Location of the Heart
a) Thoracic Cavity
b) Behind the mediastinum
c) Deep to sternum
d) Tilts 2/3 to left of mediastinum
e) Broader at the top: Base
f) Tapers to a blunt tip at the bottom of the left side: Apex
g) Size: 9-13 cm from (base-apex), 6cm thick, about the size of a fist
h) Weight: 300g
i) Averages 75 bpm, 3 million b/lifespan
- collagen framework that gives support and shape to the heart
(1) Found through out
(2) Denser in some areas - in septum between chambers
(3) Hold valves open as heart beats
(4) Anchors myosites
(5) Provides elastic re-coil, prevents stretching during breathing
(6) Non-conductive (insulative) - prevents electrical overload
i) Skeletal system
ii) Sternum acts as protective plate
iii) Apex near 5th intercostal of the rib
iv) Under mediastinum there is fatty tissue that protects and insulates
membranous sac that encloses the heart and anchors via ligaments that attach to diaphragm, it protects and suspends
(i) Two Layers
1. Fibrous Pericardium
2. Serous Pericardium
a. Parietal Pericardium
b. Pericardial Cavity
c. Visceral Pericardium
- 2nd inner layer to fibrous made of simple squamous epithelium
- serous membrane (2 layers)
lays between the parietal pericardium and the visceral pericardium and contains pericardial fluid- which is used to prevent friction
- aka Epicardium layer
- inner layer of pericardium and outer layer of myocardium
(1) made of simple squamous epithelium with overlay of Areolar CT, Adipose CT
(2) acts as shock absorber and emergency fuel supply
(3) contains Blood vessels - largest branches of the heart
muscle layer of the heart, responsible for contraction of the heart (pump)
(1) Thickest layer
(2) Composed of cardiac muscle tissue causing heart to beat in twisting motion
inner most layer of the heart, lines the valves and vessels of the heart.
(1) Composed Simple Squamous Epithelium with Areolar CT, NO Adipose CT
(2) Lines heart chambers and covers valves
(3) Directly continuous with Endothelium - lining of blood vessels
(4) Allows blood to move easily through the heart
located posterior and superior
(1) receiving chambers
(2) blood enters from great veins
(3) contains auricles
(4) Contains Pectinate Muscles
(5) Right Atria:
(6) Left Atria:
(7) Left and Right Atria are separated by Inter-atrial Septum - made of collagenous CT.
large ridges located in pockets of septum, primarily used to contract muscles and force blood to the ventricles.
located anterior and inferior
(1) Pumping chambers that eject blood
(2) Maintain circulation by taking blood into other areas
(3) Contains Trabeculae Carneae:
(4) Right Ventricle:
(5) Left Ventricle:
(a) 2-4x thicker and pushes blood through the systemic circulation
(6) Right and Left Ventricle are divided by the Interventricular Septum
groove on the surface of the heart that contains blood vessels and adipose CT.
(1) Coronary Sulcus:
(2) Anterior Interventricular Sulcus
(3) Posterior Interventricular Sulcus
aka Atrioventricular Sulcus, groove that marks the boundary between atrium and the ventricles, holds the right coronary artery
Anterior Interventricular Sulcus
extends inferiorly from coronary sulcus on the anterior surface of the heart, divides the rt and left ventricle, usually holds the great cardiac vein
Posterior Interventricular Sulcus
extends inferiorly from the coronary sulcus on the posterior surface of the heart, usually holds the posterior interventricular artery
i) Makes blood flow in 1 direction controlled by pressure gradient, preventing back flow
ii) Guarded openings between chambers and heart arteries
iii) 2-3 cusps/leaflets - curved fibrous CT with endothelium opens and closes to allow blood to move
iv) Atrioventricular Valve (AV Valve):
(1) Tricuspid Valve
(2) Bicuspid Valve or Mitral Valve:
v) Each ventricle contains papillary muscles
vi) Muscles are connected to Chordae Tendineae -
cone shaped muscular pillars in each ventricle that assist in the opening and closing of the valves
thin strong connective tissue strings to free margins of the cusps of AV valves. Used to protect against back flow.
Circulation of the Blood
i) Occurs at 75bpm which takes about a minute to complete
ii) Blood circulates in continuous loops
iii) Pulmonary Circuit
iv) Systemic Circuit:
v) Coronary Circulation
contains Deoxy Blood and lots of CO2
(1) Arteries carry de-oxy blood to other areas of the heart, veins carry oxy blood to the heart
(2) Rt. Atrium contracts blood passes through RT AV valve into Rt. Ventricle
(3) Pumps blood through pulmonary valve into pulmonary trunk
(4) Blood travels to the rt and left pulmonary arteries
(5) That carries into both lungs
(6) Then they branch into a series of small arteries into pulmonary capillaries
(7) A gas exchange occurs where blood loads up O2 and dumps CO2
(8) Blood will drain and move into Rt and Left Pulmonary veins that travels to the heart
(9) Oxygenated Blood is emptied into left atrium
contains Oxgenated Blood and almost no CO2
(1) Arteries carry oxy away from the heart, veins carry de-oxy blood to the heart
(2) from left atrium, Oxy blood passes through left AV valve into left ventricle
(3) oxy blood passes through aortic valve into ascending aorta to aortic arch
(4) then it distributes into systemic arteries that spread and branch to systemic capillaries where it will unload O2 and load CO2
(5) Deoxy blood will collect into systemic veins, converge onto superior and inferior vena cava
(6) Returns to heart and empties into the rt. atrium
heart's own circulation system that supplies its own blood for nutrients
(1) Each body had slightly different arrangements of arteries and veins
Arteries in the Coronary Circuit
(2) Two coronary arteries originate at the aorta
(a) Left Coronary Artery (LCA):
(b) Rt Coronary Artery (RCA):
Left Coronary Artery (LCA)
on left side of aorta, supply blood to left atrium, most of the left ventricle, and part of right anterior ventricle.
(i) Anterior Ventricular Artery:
(ii) Circumflex artery:
Right Coronary Artery (RCA)
originates on the rt side of the aorta, extends to coronary sulcus to the right posteriorly, supply the right atrium, most of the right ventricle, and part of the left posterior ventricle
(i) Right Marginal Artery:
(ii) Posterior Interventricular Artery:Po
(iii) SinoAtriol Branch:
Posterior Interventricular Artery
located in posterior interventricular sulcus, sends blood to poster walls of ventricles and to interventricular septum, join with anterior interventricular artery, which is branch with Circumflex artery.
drain blood from the cardiac muscle, pathways are parallel to the coronary arteries, and most drain into the coronary sinus - a large vein located within the coronary sulcus on the posterior aspect that drain into the right atrium along with some other cardiac veins.
(a) All the coronary veins runs parallel to the coronary sinus. Names are really similar.
(b) Thebesian Veins:
(c) Great Cardiac Vein:
(d) Small Cardiac Vein:
(e) Middle Cardiac Vein:
(f) Left Marginal Vein.
(g) Multiple pathways ensures the heart maintains motion.
small veins that directly drain by diffusion into the rt. Atrium and rt. Ventricle (20%) originate from myocardium near the rt. and lft atrium.
Great Cardiac Vein
drains from anterior aspect, runs along the anterior IV sulcus with the ant. IV artery
Middle Cardiac Vein
runs along posterior IV sulcus and drains blood posteriorly, located along the Posterior IV sulcus with the Post. IV artery
Left Marginal Vein
drains blood to apex, runs parallel to left marginal artery that is extended from the circumflex artery
inflammation of pericardium.
(1) Sensations of pain when the heart rubs against the pericardium as the heart beats.
(2) Due to lack of pericardial fluid
Valvular Insufficiences/ Valvular Incompetence
(1) Valvular Stenosis:
(2) Valvular Prolapse:
(d) Mitral Valve Prolapse (MVP)
valve turns inside out
(a) Movement is in opposite direction
(b) Works harder, gets larger, which make it inflexible
(c) Overtime, can result in fatigue, shortness of breath, Ischemia: chest pain, heart failure.
Mitral Valve Prolapse (MVP)
commonly symptom is Heart murmur due to turbulence of back flow.
(3) Can be corrected through valvular replacement
occurs when there is 75% of blockage
(a) sense of heaviness and pain in chest
(b) temporary ischemia
(c) may rely on anaerobic respiration for metabolism
(d) Myocardial Infarction may result
(v) blockage due to Atherosclerosis:
(vi) Collateral Circulation: alternate pathways
(e) Blockage of artery is impossible to fix to naturally, therefore prevention is the key but changing your diet and exercise will allow your body to increase the blockage.
total blockage of artery
(i) Aka Heart Attack
(ii) Begins when atheroma totally blocks coronary blood vessel
(iii) Any tissue not receiving blood will die within 3min
(iv) Fibrillation: rapid fluttery contractions
1. Cardiac arrest follows: heart stops beating
a. Stops blood supply to the brain within 4-7 min. will cause death
Prevention of Angina Pectoris
(i) Prevention: exercise and change of diet
1. Eating HDL (high density Lipoproteins) will regulate LDL's and bind them in the blood stream
2. Increase soluble fiber which are brans, whole grain, apples, beans will lower LDL's
3. Omega-3 unsaturated fatty acids (PUFAS) will lower LDL and reduce arterial thickness commonly found in fatty fishes
Surgical Remedies of Angina Pectoris
1. Angioplasty: surgical procedure to widen narrow Blood vessels
a. Balloon Angioplasty
b. Laser Angioplasty:
catheter is placed in bloackage, a ballon inflates in the blood vessel will open and a stent is placed to keep the artery open.
ii. Thrombosis: blood clot, embellism may result.
iv. Resonosis may occur - plaque regrowth.
catheter enters and the laser burns the arterial plaque,
ii. Plaque may break off and cause a heart attack
iii. It may damage arterial walls
iv. Resonosis may occur - plaque regrowth.
Coronary Bypass Surgery
cut section of the artery from somewhere else and detour it to shift the flow of blood.