The heart + blood vessels Flashcards
(26 cards)
Heart composition
Cardiac muscle (contractile, doesn’t tire, involuntary) surrounded by pericardial double membrane
Open circulatory system
blood leaves the blood vessels. Blood is pumped into open-ended vessels. The blood then passes into the body e.g. Snails
Closed circulatory system
blood is always enclosed in blood vessels, e.g. humans.
Benefits of closed circulatory system
Pumped faster - more efficient
High blood pressure better for big organs
Double circulation
When the blood passes through the heart at least twice before reaching the same point again, e.g. human
Advantages of double circulation
Separates oxygenated and deoxygenated blood
Makes blood pressure high enough to reach all the body.
Portal system
begins and ends in capillaries.
The vessels in a portal system don’t connect directly to the heart e.g. hepatic portal vein connects the stomach + intestines to liver
Double circulation - pulmonary circuit
carries blood to the lungs where it becomes oxygenated
and carries it back to the heart.
Systemic circuit
carries this oxygenated blood to the body and brings deoxygenated blood back to the heart.
septum function
Separates left and right side of heart preventing the mixing of oxygenated amd deoxygenated blood
Which ventricle is thicker and why
Left ventricle because it pumps to systemic circuit
Blood flow through the heart
Body, vena cava, right atrium, right ventricle pulmonary artery, lungs, pulmonary vein, left atrium, left ventricle, aorta
SA node - location and full name
Sino-atrial node
top right atrial wall
AV node - full name and location
Atrioventricular node
Septum at the top of the ventricles
Name the 3 stages of the heartbeat
Diastole
Atrial systole
Ventricular systole
Diastole
Heart relaxes, valves are closed, blood enters the atria
Atrial systole
Atria contracts from SA node signal
Semilunar valves close
Bicuspid and tricuspid valves open
Blood enters ventricles
Ventricular systole
Ventricles contract from AV node impulse
Semilunar valves open
Bicuspid and tricuspid valves close
Blood exits pulmonary artery and aorta
pulse defintion
the alternate expansion and contraction of the arteries
Arteries - lumen and wall sizes
Small lumen
thick wall of collegen (outer wall) and smooth muscle+ elastic fibres (inner wall)
Arteries - valves or no valves + reason why
No valves - blood moves under pressure
Veins - lumen and wall size
Large lumen thin wall
Veins - valves or no valves
Valves to prevent backflow
Capillaries - Lumen an wall size
Tiny lumen
Wall 1 cell thick
