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The Heart and the Blood Vessels - Coggle Diagram
The Heart and the Blood Vessels
Diffusion is sufficient for transport of materials in small animals, large animals need circulatory system
An open circulatory system means that blood leaves blood vessels
A closed circulatory system means that blood is always in blood vessels, moves blood around the body faster and allows alterations in blood flow to different body organs
Arteries
Carries blood away from the heart
Has high pressure
Has a thick wall
Does not have valves
Has a narrow lumen
Carry oxygen rich blood
Veins
Carries blood to the heart
Has low pressure
Has thin walls Has valves
Have a large lumen
Carry oxygen poor blood
Capillaries
Connects arteries to veins
Has thin walls
Allows exchange of materials
Valves prevent backflow of blood
Double circulation Pulmonary circuit – from the heart to the lungs and then back to the heart
Systemic circuit – from the heart to the rest of the body and back to the heart
Although the heartbeat is usually controlled by the pacemaker, it can be altered by the nervous stimulation from the brain or by hormones
Heartbeat The pacemaker (S.A. Node) is in the wall oof the right atrium, which causes the atria to contract The S.A. Node stimulates the A.V. Node, which sends electrical impulses down the septum and to the ventricles, which contract and send the blood out of the heart
Diastole is when the heart is relaxed
Systole is when the heart contracts
The stages of the heartbeat
Diastole – blood enters the atria Atrial systole – blood is pumped to the ventricles
Ventricular systole – blood is pumped out of the heart
Pulse The expansion and contraction of an artery as blood is forced through it (Ventricular systole)
Blood pressure
Is the force of the blood that is exerted against the walls of the arteries, normally the higher value is a measure of the systolic pressure, the lower value is a measure of the diastolic pressure
Smoking
Damages the heart and blood vessels Increases heart rate Increases blood pressure Increases the risk of blood clots and cancer
Diets
Bad diets affect the heart Animals' fats – causing blocked arteries
High salt intakes – raises blood pressure
Being greatly overweight – raises blood pressure and could cause a heart attack
Exercise
Strengthens the heart Improves blood circulation Reduces body weight
A heart can be dissected by cutting into the ventral surface, identifying the four chambers, the main blood vessels and the coronary artery
The effect of exercise on heartbeat are investigated by comparing the pulse rate at rest and after exercise