B2 - Organisation Flashcards
What is the order in which food passes through the digestive system?
- Mouth
- Oesophagus
- Stomach
- Small intestine
- Large intestine
- Rectum
- Anus
What is the function of the mouth in digestion?
To mechanically break up food pieces to increase the surface area of the food.
What are two functions of saliva in digestion?
- To moisten food to allow easier swallowing.
- To start chemical digestion by containing salivary amylase.
What is the function of stomach acid?
To kill potentially pathogenic microorganisms in food.
What is the function of the small intestine?
To absorb carbohydrates, lipids, amino acids, vitamins and mineral ions from digested food.
Give an adaptation of :
a) the small intestine
b) cells lining the small intestine
to aid absorption of digested molecules.
a) Small intestine has structures called villi which increase surface area
b) Epithelial cells lining the villi have microvilli on their surface which further increase surface area.
What is the function of the large intestine?
To absorb water from digested food.
What is the function of the 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 an enzyme?
A protein which can catalyse a reaction (speed it up) without being used up itself.
What is a substrate?
A molecule or atom which is acted upon by an enzyme.
Name two environmental conditions that can change an enzyme’s active site.
- pH (either higher or lower than optimum)
- Higher than optimal temperature
What do carbohydrases break down and what is produced?
Carbohydrates to simple sugars (e.g. amylase breaks down starch to glucose).
What do proteases break down and what is produced?
Proteins to amino acids.
What do lipases break down and what is produced?
Lipids (fats) to fatty acids and glycerol.
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 to the food sample, boil/heat, if glucose is present the colour will change to brick red/orange.
What is the Biuret test and how do you carry it out?
For testing if there is protein in food samples. Add Biuret reagent (blue liquid), If it turns lilac, protein is present.
Which food test can be carried out with iodine?
Testing for the presence of starch. If it turns blue/black, it contains starch.
Name the two types of chambers in the heart.
Atria and ventricles.
Which are the upper chambers of the heart?
Atria
What is the job of the heart valves?
To prevent backflow of blood in the heart.
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 go to the lungs.
Pulmonary artery.
Which blood vessels have thick walls containing muscle tissue and elastic fibers?
Arteries
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
What are the small gas exchange structures in the lungs called?
Alveoli (singular: alveolus).
Describe four adaptations of the lungs to make them well suited for gas exchange.
- Capillaries have thin walls (one cell thick), providing short diffusion pathway.
- Extensive capillary network covering the surface of each alveoli, maintains a steep concentration gradient.
- Alveoli have a folded surface which increases the surface area.
- Many alveoli provide a large surface are to volume ration.
What are the three main cell types found in blood?
Red blood cells, white blood cells, platelets.
What does blood plasma transport from the organs to the lungs?
Carbon dioxide
What do platelets do?
Help clot the blood at wound sites.
What are haemoglobins function?
Carries oxygen to your bodies tissues and organs.
What occurs in Coronary Heart Disease (CHD)?
The coronary arteries become blocked with fatty deposits, narrowing them.
How do stents treat CHD?
They re-open the blocked coronary artery, restoring blood flow.
Why are faulty heart valves life-threatening?
Allows black-flow of blood.
When would an artificial heart be used?
- To allow the heart to rest and recover.
- To keep the patient alive whilst they wait for a transplant.
What is a risk factor?
A factor linked to an increased rate of disease.