Middle Medistinum Flashcards by Jeremy Penn

Mediastinum location

Located between the lungs, sternum, diaphragm, and verterbral column.

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Mediastinum components

Heart, great vessels, trachea, esophagus, thymus, lymph vessels and nodes, nerves, vessels, and connective tissue.

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Superior Mediastinum

Superior to a “line” above the T4/T5 intervertebral disc

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Anterior Mediastinum

Between body of sternum and pericardial sac, superior to the diaphragm and inferior to the superior mediastinum

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Posterior Mediastinum

Between pericardial sac anteriorly & T5-T12 vertebrae posteriorly

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Middle Mediastinum

Pericerdial sac, heart, roots of the great vessels, phrenic nerve, pericardiacophrenic vessels, arch of azygos, and main bronchi

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The heart is surrounded by the _____________

Pericardial sac

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Pericardial sac is bound to the ____________

central tendon of the diaphragm

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Pericardial sac is fused with the ___________

tunica adventitia (externa) of the great vessels

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Pericardial sac anchors the __________

heart in the mediastinum

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Pericardial sac prevents _________

overstretching of the heart

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Outer surface of the pericardial sac

Fibrous Pericardium

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Inner surface of the pericardial sac

Serous pericardium (parietal layer and a visceral layer)

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Pericardial Fluid

Located between the parietal pericardium and visceral pericardium to allow the heart to move and beat in a frictionless environment

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What supplies blood to and from the pericardial sac?

Pericardiophrenic vessels

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What supplies blood to the visceral layer of the serous pericardium?

Coronary arteries

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What drains blood from the serous pericardium?

Cardiac veins

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Main source of sensory fibers (for pain sensations) to the pericardial sac?

Phrenic nerves (C3, C4, C5)

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Provides sensory fibers to the visceral layer of the serous pericardium

Vagus Nerves

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Apex of heart

pointed inferolateral, tip of left ventricle

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Base of heart

Superior end of the heart, where great vessels enter/exit the chambers (mainly left atrium)

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Epicardium

thin, transparent and adheres to the heart

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Myocardium

muscular wall of the heart, cardiac muscle tissue responsible for the hearts pumping action

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Endocardium

Provides smooth lining of the inside of the heart chambers and covers the valves of heart

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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