Heart structure Flashcards
What is the heart made up of
Cardiac muscle tissue contains myocytes that initiate own contraction without nerve input
How are heart cells connected
by cytoplasmic bridges - Cells form a branching structure, enabling electrical impulses to pass through tissue
What is the tip of the heart
Apex
What is the bottom of heart
Describes end with blood vessels associated with it
What is the septum
Thick muscular wall that divides the heart into the left and right halves
How is the heart divided
Left half (with oxygenated blood)
Right half (Deoxygenated blood)
Each half consists of upper atrium and a lower ventricle
Where does deoxygenated blood go
Right atrium recieves it from the body via the vena cavae, pumps it into the right ventricle
Where does the right ventricle pump deoxygenated blood
to the lungs via the pulmonary artery
Where does oxygenated blood go
Left atrium via the pulmonary vein, then pumps it into the left ventricle
Where does the left ventricle pump oxygenated blood
To the body via the aorta. It has the thickest wall of all chambers as it needs to pump blood the furthest
What does arteries branching out from the ventricles do
pump blood away from the heart
What do the veins attached to heart do
Feed into the atria and bring blood to the heart
Largest vein in body
Vena cavae
What does the pulmonary artery do
Transports deoxygenated blood to the lungs from the heart where gas exchange takes place
What do the pulmonary veins do
Transport oxygenated blood from the lungs to the heart
What does the aorta do
Transports blood from the heart to the rest of the body
What do the vena cavae do
two veins that carry deoxygenated blood to the heart from the upper body (Superior vena cava) and lower body (inferior vena cava)
What does the heart need seperate
Its own blood supply
How does the heart have its own blood supply
Via the coronary arteries - They branch out from the aorta as it leaves the heart
How many valves does the heart contain and why
4 valves - ensure blood flows in only one direction
What two types of valves are there
2 atrioventricular (AV) 2 Semilunar (SL)
What are the two Semilunar valves
The pulmonary Semilunar valve
The Aortic Semilunar valve
What does the pulmonary semilunar valve do
Prevents blood from flowing back into the right ventricle during diastole - Has 3 half moon shaped flaps (cusps)
What does the aortic semilunar valve do
Prevents flood from flowing back into the left ventricle during diastole (has 3 half moon shaped flaps (Cusps)
What are the two atrioventricular valves
The biscupid valve
The triscupid valve
What is the biscupid valve
prevents blood flowing from the left ventricle into the left atrium during ventricular contraction (Has two flaps (Cusps))
What is the triscupid valve
prevents blood flowing from right ventricle to the right atrium during ventricular contraction (Has 3 flaps (Cusps))
Where are papillary muscles attached to
Tendinous chords
What do papillary muscles do
Contract to prevent the AV valves from opening in the wrong direction, which would allow blood to flow back into the atria
Where are tendinous chords attach to
The valves
What do tendinous chords do
attach to the valves and prevent them from turning inside out due to the back pressure of blood pushing against them
What is the pericardium
A tough sac surrounding the heart comprised of two pericardial membranes
What does the pericardium do
Protects heart, lubricates it with pericardial fluid, reducing friction and prevents over expansion
What is the myocardium
main muscle mass of the heart, made up of myocytic cells
What lines the chambers of heart
Endocardium - made up of squamous vascular endothelial cells for sooth blood flow
