Cardiovascular & Respiratory Anatomy - HWDP 131 Fall 2024 PDF

Cardiovascular & Respiratory Anatomy HWDP 131 Fall 2024 Meghan M. Newcomer, PhD [email protected] A BRIEF INTRODUCTION TO ANATOMY ‘SPEAK’  All anatomical descriptions are expressed in relation to one consistent position… anatomical position...

Cardiovascular & Respiratory Anatomy HWDP 131 Fall 2024 Meghan M. Newcomer, PhD [email protected] A BRIEF INTRODUCTION TO ANATOMY ‘SPEAK’  All anatomical descriptions are expressed in relation to one consistent position… anatomical position 4 main imaginary lines, planes, intersect the body in anatomical position Sagittal Coronal Transverse Oblique  Midline Key directional terms: Medial: Lateral: Superior/cranial: Inferior/caudal: Anterior/ventral: Posterior/dorsal: Superficial: Deep: Proximal: Distal: Supine: Prone:  Key directional terms related to joints: Flexion: bending or decreasing the angle between the bones or parts of the body Extension: straightening or increasing the angle between the bones or parts of the body Abduction: moving away from the median plane Adduction: moving toward median plane  Almost all muscles extend between bones Every muscle has an origin and an insertion What’s the difference? Origin: usually the proximal end of the muscle, which remains fixed during muscular contraction Insertion: usually the distal end of the muscle, which is movable.  Common abbreviations for structures: Muscle: m. or mm. Artery: a. or aa. Vein: v. or vv. Nerve: n. or nn. Common Latin/Greek phrases (we’ll give you more as the year continues): Soma (somatic): Parietal: Visceral: Chondro-: Costo-: Phren-: Pulm- (pleu-, pneu-):  Plexus (braid): Anastomosis: Venous Nerve plexus plexus  Anatomy atlases and texts demonstrate the most common patterns observed in people; however, anatomical variation is incredibly common There are some structures that are so variable that the ‘common’ pattern is found less than half the time Veins are the most variable structure in the body, nerves the least variable Great resources (that you should have access to through the CWRU library): Moore’s Clinically Oriented Anatomy Gray’s Anatomy for Students Rohen’s Color Atlas of Anatomy https://sites.google.com/a/umich.edu/bluelink/resources/bluelink https://videos.med.wisc.edu/events/65 Outline ▪ Thoracic Wall ▪ Diaphragm ▪ Pleura & Pleural Cavity ▪ Lungs & Bronchi ▪ Mediastinum ▪ Pericardium ▪ Heart  Learning Objectives 1) Understand the structural and functional roles of the thoracic structures (i.e. skeleton, muscles, pleura). 2) Describe the location of the various organs within the thoracic cavity (lungs, heart, great vessels) and their relationship to one another. 3) Describe the innervation of the diaphragm. 4) Understand the structure of the lung and associated structures (e.g. bronchi, pulmonary vessels). 5) Understand the difference between the hilum and root of the lung. Describe what structures are found at each. 6) Describe the mediastinum and its subdivisions. 7) Understand the structure and function of the pericardium. 8) Describe each of the chambers of the heart. Describe the unique characteristics of each. 9) Understand the function of the papillary muscles and chordae tendineae in the ventricles of the heart. 10)Describe how blood flows through the heart and the role of the atrioventricular and semilunar valves. 11)Understand the difference between the extrinsic and intrinsic innervation of the heart. Thorax ▪ Thorax – superior part of trunk between neck & abdomen Thoracic cavity contains heart, lungs, thymus, distal part of trachea, & most of esophagus Thoracic wall consists of skin, fascia, neurovasculature, muscles, cartilages, & bones; functions to: ▪ Protect thoracic structures ▪ Resist negative internal pressures from elastic recoil of lungs & inspiratory movements ▪ Provide attachment & support for upper limbs, muscles of neck, abdomen, back, & muscles of respiration Skeleton of Thoracic Wall ▪ Thoracic skeleton: 12 pairs of ribs & costal cartilages Thoracic vertebrae (T1-T12) & IV discs Sternum Ribs ▪ 12 pairs of ribs 1-7 (True Ribs) 8-10 (False Ribs) 11 & 12 (Floating Ribs) Ribs ▪ Costal cartilages Flexible attachment for anterior ends of ribs to sternum 1st – 7th costal cartilages attach directly to sternum 8th, 9th, & 10th indirectly attach to sternum via costal cartilage above 7th-10th costal cartilages form costal margin  Ribs ▪ Typical rib Head – articulates with body of vertebrae Neck – connects head of rib with body Tubercle – at junction of neck and body; articulates with transverse process of vertebra Body – largest portion of rib; thin, flat, & curved, most markedly at costal angle Sternum Sternum Manubrium Body Xiphoid process Landmarks ▪ Jugular (suprasternal) notch On superior aspect of manubrium Trachea lies deep to notch ▪ Sternal angle (of Louis) Manubrium & body lie in slightly different planes superior/inferior to junction (manubriosternal joint) forming a projecting angle → Sternal angle (of Louis) Landmark for: bifurcation of pulmonary trunk, aortic arch, bifurcation of trachea; point of articulation of 2nd ribs At level of T4-T5 IV disc ▪ Xiphoid process Midline marker for superior extent of liver, central tendon of diaphragm, and inferior border of heart Thoracic Apertures ▪ Superior Thoracic Aperture (Thoracic Inlet) Structures passing through: trachea, esophagus, vessels, nerves Bounded by: T1 vertebra, first pair of ribs & costal cartilages, superior border of manubrium ▪ Inferior Thoracic Aperture (Thoracic Outlet) Closed by diaphragm, separating thorax from abdomen Structures passing between thorax & abdomen pass through openings in diaphragm Bounded by: T12 vertebra, 11th & 12th ribs, costal margin, xiphisternal joint Thoracic Wall Muscles ▪ Some muscles attached to and/or covering thoracic cage are primarily involved in serving other regions HOWEVER, they also serve as accessory muscles of respiration (e.g. pectoralis major & minor, anterolateral abdominal muscles) Thoracic Wall Muscles ▪ True muscles of thoracic wall are: *Intercostal mm. Serratus posterior mm. levatores costarum mm. Transversus thoracis mm. Subcostal mm. Intercostal Muscles ▪ External intercostals Run from inferior border of rib above to superior border of rib below Extend from vertebral column to external intercostal membranes (anterior) Fibers directed obliquely downward from lateral to medial (“hands in a pocket”) Assist with inspiration by elevating the ribs Intercostal Muscles ▪ Internal intercostals Fibers run inferior border of rib above to superior border of rib below Runs from sternum to angles of ribs where they are replaced by the internal intercostal membranes Runs deep to & at right angles to external intercostals Assist with expiration by depressing ribs Intercostal Muscles ▪ Innermost intercostals Fibers run inferior border of rib above to superior border of rib below Lie deep to internal intercostals and have same fiber direction Assist with expiration by depressing the ribs Other Thoracic Wall Muscles ▪ Serratus posterior superior ▪ Serratus posterior inferior ▪ Levatores costarum ▪ Subcostal ▪ Transversus thoracis Thoracic Wall: Arteries ▪ Anterior & Posterior intercostal arteries anastomose together 1) Anterior intercostal aa. – originate directly or indirectly from internal thoracic artery Upper 6: arise from internal thoracic a. Lower 5: arise from musculophrenic a. (branch of internal thoracic) Thoracic Wall: Arteries ▪ Anterior & Posterior intercostal arteries anastomose together 2) Posterior intercostal aa. – majority arise from thoracic aorta Upper 2: arise from supreme intercostal a. (branch of costocervical trunk from subclavian a.) Lower 9: arises from thoracic aorta Thoracic Wall: Veins ▪ Anterior & Posterior Intercostal veins anastomose together Anterior intercostal veins – tributaries of internal thoracic veins Posterior intercostal veins – most are tributaries of the azygos/hemiazygous venous system Thoracic Wall: Neurovasculature ▪ Intercostal vein, artery, & nerve: Lie in costal groove along inferior margin of rib Pass in plane between internal & innermost intercostal mm. ▪ Collateral nerve, artery, & vein: Arise from intercostal nerves & vessels Located at superior margin of rib below Diaphragm ▪ Diaphragm – primary muscle of respiration Sheet of skeletal muscle that separates thoracic cavity from abdominal cavity Descends during inspiration → increases volume of thoracic cavity & decreases intrathoracic pressure, resulting in air being taken into the lungs Diaphragm ▪ Diaphragm Attaches to sternum, ribs, & lumbar vertebrae Aponeurotic central tendon Diaphragm ▪ Crura – musculotendinous bands that arise from anterior surfaces of bodies of L1-L3 Right Crus – opening within right crus forms esophageal hiatus Left crus Diaphragm ▪ Diaphragmatic apertures – permit structures to pass between thorax & abdomen Caval opening – aperture for inferior vena cava within central tendon; lies at vertebral level T8 Esophageal hiatus – aperture for esophagus within right crus; lies at vertebral level T10 Aortic hiatus – opening for aorta posterior to diaphragm; lies at vertebral level T12 “I Ate (8) 10 Eggs At Noon (12)” Diaphragm ▪ Diaphragm innervation Motor & Sensory: Phrenic nn. (C3-C5) Diaphragm ▪ Phrenic n. (C3-C5) Causes diaphragm to contract with inspiration → flattens diaphragm & increases thoracic volume Courses along fibrous pericardium → supplies it with sensory innervation  Pleura ▪ Each pulmonary cavity is lined by pleura (thin, serous membrane) that also reflects onto & covers surface of lungs Visceral pleura covers lung & adheres to all its surfaces Parietal pleura lines the pulmonary cavities  Pleura ▪ Pleural cavity – potential space between the two layers of pleura Contains a very thin layer of serous fluid that lubricates pleural surfaces Serous fluid allows the two layers of pleura to slide smoothly over each other during respiration Pleurae  Lungs ▪ Lungs – organs of respiration; main function is to oxygenate the blood Apex – blunt superior end ascending above 1st rib into neck Base – concave inferior surface, resting on diaphragm 3 surfaces: ▪ Costal surface ▪ Mediastinal surface Hilum – where structures of the root of the lung enter/exit ▪ Diaphragmatic surface  Lungs ▪ Right lung Lobes: Superior, Middle, Inferior Fissures : Horizontal & Oblique Lungs ▪ Left lung Lobes: Superior & Inferior Cardiac notch – indentation formed from apex of heart Lingula – thin, tongue-like process of superior lobe Fissures: Oblique  Lungs ▪ Root of the Lung – structures passing from mediastinum into/out of the lung Pulmonary veins Pulmonary arteries Bronchi Pulmonary plexus of nerves Lymphatics ▪ Hilum of the lung – region on mediastinal surface where structures forming the root pass to enter/exit the lung  Lungs “R A L S” Right Anterior Left Superior *Relationship of pulmonary artery to bronchus Lungs Bronchi ▪ Trachea divides into *right & left main (primary) bronchi, which then split into: Lobar (Secondary) bronchi ▪ 3 in right lung & 2 in left lung *Right main bronchus is shorter, Segmental (Tertiary) bronchi wider, & more vertical than left → right main bronchus more prone to ▪ 8-10 segmental bronchi entrance of aspirated foreign bodies Lungs: Innervation ▪ Innervation to the lungs is derived from the pulmonary plexuses located anterior & posterior to the roots of the lungs Pulmonary plexuses – nerve networks that contain parasympathetic & sympathetic fibers Autonomic Nervous System ▪ Autonomic nervous system – part of PNS that innervates smooth muscle, cardiac muscle, & glands Subdivided into Sympathetic & Parasympathetic systems → often act in antagonistic fashion to regulate blood flow, secretions, & organ function 2-neuron pathway: Presynaptic neuron – within CNS (brainstem or spinal cord) Postsynaptic neuron – within PNS (ganglia)  Autonomic Nervous System ▪ Parasympathetic – primarily concerned with maintenance, conservation, & protection of body resources (“Rest, Digest, Read”) Vagus nerve (CN X) joins cardiac, pulmonary, & esophageal plexuses to supply thoracic viscera Autonomic Nervous System ▪ Sympathetic – principally involved with expenditure of body resources or energy (“Fight or Flight”) Cardiopulmonary splanchnic nerves (from sympathetic chain) enter cardiac, pulmonary, & esophageal plexuses to supply thoracic viscera Lungs: Innervation ▪ Parasympathetic Smooth muscle of the bronchial tree → Bronchoconstriction Pulmonary vessels → Vasodilation Glands of bronchial tree → Secretomotor ▪ Sympathetic Smooth muscle of bronchial tree → Bronchodilation Pulmonary vessels → Vasoconstriction Glands of bronchial tree → Inhibitory Mediastinum ▪ Mediastinum – central compartment of thoracic cavity located between the two pulmonary cavities Contains all of the thoracic viscera & structures (*except lungs) Divided into superior inferior portions at the transverse thoracic plane (T4/T5) Transverse thoracic plane Superior Mediastinum ▪ Superior mediastinum – superior to transverse thoracic plane Superior Mediastinum ▪ Contents: Aortic arch & its branches Left & right brachiocephalic veins (becoming the superior vena cava) Bifurcation of the trachea Esophagus Phrenic nerves Vagus (CN X) nerves ▪ Left recurrent laryngeal nerve Inferior Mediastinum ▪ Inferior mediastinum – extends between transverse thoracic plane and diaphragm Can be further subdivided by pericardium into Anterior, Middle, & Posterior mediastinum Anterior Mediastinum ▪ Anterior mediastinum Between body of sternum & pericardium; extends inferiorly to diaphragm Consists mainly of thymus (in children), loose connective tissue, fat, lymphatic vessels, lymph nodes, internal thoracic vessel branches Middle Mediastinum ▪ Middle mediastinum Situated between pulmonary cavities; extends to diaphragm Middle Mediastinum ▪ Middle mediastinum Consists of the pericardium, heart, roots of great vessels (ascending aorta, pulmonary trunk, superior vena cava), phrenic nerves Posterior Mediastinum Posterior mediastinum Between pericardium & vertebral column, extending to diaphragm Posterior Mediastinum Posterior mediastinum Contains esophagus, azygous system of veins, thoracic aorta, thoracic duct, sympathetic trunk/chain, splanchnic nerves Right Lateral View Left Lateral View Pericardium ▪ Pericardium – fibroserous membrane that covers the heart & beginning of the great vessels  Pericardium ▪ Pericardium is a closed sac composed of two layers: 1) Fibrous pericardium – tough outer connective tissue layer; attached to central tendon of diaphragm 2) Serous pericardium – inner layer composed mainly of mesothelium (single layer of flattened epithelial cells) Parietal layer – lines inner surface of fibrous pericardium Visceral layer (epicardium) – covers surface of heart Pericardial Cavity ▪ Pericardial cavity – potential space between parietal & visceral layers of serous pericardium Normally contains thin film of serous fluid that limits friction for beating heart Cardiac tamponade: ❖ Collection of excess fluid within pericardial cavity ❖ Life-threatening; fluid compresses heart, preventing heart chambers to fill properly with blood Pericardial Sinuses ▪ Parietal layer of serous pericardium is continuous with visceral layer around roots of great vessels → these reflections of serous pericardium occur in two locations: 1) Transverse pericardial sinus 2) Oblique pericardial sinus Pericardial Sinuses ▪ Transverse pericardial sinus – transversely running passage within pericardial cavity Posterior to ascending aorta & pulmonary trunk; anterior to SVC & superior pulmonary veins Important for cardiac surgery: finger can be passed through transverse sinus posterior to ascending aorta & pulmonary trunk, allowing placement of surgical clamp/ligature Pericardial Sinuses ▪ Oblique pericardial sinus – inverted U-shaped cul-de-sac between the pulmonary veins & IVC Placing hand under apex of heart and moving superiorly will enter oblique sinus Heart ▪ Heart – four chambered muscular pump responsible for circulating blood to both lungs (pulmonary circulation) & the rest of the body (systemic circulation) Right side (pulmonary circuit) – receives poorly oxygenated (venous) blood from the body via SVC & IVC & pumps it through pulmonary trunk & arteries to lungs for oxygenation Left side (systemic circuit) – receives well-oxygenated (arterial) blood from lungs via pulmonary veins & pumps it into aorta for distribution to body Heart Chambers ▪ 4 chambers: Right/Left Atria & Right/Left Ventricles Atria are receiving chambers that pump blood into the ventricles → the discharging chambers Synchronous pumping actions of the right & left chambers (atrioventricular pumps) constitute the cardiac cycle Atria ▪ Right atrium Receives venous blood from SVC, IVC, & coronary sinus Auricle → ear-like muscular pouch projecting from right atrium; increases atrial capacity Atria ▪ Right atrium Interior: ▪ Smooth, thin-walled posterior part (sinus venarum) where SVC & IVC and coronary sinus open ▪ Rough, muscular anterior wall composed of pectinate muscles ▪ Crista terminalis – internal vertical ridge that separates the rough vs. smooth parts of R. atrium ▪ Fossa ovalis (oval fossa) – remnant of foramen ovale (opening in fetus that acts as a shunt, allowing blood to pass directly from right atrium to left atrium, bypassing the lungs) Atria ▪ Left Atrium Larger smooth-walled part & smaller auricle containing pectinate muscles Pulmonary veins (2 superior and 2 inferior) enter smooth posterior wall Ventricles ▪ Right Ventricle Trabeculae carneae – roughened muscular ridges on inner surface of wall Papillary muscles – conical muscular projections that attach to cusps of the atrioventricular (AV) valves via chordae tendineae ▪ During ventricular contraction, papillary muscles contract, helping keep valves closed ▪ 3 papillary muscles in right ventricle: Anterior, Posterior, Septal Ventricles ▪ Left Ventricle Forms apex of heart Walls 2-3X thicker that those of right ventricle (pressure higher in systemic vs. pulmonary circulation) Trabeculae carneae thinner & more numerous 2 papillary muscles: Anterior & Posterior  Heart Valves ▪ Atrioventricular (AV) valves: 1) Tricuspid (Right Atrioventricular) Valve 3 cusps: anterior, septal, posterior Associated with papillary muscles Prevents blood from backflowing from right ventricle to right atrium  Heart Valves ▪ Atrioventricular (AV) valves: 2) Mitral (Bicuspid, Left Atrioventricular) 2 cusps: anterior, posterior Associated with papillary muscles Prevents blood from backflowing from left ventricle into left atrium  Heart Valves ▪ Semilunar valves: 1) Pulmonary (semilunar) valve 3 semilunar cusps (anterior, right, left) Prevents backflow of blood from pulmonary circulation into right ventricle  Heart Valves ▪ Semilunar valves: 2) Aortic (semilunar) valve 3 semilunar cusps (posterior, right, left) Prevents backflow of blood from systemic circulation into left ventricle Innervation of Heart: Intrinsic Intrinsic innervation: ▪ Sinu-atrial (SA) node Pacemaker → initiates & regulates impulses for contractions of the heart; gives off impulse ~70 times/minute Located at superior end of crista terminalis, at junction of SVC & right atrium Conduction signal spreads through musculature of both atria down to the AV node Innervation of Heart: Intrinsic Intrinsic innervation: ▪ Atrioventricular (AV) node Located in posteroinferior region of interatrial septum near opening of coronary sinus Distributes the signal to ventricles via AV bundle (bundle of His) →splits into Right & Left bundle branches ❖ Septomarginal trabecula (moderator band) – muscular bundle running from (Purkinje fibers) interventricular septum to base of anterior papillary muscle; carries right bundle branches to anterior papillary muscle Right/Left bundle branches give rise to Purkinje fibers which stimulate the papillary muscles & ventricle walls Innervation of Heart: Extrinsic Extrinsic Innervation: ▪ Autonomic nerve fibers are responsible for regulating heart rate, force of each contraction, & cardiac output Cardiac plexus: ▪ Parasympathetic (from vagus nerve) – slows the heart rate & reduces force of contraction ▪ Sympathetic (from sympathetic trunk) – increases heart rate & increases force of contraction Cardiac Plexus Innervation of the Heart Questions? 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