51 terms

Biology- Transport in Animals, chapter 9

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Heart
Hollow muscular organ of vertebrate animals that acts as a pump maintaining the circulation of the blood
Arteries
Blood vessels through which blood travels away from the heart.
Veins
Blood vessels through which blood travels towards the heart.
Capillaries
The smallest blood vessel with walls only one cell thick. Substances are exchanged through capillary walls between blood and tissue fluid.
Arterioles
Type of blood vessel between artery and capillaries. Contraction and relaxation of muscle in the wall controls flow of blood into capillaries.
Valves
Prevent backflow of blood from the ventricles back to the atria
Semi-lunar valves
Prevent backflow of blood from the arteries leaving the heart back into the ventricles
Oxygenated
Blood rich in oxygen is said to be this
Deoxygenated
Blood lacking oxygen is said to be this
Double circulation
Blood passes through the heart twice during one circuit around the body. Mammals and birds have a double circulatory system.
Septum
Wall of tissue between the right and left hand sides of the heart that prevents mixing of the blood from these
Atrium
A chamber of the heart that receives blood from veins and pumps it to a ventricle (plural atria)
Ventricles
The lower, more muscular chambers of the heart. In mammals, the right ventricle pumps blood to the lungs and the left ventricle pumps blood to the rest of the body.
Diastole
The heart muscles are relaxed - blood flows into the atria from the veins
Systole
When the heart muscles contract
Pulmonary artery
Carries deoxygenated blood from the right ventricle to the lungs. It is the only artery that carries deoxygenated blood.
Aorta
Artery that carries oxygenated blood from the left ventricle to the body.
Right atrium
Receives deoxygenated blood from the vena cava and pumps it into the right ventricle.
Vena cava
Vein that brings deoxygenated blood back to the heart from the body
Left atrium
Receives oxygenated blood from the pulmonary vein and pumps it into the left ventricle.
Dilate
Widening of arterioles to send more blood to the muscles during exercise
Pulse (rate)
When the left ventricle of the heart contracts it forces blood out of the heart along the arteries. The arteries swell and this can be felt as a pulse in various parts of the body such as the wrist.
Coronary arteries
Arteries that branch from the aorta to supply oxygenated blood to heart muscle.
ECG
Electrocardiogram. A graphical representation of the electrical activity of the heart.
Heart attack
The supply of oxygen to part of the heart is cut off by the blockage of the coronary artery causing severe pain and damage to the heart tissues
Cholesterol
A lipid based chemical made in the liver and found in the blood. High levels of cholesterol in the blood are linked to an increased risk of atherosclerosis and heart disease.
Atherosclerosis
A narrowing of the arteries caused by deposits of cholesterol in the internal walls of arteries which slows down the rate of blood flow.
Thrombosis
A blood clot that occurs in a vein or an artery.
Angina
The coronary artery becomes partly blocked with cholesterol causing lack of oxygen to the muscles during exercise or stress
Cardiac arrest
The heart stops beating altogether and must be restarted if the person is not to die
Stent
Metal or plastic tube that is put in a blood vessel to keep it open
Genes
Lengths of DNA found on a chromosome, that codes for a particular characteristic.
CHD
Coronary Heart Disease
Angioplasty
Procedure to enlarge a narrowing in a coronary artery.
Coronary bypass
A surgical procedure to improve blood supply to the heart by creating new routes for blood flow when one or more of the coronary arteries become obstructed.
Plasma
The liquid part of the blood which transports dissolved foods, urea, carbon dioxide and hormones.
Haemoglobin
The red pigment in red blood cells that combines with oxygen to form oxyhaemoglobin.
Red-blood cells
Small cells in the blood without a nucleus that carry oxygen on the haemoglobin that they contain
White-blood cells
These cells have a nucleus and are part of the immune system. There are two types - lymphocytes and phagocytes
Phagocyte
A type of white blood cell that ingests and destroys pathogens.
Lymphocytes
A type of white blood cell that makes proteins called antibodies which attack the pathogen specific for which they have been made
Platelets
Small pieces of cells that release substances to cause blood to clot.
Antibodies
Proteins released by lymphocytes to protect against pathogens.
Clotting
A series of chemical reactions that cause blood cells to stick together. At a wound this stops the loss of blood and results in the formation of a scab.
Fibrinogen
A soluble protein carried dissolved in the blood
Fibrin
An insoluble protein made from fibrinogen when blood vessels are damaged and platelets release clotting substances. Fibrin makes a mesh across the wound which blood cells get trapped in and dry into a scab.
Tissue fluid
The fluid that bathes the cells when plasma and some white blood cells pass out of the capillaries.
Lymph
The fluid formed when tissue fluid drains into lymph vessels
Lymph vessels
These are similar to veins - have thin walls and valves to stop backflow. They carry tissue fluid out of tissues and back to heart
Subclavian veins
These run under the collar bones and the lymph vessels enter into them to drain the tissue fluid back into the blood
Lymph nodes
These occur at intervals along the lymph vessels and store lymphocytes. There are groups under the armpits, in the neck and in the groin.