Heart & Circulation Flashcards
Cardiovascular System Purpose
Transport blood between the heart, organs & peripheral tissues
Pulmonary Circuit
Gas exchange
Systemic Circuit
Rest of the body
Blood Functions
Trasports gases (O2 & CO2), nutrients (e.g. glucose), & hormones (chemical messages)
Regulates normal pH (keep it 7.3/7.4)
Prevent fluid loss (blood clotting)
Defence (white blood cells)
Maintain body temperature (absorb/release heat)
Heart Location
Just behind chest wall (ant. in thorax)
In the mediastinum, in the pericardial cavity
Pericardium
Sac surrounding the heart
Fibrous (outside) & serous (inside) layers
Contains [pericardial] fluid
Ensures no irritation or inflammation on the heart as it beats
4 Muscular Chambers (pumps)
Atria x2
Ventricles x2
The left side of the heart has muscle 3 times thicker…
than the right side because it has to pump blood to most of the body’s organs
Right Atrium
Receives blood from systemic circuit and empties into the right ventricle
Left Atrium
Receives blood form the pulmonary circuit and empties into the left ventricle
Atria
Receiving chambers Expandable Connects to: - Superior vena cava - Inferior vena cava - Cardiac veins - 4 pulmonary veins (2L & 2R)
Ventricles
Heart pumps
Blood pumps from ventricle through pulmonary valve to pulmonary trunk
Blood pumped form ventricle through aortic valve to aorta
4 Valves Control Directional Blood Flow
Atria -> Ventricles
2x Atrioventricular valves (AV valves)
2x Semilunar valves
Atrioventricular Valves (AV valves)
Located between the atria & ventricle
Fibrous tissue
Cusps (leaflets) at atrioventricular border:
- Right AV has 3
- Left Av has 2
Chordae tendinae (tedious cords attached to the leaflets)
Papillary muscles (anchor the chordae tendinae)
Semilunar Valves
Located between the ventricles and blood vessels
Aortic SL valve (ventricle -> aorta)
Pulmonary SL valve (ventricle -> pulmonary trunk)
Heart Wall
Endocardium
Myocardium
Epicardium
Endocardium
Endo - inside
Lines inner surfaces of the heart
Endothelial cells - squamous, thin & compressed
Myocardium
Middle
Cardiac muscle
Muscular walls of the heart
Atria & ventricles
Cardiac Muscle Cells (Myocardium)
‘Cardiomyocytes’
Connect at attachment points (intercalated discs) so they don’t rip apart when the heart is beating
Epicardium
Epi - outside
Outer surface of the heart
Visceral pericaridum
Blood vessels travel through
Conduction System of the Heart
Coordinates contractions of the heart
Maintains blood flow to organs & tissues
Cardiac Cycle
Diastole & Systole phases
Blood moves through the heart
Valves open & close
Diastole Phase
Relaxation of ventricles AV valves open 1. Sinoatrial node 2. Internal pathways 3. AV node 4. AV bundle (bundle branches) 5. Purkinje Fibers
Systole System
Contraction of the ventricles
AV valves close
