2026 gross anat- thoracic organs topic 22

what are the compartments of the thoracic cavity?

2 lateral compartments which contain the lungs and pleurae

1 central compartment that is called the mediastinum that contain heart, pericardium and great vessels

what does the 2 lateral compartments of the thoracic cavity contain?

lungs and pleurae

what does the central compartment of the thoracic cavity contain?

called the mediastinum and contains heart, pericardium and great vessels

where is visceral pleura?

adheres to the lung surface

where is parietal pleura?

adheres to the walls of the pulmonary cavities

parts are named to correspond to the parts of the wall with which they are associated with (ex. costal, diaphragmatic, and mediastinal parts)

what makes up the root of the lung?

a tubular sleeve like covering that is made up of mediastinal pleura

connects each lung into heart and trachea

what is the pleural cavity?

the potential space btwn the visceral and the parietal layers that contain a very thin layer of serous fluid

what is the fluid in btwn the visceral and parietal pleura?

serous fluid

what is the job of the serous fluid?

lubricates and allows the surfaces to slide over each other during breathing. also provides surface tension that keeps the lung surface in contact w the thoracic wall

where is the apex of the lungs?

proximal, above the level of 1st rib (into root of the neck)

where is the base of the lungs?

distal, level of 6th rib anteriorly, 8th rib laterally, and 10/11th rib posteriorly

how many lobes does the right lung have?

3

how many lobes does the left lung have?

2

what are the 3 lobes of the right lung called?

superior, middle, and inferior lobes

what are the 2 lobes of the left long called?

superior and inferior

what are the 2 fissures of the right lung called?

horizontal and oblique fissures

what is the fissure of the left lung called?

oblique

which lung has the lingula?

the left lung

which lung has the cardiac notch?

left lung

what are the 3 surfaces of the lungs?

costal, mediastinal, diaphragmatic

the trachea bifurcates at the level of the sternal angle into what?

the 2 main bronchi (right and left)

the trachea is held open by what?

c- shaped rings of hyaline cartilage

after the trachea bifurcates, which bronchi is shorter, wider and more vertical?

the right main bronchus

which bronchus is more likely to aspirate through? why?

the right

more vertical

after the bronchi, you enter where?

the root of the lung

what carries well-oxygenated blood away from lungs?

pulmonary veins

what brings poorly oxygenated blood towards the lungs?

pulmonary arteries

which nerve is the one that travels from brainstem and carries parasympathetic supply to bronchoconstrict, vasoconstrict and secretomotor (glands)?

the vagus nerve (CN 10)

in regards to the lungs, what part of the autonomic nervous system controls bronchoconstricting, vasoconstriction and secretomotor (glands)?

the parasympathetic nervous system

n regards to the lungs, what part of the autonomic nervous system controls bronchodilating, vasodilating and inhibiting glands?

sympathetic nervous system

what innervates the diaphragm?

the phrenic nerve c3, c4, c5

what is the mediastinum?

the central thoracic compartment that contains the heart, vessels, trachea, esophagus ect (everything but the lungs)

separates the right and left pleural cavities that contain the lungs

what is the pericardium?

a double walled sac around the heart that protects

what are the 2 parts of the pericardium?

the fibrous pericardium and the serous pericardium

where is the fibrous pericardium located?

outer external sac of the heart

where is the serous pericardium located?

inner layer of the heart sac

has parietal layer (inner) and visceral layer (outer)

what are the 3 layers of the heart muscles?

epicardium, myocardium, and endocardium

in regards to the heart muscles, the thin outer layer is called the

epicardium

in regards to the heart muscles, the middle layer is called the

myocardium

in regards to the heart muscles, the thin internal layer is called the

endocardium

the fibrous skeleton of the heart is dense collagen forming 4 rings that do what?

support the valves

the majority of the heart is located where?

2/3 of the heart is located to the left of the sternum

the base of the heart is located where?

at the level of the 3rd costal cartilages

the apex of the heart is located where?

at the level of the 5th intercostal space

the apex of the heart is formed by what?

the left ventricle

what are the 4 surfaces of the heart?

the sternocostal surface (anterior)

the diaphrgmatic surface (inferior)

left pulmonary surface (left ventricle lil left atrium)

right pulmonary surface (right atrium)

in regards to the pumping of the heart, diastole is when…

ventricles fill w blood

in regards to the pumping of the heart, systole is when…

ventricles contract and discharge blood

in regards to heart sounds, lub is

the closing of semilunar valves

in regards to heart sounds, dub is

closing of tricuspid and mitral valves

in regards to the vascular supply of the heart, the right and left coronary aa supplies what part of the heart?

the epicardium and myocardium

in regards to the vascular supply of the heart, what supplies blood to the endocardium?

blood in the heart

the right coronary artery (RCA) typically supplies what structures?

right atrium

most of right ventricle

SA node (60% people)

AV node (80% people)

and part of left ventricle and interventricular septum

the left coronary artery (LCA) typically supplies what?

left atrium

most of left ventricle

SA node (40% people)

AV node (20% people)

and part of the right ventricle

in regards to the venous flow of the heart, what is the main vein of the heart?

the coronary sinus which runs in the posterior coronary groove and empties into the right atrium

the sympathetic nerve fibers that innervate the heart, enter the spinal cord btwn t1-t4 levels, at t1-t4, somatic afferent nerves also enter from their respective dermatomes. if the brain misinterprets these signals, this is called…

referred pain

the SA node is aka what?

the widow maker

the SA node does what?

initiates and regulates the impulses for contraction

the AV node does what?

receives impulses from SA node