Digestion, Respiration & Circulation. Flashcards
What does the Mouth do?
It uses saliva, which contains salivary amylase, to break down starch into maltose.
What does the stomach do?
It uses gastric juice, which contains pepsin, to break down proteins into polypeptides.
What are enzymes?
They are biological or organic catalysts which can be found in all living organisms that speed up the rate of chemical reactions without themselves being changed and are mainly made of proteins.
What can an enzyme do?
A small quantity of enzyme can bring about a large amount of chemical reaction and they are specific in action. A rate of enzyme reaction is fastest at optimum temperature.
What is digestion?
Digestion is the mechanical and chemical breaking down of food into smaller components that can be absorbed into the bloodstream.
What is peristalsis?
Wavy-like rhythmic contractions and relaxations of the longitudinal and circular muscles of the alimentary tract that helps push food down the gut and is a key feature in churning.
What is Double Circulation?
It is the phenomenon whereby blood passes through the heart twice and once to the lungs and the other to the other parts of the body.
What is a tissue fluid?
It is formed by blood plasma that leaks out and fills up the space between the capillaries.
What is Aerobic Respiration?
It is the oxidation of glucose in the presence of oxygen with the release of a large amount of energy.
What is Anaerobic Respiration?
It is the oxidation of glucose in the absence of oxygen with the release of a small amount of energy,
How does Lactic Acid form?
It occurs in muscles where there is not enough O2 reaching the cells to convert all the glucose into CO2 and H20. Glucose is partially broken down, without CO2, to lactic acid, with only some energy being released.
Which enzyme breaks starch into Maltose?
Amylase
Which enzyme breaks proteins into polypeptides?
Trypsin
Which enzyme breaks fats into fatty acids and glycerol?
Lipase
Where are the 2 areas in which proteins is broken down in polypeptides?
- Stomach (Pepsin)
2. Small Intestine, Duodenum (Trypsin)
What does Mastication do?
It increases surface area to volume ratio.
What do the Salivary glands do?
They secrete saliva which contains water, mucus and enzyme.
What does the Tongue do?
It mixes food with saliva and rolls food into a bolus which is easier to swallow.
What does the Oesophagus do?
It secrets Mucus that aids in the passage of food into the stomach.
What does the Stomach do?
It contains acidic ph 2 and has muscular walls made up of circular and longitudinal muscles which are under involuntary control which helps in churning and mixes it with gastric juice.
What is chyme?
It contains partially digested food and is passed in small amounts into the duodenum. The pyloric spinchter controls the amount of chyme that is passed from the stomach to the duodenum.
What do gastric glands do?
It secretes gastric juice which contains hydrochloric acid which kills bacteria and provides an acidic environment for stomach enzymes which are pepsin and renin.
What does the liver do?
It produces bile that is temporarily stored in the gall bladder and then secreted into the common bile duct that emulsifies fats. The liver neutralises the acidic chyme from the stomach and provides alkaline pH for the small intestine.
What is emulsification?
It is the process whereby fats is broken down into smaller globules of and increases the surface area for the digestion of fats.
