Middle Medistinum Flashcards
Mediastinum location
Located between the lungs, sternum, diaphragm, and verterbral column.
Mediastinum components
Heart, great vessels, trachea, esophagus, thymus, lymph vessels and nodes, nerves, vessels, and connective tissue.
Superior Mediastinum
Superior to a “line” above the T4/T5 intervertebral disc
Anterior Mediastinum
Between body of sternum and pericardial sac, superior to the diaphragm and inferior to the superior mediastinum
Posterior Mediastinum
Between pericardial sac anteriorly & T5-T12 vertebrae posteriorly
Middle Mediastinum
Pericerdial sac, heart, roots of the great vessels, phrenic nerve, pericardiacophrenic vessels, arch of azygos, and main bronchi
The heart is surrounded by the _____________
Pericardial sac
Pericardial sac is bound to the ____________
central tendon of the diaphragm
Pericardial sac is fused with the ___________
tunica adventitia (externa) of the great vessels
Pericardial sac anchors the __________
heart in the mediastinum
Pericardial sac prevents _________
overstretching of the heart
Outer surface of the pericardial sac
Fibrous Pericardium
Inner surface of the pericardial sac
Serous pericardium (parietal layer and a visceral layer)
Pericardial Fluid
Located between the parietal pericardium and visceral pericardium to allow the heart to move and beat in a frictionless environment
What supplies blood to and from the pericardial sac?
Pericardiophrenic vessels
What supplies blood to the visceral layer of the serous pericardium?
Coronary arteries
What drains blood from the serous pericardium?
Cardiac veins
Main source of sensory fibers (for pain sensations) to the pericardial sac?
Phrenic nerves (C3, C4, C5)
Provides sensory fibers to the visceral layer of the serous pericardium
Vagus Nerves
Apex of heart
pointed inferolateral, tip of left ventricle
Base of heart
Superior end of the heart, where great vessels enter/exit the chambers (mainly left atrium)
Epicardium
thin, transparent and adheres to the heart
Myocardium
muscular wall of the heart, cardiac muscle tissue responsible for the hearts pumping action
Endocardium
Provides smooth lining of the inside of the heart chambers and covers the valves of heart
internally separates the 2 atria
interarterial septum
internally separates the 2 ventricles
interventricular septum
internally separates the top and bottom halves of heart
atrioventricular (av) valves
Located between the right atrium and right ventricle
tricuspid valve
located between the left atrium and left ventricle
bicuspid/mitral valve
Abnormal sound that consisted of blowing or vibrating noise cause by turbulent heart flow
heart murmur
A heart murmur may indicate __________
a valve disorder (usually mitral valve)
Pulmonary circuit
occurs as the right side of the heart pumps oxygen poor/deoxy blood to the air sacs/alveoli of the lungs
Systemic circuit
occurs as the left side of the heart pumps freshly oxygenated/oxygen-rich blood into systemic circulation to all tissues of the body
Separates the smooth muscle from the pectinate muscle inside the atria
Crista Terminalis
Gas exchange occurs in the
capillaries around the walls of the lung alveoli, there the segmental arteries divide
Blood flow through the pulmonary and systemic circulation
- Flows into the heart (Low O2) via inferior/superior vena cava and coronary sinus to the right atrium
- Through tricuspid valve of right ventricle
- Through pulmonary semilunar valve into pulmonary trunk to pulmonary arteries to lungs
- CO2 is given off and O2 is taken up in capillaries/alveoli
- Blood flows into the heart from the pulmonary veins to the left atrium
- Through bicuspid valve to left ventricle
- Through aortic semilunar valve into the ascending aorta, then into various parts of the body
Blood supply to the myocardium is called the __________
coronary/cardiac circulation
Supplies blood to the myocardium and epicardium
coronary arteries
Travels left along the right ventricle toward the apex
right marginal branch
travels in the posterior interventricular sulcus toward the apex on the diaphragmatic side
posterior interventricular artery
travels in the anterior interventricular sulcus then around the apex
Anterior interventricular artery
Travels posteriorly in the coronary sulcus
circumflex artery
Narrowing of the coronary arteries sufficiently to prevent adequate blood supply to the myocardium
Coronary artery disease (CAD)
thickening, hardening, and loss of elasticity of the arterial walls
Arteriosclerosis
Deposition of plaque in the walls of medium and large arteries
Atherosclerosis
Heart attack! part of blood supply becomes blocked and cardiac muscle cells die from lack of oxygen
Ischemia/Myocardial Infarction/MI
What innervates the cardiovascular system?
the autonomic nervous system
Where is the cardiac plexus?
…………………
Nerve signals and hormones do __________ but do not ________.
modify the heartbeat; establish the fundamental rhythym
self excitable cells
auto-rhythmic cells
What is the function of the auto-rhythmic cells?
to repeatedly generate action potentials (impulses) that trigger heart contractions
The ________ ensures that the cardiac chambers contract in a coordinated manner
conduction system
Components of the conduction system
Sinoatrial (SA) node, atrioventricular (AV) node, & the conducting cells
Path of the Conduction System
slide 49
1-AutoRyth cells initiate cardiac AP (Atria Contract)
2-AV node receives APs from SA node
3-AV Bundle/Bundle of His receives APs from AV node
-Rt&Lft bundle branches receive APS from AV bundle
4-Rt&Lft bundle branches send APs tot he cardiac muscle cells (Purkinje fibers) that control and coordinate the heartbeat
5-Purkinje fibers send APs to the myocardium of the ventricles; the ventricles contract
Contraction
Systole
Relaxation
Diastole
all the activites of the heart through one complete “heartbeat”
Cardiac Cycle
device that can detect electrical currents generated by the heart from the surface of the body; records data as an _______
Electrocardiograph; electrocardiogram (ECG or EKG)
Cardiac Plexus
-receives both Sympathetic and Parasympathetic fibers
Location of the Cardiac Plexus
superior to the pulmonary trunk bifurcation, anterior to the tracheal bifurcation, and posterior to the ascending aorta
Origin of the Cardiac Plexus
Symp: inneravation arises form cervical and upper thoracic ganglia of sympathetic trunks
Parasymp: innervation comes from vagus nerve
Function of the Cardiac Plexus
Symp: stimulation causes increased heart rate and force of contraction, and dilation of coronary arteries
Parasymp: stimulation causes reduction of HR and force of contraction, and constriction of coronary arteries
