A&P 2 Unit 16 (Lab) [The Heart, Part 1] Flashcards
Describe the location of the heart within the thoracic cavity.
- Located in the mediastinum
- 2/3 of heart’s mass lies to the left of the midline.
- Apex points towards the left hip.
- Great Vessels are attached to heart’s base.
Medisstinum
An area in the throacic cavity between the lungs
Pericardial Cavity
- The heart is surounded by a fluid-filled pericardial cavity, created by serous membrane.
- Pericardial Fluid is the fluid in the pericardialcavity. It acts as a lubricant.
- Composed of fibrous pericardium & parietal pericardium
The serous membranes of the pericardial cavity.
- Parietal Pericardium
- Visceral Pericardium
Parietal Pericardium
- Parietal Layer of Serous Membrane
- There is fluid between it and the heart
- Secretes serous fluid (pericardial fluid)
Visceral Pericardium
- Visceral Layer of Serous Membrane
- Attached directly to the heart
- Secretes serous fluid (pericardial fluid)
The 3 Layers of the Heart Wall
- Endocardium
- Myocardium
- Epicardium
Endocardium
- Inner most layer of the cardiac wall.
- Type of simple squamous epithelium called endothelium
- It is continuous with the endothelium lining all blood vessels in the body.
Myocardium
- The cardiac muscle.
- The middle myocardoium is the actual muscle of the heart.
- Consists of cardiac muscle tissue & its fibrous skeleton
Epicardium
- Visceral Layer of Serous Membrane
- Outer most layer of the heart wall
- Consists of a layer of epithelial tissue & loose connective tissue.
Cardiac Muscle Histology
- Cells are short, branched, & striated, usually with a single nucleus; cells are interconnected by intercalated discs.
- Located in the heart
-
Functions:
- Circulates blood
- Maintains blood (hydrostatic) pressure
Fibrous Pericardium
- Full of collagen fibers and doesn’t stretch
- Prevents the heart from over stretching
Desmosomes
- Strong intercellular junctions
- Much like rivots
Intercalated Discs
- The area where one cardiac muscle cell joins to another cardiac muscle cell.
- Contain desmosomes & gap junctions
Gap Junctions
- Allow depolarization to spread from cell to cell.
- Little proteins are what connect the cells
The 2 Circuatory Systems of the Body
- Pulmonary Circulation
- Systemic Circulation
Pulmonary Circulation
- The right side of the heart pumps blood into the pulmonary circulation.
- Gas exchange occurs between pulmonary capillaries and air: O2 enters the blood & CO2 leaves the blood
Systemic Circulation
- The left side of the heart pumps blood into the systemic circulation.
- Gas exchange occurs between systemic capillaries & interstitial fluid: O2 leaves the blood & CO2 enters the blood.
Oxygenated Blood’s Location in the Heart
- Left side of the heart.
- Receives from lungs, pumps to rest of the body
Deoxygenated Blood’s Location in the Heart
- The right side of the heart
- Receives blodd from the body, pumps to the lungs.
Right Atrium
Right Ventricle
Left Ventricle
Left Atrium
2 Atria
- Upper
- Smaller capacity
- Receive blood
- Left & Right
2 Ventricles
- Lower
- Larger capacity
- Receive blood from atria
- Pumps blood out
- Left & Right
Right Atrium
- The right atrium is the superior right chamber.
- It receives deoxygenated blood from the body’s main veins- the superior vena cava, and the coronary sinus.
- These veins drain a series of blood vessels collectively called the systemic circuit, in which gases & nutrients are exchanged between the blood & the tissue cells.
Right Ventricle
- The right ventricle is a larger chamber inferior to the right atrium, from which it receives deoxygenated blood.
- It ejects blood into a vessel called the pulmonary trunk, or the pulmonary artery.
- The pulmonary trunk branches into right & left pulmonary arteries, which deliver deoxygenated blood to the lungs through a series of vessels collectively called the pulmonary circuit.
- Within the pulmonary circuit, gases are exchanged, & the blood becomes oxygenated.
Left Atrium
- The superior left chamber.
- It receives oxygenated blood returning from the pulmonary circuit via four pulmonary veins.
Left Ventricle
- Receives oxygenated blood from the left atrium & pumps it into the largest artery in the systemic circuit, the aorta.
- The aorta then branches repeatedly to deliver the oxygenated blood to the body’s cells.
- Note that the left ventricle is considerably thicker than the right ventricle, reflecting the fact that the pressure is much higher in the systemic circuit than it is in the pulmonary circuit.
- The higher pressure requires the left ventricle to pump harder, and thus it is thicker.
2 Atrioventricular Valves
AV Valves
- Tricuspid Valve (Right AV Valve)
- Bicuspid Valve (Left AV Valve) (Mitral Valve)
2 Semilunar Valves
- Pulmonary Valve
- Aortic Valve
Tricuspid Valve
Pulmonary Valve
Aortic Valve
Bicuspid (Mitral) Valve
Tricuspid Valve
OPEN: Blood flows from Right Atrium to Right Ventricle.
Bicuspid Valve
OPEN: Blood flows from Left Atrium to Left Ventricle
Pulmonary Valve
OPEN: Right Ventricle to pulmonary trunk (Right & Left Pulmonary Arteries)
Aortic Valve
OPEN: Left Ventricle to Aorta
Coronary Circulation
- The portion of the systemic circulation supplying blood to the myocardium (In coronary arteries) and draing the myocardium (in cardiac veins).
- The right & left coronary arteries are the first branches of the aorta.
- Deoxygenated blood in the cardiac veins flows into the coronary sinus (a large, thin-walled vein on the posterior heart), which empties into the right atrium.
Myocardial Infarction
It happens when blood stops flowing properly to part of the heart and the heart muscle is injured due to not receiving enough oxygen. Usually this is because one of the coronary arteries that supplies blood to the heart develops a blockage due to an unstable buildup of white blood cells, cholesterol and fat.
Superior Vena Cava
Right Pulmonary Artery
Right Pulmonary Veins
Opening of Superior Vena Cava
Fossa Ovalis
Opening of coronary sinus
Opening of inferior vena cava
Inferior Vena Cava
Left Common Carotid Artery
Left Subclavian Artery
Brachiocephalic Trunk
Arch of Aorta
Ligamentum Arteriosum
Left Pulmonary Artery
Pulmonary Trunk
Left Pulmonary Veins
Chordae Tendineae
Interventricular Septum
Papillary Muscle
Trabeculae Carneae
Descending Aorta
Right Auricle of Right Atrium
Right Coronary Artery
Inside
Right Atrium
Coronary Sulcus
Inside
Right Ventricle
Left Auricle of Left Atrium
Branch of Left Coronary Artery
Inside
Left Ventricle
Anterior Interventricular Sulcus