5.1.2 Excretion

Question 1

Define Excretion

Answer 1

the removal of waste products of metabolism from the body

Question 2

What is the importance of excretion in maintaining metabolism and homeostasis?

Answer 2

excretion removes waste products to maintain a stable environment
- build up of toxic waste products can do harm to cells

Question 3

What are the 3 main metabolic waste products in mammals?

Answer 3

-Carbon Dioxide
-Bile pigments
-Nitrogenous wase products (urea)

Question 4

Where does the metabolic waste carbon dioxide come from and where is it excreted?

Answer 4

-waste product of cellular respiration
- excreted from lungs

Question 5

Where does the metabolic waste Bile pigments come from and where is it excreted?

Answer 5

• from the breakdown of haemoglobin from old blood cells in liver
• excreted in bile from liver into small intestine via gall bladder and bile duct

Question 6

Where does the metabolic waste nitrogenous waste (urea) come from and where is it excreted?

Answer 6

• formed from deamination (removal of amine group) of excess amino acids by liver
• excreted by kidneys in urine

Question 7

What is the name of the nitrogenous waste products in mammals, fish, birds, and insects?

Answer 7

Mammals - urea
Fish - ammonia
Birds + insects - uric acid

Question 8

Describe the location of the liver in mammals

Answer 8

Liver lies just below the diaphragm

Question 9

Draw and label a diagram to show the blood vessels going to and from the liver DO ON FLASHCARD

Answer 9

do on flashcard

Question 10

What is the function of the hepatic portal vein?

Answer 10

supplies nutrient rich blood to the liver from the intestines

Question 11

What is the type of cell that makes up the liver?

Answer 11

hepatocytes

Question 12

What adaptations do hepatocytes have for their functions?

Answer 12

• large nuclei
• lots of mitochondria as metabolically active
• prominent golgi apparatus

Question 13

Draw and label a diagram to show the arrangement of tissues within the liver

Answer 13

Bile canaliculus - hepatocytes secrete bile into these canaliculi and from here drain it into the gall bladder to be strored

blood from venule (of hepatic portal vein) and arteriole (of the hepatic artery) mixes in the sinusoids and the venule of the hepatic vein carries it away

Question 13

Draw and label a diagram to show the arrangement of tissues within the liver info on here do diagram on flashcard

Answer 13

Bile canaliculus - hepatocytes secrete bile into these canaliculi and from here drain it into the gall bladder to be strored

blood from venule (of hepatic portal vein) and arteriole (of the hepatic artery) mixes in the sinusoids and the venule of the hepatic vein carries it away

Question 14

Label and annotate a photomicrograph of liver tissue at low and high power to show histological features DO ON FLASHCARD

Answer 14

DO ON FLASHCARD

Question 15

What is the role of Kupffer cells in the liver?

Answer 15

macrophages of the liver
- ingest foreign matter and protect against disease

Question 16

How is bile formed?

Answer 16

the breakdown products of old red blood cells by hepatocytes forms bile

Question 17

How does bile travel to where it is stored?

Answer 17

secreted by hepatocytes into canaliculi from there it drains into bile ductules which take it into gall bladder (where bile is stored)

Question 18

What are the 6 roles of the liver?

Answer 18

1- Carbohydrate metabolism
2- Bile production
3- Heat production
4- Breakdown of blood proteins
5- Production of plasma proteins
6- Detoxification
7 - Transamination
8- Deamination

Question 19

Describe the carbohydrate metabolism function of the liver

Answer 19

• control of blood glucose concentration
• blood glucose conc rises - insulin levels rise - stimulate hepatocytes
  - hepatocytes convert glucose into glycogen
• blood glucose conc fall -stimulate hepatocytes
  - hepatocytes convert glycogen back into glucose under influence of
  glucagon

Question 20

Describe the bile production function of the liver

Answer 20

• bile pigements and bile salts

Question 21

What is the role of hepatocytes when controlling blood glucose concentration?

Answer 21

-hepatocytes respond to insulin by absorbing more glucose and doing glycogenesis
-respond to glucagon by doing glycogenolysis

Question 22

Define transamination

Answer 22

conversion on 1 amino acid into another

Question 23

Define deamination

Answer 23

the removal of the amino group from amino acids

Question 24

Summarise the process of deamination

Question 25

Draw a diagram to show how urea is produced from excess amino acids via the ornithine cycle

Question 26

Define detoxificaton

Question 27

What are 2 examples of detoxification by the liver?

Question 28

What is the location of the kidneys in humans

Question 29

What are the names of the 3 main areas of the kidney and describe the role of each area?

Answer 29

-Cortex - filters the blood
-Medulla - water potential gradient to reabsorb water from urine
-Pelvis - urine collects before passing out of the ureter

Question 30

Draw and label a diagram to show the internal structure of a kidney