5.1.2 Excretion Flashcards
Define Excretion
the removal of waste products of metabolism from the body
What is the importance of excretion in maintaining metabolism and homeostasis?
excretion removes waste products to maintain a stable environment
- build up of toxic waste products can do harm to cells
What are the 3 main metabolic waste products in mammals?
-Carbon Dioxide
-Bile pigments
-Nitrogenous wase products (urea)
Where does the metabolic waste carbon dioxide come from and where is it excreted?
-waste product of cellular respiration
- excreted from lungs
Where does the metabolic waste Bile pigments come from and where is it excreted?
- 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
Where does the metabolic waste nitrogenous waste (urea) come from and where is it excreted?
- formed from deamination (removal of amine group) of excess amino acids by liver
- excreted by kidneys in urine
What is the name of the nitrogenous waste products in mammals, fish, birds, and insects?
Mammals - urea
Fish - ammonia
Birds + insects - uric acid
Describe the location of the liver in mammals
Liver lies just below the diaphragm
Draw and label a diagram to show the blood vessels going to and from the liver DO ON FLASHCARD
do on flashcard
What is the function of the hepatic portal vein?
supplies nutrient rich blood to the liver from the intestines
What is the type of cell that makes up the liver?
hepatocytes
What adaptations do hepatocytes have for their functions?
- large nuclei
- lots of mitochondria as metabolically active
- prominent golgi apparatus
Draw and label a diagram to show the arrangement of tissues within the liver
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
Draw and label a diagram to show the arrangement of tissues within the liver info on here do diagram on flashcard
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
Label and annotate a photomicrograph of liver tissue at low and high power to show histological features DO ON FLASHCARD
DO ON FLASHCARD
What is the role of Kupffer cells in the liver?
macrophages of the liver
- ingest foreign matter and protect against disease
How is bile formed?
the breakdown products of old red blood cells by hepatocytes forms bile
How does bile travel to where it is stored?
secreted by hepatocytes into canaliculi from there it drains into bile ductules which take it into gall bladder (where bile is stored)
What are the 6 roles of the liver?
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
Describe the carbohydrate metabolism function of the liver
- 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
Describe the bile production function of the liver
- bile pigements and bile salts
What is the role of hepatocytes when controlling blood glucose concentration?
-hepatocytes respond to insulin by absorbing more glucose and doing glycogenesis
-respond to glucagon by doing glycogenolysis
Define transamination
conversion on 1 amino acid into another
Define deamination
the removal of the amino group from amino acids
Summarise the process of deamination
Draw a diagram to show how urea is produced from excess amino acids via the ornithine cycle
Define detoxificaton
What are 2 examples of detoxification by the liver?
What is the location of the kidneys in humans
What are the names of the 3 main areas of the kidney and describe the role of each area?
-Cortex - filters the blood
-Medulla - water potential gradient to reabsorb water from urine
-Pelvis - urine collects before passing out of the ureter
Draw and label a diagram to show the internal structure of a kidney
