Endocrine And Integumentary System Flashcards
Why is the pressure in the glomerulus high?
As the affront arteriolar is wider than the efferent arteriol.
What does this high pressure (in the glomerolus) cause?
a bottleneck in the capillaries. Here the pressure pushes water and smaller molecules from the blood in the capillaries in the glomerulus all the way to Bowman’s capsule by ultrafiltration.
Where is selective re absorption carried out?
Proximal convoluted tubule
how is glucose reabsorbed from the filtrate in PCT?
-glucose enters the PCT (proximal convoluted tubule) by facilitated diffusion
-Glucose pairs the PCT cell at the other end and diffuses into teh blood
-Active transport is also involved in the re absorption of glucose fro the PCT cells into the blood.
what happens to the water conc as glucose is reabsorbed?
Decreases the water conc creating a water concentration gradient down which water enters PCT cells by osmosis from the filtrate.
Where does the filtrate enter after the proximal convoluted tubule?
Enters the loop of Henley which drops down into the medulla and rises back up into the cortex.
What happens in the ascending limb?
At the top they pump out sodium ions by active transport as the walls are impermeable so cannot leave. Creating a low water conc in the tissue fluid of the medulla.
What happens in the descending limb?
The cells are highly permeable to water but impermeable to sodium ions. So water moves out and enters the tissue fluid of the medulla by osmosis. This makes the filtrate in the descending limb more concentrated, reducing it’s water conc.
Label the kidney
.
Label the pancreas
.
What is the pancreas used for?
Control of blood glucose levels.
What does the islets of langerhans contain?
Alpha cells and beta cells
Label the nephron
.
What do receptors in the islets of langerhnas monitor?
The glucose concentration of the blood.
What happens when blood glucose levels climb?
-Detected by receptors in the IL
-Beta cells are secreted. targets the liver and muscle cells.
-These cells take up more glucose than normal and store the excess as glycogen
What is glycogen and what are its main features?
Glycogen is a branched polymer of alpha glucose. it is compactly so stores a large amount of glucose on a small space. It is highly branched so it has lots of ‘ends’ for enzymes to attach to and hydrolyse it quickly if needed.
What happens when low glucose levels are detected?
Receptors detect this and the alpha cells will secrete glucagon into the bloodstream. Glucagon mainly targets the liver and it causes the breakdown of glucagon into glucose which is released into the blood raising by levels.
What is glucose?
A monosaccharide that makes up carbohydrates and disaccharides. Is a hexose sugar and a main respiratory substrate.
What is glycogen?
Polysaccharide, long polymer chain of glucose. Compact so stores large amounts of glucose. Highly branched
What is glycogenisis?
When cells take up more glucose than normal and store the excess as glycogen. Condensing the glucose into glycogen.
What is glycogenlysis?
This is caused when the hydrolysis of glucagon into glucose is released into the blood raising blood glucose levels.
Where is the water in the tissue fluid of the medulla reabsorbed?
Vasa recta
Why is the loop of Henley known as the countercurrent multiplier?
As the fluid flows in the opposite directions in the two sides of the loop.
Where does the filtrate go after the loop of henle?
Distal convoluted tubule.
