Excreation Flashcards
(24 cards)
What are the 4 things that transport substances/blood to and from the liver
The Hepatic artery
The Hepatic portal vein
The Hepatic Vein
The Bile duct
What does the hepatic artery do?
supplies oxygenated nutrient poor blood to the liver
What does the hepatic portal vein do?
supplies deoxygenated nutrient rich blood to the liver
what does the hepatic vein do?
Carries deoxygenated blood out the liver and to the heart
Where do the hepatic artery and portal vein flow into?
Sinusoids which are lined with hepatocytes
What are Kupffer cells
They are macrophages which break down and recycle old red blood cells to bilirubin which make are poo brown
What are 3 functions of the Liver?
- Stores Glycogen to help control blood glucose levels
- Detoxification, breaks down alcohol
- Deamination, breaks down amino acids by removing the amine group and converting it to ammonia
Ammonia is highly toxic, after deamination how is it dealt with
NH3 is added to CO2 in the ornithine cycle to form urea which is less toxic
What is the structure of the kidney?
Outide: Cortex
Inside: Medulla
What are Kidneys made of?
Approximately 1 mil nephrons
What is the journey of substances from start to end of a nephron? (6/7)😈
Afferent and Efferent arteriole, to bowman’s capsule, through glomerulus. proximal convoluted tubule, Loop of Henle, Distal convoluted tubule (collecting duct as well)
What is Ultrafiltration?
There is high hydrostatic pressure due to difference in diameter if the efferent and afferent arteriole. This causes Fluid and molecules to go through the 3 layers of filtration in the Bowman’s Capsule/Glomerulus. resulting in glomerula filtrate
What are the 3 layers of filtration in ultrafiltration?
Endothelium
Basement membrane
Podocytes
These leave large molecules like RBC and proteins out
What is the order of processes in the nephron (4)
Ultrafiltration, selective reabsorption, water reabsorption, distal convoluted tubule
-HARD- Explain the process of selective reabsorption. (3 big) Nah epi is mid
1) Na+ is actively transported into the capillary from the epithelial cell to establish a conc gradient
2)Na+ and other substances are transported from the lumen to the epithelial cell via facilitated diffusion with a co-transport protein
3)Those substances then travel down the concentration gradient into the capillary + water via osmosis
Where does water reabsorption happen?
Loop of henle
What happens in the loop of Henle?
1) Na+ is actively transported out of the ascending limb in to the medulla decreasing water potential
2)As only the descending limb is permeable water moves from it to the medulla via osmosis
3) The water and Na+ that’s is the medulla is reabsorbed into the blood
How is the water potential gradient maintained in the loop of Henle?
The counter current flow of ions and water
How is the proximal convoluted tubule adapted for selective reabsorption? (4)
Epithelial cells have mitochondria for ATP for the active transport
Large number of Co-transport proteins
Microvili increase SA:V
Epithelial cell has short diffusion distance
What does more water being reabsorbed to to the concentration of Urine and why?
Urine becomes more concentrated as more water is reabsorbed as its being put into the body and not the urine
What environment would a longer loop of Henle be suitable for and why?
Dryer environments as longer = more Na+ pumped out of ascending limb so more water is reabsorbed in the medulla
What happens in the Distal convoluted tubule and collecting duct?
They reabsorb water further from the filtrate depending on the bodies needs, it does this by changing its permability
How is the permeability of the convoluted tubule and collecting duct controlled?
HYPE ADHD
The hypothalamus contains osmoreceptors which detect change in water pot of blood.
The release of ADH from the pituitary glands increases aquaporin channels which increases permeability and thus water absorption
Why would someone with untreated diabetes have sweet urine?(2)
High conc of sugar in blood = lots of glucose in glomerular filtrate after ultrafiltration
Selective reabsorption wont be able to reabsorb it all so some will remain the urine
