
- Adrenal gland (sits on top).
- Calyx.
- Cortex.
- Medulla.
- Renal pelvis.
- Ureter.
What are the 3 main areas of the kidneys?
- Outer cortex.
- Inner medulla.
- Renal pelvis.
Where does the kidneys receive its blood from?
Renal arteries.
Does the ureter and renal vein leave or enter the kidneys?
Leaves.
How many nephrons are there in each kidney?
1.2 million.
What are the nephrons responsible for in the kidneys?
Microscopic functional units =
- purification.
- filtration of blood.
What are the 2 parts of the nephrons?
1) . Renal corpuscle.
2) . Renal tubule.
What is the renal corpuscle responsible for?
Filtration of blood.
What is the renal tubule responsible for?
Reabsorption and secretion (converts filtrate to urine).
What are the 2 structures of the renal corpuscle?
1) . Bowman’s capsule.
2) . Glomerulus.
What brings blood to the glomerulus?
Afferent arteriole =
- brings blood at high pressure.
Where is the glomerulus?
Enclosed in the Bowmans capsule =
- containing a knot of capillaries.
What happens when blood is pushed through the capillaries of the glomerulus?
Filtration of blood takes place (glomerulus filtrate).
What does glomerulus filtrate contain?
- Water.
- Electrolytes.
- Urea.
- Amino acids.
- Glucose.
Where does blood leave the glomerulus?
Efferent arteriole.
What are the 2 layers of the Bowman’s capsule?
1) . Outer layer =
- simple squamous epithelial.
2) . Inner layer =
- cells known as podocytes.
- wrapped around capillaries of glomerulus.
Whats the difference between the afferent/efferent arteriole?
Afferent has a larger diameter.
Where does blood go once it has left the Bowman’s capsule?
Renal tubule.
What are the 3 sections of the renal tubule?
1) . Proximal convoluted tubule (PCT).
2) . Loop of Henle.
3) . Distal convoluted tubule (DCT).
Which part of the renal tubule does the filtrate go once it has left the Bowman’s capsule?
Proximal convoluted tubule =
- process of reabsorption.
What is reabsorbed at the proximal convoluted tubule?
- Glucose.
- Amino acids.
- Electrolytes.
- NaCI (salt).
Where does the distal convoluted tubule (DCT) receive the filtrate from?
Loop of Henle.
What is reabsorbed in the Henle?
Sodium and water.
What is the role of the DCT?
Secretion of electrolytes.
What electrolytes does the DCT secrete?
- H+ ions.
- Nitrogenous wastes.
- Toxins.
What happens to the secreted electrolytes?
Now become urine which flows to the collecting ducts.
Where does the removal of water take place?
In the collecting ducts.
How do the pores in the collecting ducts work?
Influence of anti-diuretic hormone (ADH).
Summarise the process of filtration in the nephrons?
1) . Glomerulus and Bowman’s capsule =
- plasma filtration.
2) . PCT =
- tubular reabsorption.
3) . Loop of Henle =
- adjusts water concentration in urine.
4) . DCT =
- tubular secretion.
5) . ADH =
- water reabsorption (collecting tubules).
What are the 3 functions of the nephrons?
1) . Filtration.
2) . Reabsorption.
3) . Secretion.
What is the main role of the glomerulus?
Filters blood.
What is the main role of the Proximal convoluted tubule (PCT)?
1). Reabsorbs =
- ions.
- water.
- nutrients.
2) . Removes =
- toxins.
3) . Adjusts filtrate pH.
What is the main role of the loop of Henle?
Reabsorbs =
- water.
- sodium.
- chloride.
What is the main role of the distal convoluted tubule (DCT)?
Secretes =
- H+.
- Nitrogenous wastes.
- Toxins.
Transported from plasma into urine.
What is the main role of the collecting duct?
Reabsorbs =
- water.
Concentrates urine.
What is antidiuretic hormone (ADH) also known as?
Vasopressin.
Where is ADH secreted?
Hypothalamus.
Where is ADH stored?
Posterior pituitary gland.
What factors influence the release of ADH?
1) . Osmoreceptors =
- detect changes in concentration of solutes in blood.
2) . Baroreceptors =
- responds to changes in plasma volume.
What are the 2 functions of ADH?
1) . Regulating fluid balance (water retention).
2) . Vasoconstriction (peripheral resistance).
What is the ADH role in water retention?
Increase water reabsorption by:
- increasing the permeability of the distal tubule and collecting duct.
What is the ADH role in vasoconstriction?
Increases peripheral resistance =
- leads to a rise in blood pressure.
Why is ADH important?
- Regulation of water in the blood.
- Long-term control of blood pressure.
