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Cardio Syst - Heart
General functions of the heart
Terms in this set (23)
General Functions of the Heart
1. Generate Blood Pressure
2. Routing Blood- Separating Pulmonary & Systemic Systems
3. Ensuring one way blood flow- valves
4. Regulating Blood Supply - Atrium
- The left side of the heart is the pump for the systemic circulation.
- Receives freshly oxygenated blood from the lungs and propel it into the largest artery in the body, the aorta - then to smaller systemic arteries - then to arterioles - and then to capillary
- Through thin capillary walls, exchange of nutrients and gases occur. Blood unloads oxygen (O2) and picks up carbon dioxide (CO2)
- Capillary conects to venule
- Carry deoxygenated (oxygen-poor) blood away from tissues and merge to form large veins, takes blood towards the heart
- The right side of the heart is the pump for the pulmonary circulation.
- Blood ejected from the right side of the heart flows into the pulmonar trunk - that branches into pulmonary arteries - carries blood to the right and left lungs.
- In pulmonry capillaries, blood picks up oxygen and unloads carbon dioxide, which is exhaled.
-Fleshly oxygenated blood then returns to the left side of the heart to begin another pass through the systemic circulation
- A triple-layered sac that surrounds and protects the heart
- 2 portions
a) Fibrous Pericardium (outer)
(b) Serous Pericardium (inner)
- A tough, inelastic, dense connective tissue
- (1) prevents overdistension of the heart,
(2) provides a tough protective membrane around the heart
(3) anchors the heart in the mediastinum
- is a thinner, more delicate membrane that forms a double layer around the heart.
1) Parietal Layer (outer)
(2) Visceral Layer (inner)
Serous Pericardium : Parietal Layer
- Directly beneath and fused to the fibrous pericardium
Serous Pericardium: Visceral layer (epicardium)
- Is beneath the parietal layer, attached to the myocardium (muscle) of the heart
- An inflammation of the pericardium
3 Layers of the HEART WALL
a) Epicardium (Visceral layer of the Serous Pericardium):
- Is the thin, transparent outer layer of the wall.
b) Myocardium (middle layer) - is the cardiac (heart) muscle tissue, constitutes the bulk of the heart.
- Responsible for the contraction of the heart. Pump action.
c)Endocardium (inner layer) - A thin layer of endothelium that lines the inside of the myocardium
Atrioventricular (AV) Valves
- lie between the Atria and Ventricles
- Tricuspid Valve - the right atrioventricular valve between the right atrium and right ventricle.
Blood enters ventricles from atria when pressure in ventricles are low.
- Bicuspid (Mitral) Valve - the left atrioventricular valve between the left atrium and left ventricle. (Half-moon shaped)
As ventricle contracts (high pressure), blood drives cusps upwards closing the valves
- lie between the heart and the arteries
- Pulmonary Semilunar Valve - lies in the opening where the pulmonary trunk leaves the right ventricle.
-Aortic Semilunar Valve - situated at the opening between the left ventricle and the aorta.
Superior vena cava (SVC)
- Which brings blood from most parts of the body superior to the heart.
Inferior vena cava
- Which brings blood from all parts of the body inferior to the diaphragm
- Which drains blood from most of the vessels serving the heart itself
Coronary (Cardiac) Circulation
- The flow of blood through the numerous vessels that pierce the myocardium. Delivers oxygenated blood to the myocardium and remove carbon dioxide from it.
- Blood collects CO2 and wastes as it delivers O2 and nutrients.
- Drains into Coronary Sinus
- a. Great Cardiac Vein drains anterior aspect of the heart.
b. Middle Cardiac Vein drains posterior aspect of the heart.
- When a reduced oxygen (reduced coronary circulation) supply weakens cells but does not actually kill them; causes Hypoxia
- Lack of adequate O2 at tissue level
- "Chest Pains", results from Ischemia of the myocardium. (May or may not involve heart or artery disease.) Angina is typically described as a tightness or choking sensation or a squeezing, pressure-type discomfort and is usually short duration.
Myocardial Infarction (MI)
- Heart Attack
- The death of an area of tissue because of an interrupted blood supply.