Chapter 4: Heart and Lungs Flashcards
Thoracic cage
-surrounds and supports organs in thoracic cavity and superior abdominal cavity
-provides support for upper limbs
-plays a role in breathing
Superior thoracic aperture
-structures passing between thoracic cavity and neck pass through this
Inferior thoracic aperture
-structures passing between thoracic cavity and abdominal cavity
Sternum
-breastbone
What structures does the sternum contain
-manubrium
-body
-xiphoid process
-sternal angle
-suprasternal (jugular) notch
-clavicular notches
What does manubrium articulate with
-first and second ribs
What do clavicular notches articulate with
-clavicles to form sternoclavicular joints
How many pairs of ribs are there in total
12
What are the true ribs
1-7
What are the false ribs
8-12
Vertebrocostal ribs
-pairs 8-10
-attach indirectly to the sternum
-attach to costal cartilages and articulate indirectly with the 7th costal cartilage
Floating ribs
-only attach posteriorly to the thoracic vertebrae as they do not attach to the sternum in any manner and are particularly short
-they do not have a neck or tubercle
Surface features of ribs
-head
-neck
-tubercle
-body
-costal angle
-costal groove
Intercostal spaces
-spaces between neighbouring ribs
Why is rib 1 atypical
-shortest true rib
-single facet on head
-lacks angle and costal groove
-has 2 grooves for subclavian vessels
-scalene tubercle
Why is rib 2 atypical
-tuberosity for serratus anterior muscle
Why is rib 10 atypical
-single facet on head
Why is rib 11 atypical
-single facet on head
-short neck
-lacks tubercle
-has a slight costal groove
Why is rib 12 atypical
-single facet on head
-lacks tubercle, angle and costal groove
Costovertebral joints
-costal demifacets: on vertebrae T1-T9
-costal facets: on vertebrae T1 and T10-T12
-on heads of ribs 1-12
Costotransverse joints
-on tubercle of ribs 1-10
-transverse costal facets: on transverse processes of matching vertebrae
Ligaments of the costovertebral joint
-fibrous capsule
-radiate and intraarticular ligaments
-only on joints 2-9
Ligaments of the costotransverse joint
-fibrous capsule
-medial costotransverse
-superior costotransverse
-lateral costotransverse
Movements of the costovertebral joints
-internal rotation and elevation of head of rib
Movements of costotransverse joints 1-6
-internal rotation of neck of rib
Movements of costotransverse joints 7-10
-posteromedial translation of neck of rib
Arteries of the intercostal space
-internal thoracic artery
-anterior intercostal arteries
-posterior intercostal arteries
-subcostal artery
Veins of the intercostal space
-anterior intercostal veins
-posterior intercostal veins
-subcostal vein
Nerves of the intercostal space
-intercostal nerves
-subcostal nerve
External intercostal muscles
-origin: inferior border of one rib
-insertion: superior border of immediate rib below
-innervated by intercostal nerves
-elevate the ribs
Internal intercostal muscles
-origin: costal groove of one rib
-insertion: superior border of immediate rib below
-innervated by intercostal nerves
-depress the ribs
Innermost intercostal muscles
-origin: costal groove of one rib
-insertion: superior border of immediate rib below
-innervated by intercostal nerves
-depress the ribs
Transversus thoracic muscle
-origin: inferoposterior surface of body of sternum and xiphoid process and sternal ends of costal cartilage of ribs 4-7
-insertion: internal surface of costal cartilages of ribs 2-6
-depresses ribs and supports intercostal spaces and thoracic cage
Diaphragm sternal part origin
-posterior aspect of xiphoid process
Diaphragm costal part origin
-internal surfaces of lower costal cartilages and ribs 7-12
Diaphragm lumbar part origin
-medial and lateral arcuate ligaments, bodies of vertebrae L1-L3 and anterior longitudinal ligament
Diaphragm insertion
-central tendon of diaphragm
Openings of the diaphragm
-aortic hiatus
-esophageal hiatus
-caval foramen
-openings for greater and lesser splanchnic nerves, and superior epigastric vessels
Recesses of the diaphragm
-costo-diaphragmatic recess
-costomediastinal recess
Innervation of the diaphragm
-phrenic nerves (C3-C5)
-sensory innervation of peripheries via 6th-11th intercostal nerves
Blood supply of the diaphragm
-lowest 5 intercostal arteries
-subcostal arteries
-superior phrenic arteries
Function of the diaphragm
-main muscle responsible for respiration
-increases abdominal pressure during defecation, vomiting and voiding
-applies pressure on the esophagus to prevent acid reflux
Parts of the abdominal surface of the diaphragm
-skeletal muscle
-central tendon
Openings of the abdominal surface of the diaphragm
-aortic hiatus
-esophageal hiatus
-caval foramen
Innervation of the abdominal surface of the diaphragm
-left and right phrenic nerves (C3-C5)
Blood supply of the abdominal surface of the diaphragm
-left and right phrenic arteries (branches of the abdominal aorta)
Where is the heart located
-between the lungs and in the mediastinum
-about 2/3 of it lies in the bodys midline
Surfaces of the heart
-anterior surface
-inferior surface
-right surface
-left surface
Surface projection
-refers to the outlining of the dimensions of an organ on the surface of the body
Surface projection points of the heart
-superior right point
-superior left point
-inferior right point
-inferior left point
Pericardium
-sac that surrounds and protects the heart
Portions of the pericardium
-fibrous pericardium
-serous pericardium
Superficial fibrous pericardium
-prevents overstretching of the heart
-provides protection
-anchors heart to mediastinum
Deep serous pericardium layers
-outer parietal layer
-inner viceral layer
Outer parietal layer
-lines inside of the fibrous pericardium
Inner visceral layer
-adheres to hearts surface
Pericardial cavity
-between parietal and visceral serous pericardial layers
-contains pericardial fluid
Pericardial fluid
-lubricating fluid that reduces friction between the membranes as the heart moves
Layers of the heart wall
-outer epicardium
-middle myocardium
-innermost endocardium
Outer epicardium
-visceral layer of the serous pericardium
Middle myocardium
-composed of thick cardiac muscle tissue
Innermost endocardium
-composed of connective tissue covered by endothelium that is continuous with the endothelium of the blood vessels
Chambers of the heart
-right atria
-left atria
-right ventricle
-left ventricle
Auricle
-structure in the atrias
-allows atrium to hold a larger volume of blood
Where do atria receive blood from
-receive blood from major systemic veins and pulmonary veins
Where do ventricles pump blood to
-pump blood into systemic and pulmonary
Pulmonary pump
-consists of the right atrium and right ventricle
-pumps blood towards the lungs
Systemic pump
-consisting of the left atrium and left ventricle
-pumps oxygenated blood towards the rest of the body
Major grooves of the surface of the heart
-coronary sulcus
-anterior interventricular sulcus
-posterior interventricular sulcus
Right atrium
-receives deoxygenated blood from 3 veins
-superior vena cava
-inferior vena cava
-coronary sinus
Superior vena cava
-brings blood from most parts of the body superior to the heart
Inferior vena cava
-brings blood from all parts of the body inferior to the diaphragm
Coronary sinus
-brings blood from most of the vessels draining the wall of the heart
Pectinate muscles
-internal parallel ridges on the superior and right atrial walls
Crista terminalis
-smooth muscular ridge in the superior portion of the right atrium
-divides the musculi pectinati and the right atrial appendage from the smooth surface of the right atrium
Interatrial septum
-on the interior of the heart
-separates the atria
-has an oval depression called fossa ovalis
Right atrioventricular valve (tricuspid valve)
-blood in right atrium flows into right ventricle through
Trabeculae carnae
-irregular surface of ridges on inner surface of right ventricle
Chordae tendinae
-ensure that the cusps of the tricuspid valve permit blood to flow into the right ventricle but prevent backflow of blood into right atrium
Interventricular septum
-separates the 2 ventricles
Where does the left atrium receive blood from
-receives oxygenated blood from the lungs via four pulmonary veins
Atrioventricular valve (bicuspid)
-blood in the left atrium flows into left ventricle through this
What forms the apex of the heart
-left ventricle
Trabeculae carnae
-irregular surface of ridges on the inner surface of the left ventricle
Aortic valve flow
-left ventricle pumps oxygenated blood through aortic valve into the ascending aorta
Left and right coronary arteries
-ascending aorta gives rise to these
-they deliver blood to the walls of the heart
Ductus arteriosus
-during fetal life this structure shunts blood from pulmonary trunk to aorta
-shortly after birth this closes
Ligamentum arteriosum
-remnant of ductus arteriosus after it closes
Myocardial walls of atria function
-relatively thin
-pump low pressure blood into ventricles
Myocardial walls of ventricles function
-relatively thick
-pump high pressure blood greater distances
Which ventricle has a thicker wall
-left
Fibrous skeleton of heart
-dense connective tissue of the heart wall
Fibrous skeleton of the heart tissue rings
-right atrioventricular ring
-left atrioventricular ring
-pulmonary fibrous ring
-aortic fibrous ring
Fibrous skeleton function
-provides a structural foundation for heart valves
-helps prevent overstretching of valves
-insertion point for cardiac muscle bundles
-electrically insulates atria and ventricles for proper action potentials
Heart valves function
-open and close in response to pressure changes as heart contracts and relaxes
-prevents backflow of blood in the heart
2 atrioventricular valves
-right atrioventricular valve (tricuspid)
-left atrioventricular valve (bicuspid)
2 semilunar valves
-pulmonary valve
-aortic valve
Pulmonary valve location
-between pulmonary trunk and right ventricle
Aortic valve location
-between aorta and left ventricle
Semilunar valves function
-permit ejection of blood from ventricles
-prevent backflow of blood into heart
Coronary (cardiac) circulation
-flow of blood through the blood vessels that penetrate the myocardium
Left coronary artery divisions
-anterior interventricular branch
-circumflex branch
Right coronary artery divisions
-inferior interventricular branch
-marginal branch
Principal tributaries of coronary sinus
-great cardiac vein
-middle cardiac vein
-small cardiac vein
-anterior cardiac veins
What does the great cardiac vein accompany
-LAD artery
What does the middle cardiac vein accompany
-PDA artery
What does the small cardiac vein accompany
-runs parallel to inferior margin of coronary/AV sulcus
What does the anterior cardiac veins accompany
-runs along right inferior margin of right ventricle
Autorhythmic cells
-happens to 1% of cardiac muscle fibres during embryonic development
Function of autorhythmic cells
-act as natural pacemaker
-form the cardiac conduction system to conduct action potentials throughout myocardium
Components of the cardiac conduction system
-sinoatrial node (SA node)
-atrioventricular node (AV node)
-atrioventricular bundle (bundle of his)
-right and left bundle branches
-subendocardial conducting network
What controls pace of contractions
-nervous system
-hormones
Cardiac plexus
-includes sympathetic and parasympathetic nerves
Sympathetic control of heart rate
-increases heart rate
-dilation of arteries
Parasympathetic control of heart rate
-decreases heart rate
2 circuits of blood circulation
-systemic circulation
-pulmonary circulation
Which side of the heart does systemic circulation
-left side
Systemic circulation
-left side of heart receieves oxygenated blood from lungs
-then pumps this blood into aorta which branches into smaller arteries
-these arteries carry blood to all organs
-capillaries merge to deliver deoxygenated blood into systemuc venules which merge to form systemic veins and carry blood to right atrium of heart
Which side of the heart does pulmonary circulation
-right side
Pulmonary circulation
-receives deoxygenated blood from systemic circulation and pumps it into pulmonary trunk
-this branches into pulmonary arteries that carry blood to left and right lungs
-in the lungs the pulmonary capillaries are site of gas exchange and the blood becomes oxygenated
-the oxygenated blood flows into pulmonary veins and returns to left atrium
What shape are the lungs
-cone shaped
Where are the lungs located
-thoracic cavity
-extend from diaphragm to above the clavicles and lie against the ribs
What separates the 2 chambers of the lungs
-heart
-mediastinum
Pleural membrane
-layer that covers and protects the lungs
Layers of the pleural membrane
-parietal pleura
-visceral pleura
Parietal pleura
-lines the walls of thoracic cavity
Visceral pleura
-adheres to the lungs
Pleural cavity
-between 2 pleura
-contains lubricating fluid that is secreted by the membranes
Base of the lungs
-broad inferior portion
Apex of the lungs
-narrow superior portion
Costal surface of the lungs
-lies against the ribs
Mediastinal surface of lungs
-medial
-contains hilum
Hilum of the lungs
-where bronchi, blood vessels, lymphatic vessels and nerves enter and exit the lung
Cardiac notch
-left lung
-on medial surface
-heart rests on this
Lobes of left lung
-superior lobe
-inferior lobe
Oblique fissure (left)
-separates superior and inferior lobe
Lobes of the right lung
-superior lobe
-middle lobe
-inferior lobe
Upper part of oblique fissure (right)
-separates superior and inferior lobe
Lower part of oblique fissure (right)
-separates inferior and middle lobe
Horizontal fissure (right)
-borders superior portion of middle lobe
Right main bronchus divisions
-superior bronchi
-middle bronchi
-inferior lobar bronchi
Left main bronchus divisions
-superior bronchi
-inferior lobar bronchi
Lobar bronchi divisions
-segmental (tertiary) bronchi
Segmental (tertiary) bronchi function
-supply air to the bronchopulmonary segments of each lung
Lobule
-small compartment in each bronchopulmonary segment
Lobule contents
-lymphatic vessel
-arteriole
-venule
-respiratory bronchiole
Respiratory bronchiole divisions
-alveolar ducts
Alveolar duct
-contains about 100 alveolar saccule and pulmonary alveoli
Alveolar saccule
-terminal dilation of an alveolar duct and is composed of 20-30 pulmonary alveoli
Pulmonary alveolus
-cup shaped
-lined by simple squamous epithelium
-supported by thin elastic membrane
Arteries supplying blood to the lungs
-pulmonary arteries
-bronchial arteries
Pulmonary arteries
-how blood is delivered to the lungs from the right ventricle
-blood is also returned to heart
Bronchial arteries
-deliver oxygenated blood to bronchi and bronchioles of the lungs
Innervation of the lungs
-pulmonary plexus
Pulmonary plexus
-formed by branches of the vagus nerve
Pulmonary ventilation
-inhalation and exhalation of air between pulmonary alveoli of lungs and atmosphere
Inhalation (inspiration)
-when alveolar pressure is lower than atmospheric pressure
Principal muscles of inhalation
-diaphragm
-external intercostal muscles
Diaphragm innervation
-phrenic nerve
Exhalation
-air pressure in pulmonary alveoli is greater than atmospheric pressure
Muscles of exhalation
-passive process
-does not require muscles
-caused by relaxation of inspiratory muscles
Labored breathing muscles
-abdominal muscles
-internal intercostal muscles
Mediastinum
-compartment of thorax located in midline of the body
-contains most of thoracic viscera, apart from lungs
Mediastinum attachments
-vertically attaches to thoracic inlet
-bounded laterally by medial surfaces of pleura
Thoracic plane of ludwig
-imaginary line extending from sternal angle to T4-T5 space
-divides mediastinum into superior and inferior divisions
Inferior division of mediastinum divisions
-anterior compartment
-middle compartment
-posterior compartment
What divides the compartments of the inferior division of the mediastinum
-pericardial sac
Anterior mediastinum
-posterior to the body of sternum
-anterior to pericardium
Middle mediastinum
-bounded by pericardium
-encloses heart and origins of the great blood vessels
Posterior mediastinum
-posterior to pericardium
-anterior to vertebrae
Structures that belong to both superior and inferior mediastinum
-esophagus
-azygos veins
-vagus nerve
-phrenic nerve
Where do most mediastinal organs drain
-thoracic duct
Where does right side of thorax and right side of head drain
-right lymphatic trunk
Superior border of mediastinum
-thoracic inlet