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The main function of the digestive system is __________.
to digest food and absorb the nutrients obtained from digestion.
The role of the pancreas and the salivary gland in the digestive system is __________.
to produce digestive juices containing enzymes.
The role of the stomach in the digestive system is __________.
to produce hydrochloric acid which kills bacteria and provides the optimal pH for protease to function.
The role of the small intestine in the digestive system is __________.
the site where soluble food molecules are absorbed into the bloodstream.
The role of the liver in the digestive system is __________.
to produce bile which emulsifies lipids and allows the lipase enzyme to work more efficiently.
The role of the large intestine in the digestive system is __________.
to absorb water from undigested food, producing faeces.
The role of enzymes in the digestive system is __________.
to act as biological catalysts which speed up the rate of breakdown of food without being used up.
The shape of an enzyme affects its function by __________.
having a specific active site which is complementary to its substrate.
Metabolism is __________.
the sum of all the reactions in a cell or an organism.
Enzymes catalyse metabolic reactions which include __________.
building larger molecules from smaller molecules, changing one molecule into another, and breaking down larger molecules into smaller ones.
The lock and key hypothesis of enzyme function states that __________.
the shape of the enzyme active site and the substrate are complementary, allowing them to form an enzyme-substrate complex.
Temperature affects enzyme action by __________.
increasing enzyme action up to a certain point, after which the active site is altered and the enzyme becomes denatured.
The optimum temperature for enzyme action is __________.
around 37°.
The optimum pH for most enzymes is __________.
7, except for proteases in the stomach.
Where are carbohydrases, proteases and lipases produced in the body? __________.
Carbohydrases: amylase in salivary gland and pancreas, maltase in small intestine; Proteases: pepsin in stomach, others in pancreas and small intestine; Lipases: pancreas and small intestine.
The role of carbohydrases in the digestive system is __________.
to break down carbohydrates into monosaccharides and disaccharides.
The role of proteases in the digestive system is __________.
to break down proteins into amino acids.
The role of lipases in the digestive system is __________.
to break down lipids into fatty acids and glycerol.
The products of digestion are used to __________.
build bigger molecules such as carbohydrates and proteins.
Bile is made by the __________ and stored in the ______________.
liver; gallbladder.
The role of bile in the digestive system is __________.
to neutralise hydrochloric acid and emulsify lipids.
The heart is __________.
an organ that pumps blood around the body.
The purpose of the circulatory system is __________.
to carry oxygen and useful substances to bodily tissues and remove waste substances.
The double circulatory system works by __________.
having one pathway for blood to the lungs and another for blood to the tissues.
Blood pumped by the right ventricle goes to __________.
the lungs.
Blood pumped by the left ventricle goes to __________.
the body tissues.
The double circulatory system is important because __________.
it makes the circulatory system more efficient by allowing higher pressure for oxygenated blood.
The heart has __________ chambers called __________.
4; right atrium, right ventricle, left atrium, left ventricle.
The wall of the left ventricle is thicker because __________.
it pumps blood at a higher pressure around the whole body.
The four main blood vessels associated with the heart are __________.
Aorta, pulmonary vein, vena cava, pulmonary artery.
The purpose of valves in the heart is __________.
to prevent the backflow of blood.
Coronary arteries supply __________.
the heart muscle with oxygenated blood.
Blood flow through the heart starts in __________ via __________, and ends in __________ via __________.
the right atrium; vena cava; the left ventricle; aorta.
The natural resting heart rate is approximately __________.
70 beats per minute.
The heart rate is controlled by __________.
a group of cells in the right atrium that act as a pacemaker.
An abnormal heart rhythm can be treated with __________.
an artificial pacemaker.
The three types of blood vessel in the body are __________.
arteries, veins, capillaries.
Arteries are adapted for their function by having __________.
a thick muscle and elastic layer to withstand high pressure.
Veins are adapted for their function by having __________.
a wide lumen and valves to prevent backflow.
Capillaries are adapted for their function by having __________.
walls that are one cell thick for short diffusion paths.
The rate of blood flow can be calculated by __________.
volume of blood divided by number of minutes.
The lungs are found in __________.
the thorax (within the chest).
The gas exchange system consists of tissues such as __________.
trachea, intercostal muscles, bronchi, bronchioles, alveoli, diaphragm.
The lungs are ventilated by intercostal muscles contracting, which causes __________.
the ribcage to move upwards, increasing chest volume and decreasing pressure.
Gas exchange occurs at the alveoli when __________.
oxygen diffuses into the capillary bloodstream and carbon dioxide diffuses into the alveoli.
Alveoli are adapted for gas exchange by being __________.
small, arranged in clusters for a larger surface area.
The breathing rate can be calculated by __________.
Number of breaths divided by number of minutes.
Plasma is __________.
a yellow liquid within blood that transports substances around the body.
Substances transported by plasma include __________.
red blood cells, white blood cells, platelets, carbon dioxide, urea, products of digestion.
The purpose of red blood cells in blood is __________.
the transport of oxygen around the body.
Red blood cells are adapted for their function by having __________.
a biconcave shape and no nucleus.
The purpose of white blood cells in blood is __________.
to protect the body from invading pathogens.
White blood cells are adapted for their function by __________.
having a nucleus and can produce antibodies.
The purpose of platelets in blood is __________.
to aid the clotting of blood at the site of a wound.
The function of platelets is important because __________.
they prevent excessive bleeding and protect against infection.
Coronary heart disease occurs when __________.
the coronary arteries become blocked with fatty material.
A stent is __________.
a metal mesh tube inserted into a blocked artery to keep it open.
Advantages of stents include __________.
quick recovery and lower heart attack risk.
Statins are __________.
drugs that reduce the level of LDL cholesterol.
The purpose of heart bypass surgery is __________.
to replace blocked coronary arteries with veins.
Leaky heart valves cause __________.
blood to flow in the wrong direction, reducing the heart's efficiency.
Mechanical valves can be described as __________.
made of metal or polymers.
Biological valves are __________.
taken from animals or other humans.
Artificial hearts are designed to __________.
support a patient’s heart while waiting for a donor heart.
Health is defined as __________.
the state of physical and mental wellbeing.
A communicable disease is __________.
a disease caused by a pathogen that can be transmitted from one person to another.
A non-communicable disease is __________.
a disease that cannot be transmitted from person to person.
Diet can affect health by __________.
leading to deficiencies or obesity.
Stress affects health by __________.
being linked to heart diseases and mental health issues.
Life situations that affect health include __________.
location, gender, financial status, and healthcare provision.
Risk factors are __________.
aspects that increase the risk of a disease.
A causal mechanism demonstrates __________.
how one factor biologically influences another.
Obesity is linked to __________.
the onset of type 2 diabetes.
Alcohol can affect liver function by __________.
leading to liver cirrhosis and increasing cancer risk.
Smoking can affect the lungs by __________.
damaging alveoli and leading to chronic obstructive pulmonary disease (COPD).
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