UNIT 3 - CIRCULATORY SYSTEM II Flashcards
Heart (4)
- Located in thoracic cavity posterior to sternum
- 2/3 of heart is left of midline of body, 1/3 to the right
- Size of clenched fist
- Divided into 4 chambers
Atria
Upper two chambers of the heart and thin walled because they only have to pump blood into ventricles
Ventricle
Lower two chambers of the heart and thick walled because it pumps blood a longer distance
Right ventricle
Pumps blood to lungs; shorter distance, lower pressure, lower resistance
Left ventricle
Pumps blood to whole body; longer distance, higher pressure, more resistance
Septum
Separates the ventricles
Which side of the heart has greater pressures
Left
Arteries
Carry blood away from heart and flows in fast high pressure
Veins
Carry blood to heart and flows in slow low pressure
Capillary
Smallest blood vessel that intermingles with cells and exchanges material
Pulmonary trunk and aorta
Major arteries that leave the heart
Aorta
Leaves the left ventricle and supplies oxygenated blood to body
Pulmonary trunk
Takes deoxygenated blood from right ventricle to lungs
Superior vena cava
Collects blood from upper half of body and carries it to the right atrium
Inferior vena cava
Collects blood from lower half of body and carries it to the right atrium
Pulmonary veins
Brings oxygenated blood from the lungs to the left atrium
2 components of pericardium:
- Fibrous pericardium
- Parietal serous pericardium
Fibrous pericardium
Dense irregular connective tissue that prevents overstretching and anchors heart
Parietal serous pericardium
Lines the fibrous pericardium
Visceral serous pericardium
Serosa layer covering entire surface of heart (epicardium)
Layers of the heart wall (3)
- Epicardium (external)
- Myocardium (middle)
- Endocardium (inner)
Epicardium
Outermost protective layer of the heart
Myocardium
Hard working, contracting, muscular layer of the heart
Endocardium
Innermost layer of epithelial tissue on layer of connective tissue that lines large blood vessels
Pericardial cavity
Between epicardium and pericardium that contains pericardial fluid to reduce friction
How much of the heart is cardiac muscle
95%
Pulmonary circulation
Blood flow from heart to the lungs and back to the heart
Blood flow of pulmonary circulation
Right atrium –> tricuspid valve –> right ventricle –> pulmonary valve –> pulmonary artery –> lungs
Systematic circulation
Blood flow from heart to the head and body and back to the heart
Blood flow of systematic circulation
Left atrium –> left ventricle –> head/body
Double circulation
Concept of blood travels through two loops (pulmonary loop and systematic loop)
Heart valves
Flaps/cusps of fibrous connective tissue covered by endocardium functioning in preventing the backflow of blood in heart
4 types of heart valves:
- Bicuspid valve
- Tricuspid valve
- Aortic valve
- Semilunar valve
Bicuspid valve
Located between the left atrium and left ventricle and has 2 flaps/cusps
Tricuspid valve
Located between the right atrium and right ventricle and has 3 flaps/cusps
Chordae tendinae
Cords of connective tissue that help anchor the flaps to the walls of the heart preventing valves from opening to prevent backflow of blood
Papillary muscle
Muscles within the cavity of the ventricles of hearts attached to walls