biology Flashcards
Aorta
The artery that takes oxygenated blood away from the heart to the body.
Artery
A type of blood vessel that carries blood away from the heart to the tissues, under
high pressure. The walls of the arteries contain thick layers of smooth muscle and elastic
fibres.
Atria
The two upper chambers of the heart that receive blood from the veins and pump
blood into the ventricles.
Atrioventricular (AV) valves
The valves found between the atria and ventricles. They
prevent the backflow of blood from the ventricles into the atria. There are two types of
AV valves: bicuspid and tricuspid.
Bicuspid valves
The atrioventricular valves found between the left atrium and left
ventricle.
Blood
A tissue containing red blood cells, white blood cells, platelets and plasma.
Blood clotting
A defence mechanism that prevents excessive blood loss and the entry of
harmful microorganisms. It involves platelets and the conversion of fibrinogen to fibrin to
form a mesh over the wound.
Capillaries
Thin, narrow blood vessels that connect the arteries and veins. They are the
site of exchange of substances between the blood and the tissues.
Circulatory system
The transport system in mammals consisting of a pump, blood vessels
and valves.
Coronary arteries
The arteries that supply the heart muscle with food and oxygen.
Coronary heart disease
A disease caused by the build-up of fatty deposits inside the
coronary arteries, narrowing them and reducing blood flow to the heart tissue. Risk factors
include a diet high in saturated fats, stress, lack of exercise, smoking, age, genetic
predisposition and gender.
Double circulatory system
A circulatory system found in mammals in which the
blood flows through the heart twice in two circuits. Blood is pumped from the heart to
the lungs before returning to the heart. It is then pumped around the body, after which
it returns to the heart again.
Electrocardiogram (ECG)
A technique used to measure the spread of electrical activity
through the heart by measuring tiny changes in the skin’s electrical conductivity. This
produces a trace which is used to detect abnormalities in heart rhythm.
Lymphocyte
A type of white blood cell that produces antibodies specific to a
particular antigen.
Phagocyte
A type of white blood cell that engulfs pathogens and digests them in a
process known as phagocytosis.
Phagocytosis
The process by which white blood cells (phagocytes) engulf and
destroy pathogens.
Plasma
The main component of the blood that carries red blood cells. It is a yellow liquid
containing blood cells, soluble nutrients, ions, carbon dioxide and hormones.
Platelets
Small fragments of cells that are involved in blood clotting.
Pulmonary arteries
The arteries that carry deoxygenated blood away from the heart to the
lungs.
Pulmonary veins
The veins that carry oxygenated blood from the lungs to the heart.
Pulse rate
The number of pulses felt in an artery (e.g. radial artery) per minute.
Red blood cell
A type of blood cell that is anucleate and biconcave. It contains
haemoglobin which enables the transport of oxygen and carbon dioxide to and from the
tissues.
Renal arteries
Blood vessels that carry oxygenated blood to the kidneys.
Renal veins
Blood vessels that drain the kidneys.
