animal tissues, organs and systems Flashcards
what is the main function of the digestive system
to digest food and absorb the nutrients obtained from digestion
what is the role of the pancreas and the salivary gland in the digestive system
the pancreas and the salivary glands are glands which produce digestive juices containing enzymes
what is the role of the stomach in the digestive system
produces hydrochloric acid - which kills bacteria present and provides the optimum acidic pH for the protease enzyme to function
what is the role of the small intestine in the digestive system
the small intestine is the site where the soluble food molecules are absorbed into the blood stream.
what is the role of the liver in the digestive system
produces bile (stored in the gallbladder) which emulsifies lipids and allows the lipase enzyme to work more efficiently.
what is the role of the large intestine in the digestive system
absorbs water from undigested food, producing faeces.
what is the role of enzymes in the digestive system
they act as biological catalysts that speed up the rate of biological reactions (the breaking down of food) without being used up
how does the shape of an enzyme affect its function
enzymes have a specific active site which is complementary to their substrate
what is metabolism
the sum of all the reactions in a cell or an organism
what types of metabolic reactions do enzymes catalyse
- building larger molecules from smaller molecules e.g glucose to starch
- changing one molecule to another e.g glucose to fructose
- breaking down larger molecules into smaller molecules e.g carbohydrates to glucose
what is the lock and key hypothesis of enzyme function
the shape of the enzyme active site and the substrate are complementary, so can bind together to form an enzyme-substrate complex
how does temperature affect enzyme action
up to a certain point, increasing temperature increases enzyme action, as molecules have higher kinetic energy. above a certain temperature, the shape of the active site is altered and the enzyme becomes denatured, so it can no longer catalyse the reaction. The optimum temperature is around 37 degrees
how does pH affect enzyme function
the optimum pH for most enzymes is 7 (except from proteases in the stomach) if the pH is too extreme, the shape of the active site may be altered and the enzyme may no longer work.
where are carbohydrates produced in the body?
- amylase - salivary gland and pancreas
- maltase - small intestine
where are proteases produced in the body?
- pepsin - stomach
- others - pancreas and small intestine
where are lipases produced in the body?
pancreas and small intestine
what is the role of carbohydrate in the digestive system
carbohydrate break down carbohydrates into monosaccharides and disaccharides. amylase breaks down starch into maltose, and maltase breaks down maltose into glucose.
what is the role of proteases in the digestive system
proteases break down protein into amino acids
what is the role of lipases in the digestive system
lipases break down lipids into fatty acids and glycerol
how are the products of digestion used
they are used to build bigger molecules such as carbohydrates and proteins. glucose is used as a substrate in respiration
where is bile made up and stored in the body
bile is made by the liver and stored in the gall bladder
what is the role of bile in the digestive system
- bile is an alkaline substance which neutralises the hydrochloric acid secreted by the stomach.
- bile emulsifies lipids to form droplets- this increases the surface area for the lipase enzyme to work on
what is the purpose of the circulatory system
carries oxygen and other useful substances to the bodily tissues and removes waste substances
how does the double circulatory system work
- one pathway carried blood from the heart to the lungs - where the gaseous exchange of oxygen and carbon dioxide takes place
- one pathway carried blood from the heart to the tissues
where does the blood pumped by the right ventricle go
the lungs
where does the blood pumped by the left ventricle go
body tissues
why is the double circulatory system important
it makes the circulatory system more efficient, for example oxygenated blood can be pumped around the body at a higher pressure by the left ventricle
how many chambers does the heart have and what are they called
- right atrium, right ventricle, left atrium, left ventricle
why is the wall of the left ventricle thicker
the left ventricle has to pump blood at a higher pressure around the whole body
what are the four main blood vessels associated with the heart
pulmonary vein, pulmonary artery, aorta, vena cava
what is the role of the aorta and what side of the heart is it on
left, carries oxygenated blood from the heart to the body
what is the role of the pulmonary vein and what side of the heart is it on
left, carries oxygenated blood from the lungs to the heart
what is the role of the vena cava and what side of the heart is it on
right, carries deoxygenated blood from the body to the heart
what is the role of the pulmonary artery and what side of the heart is it on
right, carries deoxygenated blood from the heart to the lungs
what is the purpose of valves in the heart
to prevent the back flow of blood
what is the purpose of coronary arteries
supply the heart muscle with oxygenated blood
describe the process of blood flow through the heart
- blood enters the right atrium via the vena cava, and the left atrium via the pulmonary vein
- the atria contract, forcing blood into the ventricles and causing valves to shut
- after the ventricles contract, blood in the right ventricle enters the pulmonary artery (to the lungs) and blood in the left ventricle enters the aorta (to the body)
what is the approx value of natural resting heart rate
70 bpm
how can an abnormal heart rhythm be treated
using an artificial pacemaker, which sends out electrical signals to correct the heart’s rhythm