Heart And Blood Vessels Flashcards
What is the role of diffusion ?
Diffusion is sufficient transport of materials in small animals, large animals need a circulatory system
What is an open circulatory system and a closed circulatory system ?
An open circulatory system means the blood leaves the blood vessels
A closed circulatory system means blood is always in the blood vessels
- blood moves around the body quicker
- allows alterations in blood flow to body organs
Describe arteries
Carry blood away from the heart
Have low blood pressure
Have thick walls
Do not have valves
Have narrow lumens
Carry oxygen rich blood
Describe veins
Carry blood to the heart
Have low pressure
Have thin walls
Have valves
Have large lumens
carry oxygen poor blood except for pulmonary vein
What are capillaries
Capillaries connect arteries to veins, have thin walls and allow exchange of materials
What are valves
Valves prevent the black flow of blood
What is double circulation
Double circulation means that blood flows…
- from the heart to the lungs and then back to the heart (pulmonary circuit) - from the heart to the rest of the body and back to the heart (systemic circuit)
How how is the heartbeat controlled
The heart beat is controlled by……
- the pacemaker (SA Node ) in the wall of the right atrium, which cause atria to contract
- the atrio-ventricular (AV) node, which send electrical impulses down the septum
- the ventricles, which contract
What is diastole and systole
Diastole is when the heart is relaxed
Systole is when the heart contracts
Stages of the heart beat
Diastole: Blood enters the atria
Atrial systole : Blood is pumped to the ventricles
Ventricular systole : Blood is pumped out of the heart
What is a pulse
Caused by the expansion and contraction of an artery as blood is forced through it
Caused by ventricular systole
What are the effects of excersise
The effects of excessive on heartbeat are investigated by comparing the pulse rate at rest and after exercise
What is blood pressure
Blood pressure his the force of the blood against the walls of the arteries
Higher value is measure of systolic pressure
Lower value is a measure of diastolic pressure
How does smoking effect the heart
Increasing heart rate
Increasing blood pressure
Increasing the risk of blood clots
Main dietary factors affecting the circulatory system
Saturated fats - causing blocked arteries
High Salt intake - raising blood pressure
Being greatly overweight -raises blood pressure and causes heart attacks
