Lab 9: Thorax

Question 1

breast

Answer 1

• nipples and areola may become swollen and exude a small amount of secretion immediately after birth for both sexes
• breast activity rapidly subsides after and becomes like subcutaneous tissue until puberty
• for females breasts increase in size and the glandular tissue becomes surrounded with fatty superficial fascia at puberty
• breast is rudimentary in males
• blood supply of the breast derives from the internal and lateral thoracic arteries

Question 2

female breast

Answer 2

• mammary gland

- structurally similar to apocrine sweat gland

Question 3

pectoralis major

Answer 3

• breast rests on the fascia covering the pectoralis major and a bit of serratus anterior
• anterior portion of thorax

Question 4

axillary tail

Answer 4

• extension of adipose tissue of the breast
• runs upward and lateral into the axilla (armpit)
• lymphatic drainage of the breast is primarily into nodes at the end of the axillary tail

Question 5

nipple

Answer 5

• surrounded by pigmented ring of skin -> areola
• areola has a number of small elevations -> areolar gland (montgomery tubercles) -> lubricate the nipple during lactation (milk secretion)
• nipple is pierced by 15-20 lactiferous ducts
• lactiferous ducts enlarge immediately below the areola to form -> lactiferous sinuses -> constitute milk reservoirs during lactation
• lactiferous ducts drains a glandular lobe which is comprised of a number of smaller lobules
• each lobule has a number of simple secretory sacs -> alveoli
• glandular lobes are surrounded by adipose tissue and are supported from the skin and the deep fascia overlying the pectoralis major muscle by a series of suspensory ligaments (coopers ligaments) -> form fibrous septa within the breast
• clavy pectoral fascia -> suspensory ligaments -> pectoralis major

Question 6

lactiferous sinuses

Answer 6

• constitute milk reservoirs during lactation

- stores milk after its produced

Question 7

thoracic skeleton

Answer 7

• 12 thoracic vertebrae
• 12 pairs of ribs
• sternum: manubrium, sternal body, xiphoid process
• costal cartilages (ribs articulate with sternum)
• surrounds the thoracic cavity posteriorly, laterally, and anteriorly

Question 8

sternum

Answer 8

• forms a skeletal brace in the midline anteriorly

- 3 separate components that are united by fibrocartilaginous joints: manubrium, sternal body and xiphoid process

Question 9

sternum: manubrium

Answer 9

• upper most element of sternum
• superior border has a depression known as the jugular notch -> lies at the level of the intervertebral disc between T1-T2
• superolateral corners have concave facets that articulate with the clavicles
• below each clavicular facet is a facet that articulates with the costal cartilage of the first rib
• inferior border joins the sternal body at the junction of the 2nd rib
• manubriosternal joint has a slight anterior angle (sternal angle) that can be felt as a ridge just under the skin
• sternal angle lies at the level of vertebra T5

Question 10

sternum: sternal body

Answer 10

• middle element of sternum
• made up of 4 segments (sternebrae) that fuse between puberty and age 20
• junctions can be palpated as slight transverse ridges on the front of the bone
• 2nd-7th costal cartilage articulate with the sternal body

Question 11

sternum: xiphoid procress

Answer 11

• inferior, tongue shaped portion of the sternum

- articulates with the body of the sternum at the level of vertebra T10

Question 12

Ribs and costal cartilage

Answer 12

• 12 ribs on each side
• articulate posteriorly by synovial joints with the vertebrae
• ribs 1-10- articulate anteriorly with the sternum by rods of hyaline cartilage -> costal cartilage
• costochondral junction/joint- where the rib becomes cartilage
• ribs 1-7- (true ribs) articulate directly with the sternum by their own costal cartilages
• ribs 8-10- (false ribs)- articulate with the sternum indirectly by connecting with the 7th costal cartilage
• ribs 11-12- (floating ribs) short and do not reach the sternum -> distal ends terminate in the musculature of the body wall

Question 13

respiratory movement of the thoracic skeleton

Answer 13

• heads of ribs 2-9 articulate by synovial joints with two adjacent vertebral bodies (its own and one above) across the intervertebral disk
• tubercles of ribs 1-10 articulate by synovial joints with the transverse process of the vertebra
• synovial joints permit free movement of the costal cage during forced inspiration and expiration
• ribs are elevated during inspiration -> Expands the anteroposterior dimension of the thoracic cavity in a movement analogous to the motion of a bucket handle
• increase in thoracic volume creates a partial vacuum -> filled by air rushing into the lungs

Question 14

muscles of the back

Answer 14

• 4 hypaxial muscles that attach to thoracic vertebrae and/or ribs:
• trapezius
• latissimus dorsi
• rhomboideus
• quadratus lumborum
• 3 epaxial muscles attach to thoracic vertebrae:
• erector spinae
• semispinalis
• multifidus

Question 15

muscles of upper limb

Answer 15

one muscle attaches to the sternum

• pectoralis major
• there are also 2 costoscapular muscles: a sternocostal muscle, 3 intercostal muscles and the abdominal diaphragm

Question 16

costoscapular muscles

Answer 16

• 2 muscles run from the rib cage into the scapula
• both protract the scapula (pull forward)
• one rotates the scapula upward and the other downward
• pectoralis major
• serratus anterior

Question 17

costoscapular muscles: pectoralis minor

Answer 17

• arises from the anterior surface of ribs 3-5
• inserts onto the coracoid process of the scapula
• protracts (pull forward) and rotates the scapula so the glenoid fossa faces inferiorly
• deep to pectoralis major
• innervated by medial pectoral nerve (branch of brachial plexus)

Question 18

costoscapular muscles: serratus anterior

Answer 18

-arises from the upper 1-8 ribs by series of fingerlike digitations
-inserts ventrally onto the medial border of the scapula
-travels in between the scapula and the ribcage -> inserts medially
-protracts (pull forward) and rotates the scapula so that the glenoid fossa faces superiorly
-running in the space between ribs and scapula -> anterior to scapula
-from anterior to posterior-
ribs -> serratus anterior -> subscapular muscle -> scapula
-innervated by long thoracic nerve (ventral rami C5-C7)

Question 19

sternocostal muscle: transversus thoracis

Answer 19

• transversus thoracis
• arises from the posterior surface of the sternal body and xiphoid
• inserts into the backs of costal cartilages 2-6
• draws the ribs downward in forced expiration
• weak muscle
• helps with forced expiration
• connects sternum to ribs
• innervated by intercostal nerves

Question 20

intercostal muscles

Answer 20

• 3 layers of thin muscles run in the intercostal space between successive ribs
• between the middle and innermost layers is the neurovascular plane
• run in between ribs
• intercostal nerve, artery, and vein run in this plane
• 3 muscle layers differ in the extent to which they fill the intercostal space
• fibers of the external layer are orientated differently from those of the inner two -> helps strengthen the thoracic wall
• all three layers are innervated by intercostal nerves
• external intercostal: occupies the space between the tubercle of the rib and the edge of the costochondral junction -> its fibers are directed downward and forward
• internal intercostal: occupies the space between the angle of the rib and the edge of the costosternal junction -> fibers are directed downward and backward
• innermost intercostal: lies deep to the neurovascular plane -> fibers are directed downward and backward

Question 21

abdominal diaphragm

Answer 21

• thoracic and abdominal cavities are separated by a muscular diaphragm
• principal force behind respiration
• dome-shaped muscle that is convex upward
• fibers originate peripherally from the back of the xiphoid process, internal surfaces of ribs 9-12, costal cartilages 6-8, the epimysium over the quadratus lumborum and psoas major muscles, and the bodies of L1-L3 -> all attached to tendon
• enclosed all the way around except for openings for the aorta, esophagus, and inferior vena cava
• left and right crus attach to aorta
• these fibers converge upon a thin, crescent shaped central tendon
• this tendon has 3 parts known as leaves
• left and right leaves are below the lungs
• middle leaf is below and fused to the lower surface of the fibrous pericardium around the heart
• also has 3 major orifices that permit the passage of structures between the thorax and abdomen (respectively from front to back):
• vena caval foramen- through the middle leaf and the central tendon, for the inferior vena cava -> lies at the level of vertebra T8
• esophageal hiatus- through posterior muscular fibers, for the esophagus -> lies at the level of vertebra T10
• aortic hiatus- (behind the diaphragm for the descending aorta) -> lies at the level pf vertebra T12
• abdominal diaphragm is innervated by phrenic nerve (C3, C4, C5) -> travels inferiorly to the left and right sides of the heart (pericardium) and branch out along diaphragm

Question 22

thoracic cavity

Answer 22

• ribs and abdominal diaphragm enclose the thoracic cavity
• contains the trachea and lungs, the heart and some very large blood vessels, the esophagus as well as nerves and lymphatic channels

Question 23

coelom

Answer 23

• in the embryo a large blood vessel (heart tube), the trachea and its lung buds, and the gut tube develop in the front of the primordial vertebral column and behind a membranous sac -> this is the coelom
• coelom extends throughout the thorax and abdomen
• as the heart tube grows in size into the heart and as the lung buds increase in size into the lungs -> the tissues of the coelomic sac are pushed inward -> forming septa that subdivide the original single coelomic cavity into 3 separate cavities

Question 24

pericardial cavity

Answer 24

-middle cavity into which the heart grows

Question 25

pleural cavities

Answer 25

-2 lateral cavities into which the lungs grow

Question 26

parietal and visceral layer of pericardial and pleural cavities

Answer 26

- sacs of the pericardial and pleural cavities are composed of serous membrane - part of the membrane lies against the outer thoracic wall -> forms the parietal layer of the sac - part of the membrane is adherent to the organ (heart of lung) -> forms the visceral layer of the sac - space between the parietal and visceral layers contain serous fluid -> permits free movement of the heart and lungs, and their adherent visceral membranes, against the parietal membrane and thoracic wall - some of the fibrous connective tissue from the septa around the pericardial cavity adheres to the outside of its parietal layer -> forms fibrous pericardium

Question 27

mediastinum

Answer 27

- structures that occupy the space between the lungs form a partition between them - largest structure here is the heart - entering the top of the pericardial sac on the right is the superior vena cava - to the left and right of the superior vena cava is the aortic arch -> emerges from the pericardial sac - brachiocephalic trunk, left common carotid artery, and left subclavian artery come off the aortic arch - pulmonary arties are below the superior vena cava and aortic arch -> they emerge by the pulmonary trunk from the heart and run into the lungs - trachea is behind the superior vena cava and aorta -> left and right bronchi bifurcate from the traches behind pulmonary arteries at about the level of sternal angle (posterior) - esophagus is behind trachea -> runs through the abdominal diaphragm - aortic arch runs upward and then curves back over the left bronchus of trachea -> then it descends through the thorax as the descending aorta between the vertebral column and esophagus -> descending aorta runs through the abdominal diaphragm - also contains the main lymphatic channel of thorax -> thoracic duct, the phrenic nerve and vagus nerves, and the azygos and hemiaxygos veins -> run along either side of vertebral column

Question 28

superior vena cava

Answer 28

-drain the left and right brachiocephalic veins

Question 29

respiratory apparatus

Answer 29

- consists of the oral and nasal cavities in the head: the pharynx, larynx, and trachea - in the neck: trachea, bronchial tree, and lungs within the thorax

Question 30

trachea

Answer 30

- 4-5 inches long - diameter is 1 inch - begins immediately below the cricoid cartilage - tracheal lumen is kept open by series of C-shaped tracheal cartilages - tracheal cartilages partially surround it except on the posterior aspect - cartilages are connected by fibroelastic tissue and smooth muscle fibers - at the level of sternal angle -> trachea divides into left and right bronchial trees

Question 31

bronchial tree

Answer 31

- at the level of sternal angle -> trachea divides into left and right bronchial trees - last cartilaginous ring of the trachea has a projection that runs in the sagittal plane through its center -> separates the left and right bronchi - keel-like ridge at the orifices of the primary bronchi -> carina - bronchial tree has 3 levels of division: - bronchus: primary bronchus, secondary (lobular) bronchus, tertiary (segmental) bronchus - bronchiole: bronchiole, terminal (respiratory) bronchiole - alveolar portion: alveolar duct, alveolar sac, alveolus

Question 32

bronchial tree: bronchus

Answer 32

- trachea bifurcates into the left and right primary bronchi - right primary bronchus is about 1 inch long - left is longer by about 1 inch bc the entrance (hilum) of left lung is pushed laterally by the heart - once primary bronchus enters the lung -> divides into secondary (lobar) bronchi (3 in right lung, 2 in left) - 3 lobar bronchi in the right lung bc it has 3 lobes - there are 2 lobar bronchi in the left lung bc it has only 2 lobes - lobar bronchi divide into tertiary (segmental) bronchi - segmental bronchus serves 1 bronchopulmonary segment of the lung -> each lung has 10 segmental (tertiary) bronchi - segmental bronchi divide into bronchioles

Question 33

bronchial tree: bronchioles

Answer 33

- not supported by cartilage - segmental bronchi divide into bronchioles - bronchioles differ from bronchi bc they lack cartilaginous rings - bronchioles divide into even smaller terminal respiratory bronchioles - respiratory bronchioles branch into a number of alveolar ducts

Question 34

bronchial tree: alveolar portion

Answer 34

- respiratory bronchioles branch into a number of alveolar ducts - they enter into alveolar sacs that bud numerous microscopic alveoli - gas exchange takes place in alveoli - alveolar ducts -> alveolar sacs -> alveoli - alveoli have capillary beds for gas exchange - at the ends of terminal bronchioles

Question 35

lungs

Answer 35

- fill most of the thoracic cavity - each composed of a mass of spongy tissue -> the alveoli (respiratory portion) - each also contain a branching network of tubes -> bronchi and bronchioles (conducting portion) - lung is covered by visceral pleura which is separated from the parietal pleura that lines the thoracic wall by an intrapleural space with a slightly lower pressure than that of the atmosphere - this space also contains serous fluid that facilitates movement of the lungs during inspiration and expiration - the top (apex) of lung is somewhat pointed - bottom (base) of lung is concave bc it rests upon the dome-shaped abdominal diaphragm - bc the heart takes up more space on the left side of the thoracic cavity -> left lung differs slightly in its gross appearance from the right lung - both lungs have 10 bronchopulmonary segments -> these blocks of lung tissue receive air supply from a separate bronchus and its blood supply from a separate branch of lobar artery

Question 36

right lung

Answer 36

- has 3 lobes separated by 2 fissures - uppermost is the superior lobe - below is the middle lobe - lowermost is the inferior lobe - horizontal fissure separates the superior and middle lobes - the oblique fissure separates the inferior lobe from the superior and middle lobes

Question 37

left lung

Answer 37

- has 2 lobes separated by one fissure - uppermost is the superior lobe - separated from the inferior lobe by the oblique fissure - left lung has no middle lobe - it has concavity -> the cardiac notch -> where the heart fits - below the cardiac notch the anterior aspect of the superior lobe has a tongue-like protrusion -> lingula

Question 38

heart

Answer 38

- large part of mediastinum - 4 chamber muscular pump - takes deoxygenated blood from body and pumps it into lungs -> then pumps oxygenated blood from lungs into body - provides blood to its own cardiac muscle via a separate network of vessels - size of clenched fist - cone shaped - located in center of chest - mass is to the left of the midline - lies closer to the front than the back of the thorax

Question 39

upper margin of the heart

Answer 39

- on the left side of the upper margin -> located on the lower border of the left 2nd costal cartilage - one finger breadth from the edge of the sternum - (2nd costal cartilage articulates with the sternum at sternal angle) - right side of upper margin -> on the upper border of the right 3rd costal cartilage - one finger breadth from the edge of the sternum

Question 40

lower margin of the heart

Answer 40

- right side of lower margin of heart -> on the lower border of the right 5th costal cartilage - one finger breadth from the edge of the sternum - left side of the lower margin of heart -> is in the left 5th intercostal space - it is three thumb breadth from the midline of the sternum

Question 41

pericardium

Answer 41

- membranous sac heart hangs in - suspended from the roots of the large blood vessels that exit and enter the heart - serves to restrict excessive movement of heart - provides moveable but not expandable, lubricated containment -> able to beat freely - pericardium consists of 2 sacs: fibrous pericardium and serous pericardium

Question 42

pericardium: fibrous pericardium

Answer 42

- outermost sac of pericardium - thick, fibrous - sac is continuous with the coverings of the great blood vessels that pass through it: aorta, superior and inferior venae cavae, pulmonary trunk, and pulmonary veins - fibrous pericardium is firmly attached to central tendon of the diaphragm and to back of sternum

Question 43

pericardium: serous pericardium

Answer 43

- within the fibrous pericardium - has 2 layers: parietal serous pericardium and visceral serous pericardium - parietal serous pericardium- adheres to the fibrous pericardium (outer layer) and reflects around the roots of the great vessels to become continuous with the visceral serous pericardium (epicardium) - visceral serous pericardium (epicardium)- adherent to the outer surface of the heart

Question 44

pericardial cavity

Answer 44

- narrow space between the parietal and visceral layers of the serous pericardium - contains a small amount of lubricating fluid that facilitates the beating movement of the heart

Question 45

heart as a pump

Answer 45

-4 chamber muscular pump -chambers are separated by internal septa -superior chambers are the aorta -inferior chambers are the ventricles -atria receives blood from outside the heart -bc atria pump only into the ventricles the muscular walls are comparatively thin -ventricles are more heavily muscled bc they pump blood out of the heart and through high resistance capillary networks -heart pushes deoxygenated blood into the lungs and receive oxygenated blood from the lungs by a series of vessels that constitute the pulmonary circulatory system -heart also pumps oxygenated blood into and receives deoxygenated blood from the rest of the body by a series of arteries and veins that constitutes that systemic circulatory system -

Question 46

deoxygenated blood

Answer 46

- from the body flows form the capillary beds and through systemic veins into 1 of 2 large vessels known as the venae cavae - venae cavae empty into the right atrium of the heart - right atrium pumps this deoxygenated blood into the right ventricle - right ventricle pumps it into the pulmonary arteries - pulmonary arteries carry the deoxygenated blood to the lungs where it receives oxygen

Question 47

oxygenated blood

Answer 47

- returned from the lungs to the heart through pulmonary veins - pulmonary veins empty into the left atrium of the heart - left atrium pumps this oxygenated blood into the left ventricle - left ventricle pumps it into the aorta - aorta branches into a series of subsidiary arteries through which the oxygenated blood reaches the capillary networks of the body

Question 48

anterior aspect of the heart

Answer 48

- front of heart is dominated by right ventricle - shallow groove separates it from the left ventricle - above and to the right of the right ventricle is the right atrium - a fleshy flap that projects anteriorly from it is the auricle of the right atrium - above the left ventricle is the auricle of the left atrium

Question 49

posterior aspect of the heart

Answer 49

- back of the heart is dominated b the left atrium - its auricle was visible in anterior view - between the left atrium and the left ventricle is a sulcus

Question 50

great vessels: entering the right atrium

Answer 50

- entering the top of right atrium is the superior vena cava - receives blood from its main tributaries -> left and right brachiocephalic veins - these drain deoxygenated blood from the head, neck, and upper limbs - also draining into the back of superior vena cava is the azygos vein - carries blood from the wall of the thorax - entering the bottom of the right atrium is the inferior vena cava - carries deoxygenated blood from the abdomen, pelvis, and lower limbs

Question 51

greater vessels: entering the left atrium

Answer 51

- emerging from the top of the right ventricle is the pulmonary trunk - soon divides (below the arch of the aorta) into the left and right pulmonary arteries - carry deoxygenated blood into the lungs

Question 52

greater vessels: entering the left ventricle

Answer 52

- emerging from the top of the left ventricle (between the pulmonary trunk and the right auricle) is the ascending aorta - soon turns to the left and arches backward as the aortic arch over the pulmonary arteries - aortic arch gives off 3 main branches -> brachiocephalic trunk, left common carotid artery, and left subclavian artery -> before turning downward as the descending aorta

Question 53

right atrium

Answer 53

- internal walls are smooth at the back but roughened in front by bundles of muscle fibers called -> pectinate muscles - medial wall of the right atrium has an oval depression just above the entrance of the inferior vena cava -> fossa ovalis -> remnant of foramen ovale that existed in fetal life between the right and left atria - foramane ovale enables blood to bypass the right ventricle and the non functional fetal lungs

Question 54

right ventricle

Answer 54

- right atrium opens into the right ventricle by an orifice that has 3 flaps of fibrous connective tissues (cusps) around its circumference - cusps project into the right ventricle, forming the right atrioventricular (tricuspid) valve - internal wall has a number of muscular ridges called trabeculae carneae - 3 of the trabeculae carneae project toward the cusps of the tricuspid valve and are attached to the cuspal margins by tendons - muscular extensions are called papillary muscles and their tendons are called chordae tendineae - chordae tendineae prevent the tricuspid valve cusps from being pushed up into the right atrium when the right ventricle contracts

Question 55

pulmonary semilunar valve

Answer 55

- entrance to the pulmonary trunk is guarded by another valve with 3 cups - each cup is shaped like a half moon - blood that flows back toward the right ventricle from the pulmonary trunk run into the space between the cups and the wall of the trunk - causes the cusps to balloon out and contact one another -> closing the orifice

Question 56

left ventricle

Answer 56

- left atrium communicates with left ventricle by an orifice with 2 cusps that project into the ventricle - this valve is called the left atrioventricular (mitral) valve - edges of these cusps are connected to the 2 papillary muscles of the left ventricle by chordae tendineae - prevent the mitral valve cusps from being pushed up into the left atrium when the left ventricle contracts - walls of the left ventricle are thickest and are lined with trabeculae carnae

Question 57

aortic semilunar valve

Answer 57

- entrance to the ascending aorta is guarded by a 3-cusped valve (aortic semilunar valve) - it is like the pulmonary semilunar valve in its structure and mechanism of operation

Question 58

surface projection and auscultation of the heart valve

Answer 58

- it is possible to hear the sound that each valve produces as it closes - if you listen to the heart with a stethoscope (surface auscultation), you will hear 2 beats: lub-dup - lub- produced by the contraction of the ventricles and the concomitant closure of the left and right atrioventricular valves - dup- is produced by the sharp closure of the pulmonary and aortic semilunar valves - noise that each produces upon closure is not necessarily heard best directly over the valve

Question 59

right atrioventricular (tricuspid) valve

Answer 59

- lies behind the right half of the sternum at the level of the fourth intercostal space - is best heard over the left or right edge of the sternum at the level of the 5th intercostal space

Question 60

left atrioventricular (mitral) valve

Answer 60

- lies behind the medial end of the left 4th costal cartilage - best heard over the left 5th intercostal space about 3 1/2 inches front he midline

Question 61

pulmonary semilunar valve

Answer 61

- lies behind the medial end of the left 3rd costal cartilage - best heard over the medial end of the left 2nd intercostal space

Question 62

aortic semilunar valve

Answer 62

- lies behind the left half of the sternum at the level of the 3rd intercostal space - best heard over the medial end of the right 2nd intercostal space

Question 63

conducting system

Answer 63

- cardiac muscle cells have intrinsic ability to generate and conduct impulse - cells contact each other at their ends via jap junctions - interconnected cardiac muscle cells form functional mass called -> syncytium - bc the heart has a fibrous internal skeleton that supports it valves the entire heart cannot be a single syncytium - fibrous tissue effectively divides the heart into 2 functional masses: atrial syncytium and ventricular syncytium - in order to spread impulses across the skeletal boundary between atria and ventricles and speed the rate at which impulses spread -> the heart has a conducting system composed of specialized cardiac muscle cells

Question 64

sinoatrial (SA) node

Answer 64

- impulse that initiates each heartbeat begins here - group of cells that lies in the wall of the right atrium near the opening of the superior vena cava - SA node is the cardiac pacemaker - impulses from it spread throughout the atrial syncytium causing the atria to contract at the same time - impulses reach a 2nd node where they are transmitted to the ventricular syncytium

Question 65

atrioventricular (AV) node

Answer 65

- located in the lower part of the interatrial septum - impulse travels form the AV node through a series of cellular fibers into and around the ventricles - impulse crosses the fibrous partition into the ventricular mass along the fibers of the atrioventricular bundle -> runs into the interventricular septum - this fiber bundle soon divides into left and right bundle branches that transverse the septum - at the base of the septum the fibers turn upward into the external walls of the ventricles - recurrent fibers are known as purkinje fibers - these speed impulse transmission throughout the ventricular syncytium

Question 66

innervation of heart

Answer 66

- hearts inherent rate of contraction is set by SA node - depolarization rate of SA node can be altered by extrinsic motor impulses carried by the autonomic nervous system - parasympathetic innervation by means of vagus nerve slows the rate of the heart contraction - sympathetic innervation by fibers from sympathetic chain ganglia in the neck and thorax increases the rate of heart contraction

Question 67

blood supply of heart

Answer 67

- 3 quarts of blood move through the heart every minute - cardiac muscle cells do not receive any nutrients from it - this is bc the internal walls of the atria and ventricles are lined with a layer of tissue called endocardium (also bc the blood is deoxygenated from the right atrium and ventricle) - heart is suppled by separate system of arteries and veins -> coronary circulation

Question 68

coronary circulation: arteries

Answer 68

- 2 coronary arteries branch form the aorta as it emerged from the heart -> left and right coronary arteries - *left coronary principal branches -> anterior interventricular artery (LAD) and circumflex artery - right coronary principal branches -> marginal branch and posterior interventricular artery - there are some anastomotic connections between the branches of the coronary arteries - for left dominant heart the posterior interventricular artery comes off the left coronary artery (branch of circumflex)

Question 69

coronary circulation: left coronary artery

Answer 69

- 2 main branches -> anterior interventricular and circumflex arteries - emerges between the left atrium and pulmonary trunk - one of its main branches is the anterior interventricular artery - runs to the apex of the heart in a groove on the anterior surface between the left and right ventricles - other main branch is the circumflex artery -> curves around to the back of the heart in a groove between the left ventricle and the auricle of the left atrium - shorter than the right coronary artery

Question 70

coronary circulation: right coronary artery

Answer 70

- 2 main branches -> marginal branch and posterior interventricular artery - emerges from the aorta between the auricle of the right atrium and the pulmonary trunk - curves around toward the back of the heart in a groove between the right auricle and right ventricle - fives off a marginal branch which runs down the right side of the heart towards the apex - right coronary artery runs to the back of the heart and turn toward the apex as the posterior interventricular artery - runs in a groove between the left and right ventricles

Question 71

coronary circulation: veins

Answer 71

- blood form the heart drains into the right atrium just to the left of the inferior vena cava via the coronary sinus - coronary sinus dumps into the right atrium of the heart - coronary sinus receives blood form 3 major tributaries: - great cardiac vein- accompanies the anterior interventricular and circumflex arteries - small cardiac vein- accompanies the marginal branch of the right coronary artery - middle cardiac vein- accompanies the posterior interventricular artery

Question 72

lymphatics in the thorax

Answer 72

- lymphatic drainage of the breast is primarily into nodes at the end of its axillary tail - these axillary nodes also receive lymph from the thoracic wall - deep structures of the thorax -> lungs, heart, esophagus -> drain their lymph into ducts on the left and right sides known as -> bronchomediastinal trunks - left bronchomediastinal trunk drains into a large channel known as the thoracic duct - thoracic duct runs along the front of the vertebral column behind the esophagus and between the azygos vein and descending aorta - originates just below the abdominal diaphragm as a dilated midline sac -> cisterna chyli - the cisterna chyli receives lymph from the abdomen, pelvis, and lower limbs - just above the level of the 1st rib the thoracic duct bends to the left to enter the venous angle -> where the subclavian and jugular veins merge to form the -> left brachiocephalic vein - thoracic duct also receives lymph from the left upper limb and left upper limb and left axillary nodes by a channel known as -> left subclavian trunk - this joins the thoracic duct just before it enters the left brachiocephalic vein - thoracic duct also receives lymph from the left side of the head and neck by a channel -> left jugular trunk - right upper limb and right axillary nodes are drained of lymph by the right subclavian trunk - lymph is drained from the right side of the head and beck by the right jugular trunk - these trunks merge with the right bronchomediastinal trunk to form -> right lymphatic duct just above 1st rib - right lymphatic duct drain into the venous angle where the subclavian and jugular veins merge to form the right brachiocephalic vein - right bronchomediastinal trunk also drain into the right brachiocephalic bein near it origin - lymph is drained from the right upper limb, right side of the head and neck, right breast, and right thoracic cavity and wall by the right lymphatic duct - the rest of the body is drained by the thoracic duct

Question 73

systemic vessels of thoarx

Answer 73

- arteries: aorta, brachiocephalic trunk, left common carotid artery, left subclavian artery - veins- inferior vena cava, superior vena cava, superior vena cava, right brachiocephalic vein, left brachiocephalic vein

Question 74

pulmonary vessels of the thorax

Answer 74

- arteries- pulmonary trunk and pulmonary arteries | - veins- pulmonary veins

Question 75

coronary vessels

Answer 75

- arteries- left coronary, anterior interventricular, circumflex, right coronary, marginal, posterior interventricular - veins- coronary sinus, great cardiac vein, small cardiac vein, middle cardiac vein

Question 76

arteries

Answer 76

- descending aorta gives off 12 pairs of intercostal arteries into the neurovascular plane as it passes by the intercostal spaces - these arteries supply the posterior wall of the thorax - aorta also gives off several pairs of unnamed subcostal arteries that supply the posterior abdominal wall - subclavian and axillary arteries give off branches that supply the anterior wall of the thorax - subclavian arteries gives off the internal thoracic artery - descends behind the costal cartilages, wedged between them and the transversus thoracis muscle - at the bottom of the rib cage, it divides into 2 terminal branches the superior epigastric and musculophrenic arteries - the internal thoracic artery gives off branches that perforate the intercostal spaces anteriorly - some of these perforating arteries give off medial mammary branches to the breast - axillary artery gives off the lateral thoracic artery just lateral to the rib cage - it descends along the side of the cage, providing lateral mammary branches to the breast

Question 77

veins

Answer 77

- the descending aorta gives off intercostal arteries as it passes by each intercostal space, but there is no great vessel that runs along the back of the thoracic wall into which the intercostal veins can drain - rather the intercostal veins that drain blood from the posterior wall of the thorax from vessels that empty blood into the superior vena cava - each intercostal space is drained by an intercostal vein - on both sides of the body, the 1st intercostal space is drained by a vessel known as the supreme intercostal vein - it empties into the brachiocephalic vein on each side - on the right side of the body, the second through 12th intercostal veins empty into a vessel that ascends alongside the vertebral column - this vessel, which originates in the abdomen, is known as the azygos vein - 2nd through 4th right intercostal veins usually from a single vessel, the superior intercostal vein, that joins the azygos vein - all other right intercostal veins empty directly into the azygos vein - azygos vein ascends behind the pericardium and the root of the lung - at the top of the root of the lung, it arches forward to enter the superior vena cava - on the left side of the body the 2nd-4th intercostal veins form a single vessel, the superior intercostal vein, that empties into the left brachiocephalic vein - vein from the abdomen is joined by the lower four left intercostal veins as the hemiazygos vein - runs to the right, across the front of the vertebral column at the level of T9 to join the azygos vein - middle thoracic intercostal veins on the left join together to form the accessory hemiazygos vein - it runs to the right across the front of the vertebral column at the level of T8 to join the azygos vein

Question 78

nerves of thorax

Answer 78

- thoracic skeleton muscles are supplied by spinal nerves - the heart, lungs, and lower part of the esophagus are supplied by autonomic fibers - parasympathetic from the vagus and sympathetic from cervical and thoracic ganglia of the sympathetic chain

Question 79

spinal nerves in the thorax

Answer 79

- with exception of T1, the thoracic spinal nerves are not involved in the formation of a plexus - instead, each runs rights into the neurovascular plane of an intercostal space - T1 contributes to the brachial plexus - phrenic nerve derives from spinal nerves in the neck and makes its way into the thorax - derives from the ventral rami of C3-C5 and enters the thoracic cavity behind the subclavian vein - it descends through the thoracic cavity in contact with the superior vena cava (right side) or aorta (left side) and crosses the pericardium to reach the abdominal diaphragm, which it innervates

Question 80

cranial nerves in the thorax

Answer 80

- vagus nerve (CN X) is the only cranial nerve to enter the thoracic cavity - provides parasympathetic fibers to the heart and lungs - right vagus runs along the trachea and onto the esophagus adjacent to the azygos vein - it descends into the abdomen on the esophagus as the posterior vagal trunk - in the thorax, the left vagus sends off the recurrent laryngeal nerve which curves around the aortic arch to run back up into the neck - left vagus runs onto the esophagus becoming the anterior vagal trunk - both trunks contribute to the pulmonary plexus and cardiac plexus - axon destined for the lungs and heart come from these plexuses

Question 81

sympathetic chain in thorax

Answer 81

- cell bodies of the preganglionic sympathetic neurons lie in the spinal cord - myelinated axons of these neurons travel through the ventral root and into the ventral ramus of a spinal nerve - these myelinated preganglionic axons then jump off the ventral ramus and enter a paravertebral sympathetic ganglion through the white ramus communicans - once the axon enters the ganglion it can do 2 things -> it can either synapse in the paravertebral ganglion or not synapse in the paravertebral ganglion - the preganglion neuron synapses with a 2nd neuron (post ganglionic neuron) whose cell body resides in the ganglion - postganglionic axons are unmyelinated and they exit the ganglion - postganglion may take one of 2 paths: 1. Travel directly to a target organ (such as the heart). In the thorax, these axons join together to form an organ nerve (cardiac nerve) that synapse in the wall of the target organ 2. Reenter the ventral ramus of the spinal nerve through the gray ramus communicans. Along the ventral ramus, the gray ramus communicans is proximal to the white ramus communicans. Once in the spinal nerve, these axons will travel to the body wall structures (arrector pilli muscles) that respond to autonomic innervation - the axon does not synapse in the sympathetic ganglion that it enters, but instead ascends or descends to another paravertebral ganglion through the sympathetic trunk - once it reaches another ganglion it may synapse there or it may simply pass through on its way to a ganglion that is even farther away along the chain - once the preganglionic axon reaches a ganglion in which it will synapse, it synapse on a postganglionic neuron, whose axon will either travel directly to a target organ or enter the ventral ramus of an adjacent spinal nerve for distribution to the body wall

Question 82

rib articulation

Answer 82

- superior articular facet- articulates with rib above - inferior articular fact- articles with rib below - tubercle- articulates with transverse process of corresponding vertebrae - synovial joints - costal groove- passageway of a neurovascular bundle -> intercostal nerve, artery and vein

Question 83

forced inspiration

Answer 83

- ribs are elevated -> thoracic cavity increases in volume - change in pressure - move up and out like the handles of a bucket - synovial joints - sternum moves up like the handle of a pump

Question 84

intercostal muscles layers

Answer 84

- external intercostal (hands in pockets direction) -> internal intercostal (opposite direction) -> neurovascular bundle -> innermost intercostal - hand in pocket - intercostal nerves are the ventral rami of spinal nerves - external intercostal layer is deep to pectoralis minor and serratus anterior - strengthens thoracic wall

Question 85

neurovascular bundle: intercostal muscles

Answer 85

- neurovascular bundle - superior to inferior- VAN - intercostal vein, intercostal artery, intercostal nerve

Question 86

abdominal diaphragm opening

Answer 86

- openings for inferior vena cava, esophagus, and aorta - vena caval foramen (T8) - esophageal hiatus (T10)- compressed - aortic hiatus (T12) - I8 10 EGGS AT 12

Question 87

pleural cavities

Answer 87

- do not include the lungs but they do wrap around the lungs - lungs are not in the pleural cavity - serous fluid is in the pleural cavity

Question 88

pneumothorax

Answer 88

- adding air into the pleural space - lung collapse - lung isnt sticking to anything anymore - stab through the parietal layer - suctioned cup to the wall

Question 89

aortic arch

Answer 89

- coming out of left ventricle -> ascending aorta - brachiocephalic trunk - left common carotid - left subclavian

Question 90

brachiocephalic veins

Answer 90

-empties into the superior vena cava into the pericardial sac (heart)

Question 91

respiratory apparatus

Answer 91

-nasal cavity -> pharynx -> larynx -> trachea -> primary bronchi -> bronchioles

Question 92

hilum

Answer 92

- cartilage reinforced bronchi enter | - pulmonary arteries and veins enter and exit here

Question 93

pulmonary veins

Answer 93

- 4 | - left atrium

Question 94

interventricular septum

Answer 94

-between left and right ventricle

Question 95

papillary muscles

Answer 95

- bicuspid- 2 papillary muscles - tricuspid- 3 papillary muscles - only in ventricles

Question 96

right dominant heart

Answer 96

-we get most of the blood from right coronary artery

Question 97

right side of body

Answer 97

-drain into the azygos vein -> drains into the superior vena cava -> right atrium

Question 98

left side of body

Answer 98

-left intercostal veins drain into the accessory/ hemiazygos vein -> drain into the azygous vein -> drains into superior vena cava -> right atrium