Kidneys, Urine and diagnosis: Flashcards
How to tell the difference between the renal vein and renal artery?
The renal vein has a larger diameter than the renal artery.
What are the main functions of the kidney?
Excretion, osmoregulation, production of erythrocytes.
What are the plectrum shaped regions of the medulla called?
Renal pyramids.
What is the peripheral region of the kidney called?
Renal cortex
What is the name of the central part of the kidney leading to the renal blood vessels and is where the ureter joins the kidney.?
Renal Pelvis.
Purpose of the renal artery?
To supply oxygenated blood (containing urea and salts) to the kidneys
What is the purpose of the renal vein?
Carries deoxygenated blood (that has urea and excess salts removed) away from the kidneys.
Role of the bladder?
To temporarily store urine.
Fibrous Capsule:
Outerlayer of the kidney that protects the kidney from damage.
What is a nephron?
A specialised filtration unit in both the medulla and cortex that produces urine.
Which parts of a nephron are located in the cortex?
The glomerulus, bowman’s capsule, proximal convoluted tubule, distal convoluted tubule.
Which parts of a nephron are located in the medulla?
Loop of henle and the collecting duct.
What is the vasa recta?
Network of capillaries surrounding the loop of henle.
What is the afferent arteriole?
The arteriole that carries blood to glomerulus.
What is the efferent arteriole?
The arteriole that carries blood away from the glomerulus into a network of capillaries that carry blood alongside the nephron -> reabsorb water and useful substances and transport hormones.
What blood vessel carries blood away from the network of capillaries surrounding a nephron?
The renal vein.
How will blood in the renal vein differ to the blood in the renal artery?
Less urea, less water and ions, less glucose (used in respiration), more carbon dioxide, mineral ions restored to optimum levels.
Function of the loop of Henle:
To establish a water potential gradient down into the medulla so when urine travels through the collecting duct, water can diffuse by osmosis into the surrounding tissues.
What two components of the nephron are impacted by ADH:
The Distal convoluted tubule and the collecting duct.
Describe ultrafiltration in the bowman’s capsule:
Small molecules (including amino acids, water, glucose, urea and inorganic ions) are filtered out of the blood capillaries of the glomerulus and into the bowman’s capsule to form filtrate.
Describe selective reabsorption in the PCT:
Useful molecules are reabsorbed from the filtrate and returned to the blood as the filtrate flows.
Structure of the bowman’s capsule and glomerulus.
The glomerulus consists of a knot of fenestrated capillaries, which are perforated by tiny fenestrations. \the inner epithelium of the capsule are lined by podocyte cells, which have cellular extension called pedicels that wrap around the blood vessels of the capillaries. Between the podocytes and capillaries is a layer called the basement membrane. The high hydrostatic of the blood size selectively pushes nutrients through the fenestrations and the gaps between podocytes.
Basement membrane:
A mesh between the glomerulus and the bowman’s capsule -> which functions as the sole filtration barrier within the nephron.
During ultrafiltration, what three layers do molecules pass through?
The capillary endothelium, basement membrane and the bowman’s capsule epithelium.
Compare the water potential of the blood plasma of the glomerulus compared to the filtrate:
The water potential of the blood plasma is higher than the filtrate. Therefore blood flows through the glomerulus and there is an overall movement of water from the glomerulus down the water potential gradient into the bowman’s capsule.
Glomerular Filtration Rate:
The volume of blood filtered through the kidneys in a given time.
How pressure affects water potential in the glomerulus:
Afferent arteriole is wider than the efferent arteriole, bottle necking the blood, causing an increase in water potential, as the water is pushed through the fenestrated capillaries.
How solute concentration affects water potential in the glomerulus:
The basement membrane allows for most solutes to filter into the bowman’s capsule. The plasma proteins are too big to exit, keeping the solute concentration of the blood higher, decreasing the water potential of the blood plasma.
Why is it important the solute concentration of the blood plasma decreases the capillary’s water potential?
To prevent too much water from exiting the blood and impacting the function of the kidneys.
Describe how the cells of the proximal convoluted tubule are adapted to their function:
- Microvilli - Increased SA:vol ratio
- Co-transporter - Actively moved through protein passively moves others
- Tightly packed - no “leaking” - ensure selective reabsorption.
- High number of mitochondrion - Active transport.
Selective Reabsorption:
- Many substances filtered out of the glomerulus need to be kept in the body.
- These substances are reabsorbed.
- Takes place in Proximal Convoluted Tubule.