Heart Anatomy Flashcards
Cardiac Cycle
2 Coordinated systole - First in the atrium, then in the ventricle.
Heart Features
70 beats/min
300g male, 250g female. Size of a fist.
Function: circulation pump to transport the blood around the body.
Apex of the Heart
Oriented inferiorly, anteriorly toward left hip.
Located between 5th and 6th rib.
Location of the Heart
Inferior, middle mediastinum. Behind sternum Between lungs On the diaphragm Extends obliquely from 2nd rib to 5th intercostal space Base towards right shoulder Left ventricle is anterior.
Heart Chambers
Right atrium
Right ventricle
Left atrium
Left ventricle
Valves and septum
Valves between chambers
Mitral valve - between left atrium and ventricle
Tricuspid valve - between right atrium and ventricle
Septum between sides (right and left)
Ventricular septum - between ventricles
Atrial septum - between atriums
Systolic Blood Pressure
120 mmHg
Diastolic Blood Pressure
80 mmHg
Pulmonary Artery Pressure
15-25 mmHg
Low Oxygenated Blood - Travel
Comes from the superior and inferior vena cava into the right atrium to right ventricle into the pulmonary arteries to the lungs.
High Oxygenated Blood - Travel
From lungs, through the pulmonary veins, to left atrium, to left ventricle to the rest of the body through the aorta.
Anterior Sternocostal Surface of the Heart
Ascending aorta
Pulmonary trunk
Right ventricle in the middle, left ventricle on the right side.
Posterior Surface (Base) of the Heart
Arch + descending aorta
Left and right pulmonary arteries
Left and right pulmonary veins
Superior and inferior vena cava
Heart Arteries
Left and Right coronary arteries (ascending aorta)
Crown:
- Brachiocephalic trunk: Right subclavian artery, right common carotid artery.
- Left common carotid artery, left subclavian artery.
Left and Right aortic sinuses within the aorta.
Heart Veins
Coronary Sinus: - Great cardiac vein - Small cardiac vein - Middle cardiac vein - Left marginal vein Left posterior ventricular vein
Aortic Sinuses
Left coronary artery: → Circumflex artery → Left marginal artery → Anterior interventricular artery Right coronary artery: → Right marginal artery → Posterior interventricular artery
Valves
Ensure blood flow in one direction
Composed of connective tissue
4 valves, 2 categories:
- Atrioventricular valves: tricuspid and mitral
- Semilunar valve: pulmonary valve and aortic valve
Tricuspid Valve
Between right atrium and right ventricle
Prevents backflow of blood from right ventricle to right atrium.
Low oxygenated blood (pulmonary circulation)
3 cusps
Mitral Valve
Bicuspid valve
Between left atrium and left ventricle
Prevents backflow of blood from left ventricle to left atrium.
High oxygenated blood (systemic circulation)
2 Cusps
Aortic Valve
Between left ventricle and aorta
Prevents backflow of blood from aorta to left ventricle
High oxygenated blood (systemic circulation)
3 cusps
Pulmonary Valve
Between right ventricle and pulmonary trunk
Prevents backflow of blood from pulmonary artery to right ventricle.
Low oxygenated blood (pulmonary circulation)
3 cusps
Opening and Closing of the Valves
Diastole: - Mitral valve and tricuspid valve open - Pulmonary and aortic valves closed Systole: - Mitral valve and tricuspid valve closed - Pulmonary valve and aortic valve open
Heart Wall Structure
- Pericardium
- Epicardium
- Myocardium
- Endocardium
Pericardium
- Fibrous layer (outer)
- Double serous layer
- Parietal layer
Function: - Protection against infection
- Reduce friction, lubrification
- Help to avoid overfilling of the heart
- Sets the heart in the correct place so it doesn’t move around the mediastinum
Epicardium
Visceral layer pericardium
coronary blood vessels
Myocardium
Cardiac muscle fibers
Tunica media
Endocardium
Connective tissue/endothelium
Tunica intima
Heart Papillary Muscles
Located in the ventricles, extend to the valve cusps.
3 papillary muscles in the right ventricle, corresponding to the tricuspid valve (3 cusps).
2 papillary muscles in the left ventricle, corresponding to the bicuspid (mitral) valve (2 cusps).
Prevents prolapse of the leaflets of the valves during ventricular contraction.
Heart Pectinate Muscels
Parallel ridges in the walls of the atria (similar to a comb).
Increase muscle contractions.
Heart Trabeculae Carnae
Rounded irregular muscular columns
Project from inner surface of ventricles
Increase muscular contractions
Myocardium
Muscular tissue of the heart.
Pumps the blood through the heart and out of the heart.
Nerves of the Heart
Right and left vagus nerves (parasympathetic)
Sympathetic cardiac nerve
Phrenic nerve
What is the pacemaker?
Sinoatrial node
Works independently. Does not need CNS stimulation to beat, needs sympathetic and parasympathetic nervous system.
Cardiac Conduction System
Generation and propagation of electrical signals → cardiac muscle contraction.
Sequence:
1. Sinoatrial node
2. Atrioventricular node
3. Atrioventricular bundle (bundle of HIS)
4. Left and Right bundle branches
5. Purkinje fibers
Electrocardiograph - p-wave, q-wave, qrs complex, t-wave
P-wave: Atrial depolarization (contraction)
Q-wave: Electrical signal through bundle of his and along upper part of septum.
QRS Complex: Spike - depolarization of ventricles (contraction)
T-wave: Repolarization of ventricles
