The heart Flashcards
what membrane surrounds the heart
the pericardium
how many chambers are in the heart
4
what are the different chambers in the heart
- right atrium
- left atrium
- right ventricle
- left ventricle
what are the different veins in the heart
- inferior vena cava
- superior vena cava
- pulmonary vein
what are the different arteries in the heart
- pulmonary arteries
- aorta
what are the different valves in the heart
semilunar valves between ventricles and arteries
atrioventricular valves between atria and ventricles
Tricuspid valve - right side
bicuspid valve - left side
what do arteries do
carry blood away from the heart
what do veins do
carry blood towards the heart
what do capillaries do
tiny vessels that carry blood between cells. Where the transported substances actually enter and leave the blood.
describe in detail what veins do
Veins carry blood from every tissue in the body to the heart.
As the pressure is so much lower in the veins than in the arteries, there is little need for elastic fibres and smooth muscle in the walls.
what do veins have
semi lunar valves to stop blood flowing backwards
why does the exchange of material not take place in the arteries and veins
Because their walls are too thick and too impermeable
describe the structure of capillaries
very narrow and thin-walled and compose of endothelium and are single-celled. Is often highly permeable, because its very thin and has holes between cells in some capillaries
because there is a large number of capillaries what does this help with
there is a number of capillaries and have a huge surface area to volume ratio, helping rapid diffusion of substances between blood and cells.
what is the arrangement of capillaries called
capillary beds
what is double circulation
The first loop travels from the right side of the heart through the lungs to gain oxygen.
The second loop travels from the left side of the heart around the body to lose oxygen and gain carbon dioxide.
what are antigens
Antigens are proteins found on the outside of the cells.
what are antibodies
antibodies are produced by B cells in response to a specific antigen.
what is the cardiac cycle
The cardiac cycle is the sequence of events that occurs in one complete heart beat
what is the pumping phase of the cardiac cycle
systole
what is the relaxing phase of the cardiac cycle
diatole
what are the 3 stages of the cardiac cycle
- atrial systole
- ventricular systole
- diastole
what is atrial systole
The Atria contract, and ventricles relax forcing blood into the ventricles
what is ventricular systole
The ventricles contract forcing blood out of ventricle into arteries and the atria relax and fill with blood
what is diastole
Is when both atria and ventricles relax
what is stroke volume
is the volume of blood forced from a ventricle of the heart with each contraction.
what is cardiac output
is the amount of blood leaving one of the ventricles every minute.
how do you calculate cardiac output
stroke volume x heart rate
how is blood flow altered
by altering the diameter of blood vessels
describe how blood vessels alter there diameter
- arteries stretch to accommodate extra blood flow
- Smooth muscle in arteries contracts to reduce diameter which reduces blood flow.
- Smooth muscle in arteries relax to increase diameter which increases blood flow.
can veins change their dimateretrer
no
do arteries have valves
no
do veins have valves
yes
what type of walls do arteries have
thick, muscular, elastic walls
what type of walls do veins have
have thin, inelastic walls with little muscle
what is the difference between the left and right sides of the heart
The left ventricle is much thicker and muscular compared to the right ventricle which is thinner and less muscular because it has to pump blood all around the body
