AS Level Biology > Topic 1B (Definitions) > Flashcards

Topic 1B (Definitions) Flashcards

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1
Q

Term

A

Definition

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2
Q

diffusion

A

the movement of the particles in a liquid or a gas down a concentration gradient from an area where they are at a relatively high concentration to an area where they are at a relatively low concentration

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3
Q

concentration gradient

A

the change in the concentration of solutes present in a solution between two regions; in biology, this typically means across a cell membrane

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4
Q

surface area to volume ratio (sa: vol)

A

the relationship between the surface area of an organism and its volume

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5
Q

vertebrates

A

animals with a backbone or spinal column; they include mammals, birds, reptiles, amphibians and fish

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6
Q

mass transport system

A

an arrangement of structures by which substances are transported in the flow of a fluid with a mechanism for moving it around the body

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7
Q

single circulation system

A

a circulation in which the heart pumps the blood to the organs of gas exchange and the blood then travels on around the body before returning to the heart

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8
Q

double circulation system

A

a circulation that involves two separate circuits, one of deoxygenated blood flowing from the heart to the gas exchange organs to be oxygenated before returning to the heart, and one of oxygenated blood leaving the heart and flowing around the body, returning as deoxygenated blood to the heart

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9
Q

systemic circulation

A

carries oxygenated blood from the heart to the cells of the body where the oxygen is used, and carries the deoxygenated blood back to the heart

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10
Q

oxygenated blood

A

blood that is carrying oxygen

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11
Q

deoxygenated blood

A

blood that has given up its oxygen to the cells in the body

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12
Q

pulmonary circulation

A

carries deoxygenated blood to the lungs and oxygenated blood back to the heart

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13
Q

cardiovascular system

A

the mass transport system of the body made up of a series of vessels with a pump (the heart) to move blood through the vessels

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14
Q

circulation

A

the passage of blood through the blood vessels

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15
Q

active transport

A

the movement of substances into or out of the cell using ATP produced during cellular respiration

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16
Q

buffer

A

a solution which resists changes in pH

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17
Q

leucocytes

A

white blood cells; there are several different types which play important roles in defending the body against the entry of pathogens and in the immune system

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18
Q

platelets

A

cell fragments involved in the clotting mechanism of the blood

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19
Q

megakaryocytes

A

large cells that are found in the bone marrow and produce platelets

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20
Q

oxyhemoglobin

A

the molecule formed when oxygen binds to haemoglobin

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21
Q

carbaminohaemoglobin

A

the molecule formed when carbon dioxide combines with haemoglobin

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22
Q

carbonic anhydrase

A

the enzyme that controls the rate of the reaction between carbon dioxide and water to produce carbonic acid

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23
Q

Bohr effect

A

the name given to changes in the oxygen dissociation curve of haemoglobin that occur due to a rise in carbon dioxide levels and a reduction of the affinity of haemoglobin for oxygen

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24
Q

fetal haemoglobin

A

a form of haemoglobin found only in the developing fetus with a higher affinity for oxygen than adult haemoglobin

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25
serotonin
a chemical that causes the smooth muscle of the blood vessels to contract, narrowing them and cutting off the blood flow to the damaged area
26
thromboplastin
an enzyme that sets in progress a cascade of events that leads to the formation of a blood clot
27
prothrombin
a large, soluble protein found in the plasma that is the precursor to an enzyme called thrombin
28
thrombin
an enzyme that acts on fibrinogen, converting it to fibrin during clot formation
29
precursor
a biologically inactive molecule which can be converted into a closely related biologically active molecule when needed
30
fibrinogen
a soluble plasma protein which is the precursor of the insoluble protein fibrin
31
fibrin
an insoluble protein formed from fibrinogen by the action of thrombin that forms a mesh of fibres that trap erythrocytes and platelets to form a blood clot
32
arteries
vessels that carry blood away from the heart
33
veins
vessels that carry blood towards the heart
34
capillaries
tiny vessels that spread throughout the tissues of the body
35
lumen
the central space inside the blood vessel
36
arterial system
the system of arteries in the body
37
arterioles
the very smallest branches of the arterial system, furthest from the heart
38
peripheral arteries
arteries further away from the heart but before the arterioles
39
venules
the very smallest branches of the venous system, furthest from the heart
40
inferior vena cava
the large vein that carries the returning blood from the lower parts of the body to the heart
41
superior vena cava
the large vein that carries the returning blood from the upper parts of the body to the heart
42
venous system
the system of veins in the body
43
semilunar valves
half-moon shaped, one-way valves found at frequent intervals in veins to prevent the backflow of blood
44
septum
the thick muscular dividing wall through the centre of the heart that prevents oxygenated and deoxygenated blood from mixing
45
cardiac muscle
the special muscle tissue of the heart, which has an intrinsic rhythm and does not fatigue
46
myoglobin
a respiratory pigment with a stronger affinity for oxygen than haemoglobin.
47
right atrium
the upper right-hand chamber of the heart that receives deoxygenated blood from the body
48
right ventricle
the lower chamber that receives deoxygenated blood from the right atrium and pumps it to the lungs
49
tricuspid valve (atrioventricular valve)
the valve between the right atrium and the right ventricle that prevents backflow of blood from the ventricle to the atrium when the ventricle contracts
50
tendinous cords (valve tendons, heartstrings)
cord-like tendons that make sure the valves are not turned inside out by the large pressure exerted when the ventricles contract
51
pulmonary arteries
the blood vessels that carry deoxygenated blood from the heart to the lungs
52
pulmonary veins
the blood vessels that carry oxygenated blood back from the lungs to the heart
53
left atrium
the upper left-hand chamber of the heart that receives oxygenated blood from the lungs
54
left ventricle
the chamber that receives oxygenated blood from the left atrium and pumps it around the body
55
bicuspid valve (atrioventricular valve)
the valve between the left atrium and the left ventricle that prevents backflow of blood into the atrium when the ventricle contracts
56
aorta
the main artery of the body; it leaves the left ventricle of the heart carrying oxygenated blood under high pressure
57
systole
the contraction of the heart
58
atrial systole
when the atria of the heart contract
59
ventricular systole
when the ventricles of the heart contract
60
diastole
when the heart relaxes and fills with blood
61
cardiac cycle
the cycle of contraction (systole) and relaxation (diastole) in the heart
62
cardiovascular diseases
diseases of the heart and circulatory system, many of which are linked to atherosclerosis
63
atherosclerosis
a condition in which yellow fatty deposits build up (increase in amount) on the lining of the arteries, causing them to be narrowed and resulting in many different health problems
64
plaques
yellowish fatty deposits that form on the inside of arteries in atherosclerosis
65
atheroma
another term for a plaque formed on the arterial lining
66
aneurysm
a weakened, bulging area of artery wall that results from blood collecting behind a blockage caused by plaques
67
angina
a condition in which plaques are deposited on the endothelium of the arteries and reduce the blood flow to the cardiac muscle through the coronary artery; it results in pain during exercise
68
myocardial infarction (heart attack)
the events which take place when atherosclerosis leads to the formation of a clot that blocks the coronary artery entirely and deprives the heart muscle of oxygen, so it dies; it can stop the heart functioning
69
anaerobic respiration
cellular respiration that takes place in the absence of oxygen
70
stent
a metal or plastic mesh tube that is inserted into an artery affected by atherosclerosis to hold it open and allow blood to pass through freely
71
thrombosis
a clot that forms in a blood vessel
72
stroke
an event caused by an interruption to the normal blood supply to an area of the brain which may be due to bleeding from damaged capillaries or a blockage cutting off the blood supply to the brain, usually caused by a blood clot
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