Core Questions Flashcards
What is the order in which food passes through the digestive system.
Mouth into the oesophagus than into the stomach than the small intestine then the large intestine then the rectum and then the anus.
What is the function of the mouth in the digestive system
To mechanically break up food into smaller pieces to increase the surface area.
What are the two functions of saliva in digestion?
1) To moisten food to allow easier swallowing
2) To Start chemical digestion by containing salivary amylase
What is the function of stomach acid
To kill potentially pathogenic micro-organisms in food
What is the function of the small intestine.
To absorb carbohydrates,lipids,amino acids,vitamins and mineral ions from digested food.
Give adaptation of small intestine and the cells lining the small intestine to aid absorption of digested molecules
1) Small intestines has structures called villi which increase surface area.
2) Epithelial cells lining the villi have microvilli on their surface area which further increases surface area
What is the function of the large intestine?
To absorb water from digested food.
What is the function of liver in digestion
To produce bile, an emulsifying and neutralising substance.
What is the function of the gall bladder?
To store bile until it can be released into the small intestine
What is the function of the rectum?
To store undigested material before excretion.
What is an enzyme?
A protein which can catalyse a reaction(speed it up) without being used up itself.
What is a substrate?
A molecule pr atom which is acted upon by an enzyme.
How does an enzyme “recognise” its specific substrate.
A complementarily-shaped “active-site” - a region on the enzyme which fits the substrate.
Name two environmental conditions that can change an enzyme’s active site.
1) pH (either higher or lower than optimum)
2) Higher than optimal temperature
Name where carbohydrase is made in the body
Salivary glands,pancreas and small intestine.
What do carbohydrases break down and what is produced?
Carbohydates to simple sugars
Name where protease is made in the body
Stomach,pancreas and small intestine.
What do proteases break down and what is produced
Proteins to amino acids
Name where lipase is made in the body
Stomach,pancreas and small intestine
What do lipases break down and what is produced?
Lipids to fatty acids and glycerol
What are the products of digestion used for?
To build new carbohydrates,lipids and proteins.
How does bile help the actions of lipase
1) Provides alkaline conditions by neutralising acid from the stomach
2) Emulsifies fat to form droplets with a larger surface area
What is the Benedict’s test and how do you carry it out?
For testing if there is sugar in food samples.Add Benedict’s reagent. Leave in a hot water bath for 5 minutes. if it turns orange/brick red it contains sugar.
What is the biuret test and how do you carry it out?
For testing if there is protein in food samples.Add biuret reagent. If it turns lilac then there is protein.
Which food test can be carried out with iodine?
Testing for the presence of starch. Add iodine drops to food sample. If it turns blue/black it contains starch.
Which system transports substances around the body
The circulatory system.
What is the heart?
An organ
What does the heart do?
It pumps blood around the body.
What are the walls of the heart made from?
Muscle tissue
What are the two types of chambers in the heart.
The atria and ventricles
Which are the upper chambers of the heart?
The atria
Which are the lower chambers of the heart
The ventricles
Where do the atria force blood upon contraction
To the ventricles
Where do the ventricles force blood upon contraction
Out of the heart
What is the job of the heart valves?
To prevent backflow of blood in the heart
To where does blood flow after leaving the right hand side of the heart?
The lungs
To where does blood flow after leaving the left hand side of the heart
the rest of the body
Through which vessel does blood flow away from the heart?
Arteries
Through which blood vessel does blood flow back into the heart
Veins
Name the blood vessel by which blood leaves to the rest of the body?
Aorta
Name the blood vessel by which blood arrives back from the rest of the body?
Vena cava
Name the blood vessel by which blood leaves the heart to the lungs
Pulmonary artery
Name the blood vessel by which blood leaves the lungs to go back to the heart
Pulmonary vein
Which blood vessels have thick walls containing muscle tissue and elastic fibres
Arteries
Which blood vessels have thinner walls and contain valves
Veins
Name two key adaptations of capiliaries
1) Very thin(one cell thick) to reduce diffusion has to occur across
2) Very narrow to reduce diffusion has to occur across
Where is the “natural” pacemaker of the heart located?
The right atrium
Which are the lungs located?
The upper part of the body(thorax)
What protects the lungs?
The ribcage
What separates the lungs from the abdomen(lower part of the body)
The diaphragm
Which gas diffuses into the bloodstream
Oxygen
Which gas diffuses out of the bloodstream
Carbon dioxide
Name the structure which carries air from the nose/mouth
Trachea
Name the two structures which branch off from the trachea
Bronchi - single is bronchus
Name the structure which branch off from the bronchi
Bronchiole(s)
What are the small gas exchange structures in the lungs called
Alveoli (singular - alveolus)
Describe 4 adaptations alveoli have to make them well suited for gas exchange
1) Thin walls(one cell thick)
2) Extensive capillary network covering the surface of each alveolus
3) Efficient movement of blood through capiliaries to maintain a concentration gradient for diffusion and carbon dioxide
4) Folded inner surface to give a large surface area
What is the liquid part of blood called
Plasma
What are the 3 main cell types found in blood
Red and white blood cells and platelets
What does blood plasma transport from the organs to the lungs
Carbon dioxide
