cardiovascular system - structure and function of heart Flashcards
what is cardiac
Hardest working muscle of all
what is cardiology
Study of heart & associated diseases
describe the direction of blood flow of the human heart
oxygenated blood exits the lungs from the top and enters the lower half of the heart, heart the processes this and send the deoxygenated blood out the top of the heart vessels to the lower half of the lungs
explain the pericardium
Double-walled sac enclosing heart
To isolate & give room for expansion
Resists compression
Pericardial space/cavity
- Fluid filled
what is Cardiac Tamponade
Compression of heart
by abnormal accumulation of fluid on pericardial cavity
e.g., pericarditis
due to viral infection or cancer etc.,
name the 3 layers of the heart wall
Outer: EPICARDIUM
Middle: MYOCARDIUM
Inner: ENDOCARDIUM
explain the Outer: EPICARDIUM layer of the heart wall
same layer as visceral pericardium, simple squamous epithelium
explain the Middle: MYOCARDIUM layer of the heart wall
thickest layer, cardiac muscle
explain the inner endocardium layer of the heart wall
simple squamous
epithelium, forms inner lining of chamber
explain the divisions of the pericardium layer which is the outer layer of the heart wall
most outer layer to most inner layer:
fibrous pericardium
parietal layer of serous pericardium
pericardial cavity
visceral layer of serous pericardium (epicardium)
what is the fibrous skeleton of the heart made up of
Dense connective tissue surrounding valves
what does the Fibrous Skeleton of the Heart form and do
Forms foundation to which heart valves attached
Point of insertion for cardiac muscle fibres
Prevents overstretching of valves
Electrical insulator
name the Fibrous Skeleton parts of the Heart
in order from posterior to anterior
right fibrous anulus
left fibrous anulus
right fibrous trigone
left fibrous trigone
fibrous ring of aortic valve
tendon of conus
fibrous ring of pulmonary ring
name the 4 chambers of the heart
left atrium
right artium
left ventricle
right ventricle
explain the right atrium of the heart
Receives deoxygenated blood from the body
blood enters it via 3 veins:
- superior vena cava
- inferior vena cava
- coronary sinus
explain the left atrium
Receives oxygenated blood from the lungs
- Via L&R pulmonary veins
Blood pumped to left ventricle then back into systemic circulation
right and left atria function to do what
to promote continuous venous flow
- No atrial inlet valves
- Contact incompletely
- Contractions are mild
- Relax before ventricular contraction starts
what is septal defect
‘hole in the heart’
when interatrial septum which is between left and right atrium has an atrial septal defect
explain the right and left ventricles
Large chambers at bottom of the heart
Collect and expel blood
RV —–> pulmonary circulation
LV ——> systemic circulation
explain what direction blood flows and via what
right atrium to right ventricle
via tricuspid valve
(= R atrioventricular valve)
explain the process of blood flow from the right ventricle
RV blood leaves through pulmonary semilunar valve
to
pulmonary trunk (large artery)
to either
Left Pulmonary Artery
or
right Pulmonary Artery
explain the flow of blood from the left atrium
LA receives blood from 4 pulmonary veins via bicuspid (Mitral) valve (=L atrioventricular valve)
to
left ventricle, where,
blood leaves through Aortic Semilunar Valve
to
AORTA (largest artery of body)
to either
coronary arteries
or
arch of aorta, then to body
describe the operation of heart valves
Ensure one-way flow of blood
explain AV valves
AV valves involve:
- Chordae tendineae (strings of connective tissue)
- Papillary muscle
explain SL valves
Pocket-like cusps
when heart is pumping what happens to alternate valves
they close
ex :
if pulmonary and aortic valve closed then bicuspid and tricuspid valves open
and vice versa
name the 4 heart valves
pulmonary valve
aortic valve
bicuspid valve (left AV)
tricuspid valves (right AV)
explain bioengineered heart valves
Current options for paediatric patients:
- bioprosthetic valves made from chemically treated animal tissues.
- These generally calcify and do not grow with the child.
2021
- bioengineered heart valves implanted into lambs have been shown to grow with the recipient.
Prospect for humans?
- Long-lasting product for paediatric heart surgery.
