Chapter 18: The Heart Anatomy

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Chapter 18: The Heart Anatomy by Mind Map: Chapter  18: The Heart Anatomy

1. Cool Facts about your heart:

1.1. The average heart is the size of a fist in an adult

1.2. your heart pumps about 2k gallons of blood every day

1.3. An electrical system controls the rhythm of your heart. Its called the CARDIAC CONDUCTION SYSTEM

1.4. The earliest known case of heart disease was identified in the remeains of a 3500 year old Egyptian mummy

1.5. Christmas day is the most common day of the year for heart attacks to happen

1.6. The beating sound of your heart is caused by the valves of the heart OPENING AND CLOSING

1.7. If you were to stretch out your blood vessel system it would extend over 60k miles :0

1.8. Heart cells stop dividing which means heart cancer is extremely rare

2. Cardiovascular System:

2.1. Main function: Transportation

2.1.1. Blood = transport vehicle

2.1.2. Heart = pump

2.1.3. Blood vessels = network of tubes

3. Anatomy of Heart

3.1. Layers of the pericardium and heart wall:

3.1.1. Heart is surrounded by PERICARDIUM the membrane enclosing the heart, a double walled sac, consisting of an outer fibrous layer and an inner double layer of serous membrane.

3.1.2. Pericardium Layers Superficial FIBROUS PERICARDIUM Functions to protect, anchor heart to surrounding structures, and prevents overfilling Deep two-layered SEROUS PERICARDIUM Two layers separated by fluid filled PERICARDIAL CAVITY (decreases friction)

3.1.3. Layers of the Heart Wall Epicardium: a serous membrane that forms the innermost layer of the pericardium and the outer surface of the heart. Myocardium: cardiac muscle, the muscular tissue of the heart. Consist of circular or spiral bundles of contractile cardiac muscle cells Endocardium: the thin, smooth membrane which lines the inside of the chambers of the heart and forms the surface of the valves; ENDOTHELIUM lines the chambers Endothelium: the tissue which forms a single layer of cells lining various organs and cavities of the body, especially the blood vessels, heart, and lymphatic vessels. It is formed from the embryonic mesoderm.

3.1.4. Clinical: Homeostatic Imbalance 18.1 Pericarditis: Inflammation of pericardium Roughens membrane surfaces, causing PERICARDIAL FRICTION RUB which can be heard with a stethoscope Cardiac tamponade

3.2. Size of fist

3.3. Weighs less than 1lb

3.4. Apex of heart towards left hip

3.5. Flanked by lungs

3.6. In Mediastinum between second rib and fifth intercostal space

3.6.1. Mediastinum: a membranous partition between two body cavities or two parts of an organ, especially that between the lungs.

3.6.2. On superior surface of the diaphragm

3.6.3. 2/3 of the heart to the left of the MIDSTERNAL line Midsternal: The largest and middle portion of the STERNUM. Sternum: the breastbone.

3.6.4. ANTERIOR to the VERTEBRAL COLUMN, POSTERIOR to the sternum Anterior: nearer the front, especially situated in the front of the body or nearer to the head. Vertebral Column: another term for spinal column. The major function of the vertebral column is protection of the spinal cord; it also provides stiffening for the body and attachment for the pectoral and pelvic girdles and many muscles. In humans an additional function is to transmit body weight in walking and standing Posterior: Posterior or dorsal - back (example, the shoulder blades are located on the posterior side of the body)

3.7. Heart BASE leans toward the right shoulder

3.8. APEX points toward left hip

3.9. APICAL IMPULSE palpated between fifth and sixth ribs, just below left nipple

3.9.1. The apex beat (lat. ictus cordis), also called the apical impulse, is the pulse felt at the POINT OF MAXIMUM IMPULSE (PMI), which is the point on the PRECORDIUM farthest outwards (laterally) and downwards (inferiorly) from the sternum at which the CARDIAC IMPULSE can be felt. The Point of Maximum Impulse: known as PMI, is the location at which the cardiac impulse can be best palpated on the chest wall. Precordium: the region or the thorax immediately in front of the heart. Cardiac Impulse: basically the heartbeat: the wave of cardiac excitation passing from the sinoatrial node to the atrioventricular node and along the bundle of His and initiating the cardiac cycle

3.10. Heart Chambers:

3.10.1. Left and Right Atrium: receives blood (entry way to the heart) Definition: the upper chamber through which blood enters the ventricles of the heart. There are two atria in the human heart – the left atrium receives blood from the pulmonary (lung) circulation, and the right atrium receives blood from the venae cavae (venous circulation) Interatrial septum: separates the atria Fossa Ovalis: remnant of foramen ovale of the fetal heart

3.10.2. Left and Right Ventricle: Pumps blood out Definition: The left ventricle is the thickest of the heart's chambers and is responsible for pumping oxygenated blood to tissues all over the body. By contrast, the right ventricle solely pumps blood to the lungs.

3.10.3. Septum: wall between the Atria and Ventricles

3.10.4. Valves: prevent the backflow of blood Ensure unidirectional blood flow through heart Open and close in response to pressure changes Two Major Types of Valves: Atrioventricular Valves: located between atria and ventricles Semilunar Valves: located between ventricles and major arteries

4. Helpful Links!!!

4.1. Visible Body

4.1.1. At the Heart of It All: Anatomy and Function of the Heart

4.1.2. Physiology & Pathology: Four Common Cardiovascular Conditions

4.1.3. Pulmonary Circulation and Systemic Circulation: The Routes and Function of Blood Flow

4.2. YouTube Videos

4.2.1. Cardiovascular | Structures and Layers of the Heart:

4.2.2. Cardiovascular | Anatomy of the Heart | Heart Model

4.2.3. The Heart, Part 1 - Under Pressure: Crash Course A&P #25

4.2.4. The Heart, Part 2 - Heart Throbs: Crash Course A&P #26

4.2.5. Blood Vessels, Part 1 - Form and Function: Crash Course A&P #27

4.2.6. Blood Vessels, Part 2: Crash Course A&P #28

4.3. From Powerpoints

4.3.1. Anatomy of Heart Web Activity Anatomy of Heart Video Alternative

5. Electrical activity of the heart concept map

5.1. Answer:

6. Blood Flow Through the Heart Concept Map

6.1. Answer:

7. Blood Circulation

7.1. The Heart is a Double Pump: Each side provides own circuit

7.1.1. Pulmonary Circuit: Blood to/from the LUNGS Right Ventricle = low pressure

7.1.2. Systemic Circuit: Blood to/from ALL BODY TISSUES Left Ventricle = high resistance to blood flow Ventricle is 3x as thick as right ventricle More powerful pump

7.2. Coronary Circulation

7.2.1. Functional blood supply to the heart muscle itself

7.2.2. Shortest circulation in the body

7.2.3. Delivered when heart is relaxed

7.2.4. Left Ventricle receives most of the coronary blood supply

7.2.5. Coronary Arteries Both Left and Right arteries aries from the base of the aorta and supply arterial blood to the heart Left Coronary Artery: Right Coronary Artery: Both encircle heart in CORONARY SULCUS Coronary Sulcus: A groove on the outer surface of the heart marking the division between the atria and the ventricles. Branching of coronary arteries varies among individuals Arteries contain many anastomoses (junctions) Provide additional routs for blood delivery Cannot compensate for CORONARY ARTERY OCCLUSION Heart receives 1/20th of body's blood supply

7.2.6. Coronary Veins Cardiac Veins collect blood from CAPILLARY BEDS Capillary Beds: Capillaries are microscopic blood vessels that connect the ARTERIOLES with the VENULES, and a network of capillaries is known as a capillary bed Coronary Sinus empties into the right atrium, formed by merging cardiac veins Great Cardiac Vein of anterior interventricular sulcus Middle Cardiac Vein in posterior interventricular sulcus Small Cardiac Vein from inferior margin Several Anterior Cardiac Veins empty directly into right atrium anteriorly

7.2.7. Homeostatic Imbalances Angina Pectoris Thoracic pain caused by fleeting deficiency in blood delivery to myocardium Cells are weakened Myocardial Infarction (HEART ATTACK) Prolonged coronary blockage Areas of cell death are repaired with noncontractile scar tissue

7.3. Pathway of Blood Through the Heart

7.3.1. To Right Atrium Superior Vena Cava (above Diaphragm) Inferior Vena Cava (below Diaphragm) Coronary Sinus (from myocardium)

7.3.2. Tricuspid Valve

7.3.3. Right Ventricle: 2 Pulmonary arteries (to lungs)

7.3.4. Pulmonary Valve

7.3.5. To Left Atrium: 4 Pulmonary Veins (lungs to heart)

7.3.6. Mitral (Bicuspid) Valve

7.3.7. Left Ventricle:

7.3.8. Aortic Valve:

7.3.9. Aorta (to body) Coronary Arteries

8. Microscopic Anatomy

8.1. Cardiac Muscle Cells: striated, short, branched, fat, interconnected

8.1.1. One central nucleus (at most 2)

8.1.2. Contain numerous large mitochondria (25-35% of cell volume) that afford resistance to fatigue

8.1.3. Rest of volume composed of SARCOMERES Sarcomere: a structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band. Z discs, A bands, and I bands present

8.1.4. T tubules are wider, bud less numerous Enter cell only once at Z discs

8.1.5. SR simpler than skeletal muscle, no triads

8.1.6. Similarities and differences with Skeletal Muscle? Similarities: Muscle contraction is preceded by depolarizing action potential Depolarization wave travels down T tubules, cakusin sarcoplasmic reticulum (SR) to release Ca2+ Excitation contraction coupling occurs Differneces [SOME] cardiac muscle cells are self excitable Heart contracts as a UNIT Influx of Ca2+ from extracellular fluid triggers Ca2+ release from SR Tetanic contractions cannot occur in cardiac muscles Heart relies almost exclusively on aerobic respiration

8.2. Intercalated Discs: connecting junctions between cardiac cells that contain:

8.2.1. Desmosomes: hold cells together, prevent cells from separating during contraction

8.2.2. Gap Junctions: allow ions to pass from cell to cell, electrically couple adjacent cells Allows heart to be a functional syncytium (single coordinated unit)