chapter 15 - homeostasis(liver and kidney) Flashcards
1
Q
What is excretion?
A
- The removal of waste products from the body e.g. Urea and CO2
2
Q
What are the functions of the liver?
A
- Excretion
- Detoxification(breaking down harmful substances into less harmful ones)
- glycogenesis(storing excess glucose as glycogen)
3
Q
Name the structure of the liver
A
- hepatic portal vein
- hepatic artery
- hepatic vein
- gall bladder
- bile
4
Q
What is the role of the hepatic artery, hepatic portal vein and hepatic vein?
A
- hepatic artery, carries oxygenated blood for respiration
- hepatic portal vein, blood carrying a high concentration of digested food
- hepatic vein, carries deoxygenated blood away from the liver
5
Q
what is the role of the gall bladder and bile?
A
- gall bladder, stores bile
- bile, emulsifies fats
6
Q
What does a liver lobule consist of?
A
- hepatic artery
- hepatic portal vein
- sinusoid
- bile duct
- kupffer cells
- hepatocytes
- central vein
7
Q
What are the roles of the kupffer cells and hepatocytes?
A
- kupffer cells, are resident macrophages that break down bacteria
- hepatocytes, detoxification(breaking down toxic substances)
8
Q
What occurs at the sinusoid?
A
- the blood from the hepatic artery and hepatic portal vein mix flowing towards the central vein
9
Q
What is deamination?
A
- its the removal of the amine group from an amino acid
10
Q
What happens to the amine group after deamination?
A
- the amine group is converted into ammonia which enter the ornithine cycle
11
Q
What is the purpose of the ornithine cycle?
A
- To convert ammonia into urea so it can be excreted
12
Q
What happens in the ornithine cycle?
A
- Ammonia combines with CO2 and ornithine to produce citruline
- citruline leaves the mitochondria and is the converted into arginine
- Arginine combines with water to produce ornithine whilst releasing urea
- A high concentration of urea decreases the water potential of the blood as result increasing water reabsorption by the kidneys
13
Q
Where does deamination occur?
A
- it occurs in the mitochondria of the liver cells
14
Q
what is the process of ultrafiltration?
A
- High hydrostatic pressure is created as the afferent arteriole is wider than the efferent arteriole
- small molecules are forced into the Bowmans capsule to form the filtrate(glucose, H20, amino acids, urea and ions)
- large molecules don’t fit through the gaps(RBC and proteins)
15
Q
What layers of protection ensures that no large molecules enter the Bowmans capsule?
A
- Gaps in the capillary walls
- Gaps in the basement membrane
- Gaps in the podocytes
16
Q
what is selective reabsorption?
A
- its where useful products are reabsorbed from the glomerular filtrate by the nephron