This is a draft cheat sheet. It is a work in progress and is not finished yet.
key terms
metabolism |
- the sum total of all chemical recations in the body |
metabolic waste |
- substances produced by metabolism found in excess or are toxic |
excretion |
- removal of metabolic waste from the body |
egestion |
- removal of undigested food from the body by the eprocess of defication |
|
excretion on mammals
The main metabolic waste products are... |
- CO2 |
- made by cellular respiration and is excreted by the lungs |
- urea |
- made by deamination in the liver and excreted in the urine |
- bile pigments |
- made by the breakdown of erythrocyes in the liver and excreted in samll amounts in the urin. |
Why must metabolic waste be removed? |
- metabolic products are highly toxic if they build up.
- CO2 can take the place of oxygen and copetes for haemoglobin - this increases blood acidity
- Urea is highly toxic and is very soluble so must be converted to ammonia. |
|
|
The Liver Blood Vessels
blood enters into the liver by the hepatic artery
- the blood is under high pressure and is oxygenated as it is coming from the heart |
blood also enters into the liver by the hepatic portal vein
blood is carrying products of digestion such as glucose as it comes from the small intestine. the blood is not oxygenated and is at a lower pressure as it doesnt come from the heart |
blood leaves the liver by the hepatic vein
the blood is cleaned and ready to be returned to the heart to pick up oxygen. |
the bile duct also leaves the liver
the bile duct carries bile from the bile cannivulus to the gall bladder where it is stored before being secreted into the small intestine to emulsify fats. |
How to identify vessels in the liver |
hepatic artery
- blood flows into the liver
- blood vessel is narrower to maintain a higher pressure |
hepatic portal vein
- blood flows into the liver
- blood vessel is wider to reduce friction
- blood vessel is branched |
hepatic veim
- blood flows out from the liver
- blood vessel is thinner to maintain a higher pressure |
bile duct
- connects to the bile duct
bile flows out of the liver |
|
|
Hepatocytes
the liver is made up of lobules which are hexagonally shaped areas of tissues that contain a branch of the hepatic vein. |
lobules are made up of hepatocytes - hepatocytes are liver cells |
Vesseles of the lobule... |
- branch of the hepatic artery - takes oxygenated high pressure blood to the liver from the heart |
- branch of the hepatic portal vein - takes blood rich in digestive products such as glucose to the liver from the intestine |
- hepatic artery - takes deoxygenated low pressure blood that has been cleaned back to the heart to pick up oxygen |
- bile duct - takes bile from the bile canniculus to the gall bladder to be stored before it is released into the intestine to emulsify fats |
All the blood entering into the liver from the hepatic artery and the hepatic portal vein enters into a sinusoid so that there is a mixture of oxygenatd and nutrient rich blood |
Labelling vessels |
- hepatic artery
- narrower to maintain high blood pressure
- blood flows into the liver |
- hepatic portal vein
- wider to reduce friction
- blood flows into the liver
- hepatic portal vein is branched |
- hepatic vein
- blood flows out of the liver |
- bile duct - extends further out of the lobule
- connects to a bile canniculi rather than a sinusoid |
|
