The Noted Anatomist Notes.pdf

Noted Anatomist Notes for Midterm #1 Thoracic Wall Anatomy: ● Thoracic Skeleton ○ Ribs ■ 12 pairs of ribs attach laterally to the 12 thoracic vertebrae ■ 7 true ribs, 3 false ribs, and 2 floating ribs ● True ribs (1-7) attach directly to the sternum by costal cartilage ● False ribs (8, 9, 10) attach...

Noted Anatomist Notes for Midterm #1 Thoracic Wall Anatomy: ● Thoracic Skeleton ○ Ribs ■ 12 pairs of ribs attach laterally to the 12 thoracic vertebrae ■ 7 true ribs, 3 false ribs, and 2 floating ribs ● True ribs (1-7) attach directly to the sternum by costal cartilage ● False ribs (8, 9, 10) attach indirectly to the sternum by superior costal cartilage ● Floating Ribs (11,12) no costal cartilage & do not articulate with the sternum ○ Costal Cartilage ■ Meaning ribs; it is hyaline cartilage that connects ribs to the sternum ■ Contributes to thoracic elasticity ● “Breathing” ○ Sternum ■ Made up of the manubrium, body and xiphoid process ■ Makes the jugular notch and the eternal angle ● Muscles of the trunk wall ○ Intercostal muscles ■ 3 layers of muscles segmentally located between the ribs and costal cartilage ■ External, internal, and innermost intercostal muscle layers ■ Attach b/w adjacent ribs ○ Actions ■ External IM: It elevates the ribs to increase lung volume and thus assists with inspiration/inhalation ■ Internal IM: It depresses the ribs to decrease volume and assists with expiration ■ Innermost IM: part closest to the costal parietal pleura and stiffens this space (sucked inwards) during inspiration/inhalation (keeps firm wall) Posterior and Superior Mediastinum ● The mediastinum is a point midway between the lungs anteriorly and sagittally it is between the sternum and vertebrae ● Posterior mediastinum ○ Is like the area b/w or living room TV; bunch of wiring ○ The P. Mediastinum contains the wiring for all the systems in the thorax ○ D.A.T.E.S → Descending aorta, azygos system of veins, thoracic duct, esophagus, sympathetics ○ Descending aorta: main “highway for delivery of oxygenated blood to the thorax” ○ Azygos Vein Systems: drain venous blood from posterior wall of the abdominal and thoracic cavities ■ Ascending Hemiazygous veins ■ Hemiazygos vein ■ Main vein and delivers deoxygenated blood to the SVC ○ Thoracic duct: largest lymphatic vessel; goes from abdominal to thoracic, to the next area; drains into systemic circ. ○ Esophagus: food delivery from pharynx (must pierce diaphragm before stomach); R&L vagus nerves travel within the esophagus and course along to/in the Celiac ganglion ○ Sympathetics: the sympathetic trunk spans the thoracic cavity superiorly to inferiorly ■ “Pearl” = “Symp gang” ■ “Pearl Necklace” = “Symp chain” ■ These are cell bodies of post ganglionic, sympathetic neuronal cell bodies → destined for sweat glands, head, neck, heart, and lungs ● Superior Mediastinum ○ 3 planes ■ Venous plane: collection of veins (like the R&L brachiocephalic vein) that eventually forms the SVC and dumps into the right atrium of the heart ● Thoracic duct: drains into the junction of the LIJ and LSV ■ Arterial Plane: system that supplies blood to the upper limbs and head/neck ■ Visceral Plane: essentially the trachea and esophagus Sternal Angle ● …is like “X” on a treasure map; the SA is the junction bw the manubrium and the sternum (163 degrees) ○ Also known as the “sternal angle of Louis” ○ Located at the T4/T5 junction ● “RAT PLANT” ○ Rib 2, Aortic arch, Tracheal bifurcation, Pulmonary trunk, Ligamentum arteriosum, Azygos vein, Nerves, Thoracic duct ○ Finding the sternal angle is even with the 2nd rib ■ Transverse Thoracic Plane (TTP) ○ Aortic arch begins and ends at TTP ○ Where trachea divides into the two main bronchi ○ Pulmonary trunk splits at TTP ○ Azygos vein dumps into the SVC at TTP ○ Nerves: where CN X “turns” into ascending and innervates laryngeal functions & contribute to autonomic cardiopulmonary plexus ○ Thoracic Lymphatic Duct: at TTP goes from right side of the body to the left and dumps into the left subclavian Intercostal V.A.N. ● Intercostal Vein ○ If drains posteriorly it drains into the azygos system ■ Drains “segmentally” ○ if draining anteriorly it will drain “segmentally” into the internal thoracic vein which goes to the brachiocephalic vein into the SVC ● Intercostal Arteries ○ Segmentally supply tissue w/in IC spaces and overlying skin ○ Anterior & Posterior IC Arteries ■ Posterior → come off from the aorta ■ Anterior → get blood from the internal thoracic artery ● Intercostal Nerves ○ Segmentally supply motor innervation to IC muscles and sensory innervation to underlying parietal pleura + overlying skin ○ Motor component innervates IC muscles ■ External IC ■ Internal IC ■ Innermost IC ○ Sensory nerves provide anterior and lateral sensory info from nerves that underlie the skin ○ The nerves are supplied from each level and that is what makes up the T1-T12 dermatomes The Anatomy of the Lungs: ● Right Lung ○ 3 lobes —> Upper, Middle, & Lower ○ U-M separated by horizontal fissure ○ M-L separated by Oblique Fissure ● Left Lung ○ 2 lobes —> Upper & Lower ○ Has the “Lingula” which would have developed into the middle lobe if not for the development of the heart ○ Has the “Cardiac Notch” ● Airways ○ Trachea ■ Bifurcates at Sternal Angle at a point called the Carina and becomes the right and left main bronchi ■ Right main bronchi is wider and shorter while left main bronchi is thinner and longer ■ Become secondary bronchi which split from the main bronchi to supply each of the respective lobes of the lungs ■ Lastly become tertiary bronchi which supply certain segments of the separate lobes ● Bronchopulmonary segment: section of a pulmonary lobe that is supplied by a single tertiary bronchus ● Innervation ○ Sympathetic Innervation ■ Arises from T1-T4 levels ■ Bronchodilation ○ Parasympathetic Innervation ■ Arises from the medulla ■ Bronchoconstriction ● Bronchioles ○ Made of cartilage and smooth muscles which is what the sympathetic and parasympathetic systems affect (dilate/constrict) ○ These “control” how much O2 is getting to the blood in the Alveolar sacs ○ Pulmonary arteries from the right side of the heart bring deoxygenated blood to the pulmonary capillaries where gas exchange happens ○ O2 brought in and courses to the pulmonary veins while CO2 is diffused out towards the bronchioles and out the trachea to the outside world The Heart: ● Pericardial Sac - double walled sac ○ 2 layers (fibrous and serous) ■ Fibrous - outside (parietal pericardium); prevents from overfilling ■ Serous - inner-side (parietal pericardium); has two layers (parietal & visceral); ○ Adheres to the outside of the heart ○ Pericardial space = full of fluid that lubricates the heart (water-like) ● Heart Chambers ○ SVC ■ Vein that delivers deoxygenated blood from tissues above the diaphragm to the Right Atrium ○ IVC ■ Vein that delivers deoxygenated blood from all tissues below the diaphragm to the RA ○ Coronary Sinus ■ Delivers deoxygenated blood from myocardium (coronary circulation) to the RA ○ Right Atrium ■ Receives all deoxygenated blood from the body (from SVC, IVC, coronary sinus) ■ Contains the fossa ovalis - fetal development remnant ■ Forms the right border of the heart ○ Tricuspid Valve ■ “Tri” to be “right” ■ Right AV Valve ■ Opens to let blood flow to the Right Ventricle from the Right atrium ■ Closes during systole to prevent backflow ○ Right Ventricle ■ Pumps deoxygenated blood (from RA) into the pulmonary trunk → pulmonary arteries → lungs ■ Forms anterior border of the heart ● Heart Valves ○ AV Valves ■ Atrium to the Ventricle ■ Papillary muscles (extension of myocardium) and are connected to the AV valve via chordae tendineae (dense connective tissue); ■ Function: enable blood flow from A-V during DIASTOLE and prevent backflow from V-A during SYSTOLE ■ “Lub” of the “lub-dub” sound (1st heart noise) ■ Chordae tendineae ensures that AV leaflets do not prolapse; otherwise, regurgitation of blood into the atrium ○ Pulmonary Valve ■ Most anterior heart valve; semilunar valve ■ Opens to let blood flow from RV-PA ■ Closes during diastole; prevents backflow into the ventricle ○ Semilunar Valves ■ Enable blood to flow out of ventricles ■ Prevent blood from regurgitating back into the ventricles ■ Second heart sound (“dub”) ○ Pulmonary arteries ■ Transports deoxygenated blood from RV to the lungs (only artery in the adult that transports DEOXYGENATED BLOOD) ■ Still Artery = Away ● Pulmonary Capillaries ○ Pulmonary arteries send blood to bronchioles where O2 is inhaled and then gas exchange occurs in the alveolar sacs (terminal airspace) ○ During exhalation, CO2 diffuses into the alveolar sacs while oxygen is diffused into the pulmonary capillaries and sent back to the heart (LA) to be delivered to the rest of the body ● Pulmonary Veins ○ Transports oxygenated blood from the lungs to the LA (only vein in the adult that does this) ○ Makes up the posterior side of the heart and can see both pulmonary veins dumping into the LA ● Left Atrium (LA) ○ Receives O2 blood from the lungs and forms the posterior border of the heart ○ Rests against the esophagus in the thoracic cavity ● Bicuspid Valve ○ AKA mitral valve, left AV valve ○ Opens to let blood flow from the LA to the LV ○ Closes during systole; prevents backflow of blood into the LA ○ Chordae Tendineae involved again (Atrioventricular type valve) ○ 1st heart sound again (“Lub”) ● Left Ventricle ○ Receives O2 blood from LA and pumps it into the aorta ○ Has thicker myocardium than the right ventricle because of the mean arterial pressure needed to pump blood to the whole body is greater than the RV where it is only pumping to the pulmonary trunk ○ Forms left border and the APEX of the heart ● Aortic Valve ○ Opens to let blood flow from LV-Aorta ○ Posterior to the pulmonary valve ○ Can see the left and right coronary arteries coming off of it ○ Closes during diastole; prevents backflow into the LV ○ Second heart sound ● Aorta ○ Delivers blood to systemic and coronary circulations ○ Largest artery in the body ● Coronary circulation ○ Blood supply for the heart; heart pumping blood into the heart and the heart pumping blood back into the heart… (is confusing right, but makes sense) ○ LV-Aorta —> coronary circulation —> myocardium —> cardiac veins —> RA ○ Right coronary artery (RCA) - supplies the right side of the heart; forms the coronary sulcus around the heart ■ Gives rise to the SA nodal artery = blood to the SA node (pacemaker of the heart) ■ Also the Posterior Descending Artery (PDA) which supplies the posterior IV septum ○ LCA - supplies left side of the heart with blood ■ Doesn’t really supply much blood ■ Gives rise to the LAD and LCX ● LAD - left anterior descending artery; supplies anterior IV septum & apex ● LCX - left circumflex artery; supplies the left lateral wall ○ Coronary sinus - drains all of the heart ■ Great cardiac vein - empties what the LAD delivered ■ Middle and small cardiac veins - drains same area as the RCA supplies ■ Eventually dumps into the Vena cava and then the RA ■ Minor roles controlled by: ● Sympathetic Input (NE) = vasodilation ● Parasympathetic Input (ACh) = vasoconstriction ■ Mainly controlled by “local metabolites” (hypoxia, adenosine)