The Circulatory System 2 Flashcards
(27 cards)
What are the 3 parts of the circulatory system
The blood
The heart
The blood vessels
What does blood do
Transports oxygen to all structures of the body, carries carbon dioxide and waste products to be removed
Blood consists of the following 4 components
Red blood cells
White blood cells
Platelets
Plasma ( the above are suspended in plasma)
Red blood cells
Produced in the red bone marrow.
Contain haemoglobin which binds to oxygen and has a pigment which gives rbc its colour.
Blood volume consists of 40% rbc’s
White blood cells
Transparent and do not contain haemoglobin
Produced in red bone marrow
Are the cells of the immune system, destroy harmful bacteria to fight infection
Platelets
Platelets are cell fragments
Release chemicals to promote blood clotting
Plasma
Straw coloured liquid portion of the blood
Consists of water, proteins, electrolytes,nutrients and waste products
The upper chambers in the heart are called
Atria, which receives the blood via the veins from different parts of the body and pumps the blood down into the ventricles
The bottom chambers in the heart are called
Ventricles, which push the blood to its various destinations hence they have larger muscular walls
What are the names of the valves which separate the atria and ventricles
Atrioventricular valves
Which valves prevent the flow of blood back into the left ventricles and right pulmonary valve during ventricular relaxation
The semi lunar valves
Ventricular contraction is called
Systole
Ventricular relaxation is called
Diastole
Arteries always carry blood……
Away from the heart
Veins always carry blood …….
To the heart
What is the name of the hearts pacemaker
The sinoatrial (SA) node which initiates the cardiac muscle contraction. Located in the wall of the right atrium
The myocardium ( heart muscle ) is stimulated to contract…..
72 beats per minute by the SA node
What are the 3 types of blood vessels
Arteries
Capillaries
Veins
Define arteries
Muscular tubes with thick walls
Can contract to squeeze blood away from the heart
Define capillaries
Extremely thin walls, allow diffusion of nutrients and gases through their walls.
Define veins
Thinner walled tubes compared to arteries with little muscular contractility
Carry blood from the tissues back towards the heart
Carry blood under low pressure therefore have valves
What is venous return
The return of blood back to the heart via the veins
Factors that assist venous return are
Gravity
Non return valves
smooth muscle contraction ( peristalsis)
Skeletal muscle contraction
Diaphragm- produces a suction effect on the veins
Right atrium helps to suck the blood back
What is hypertension
Higher than normal pressure at rest
