Anatomy - Cardiorespiratory System Flashcards
1
Q
The ‘body’ of the sternum articulates with which ribs…
A
the 2-7 ribs
- second rib articulates with the angle of Louis)
- seventh rib articulates with the inferior part of the body and the superior part of the xiphoid process
2
Q
The costal cartilage of ribs 1-7 articulates directly with…
A
- the sternum at sternocostal joints
- ‘true’ ribs
3
Q
The costal cartilages of ribs 8-10 unite and join…
A
- the seventh cartilage
- ‘false’ ribs
4
Q
True or false? Costal cartilage of 7-10 forms costal margin (which is palpable)
A
true
5
Q
True or false? Ribs 11 and 12 are short
A
true - they do not articulate with the sternum (‘floating’ ribs)
6
Q
Typical ribs
A
- look similar and share common anatomical features
- 3-9
- head, neck and tubercle and body (shaft)
7
Q
Atypical ribs
A
- look different to typical ribs and/or lack some of the features of typical ribs
- 1,2, 10-12
- e.g. 1,11,12 are much shorter
8
Q
The thoracic vertebrae articulate with the posterior parts of the ribs at what joint?
A
costovertebral joints
9
Q
What does the tubercle of ribs articulate with?
A
the transverse process of the vertebrae
10
Q
Superior thoracic aperture
A
- the ‘passageway’ through which structures pass between the neck and thorax
- manubrium, first ribs and first thoracic vertebrae
11
Q
Sternoclavicular joint
A
between manubrium and clavicle
12
Q
Costal margin
A
lower edge of the chest formed at the bottom edge of the rib cage
13
Q
What is the skin of the thoracic wall innverated by?
A
spinal nerves T1-T12 (containing somatic sensory, motor and sympathetic fibres)
14
Q
Somatic sensory fibres in the spinal nerves carries what information?
A
sensation of the skin of the thoracic wall reaches conscious perception
15
Q
What do the Somatic motor fibres in spinal nerves T1-T12 innervate?
A
innervate skeletal muscles of thoracic wall
16
Q
What do Somatic sympathetic fibres innervate?
A
innervate sweat glands and smooth muscle of blood vessels and hair follicles in skin
17
Q
Dermatome
A
area of skin innervated by a single spinal nerve
18
Q
What are the breasts also known as?
A
the mammary glands
19
Q
In females, to where does the breast tissue extend towards?
A
anterior axilla (this part is known as the axillary tail)
20
Q
What does the breast contain?
A
- fat
- glandular/secretory tissues arranged in lobules
- ducts (which cover the nipple)
- connective tissue and ligaments
- blood vessels and lymphatics
21
Q
Areola
A
the region of the breast of pigmented skin surrrounding the nipple
22
Q
Blood supply of the breast
A
- internal thoracic artery
- axillary artery
(blood returns to axillary and internal thoracic veins)
23
Q
Internal thoracic artery
A
- courses deep to the lateral edge of the sternum
- gives rise to anterior intercostal arteries that supply the breast and intercostal spaces
24
Q
What nerves supply the breast?
A
- somatic nerves
- sympathetic fibres
via intercostal nerves
(somatic sensory fibres innervate the skin of the breast and sympathetic fibres innervate smooth muscle in the blood vessel wall and nipple)
25
How does the lypmph drain from the breast?
most drains to lymph nodes in axilla
26
Why are the patterns of lymph drainage in the breast complex?
because axillary nodes communicate with other groups of lymph nodes in the thorax
27
What are the five groups of lymph nodes?
- central
- pectoral
- humeral
- subscapular
- apical
28
Apical nodes
- in apex of axilla
- recieve lymph from all other lymph nodes in axilla
- since they drain most of lymph from breast, they are often involved in the spread of breast cancer
29
What are the three layers of muscle in each intercostal space?
- external intercostal
- internal intercostal
- innermost intercostal
30
Pectoralis major including origin and insertion
most superficial muscle of anterior chest wall (attaches to the upper humerus, the clavicle and upper six ribs)
31
Pectoralis minor- including origin and insertion
- smaller muscle that lies deep to pectorals major
- attaches to scapula (coracoid process) and ribs 3-5
32
Serratus anterior
- superficial muscle that sweeps around lateral aspect of the thoracic cage
- attaches to the scapula (medial border) and upper eight ribs
33
What are the functions of the muscles: pectoralis major/minor and serratus anterior?
- to move upper limb (PRIME FUNCTION)
- can function as accessory muscles of breathing and hence can move ribs if humerus and scapula are fixed
- use of these muscles is sign of respiratory distress
34
How do the pectoralis major/minor and serratus anterior move upper limb?
- pectoralis major adducts the humerus
- pectoralis minor and serratus anterior protract the scapula
35
Rib fractures
- result from blunt trauma to chest wall
- painful (worse on inspiration)
- isolated fracture treated conservatively but adequate pain relief required
- multiple more serious and complex and can lead to dysfunctional movements of chest wall and inadqequate ventilation
36
Shingles
- common skin condition affecting older people mostly
- red, painful, itchy rash on chest or abdomen
- one side of body only
- strip-like distribution (as it affects dermatomes)
- caused by reactivation of herpes zoster virus if previously had chicken pox
(virus lays dormant in dorsal root ganglion and when reactivated causes rash and pain in dermatome associated with affected spinal nerve)
37
Breast cancer
- metastasizes to axillay lymph nodes first
- malignant axillary node may be palpable as a lump before noticed as mass in breast
- if breast lump determined as malignant then axillary lymph nodes are biopsied to assess if malignency has metastasized to them, if so, are removed
- removal can cuase fluid accumulation = swelling LYMPHOEDEMA
38
What do the intercostal spaces contain?
- three layers of intercostal muscles + associated membranes
- intercostal neurovascular bundle (intercostal nerve, artery and vein)
39
True or false? the three layers of intercostal muscle fibres run in different directions to each other
false
40
How are the fibres arranged in external intercostal muscle?
antero-inferiorly
41
How are the fibres arranged in internal intercostal muscle?
- fibres run perpendicular to those of the external intercostal
- postero-inferior
42
In what part of the intercostal space does the external intercostal muscle become membranous?
- anterior
- forms external intercostal membrane
43
In what part of the intercostal space does the internal intercostal muscle become membranous?
- posterior
- form internal intercostal membrane
44
What is the third layer of intercostal muscle?
- innermost intercostal
- fibres are in same direction as those of the internal intercostal
45
What lies deep to the innermost intercostal?
endothoracic fascia
46
Where does the neurovascular bundle lie in the intercostal space?
- in the plane between the internal and innermost intercostal muscle
- inferior border of rib superior to the space
- lies in a shallow costal groove deep to surface of rib
(supplies the intercostal muscles, the overlying skin and underlying parietal pleura)
47
Where does the anterior intercostal artery rise from?
internal thoracic artery (branch of the subclavian artery)
48
Where does the posterior intercostal artery rise from?
from the descending aorta in the posterior thorax
49
Where does the anterior and posterior intercostal vein drain into?
Anterior drain into the internal thoracic vein and posterior intercostal vein drains into the azygos system of veins
50
True or false? intercostal nerves are somatic
True - motor and sensory fibres too
(innervate the intercostal muscles, skin of chest wall and parietal pleura)
51
What are the two layers of pleurae covering the lungs?
- parietal pleura (lines inside of thorax, visible with naked eye)
- visceral pleura (covers surface of lungs + extends into fissures)
52
What lies in between the parietal and visceral pleura?
pleural cavity (VERY THIN)
53
Pleuras- including secretion and innervation
- the two layers are continuous with each other
- pleural cels produce a small amount of pleural fluid filling the pleural cavity
- innervated by intercostal nerves that innervate overlying skin of chest wall (somatic sensory fibres)
54
Parts of parietal pleura
- cervical pleura (covers apex of lung)
- costal pleura (lies adjacent to ribs)
- mediastinal pleura (adjacent to heart)
- diphragmatic pleura (adjacent to diaphragm)
55
Costodiaphragmatic recess
- 'gutter' around periphery of diaphragm
- costal pleura beceomes continuous with diaphragmatic pleura
- lungs expand into during deep inspiration
56
Costomediastinal recess
- smaller
- lies at junction of costal and mediastinal pleura
- lungs expand into during deep inspiration
57
What type of sensory nerve innervates the visceral pleura?
autonomic sensory nerve (sensation does not reach conscious perception)
58
Lingula
an anterior extension of the superior lobe in the left lung which extends over the heart
(remnant of middle lobe)
59
anterior border (lung)
sharp and tapered
60
posterior border (lung)
thick and rounded
61
inferior border (lung)
sharp and tapered
62
Where are the impressions (indentaitons) made by the left ventricle and descending aorta seen on the lung?
mediastinal surface of the left lung
63
Where are the impressions (indentations) made by the superior vena cava and azygos vein seen on the lung?
mediastinal surface of the right lung
64
Root of lung
- lies between heart and lung
- comprises the pulmonary artery, pulmonary veins and main bronchus
- pleura encloses root of lung like a sleeve
65
Hilum
- region on the mediasternal surface of the lung where the pulmonary artery, veins and main bronchus enter and exit the lung
- hilum on right is ANTERIOR to pulm. artery
- hilum on left is INFERIOR to pulm. artery
66
Why is a foreign body entering the trachea more likely to enter the right main bronchus than left?
the right is shorter, wider and decends more vertically than the left
67
Lobar bronchi
- division of bronchus
- three in right
- two in left
- each gives rise to segmental bronchi
68
How many segmental bronchi in each lung?
10
69
Bronchopulmonary segment
an independent region of the lung supplied by a segmental bronchus (breakdown into bronchioles)
70
True or false? Bronchial veins return blood to the azygos system of veins
true
71
Parasympathetic fibres in the lungs stiumlate...
- contriction of bronchial smooth muscle (bronchoconstriction)
- secretion from the glands of the bronchial tree
72
Sympathetic fibres in the lungs stimulate...
- relaxation of bronchial smooth muscle (bronchodilation)
- inhibits secretion from the glands
73
Visceral afferents also known as...
visceral sensory fibres (relay sensory information from the lungs and visceral pleura to the CNS - do not reach conscious perception)
74
How does lymph drain from the lungs?
into the venous system via the thoracic duct/ right lymphatic duct
75
Where can the apex of the heart be found?
- projects into the lower neck
- superior to medial end of clavicle
76
Where is the inferior border of the lungs?
- 6th rib anteriorly (midclavicular line)
- 8th rib laterally (midaxillary line)
- 10th rib posteriorly (at the vertebral column)
77
Where does the parietal pleura extend to?
- 8th rib anteriorly (midclavicular line)
- 10th rib laterally (midaxillary line)
- 12th rib posteriorly (at the vertebral column)
78
Where do the oblique fissures of the left and right lungs extend to?
- 4th rib posteriorly to 6th costal cartilage anteriorly
- deep to the 5th rib
79
Where does the horizontal fissure of the right lung extend to?
- anteriorly from 4th costal cartilage and intersects the oblique fissures
80
Diaphragm
- broad, thin sheet of skeletal muscle
- separates thoracic and abdominal cavities
- superior thoracic surface adjacent to parietal pleura
- apertures in diaphragm allow passage of structures between thorax and abdomen
- function: mechanics of breathing
- innervated by phrenic nerves
81
Where is the diaphragm attached?
- xiphoid process
- costal margin
- tips of 11th and 12th ribs
- lumbar vertebrae
82
True or false? the central part of the diaphragm is not muscular but fibrous
True - known as the central tendon
83
Diaphragm contraction
- muscle fibres of right and left domes pulled towards their peripheral attachments
- domes flatten
- increases intrathoracic volume for lungs to expand
84
Diaphragm relaxation
- domes return to superior shape
- decreases volume and drives expiration of air from lungs
85
Phrenic nerves
- left and right innervate left and right sides
- somtic nerves
- formed in nerck by fibres from C3 C4 and C5 spinal nerves therefore motor + sensory
- innervate diaphragm
- course over the pericardium and pierce the diaphragm
- descend through the neck and enter the thorax through the superior thoracic aperture
86
What three planes does the dimension of the thoracic cavity change during ventilation?
- vertically - due to contraction and relaxation of diaphragm
- laterally - due to contraction of the intercostal muscles (which moves the ribs)
- antero-posteriorly (AP) - due to movement of the sternum secondary to movement of the ribs
87
Ventilation
- pleural fluid creates surface tension between parietal pleura lining the thoracic cavity and visceral pleura on surface of lung
- surface tension keeps lung and thoracic wall together (change volume together)
- it also keeps the two pleural membranes in contact with each other preventing lung from collapsing away from the thoracic wall
- if surface tension breaks then ventilation may become dysfunctional
88
Muscles involved in vigorous breathing
- intercostal muscles important
- active expiration uses internal intercostal muscles
89
Muscles involved in very vigorous or forced breathing
- acessory muscles contribute to movement of ribs to aid ventilation
90
Accessory muscles
- sternocleidomastoid
- pectoralis major
- pectoralis minor
- serrated anterior
91
Pleuritic chest pain
- pleura inflamed/injured
- sharp pain
- well localised + worse on inspiration
- pain felt from parietal pleura only
92
Pneumothorax
- presence of air in pleural cavity
- usually caused by trauma but can happen spontaneously
- if air keeps entering pleural cavity but cannot escape tension pneumothorax develops in which a rapidly increasing volume of air progressively compresses the lung, heart, great vessels and opposite lung
- rapidly fatal without immediate intervention
- presented wiht severe respiratory distress
93
Haemothorax
- a collection of blood in the pleural cavity
- occurs secondary to trauma when blood vessels are torn or cut
94
Pleural effusion
- presence of excess fluid in pleural cavity
- not a diagnosis (fluid could be pus from infection, blood or malignancy)
- chest drain used to remove air/fluid from pleural space
- must consider surface anatomy of heart and lungs to ensure tip of drainage tube does not injure them
- incision made in lower part of chosen intercostal space to avoid neurovascular bundle (lies in costal groove of rib superior to space)
95
Mesothelioma
malignancy of pleura
96
Pulmonary embolism (PE)
- blood clot in pulmonary circulation
- forms deep in veins in one of legs and carried in venous circulation back to right side of heart into pulmonary trunk
- large clot lodging pulmonary trunk or one of pulmonary arteries cuases severe respiratory distress and may be rapidly fatal
- smaller that occlude smaller pulmonary vessels may cuase infection of part of lung they supply
97
Dyspnoea
- breathlessness or shortness of breath
- use of accessory muscles is sign of respiratory distress
- upper limbs 'fix' steady (holding ont side of bed or chair) allowing upper limb muscles that attach to chest wall to move ribs and aid ventilation
98
Paralysis of diaphragm
- injury to phrenic nerve, C3-5 spinal nerves of C3-5 spinal cord segments on one side may paralyse ipsilateral side of diaphgram
- may not cause symptoms in healthy patient
- patients with bilaateral paralysis of diaphragm require ventilatory support
99
What is the mediastinum?
- the part of the thoracic cavity that lies between the lungs
- contains all thoracic viscera apart from the lungs
- divided into superior and inferior compartment
100
Where does the mediastinum extend from?
- superior thoracic aperature superiorly to the diaphragm inferiorly
- sternum anteriorly to the thoracic vertebrae posteriorly
101
What does the mediastinum contain?
- the heart and pericardium
- great vessles that enter+leave the heart
- veins that drain the chest wall
- trachea and main bronchi
- oesophagus
- nerves (somatic and autonomic)
- lymphatics
- thymus gland
102
What is the pericardium?
the fibrous sac around the heart
103
Inferior mediastinum
- divided into three: anterior, middle and posterior
104
(inferior) Anterior mediastinum
- lies between the posterior aspect of the sternum and anterior aspect of pericardial sac
- narrow space containing the thymus gland in children and its remnant in adults
105
(inferior) Middle mediasternum
- contains the heart inside the pericardial sac, pulmonary trunk and ascending aorta
106
(inferior) Posterior mediasternum
- lies between the posterior aspect of the pericardial sac and vertebrae
107
Contents of the superior mediasternum
- arch of aorta and its three branches
- superior vena cava and its tributaries
- trachea
- oesophagus
- phrenic nerves (left and right) and vagus nerves (left anf right)
- thoracic duct
- thymus gland
108
What are the vena cava tributaries?
the left and right brachiocephalic veins
109
What are the three parts of the aorta in the thorax?
- ascending aorta (short first part giving rise to coronary arteries)
- arch of aorta (curves posteriorly and lies in superior mediastinum)
- descending (thoracic) aorta descends through posterior mediastinum into abdomen posterior to diaphragm
110
What three major branches rise from the arch of the aorta in the superior mediastinum?
- brachiocephali trunk (bifurcates into right common carotid artery and right subclavian artery)
- left common carotid artery
- left subclavian artery
111
What does the Right common carotid artery supply?
supplies the right side of the head and neck, including brain
112
Right subclavian artery
supplies right upper limb
113
Left common carotid artery
supplies left side of the head, neck and brain
114
Left subclavian artery
supplies left upper limb
115
Arch of aorta- what does it contain
- contains aortic bodies (where chemoreceptors are located)
116
What do the chemorecpetors in the arch of the aorta monitor?
arterial oxygen and carbon dioxide (this visceral sensory information travels back to CNS along the path of the vagus nerve resulting in reflex responses that regualte ventilation)
117
What is ligamentum arteriosum?
- a fibrous cord-like connection between the pulmonary trunk and arch of aorta
- it is the remnant of the ductus arteriosus
118
What is the ductus arteriosus?
- a foetal circulatory shunt
- it diverts most of the blood entering the pulmonary trunk directly into the aortic arch (gas exchange occurs in placenta in foetus)
- only a small amount of blood circulates through the foetal lungs (enough for them to develop)
119
What happens when the baby starts to use their lungs at brith?
the ductus arteriosus closes and blood in the pulmonary trunk enters the lungs
120
Superior Vena Cava
- returns blood to heart from head, neck and upper limbs
- it and its tributaries lie in the superior mediastinum
- it is formed by the union of the left and right brachiocephalic veins
121
What forms the brachiocephalic veins?
the union of the internal jugular vein (which darins the head and neck) and the subclavian vein (which drains the upper limb) forms each brachiocephalic vein
122
Inferior Vena Cava
- return blood to heart from all regions inferior to diaphragm (abdomen, pelvis and lower limbs)
- thoracic part is very short (as soon as it enters the thorax through the diaphragm it enters the right atrium)
123
Trachea- including termination
- semi-rigid due to C-shaped incomplete rings of cartilage
- extends from larynx in middle of neck into the superior mediastinum
- is palpable just superior to the suprasternal notch
- termiantes at level of sternal angle (+ junction between T4 and T5 vertebrae) by bifurcating into the left and right main bronchi
124
Oesophagus
- muscular tube that extends from pharynx in midline of neck to the stomach
- 'waves' of contractions of smoot muscle in oesophageal wall move swallowed food and fluid distally (peristalsis)
- lies in midline of thorax in superior mediastinum, posterior to trachea
- decends into posterior mediastinum
125
Peristalsis
a series of wave-like muscle contractions that move food through the digestive tract
126
Vagus nerves
- left and right arise from brainstem
- contain somatic: sensory, motor and also parasympathetic fibres
- innervate structures of the thorax and abdomen, in addition to head and neck
- they descend through the neck alongisde the internal carotid artery and internal jugular vein and enter the thorax via superior thoracic aperture
- each give rise to reaccurent laryngeal nerve (RLN)
- descend in the thorax posterior to the root of the lung
- contribute parasympathetic fibres to the heart, lungs, and oesophagus
- they transverse the diaphragm and convey parasympathetic fibres to most of the abdominal viscera
127
Reacurrent laryngeal nerves
- left and right
- ascend back up into the neck to innervate the muscles of the larynx
128
Left RLN
loops under the arch of the aorta before ascending back up the left side of the neck (alongside the trachea) to the larynx
129
Right RLN
descends anterior to the right subclavian artery and then loops under the inferior border of the artery before ascending back up the right side of the neck (between the trachea and oesophagus) to the larynx
130
Thoracic duct
- major channel for lymphatic drainage from most regions of the body
- it ascends through the posterior mediastinum and into the superior mediastinum where it empties into the venous system at the union of the left internal jugular vein and left subclavian vein
131
Thymus gland
- a lymphoid organ
- lies anteriorly in the superior mediastinum
- important in children but atrohpies with age
- eventually becomes fatty
132
Pericardium
- tough fibrous sac that encloses the heart like a loose-fitting bag
133
Why is the pericardium loose?
to allow for movement of the heart within it
134
What two layers is the pericardium composed of?
- tough outer fibrous layer (attached superiorly to the great vessels and inferiorly to the central tendon of the diaphragm)
- thin inner serous layer which has two parts: parietal layer lines the inner aspect of fibrous pericardium and visceral layer covering the surface of the heart
- the two layers are continuous with each other
135
Pericardial cavity
- narrow space between the two layers of serous pericardium
- contains small amount of pericardial fluid that lubricates the serous membranes and allows them to slide over each other with movements of the heart.
136
What innervates the fibrous pericardium?
the sensory branches from the left and right phrenic nerves
137
What are the surfaces of the heart?
- base - it 'faces' posteriorly (also called posterior surface)
- inferior surface - lies on central tendon of diaphragm (called disphragmatic surface)
- anterior surface - faces sternum and ribs (called sternocostal surface)
- left anf right sides of heart face lungs (pulmonary surfaces)
138
True or false? the surfaces of the heart correspond to specific parts of the heart
true
- posterior surface = left atrium, part of right atrium
- diaphragmatic surface = left ventricle, part of right ventricle
- sternocostal surface = right ventricle
- left pulmonary surface = left ventricle
- right pulmonary surface = right atrium
139
Apex of the heart
- formed by left ventricle
- lies at 5th intercostal space in midclavicular line
- apex beat is palpable here
140
Borders of the heart
- 'edges' of the heart on a chest x-ray
- right border = right atrium
- left border = left ventricle
- inferior border = right ventricle and part of the left ventricle
141
Where is the right border of the heart?
- lateral to the right sternal edge
- from right 3rd costal cartilage to right 6th costal cartilage
142
Where is the left border of the heart?
- extends from left 2nd intercostal space to left 5th intercostal space in the midclavicular line
143
Where is the superior border of the heart?
- along the line connecting the superior extents of the right anf left borders
- from right 3rd costal cartilage to the left 2nd intercostal space
144
Where is the inferior border of the heart?
- along the line connecting the inferior end of the right border with the apex (mostly formed by the right ventricle)
145
Auricles
- auricular appendages
- named because of their ear-like appearance
- outpouchings from the walls of the right and left atria
146
Coronary circulation
- arteries and veins supplying the heart are visible on the external surface
- major arteries lie in grooves on the external surface called SULCI
147
Patent ductus arteriosus (PDA)
- when the ductus arteriosus does not close and remains open in some infants
- after brith the pressure in the aorta exceeds pressure in pulmonary trunk hence blood flows through a patent ductus arteriosus from aorta into pulmonary trunk
- over time increased flow through the pulmonary vessels can lead to pulmonary hypertension which strains the right side of the heart
148
Hoarseness of the voice and lung cancer
- cancer at apex of lung may involve the recurrent laryngeal nerve (which supplies most of the msucles of the larynx
- nerve injury results in weakness/paralysis of ipsilateral intrinsic laryngeal muscles which move the larynx and the vocal cords
- hoarseness results as the patient can no longer fully adduct their vocal cords
149
Pathology of pericardium
- pericardial space allows heart to move within the pericardial sac with each contraction
- pericardial effusion can occur from result of inflammation of the pericardium (pericarditis) or an accumulation of blood (due to trauma.
- rapid fluid accumulation in the pericaridal space can be rapidly fatal because the fibrous pericardium cannot stretch and so the heart is compressed and unable to fill properly CARDIAC TAMPONADE
150
What is Pericardial effusion?
an increase in fluid volume in the pericardial space
151
What is Pericarditis?
inflammation of the pericardium
152
What is cardiac tamponade?
when the heart is compressed and unable to fill properly
153
Where do left and right coronary arteries arise from?
ascending aorta (gives rise to several named branches)
154
Where do cardiac veins return venous blood to?
the coronary sinus (which enters the right atrium)
155
What does the right coronary artery and its branches supply?
- the conducting system of the heart
- right atrium
- right ventricle
- left ventricle
- part of intraventricular septum
156
Branches of the right coronary artery
- branches to SAN and AVN
- right marginal artery supplying inferior border of the heart
- posterior interventricular artery (PIV) is the continuation of the right coronary artery on the diaphragmatic surface of the heart (runs in posterior intraventricular sulcus and supplies both ventricles)
157
What does the left coronary artery and its branches supply?
- parts of conducting system of the heart
- left atrium
- most of left ventricle
- part of right ventricle
- part of intraventricular septum
158
Terminal Branches of the left coronary artery
(LCA only runs a short course before it divides into two large terminal branches)
- short segment = left main stem
Two terminal branches of LCA:
- anterior interventricular artery (or left anterior descending)
- circumflex artery
159
Main branches of the left coronary artery
- anterior intervetricular artery (LAD) (runs in the anterior interventirucluar sulcus towards apex and supplies both ventricles)
- one or two diagonal branches arise from LAD
- circumfelx artery runs around the heart onto the diaphragmatic surface (supplies left atrium and part of right ventricle and left ventricle)
- left marginal artery arises from circumflex and supplies left ventricle
160
What do valves in the heart ensure?
unidirectional flow of blood through the chambers of the heart
161
Main features of right atrium
- interatrial septum (separates it from LA)
- fossa ovalis (depressoin in interatrial septum which is remnant of foetal foramen ovale)
- crista terminalis
162
Foetal foramen ovale
shunts oxygenated blood from right atrium to left atrium, hence bypassing the lungs
163
Crista terminalis
- muscular ridge that separates smooth-walled posterior part of atrium from anterior part (which had a ridged muscular wall)
- ridges are pectinate muscles and extend into right auricle
164
Main internal features of rigth ventricle
- interventricular septum (separates it from LV)
- trabeculae carneae (muscular ridges on internal wall)
- papillary muscles
- chordae tendineae
- moderator band
165
What are papillary muscles?
modified regions of trabeculae carneae which project into the lumen of the ventricle
166
What is the chordae tendineae?
fibrous cords which connect the tips of the papillary muscles to the tricuspid valve
167
What is the moderator band?
modified region of trabeculae carneae which connects the interventricular septum to one of the papillary muscles
168
What is the left atrioventricular valve also known as?
the mitral valve
169
Parts of the left ventricle
- trabeculae carneae
- papillary muscles (x2)
- chordae tendineae (connect tips of papillary muscles to mitral valve)
170
Why are the papillary muscles and chordae tendineae crucial for the normal functioning of the AV valves?
- do not close but allow closed valves to resist the pressure generated inside the ventricles during contraction and prevent them from being forced open
171
When ventricles contract...
the papillary muscles also contract (tense the cords which then 'pull' on the valve cusps and prevent them everting into the atria
172
Cusps of semi-lunar valves
- have three semi-circular cusps
- each cusp is attached to the inner wall of vessel
- free edge that projects into the vessel lumen
- each cusp forms a pocket (sinus) between its free edge and vessel wall
173
What happens when the blood is forcefully propelled from the ventricles during ventricular systole?
- valve cusps are flattened onto the vessel wall and blood flows through the valve unimpeded
174
What happens when pressure drops in ventricle?
- backflow
- blood is immediately caught in the valve cusps
- sinuses fill with blood and then cusps balloon out into the lumen
- free edges of three valve cusps contact each other in the lumen and close the vlave orifice
175
Ascultatory areas for each valve
- aortic valve = 2nf intercostal space R
- pulmonary valve = 2nd intercostal space L
- tricuspid valve = 5th intercostal space L
- mitravl valve = 5th intercsotal space M
176
At what rate does the SAN generate impulses?
~70 per minute
177
How does the atrioventricular bundle divide?
- two groups the left and right bundle branches (which give rise to purkinje fibres
178
Purkinje fibres
enter the myocardium of the left and right ventricles and stimulate contraction
179
Blood supply to SAN
~60% of people = RCA
~40% of people = LCA
180
Blood supply to AVN
posterior interventricular artery (mostly arising from RCA)
181
Blood supply to Bundle of His
most people = LCA
182
Sympathetic stimulation...
increases heart rate and force of contraction
183
Parasympathetic stimulation...
slows heart rate and force of contraction
184
True or false? the heart is also innervated by visceral afferent fibres
true - they convey sensory information from heart back to CNS (doesnt usually reach conscious perception)
185
Referred pain
when pain cannot be pinpointed
186
When does visceral sensory infroamtion reach conscious perception?
when myocardium is ischaemic, may be percieved as pain, burning, tightness or pressure in the chest
(pain usually felt generally in chest/left side of neck)
187
Myocardial infarction
- death of region of myocardium secondary to occasion of coronary vessel
- caused mainly by atherosclerosis in CA
- fatty plaque in CA may grow unti lit narrows the vessel lumen (stenosis) and severly restricts blood flowing through it
- fatty plaque may shear from vessel wall causing a clot to form in the lumen which occludes blood flow
188
Valve dysfunction
- AV and semilunar valves become narowed (stenosis) or incompetent
- allows regurgitation of blood back
- results in turbulent blood flow producing murmurs on auscultation
- sometimes minor/major
- could be congenital or acquired
189
Congenital
patient born with it
190
Cardiomyopathies
- disease of myocardium (mostly inherited)
- some cause myocaridum to thin, wheras others result in the myocardium becoming thick and stiff
- affects heart's abilty to pump efficiently and can lead to heart failure
191
Conducting system abnormalities
- myocardial infarction can cause conduction disturbances if the vessles that supply the conductin system are affected
- managed by fitting a pacemaker or internal cardiac defribilator
192
Heart Faliure
- heart does not pump efficiently
- caused by dysfunction of valves or inability of myocradium to caontract properly
- symptoms - tiredness, shortness of breath and leg swelling
193
Cardiac arrest
- cessation of cardiac contraction
- heart does not contract in response to electrical activity
- causes could be myocardial infarction and conducting system abnormalities
194
What does the posterior mediastinum contain?
- descending aorta
- azygous veins
- oesophagus
- thoracic duct
- sympathetic trunk and splanchnic nerves
- posterior intercostal vessels and nerves
195
What branches off the descending aorta?
- posterior intercostal arteries
- bronchial arteries
- oesophageal branches
- pericardial branches
- phrenic branches (supply diaphragm)
196
Where does the aorta pass through the diaphragm?
T12
197
Where does the azygos system of veins arise in the abdomen?
L1/L2
198
Azygos Veins
- drain blood from posterior thoracic wall and return it to superior VC
- lies on bodeis of thoracic vertebrae
199
What does the azygos system of veins comprise of?
- azygos vein on right side of vertebral bodies
- smaller (shorter) hemiazygos vein on the left side of vertebral bodies
- one or more veins connecting the above veins to each other
200
Where does the azygos system recieve blood from?
- posterior intercostal veins
- oesophageal veins
- bronchial veins
201
Where is the oesophagus?
- right of the aorta
- posterior mediastinum
- passes through the oesophageal hiatus in the diaphragm at the level of T10
202
Oesophagus blood supply
- oesophageal arteries from descending aorta
- oesophageal veins return venous blood to azygos system
203
True or false? the smooth muscle in the wall of the oesophagus is under autonomic control
true - we do not conciously control it
204
Where is the most distal part of the oesophagus?
inferior to diaphragm
205
What is the thoracic duct?
vessel that returns most of the body's lymph to the venous system
206
Where is the thoracic duct?
- lies between the azygos vein and aorta
207
Thoracic duct
- lymph from lower limbs, pelvis and abdomen flows towards the cisterna chyli which ascends into the thorax
- in thorax duct recieves lymph from intercostal spaces and lymph nodes
- duct ascends into the neck, recieving lymph from the left side of head and neck and left upper limb
- terminates by opening into the venous system at the junction between the left internal jugular vein and left subclavian vein
208
Cisterna chyli
a sac-like swelling that gives rise to the thoracic duct
209
Sympathetic trunks
- lie on posterior throacic wall (either side of vertebral column and posterior to parietal pleura)
- thin longitudinal fibres tracts regularly interspersed with ganglia
- trunks extend from skull base to coccyx
- allow the sympatheitc fibres to be distributed to all parts of the body
210
Ganglion
a collection of cell bodies outside the CNS
(ganglia in sympathetic trunks also referred to as paravertebral ganglia since they lie alongside the vertebral column)
211
Where do the cell bodies of the preganglionic sympathetic neurones lie?
in thoracic and upper spinal cord segments (T1-L2/3)
212
Why do the sympathetic fibres in the sympathetic trunk leave the spinal cord from its ventral aspect and enter spinal nerves T1-L2/3 along the somatic motor nerves?
because they are visceral motor fibres
(their cell bodies lie in the ventral grey horn)
213
Why do the sympathetic fibres in the sympathetic trunk leave the spinal cord from its ventral aspect and enter spinal nerves T1-L2/3 along the somatic motor nerves?
because they are visceral motor fibres
(their cell bodies lie in the ventral grey horn)
214
Where do the preganglionic sympathetic fibres exit the spinal cord?
spinal nerves T1-L2/3
(almost immediately they separate from the spinal nerves and enter the sympathetic trunk via a short communicating/ connecting branch - white ramus communicans)
215
What does the preganglioinc axon do once in the sympathetic trunk?
one of the following:
- synapses in the ganglion at its level of entry
- ascends or descends in the trunk before synapsing in a ganglion
FOLLOW UP QS NEXT FOR TOP TWO
- travels through a ganglion (and the trunk) without synapsing
216
In scenarios 1 and 2, the postganglionic axons leaving the ganglia...
- enter the spinal nerves via a communicating branch (grey ramus communicans). Through this arrangement, sympathetic fibres enter all 31 pairs of spinal nerves
- form visceral nerves that convey sympathetic fibres to the head
- form visceral nerves that convey sympathetic fibres to the thoracic viscera (cadiopulmonary splanchnic nerves)
217
What are the abdominopelvic splanchnic nerves?
- greater splanchnic nerve (sympathetic preganglionic fibres originating from T5-T9 segments of the spinal cord)
- lesser splanchnic nerve (T10-11)
- least splanchnic nerve (from T12)
- lumbar splanchnic nerves (from L1-L2)
218
Where do the greater, lesser and least splanchnic nerves form?
in the posterior mediastinum and transvere the diaphragm to enter the abdomen
219
True or false? the preganglionic sympathetic fibres in these splanchnic nerves ultimately synapse with the second neurons in prevertebral ganglia that lie close to major blood vessels in the abdomen
true - after synapsing the postganglionic fibres innervate abdominal viscera
220
What does the posterior intercostal space contain?
- intercostal muscles
- posterior intercostal artery (branch of thoracic artery)
- posterior intercostal vein (which drains to the azygos system)
- posterior intercostal nerve
221
What is the thoracic viscera innervated by?
sympathetic (cadiopulmonary splanchnic nerves) and parasympathetic (vagus nerves) fibres which form AUTONOMIC PLEXUSES around the thoracic viscera
222
Plexus
networks of veins and arteries
223
Plexuses in the thoracic
- cardiac plexus
- pulmonary plexus
- oesophageal plexus
224
Cardiac plexus
- innervates the sinoatrial node of the heart
- sympathetic fibres increase the heart rate and force of contraction
- parasympathetic fibres decrease the heart rate and force of contraction
225
Pulmonary plexus
- innervates the bronchi
- sympathetic stimulation relaxes the bronchi
- parasympathetic stimulation constricts them
226
Oesophageal plexus
- overlies anterior syrface of oesophagus
- sympathetic fibres inhibit peristalsis
- parasympathetic fibres stimulate peristalsis
227
Visceral afferents
relay sensory information from the thoracic viscera back to the CNS along the paths of the vagus and thoracic splanchnic nerves
228
What is the heart innervated by?
- cardic plexus
- visceral sensory nerves
229
Cardiax Plexus
- sympathetic from spinal cord segments T1-T5 via cardiopulmonary splanchnic nerves
- parasympathetic
230
Visceral Sensory nerves
- convey sensory information from the heart back to the CNS
- visceral sensory information enters spinal cord segments T1-T5
- sensation does not normally reach conscious perception
231
True or false? Somatic sensory information from the skin of the chest wall, neck and arm also returns to spinal cord segments T1-T5
True - this and sensory information of heart entering the spinal cord segments T1-T5 is what causes brain to interpret the cardiac pain as pain from chest, neck and arm
232
Example of referred pain (shoulder)
- results from diaphragm
- cervical cord segments 3-5 contribute spinal nerve fibres to the phrenic nerve
- cord segments C3-5 also contribute to the nerves that innervate the skin of the neck and shoulder
- therefore the brain interprets this pain coming from the diaphragm as coming from the shoulder region
233
Aortic dissection
- longitudinal tear in aortic wall that allows blood to collect between the intima and media
- can happen in ascending aorta, arch or descending aorta
- typically presents with sudden onset severe chest and back pain
- blood collects in the false lumen created by the tear
234
Horner's syndrome
- small pupil, drooping upper eyelid and lack of sweating on one side of face
- caused by interruption to the sympathetic nerves that innervate the head
- cancer in apex of lung that invades the sympathetic chain can cause Horner's syndrome of the ipsilateral side of the head
235
Miosis
small pupil
236
ptosis
drooping upper eyelid
237
anhidrosis
lack of sweating on one side of the face
238
hiatus hernia
- occurs when abdominal segment of the oesophagus (inferior to the diaphragm) and part of the stomach moves proximally through the oesophageal opening in the diaphragm and into the chest
- patients may experience symptoms such as heartburn and acid reflux
239
Why is the neck slender?
- allows optimal positioning of the head
- (the cervical spine is also flexible however this felxibility means the neck is prone to injury)
240
What structures does the neck contain?
- respiratory tract (pharynx, larynx, trachea)
- gastrointestinal tract (pharynx, oesophagus)
- glands (thyroid and parathyroid)
- arteries and veins
- nerves
- muscles (including those that move the head and neck, larynx in spee + swallowing and that form the mouth
- platysma
241
What nerves pass through the neck?
- nerves that serve the head and neck
- upper limbs
- thoraco-abdominal viscera (via vagus)
- diaphragm (via phrenic)
242
Platysma
very thin subcutaneous muscle deep to the skin of the neck
243
What allows the cervical spine to have a good range of flexion?
cervical vertebrae are small and articulate with each other at facet joints that are orientated obliquely
244
Hyoid bone
- a slender bone situated anteriorly in uper neck
- inferior to mandible
- helps keep pharynx open
- provides attachment point for muscles in neck + tongue
245
Larynx
- voice box
- composed of a skeleton of small cartilages connected by membranes and small joints
- protects the airway
- muscles attach to laryngeal cartilages and move them (in turn moving the vocal cords and allowing phonation)
246
How is the neck described?
in terms of anterior and posterior triangles (separated by sternocleidomastoid muscle
247
Sternocleidomastoid muscle
- attached to sternum, clavicle and mastoid process (part of temporal bone)
- can act unilaterally or bilaterally (both L and R muscles act together)
- innervated by accessory nerve (cranial nerve XI)
248
Boundaries for anterior triangle
- anterior: midline of neck
- posterior: anterior border of sternocleidomastoid
- superior: lower border of mandible
249
What does the anterior triangle contain?
- trachea and larynx
- thyroid, parathyroid and submandibular salivary glands
- suprahyoid muscles which connect the hyoid to skull
- infrahyoid muscles (strap muscles)
- common carotid (internal + external)
- branches of external CC to head and neck
- internal jugular vein
- nerves
- ansa cervicalis
250
What forms the floor of the mouth?
the suprahyoid muscles which connect the hyoid to the skull (move hyoid and larynx in speech and swallowing)
251
Infrahyoid muscles
- connect hyoid to sternum and scapula
- move hyoid and larynx in speech and swallowing
252
Nerves in anterior triangle
- facial nerve (VII)
- glossopharyngeal nerve (IX)
- vagus nerve (X)
- acessory nerve (XI)
- hypoglossal nerve (XII)
253
Ansa cervicalis
fibres from C1-C3 which innervate infrahyoid muscles
254
Boundaries of posterior traingle
- anterior: posterior border of sternocleidomastoid
- posterior: snterior border of trapezius
- inferior: clavicle
255
True or false? superiorly, the apex of the posterior triangle is formed by sternocleidomastoid and trapezius
true
256
What does the posterior triangle contain?
- muscles that move the head
- part of subclavian artery and subclavian vein
- external jugular vein
- accessory nerve (XI)
- roots of brachial plexus
- cervical plexus
- phrenic nerve
257
External jugular vein
- drains the scalp and face
- joins the subclavian vein
258
Brachial plexus
spinal nerves that supply the upper limb
259
Cervical plexus
fibres from C1-4
260
Suprahyoid muscles
- four paird muscles
- mylohoid, geniohyoid, stlyohoid and digastric
- lie superior to hyoid bone and form floor of mouth
- when they contract they raise the hyoid bone and larynx during speech and swallowing
261
Infrahyoid muscle
- four paired 'strap' muscles
- sternohyoid, omohyoid, sternothyroid, thyrohyoid
- lie inferior to hyoid bone just lateral to anterior midline of neck
- they draw the hyoid bone and laryn inferiorly during speech and swallowing
262
Sternohyoid and Omohyoid
- lie superficially
- attach the hyoid to sternum and scapula (respectively)
263
The Thyroid Gland
- composed of L and R lobes that lie lateral to lower larynx and upper trachea
- each lobe lies deep to the sternohyoid muscle
- two lobes are joined by isthmus (which lies anterior to trachea)
- produces hormones important in metabolic processes
- pituitary gland regulates hormone secretion from thyroid gland
264
Blood supply to thyroid gland
- L and R superior thyroid arteries (branches of external carotid arteries
- L and R inferior thyroid arteries (branches of thyrocervical trunks - branches of subclavian artery)
265
True or false? Some people have an additional thyroid ima artery
True - superior, middle, inferior thyroid veins drain the thyroid gland
266
Parathyroid glands
- four parathyroid glands
- L and R superior and inferior
- located posterior to thyroid gland
- produce parathyroid hormone which plays a role in Ca regulation
- typically supplied by inferior thyroid arteries
267
Where can the pulsation of internal carotid be palpated?
immediately lateral to the larynx
268
Internal carotid artery
- does not give rise to any branches in neck
- enters cranium and supplies the brain
269
External carotid artery
- gives rise to bracnhes supplying pharynx, scalp, thyroid gland, tongue and face
270
Carotid sinus
- small welling at point of bifurcation of common carotid
- baroreceptors here constantly monitor arterial blood pressure
- visceral sensory information is relayed back to CNS via glossopharyngeal nerve (results in reflex response that regulate blood pressure)
271
Internal jugular vein
- drains blood from the brain and part of face
- unites with subclavian vein which returns blood from upper limb to form brachicephalic vein
- R and L brachiocephalic veins unite to form superior vena cava
272
Facial nerve (VII)
supplies platysma in neck
273
Glossopharyngeal nerve (IX)
- pharynx (sensory innervation)
- carotid sinus (visceral sensory fibres that return to the CNS via)
274
Vagus nerve (X)
- vital for normal speech and swallowing
- supplies muscles of the pharynx (motor innervation)
- larynx (motor and sensory innervation)
- runs between the internal jugular vein and internal carotid artery (above its bifurcation) and between the internal jugular vein and common carotid (below its bifurcation)
- the three structures run together in a fascial sleeve called carotid sheath
275
Carotid sheath
- vagus nerve
- jugular vein
- carotid artery
276
Accessory nerve (XI)
supplies sternocleidomastoid and trapezius muscles
277
Hypoglossal nerve (XII)
- motor to muscles of the tongue
- does not supply any structures in neck but travels through it
- lies lateral to internal carotid artery
- deep to jugular vein
278
Phrenic nerve
- formed by C3, C4 and C5 nerve fibres
- decends through neck to enter thorax
- innervated diaphragm
279
True or false? The head and neck are richly innervated with sympathetic nerves
true
- sympathetic trunk extends as far as the base of the skull
280
What are the associated sympathetic ganglia in the neck?
- superior
- middle
- inferior cervical ganglia
(postganglionic fibres from these ganglia innervate the head and neck)
281
Thyroidectomy
- removal of thyroid gland (may risk injury to recurrent laryngeal nerves which lie close to inferior thyroid arteries)
- nerve may be cut when artery is ligated
- injury to recurrent laryngeal nerve results in inability to move ipsilateral vocal cord and this affects the quality of the voice
- also: parathyroid glands may be removed which disturbs calcium homeostasis
- after thyroidectomy patients must take hormone replacements
282
Penetrating injuries to the neck
- often injure multiple structure since many vital neurovascular structures are located very closely to each other
- such injuries are often fatal or cause severely debilitating injuries
283
Carotid artery stenosis
- atheroma in carotid artery
- narrowed lumen (stenosis)
- impeded blood flow to brain
- if plaque breaks up the fragments will be carried up into cerebral arteries causing stroke (fatal/debilitating)
- prevention: atheroma surgically removed from wall of carotid artery: CAROTID ENDARTERECTOMY
- risk of severe bleeding in procedure from carotid artery and stroke
284
Central line insertion into internal jugular vein
- patients that need fluid and drugs intravenously
- large line with multiple ports placed into large central vein
- IJV is vein of choice (relatively easy to access and can easily be visualised with ultrasound)
285
Pharynx
- muscular tube which lies in neck
- forms part of respiratory and gastrointestinal systems
- one continuous passageway composed of three parts: nasopharynx (posterior to nasal cavity), oropharynx (posterior to oral cavity), laryngopharynx (posterior to larynx)
286
Other name for laryngopharynx
hypopharynx
287
What are the walls of the pharynx composed of?
- outer layer of circular muscle
- inner layer of longitudinal muscle
288
External circular muscle layer
composed of three constrictor muscles
- superior
- middle
- inferior constrictors that overlap each other
They constrict superior to inferior so that swallowed food moves down the pharynx towars the oesophagus
289
True or false? During swallowing, food in oral cavity is pushed into oropharynx by the tongue
true
- soft palate rises and closes off nasopharynx from oropharynx
- food enters laryngopharynx and constriction of msucles of pharyngeal wall move the food into the oesophagus
- epiglottis closes off laryngeal inlet and prevents food or liquids from entering the larynx
290
epiglottis
one of the cartilages of the larynx
291
Which nerves innervate the pharynx?
- sensory fibres from glossopharyngeal nerve (IX)
- motor fibres from vagus nerve (X)
292
Nerves which lie close to posterior pharyngeal wall
- cervical part of sympathetic trunk and superior cervical ganglion
- superior laryngeal nerve
- hypoglossal nerve (lies close to vagus nerve)
- glossopharyngeal nerve (lies deep to internal carotid artery, posteriorly)
293
Nerves which lie close to posterior pharyngeal wall
- cervical part of sympathetic trunk and superior cervical ganglion
- superior laryngeal nerve
- hypoglossal nerve (lies close to vagus nerve)
- glossopharyngeal nerve (lies deep to internal carotid artery, posteriorly)
294
True or false? the larynx protects the airway and contributes to phonation/speech
True
295
Laryngeal skeleton
- nine cartilages, three paired, three upaired
- unpaired: epiglottis, thyroid cartilage and cricoid cartilage
- paired much smaller
- paired: arytenoids, cuneiforms, corniculate cartilages
296
Thyroid cartilage
- composed of two flat cartilages (laminae) that meet in the anterior midline
- form laryngeal prominence "adam's apple"
- usually visible in males
297
Superior and inferior horns
- posterior extension of thyroid cartilage that projects superiorly and inferiorly
- superior horns attach to hyoid bone
- inferior horns articulate with the cricoid cartilage below
298
Cricothyroid membrane
- connects inferior border of the thyroid and superior border of cricoid
- membrane is pierced to create emergency airway
299
Epiglottis
- attached to superior aspect of thyroid cartilage where the two thyroid laminae meet
- during swallowing the epiglottis covers the entrance to the larynx (larygneal inlet)
- protects the airway from the entry of liquid or food
300
Arytenoids
- sit on the superior surface of the cricoid cartilage
- they articulate with the cricoid cartilage at small joints
- small but vital for phonation as the vocal cords attach to them
- movements of the arytenoids move vocal cords
301
What are the two groups of muscles that act upon the larynx?
- extrinsic muscles - suprahyoid + infrahyoid (do not move the individual cartilages but move larynx as one)
- intrinsic muscles - small muscles move individual cartilages of the larynx relative to each other, moving the vocal cords in turn altering the quality of speech
302
Structures in the neck that are palpable on examination
- hyoid bone inferior to mandible
- thyroid cartilage in midline of neck
- cricoid cartilage in midline, inferior to thyroid cartilage
- first tracheal cartilage inferior to cricoid cartilage
- cricothyroid membrane between the thyroid cartilage and cricoid cartilage
-
303
Structures in the neck that are palpable on examination
- hyoid bone inferior to mandible
- thyroid cartilage in midline of neck
- cricoid cartilage in midline, inferior to thyroid cartilage
- first tracheal cartilage inferior to cricoid cartilage
- cricothyroid membrane between the thyroid cartilage and cricoid cartilage
- lobes of thyroid gland either side of the upper trachea and inferior larynx
- carotid pulse
304
What can be punctured to create an emergency airway?
cricothyroid membrane
305
Where is the carotid pulse best palpated?
- anterior to sternocleidomastoid at level of thyroid cartilage
306
Gag reflex
- protects airway
- mediated by glossopharyngeal and vagus
- when back of mouth, posterior wall of the pharynx or the tonsils are stimulated, this sensation is carried to the CNS via glossopharyngea, nerve
- response: muscles of soft palate and pharynx immediately contract (via motor fibres in vagus nerve)
- reflex does not occur in normal swallowing but does occur at any other time the posterior mouth or pharynx are touched
307
Swallowing difficulties after stroke
- may be difficult if part of brain involved is affected
- normally vagus nerve coordinates contraction of pharyngeal muscles and soft palate and converys sensation from larynx. glossopharyngeal provides sensory innervation of pharynx
- if pathway disrupted swalloing is dysfunctional and loss of sensation impairs cough reflex
- patients risk for aspiration
308
Aspiration
swallowed liquid or food may pass into the lungs and cause infection
309
Emergency airway
- if airway obstucted avove level of cricoid cartilage an emergency airway that bypasses upper airway can be created by piercing cricothyroid membrane
- lifesaving but temporary measure
- more secure airway is established as soon as possible
310
What are the tonsils collections of?
lymphoid tissue in the upper parts of the pharynx
311
Types of tonsils
- pharyngeal and tubal tonsils found in nasopharynx
- palatine tonsils lies next to pharyngeal wall in oropharynx
- lingual tonsil
312
Where are the tonsils found?
in the internal larynx
313
lingual tonsil
collection of lymphoid tissue on posterior aspect of the tongue
314
pharyngeal tonsil
- lies in the rood of nasopharynx
- also called adenoid tonsil
315
tubal tonsil
- surrounds the opening of the auditory tube (which connects the nasopharynx to the middle ear - we will coma back to this in a later session)
316
True or false? the internal aspect of the larynx is modified for phonation
true - intrinsic muscles of the larynx move the laryngeal cartilages which in turn move the vocal cords that lie inside the larynx.
- injury to nerves that innervate the intrinsic laryngeal muscles therefore affect speech
317
Vocal folds in the larynx
- vestibular folds (false vocal cords) superiorly
- vocal folds (true vocal cords) inferiorly
- a narrow space separates the vestibular and vocal folds
318
Vestibular folds (false folds)
folds of mucous membrane that lie superior to the vocal folds
319
Vocal folds (true folds)
folds of mucous membrane that cover and protect the vocal ligaments - together they form the true vocal cords
320
How are vocal ligaments attached to laryngeal prominence?
attached anteriorly to internal aspect of the laryngeal prominence and posteriorly to the arytenoid cartilages
321
Rima glottidis
- space between the true vocal cords
- adduction of the true vocal cords closes the rima glottidis
- abduction of the folds opens it
322
What does phonation require?
adduction of the cords and close of the rima glottidis
323
Abduction of the cords opens the rim glottidis...
- to a small degree in whispering
- partially in normal breathing
- fully in forced breathing
324
What moves the vocal cords and how does this affect the rima glottidis?
325
What moves the laryngeal cartilages and hence the vocal cords?
Sevel pairs of intrinsic muscles
326
What are some of the pairs of intrinsic muscles?
- Cricothyroid
- Posterior crcoartytenoids
- Transverse arytenoids
327
Cricothyroid
- anteriorly (between thyroid and cricoid cartilages)
- muscle tips the thyroid cartilage anteriorly and inferiorly
- this places tension on the vocal cords
328
Posterior cricoarytenoids
- posterior surface of the cricoid
- attach to arytenoids
- muscles abduct the vocal cords and open the rima glottidis
329
Transversus arytenoids
- posterior aspect of the larynx
- connecting the two arytenoid cartilages
- these muscles adduct the vocal folds and close the rima glottidis
330
Which nerve innervates the cricothyroid muscle?
- superior laryngeal nerve (from the vagus nerve)
- it is sensory to the larynx above the vocal folds
331
Which nerve innervates the rest of the intrinsic muscles (besides the cricothyroid muscle)?
- recurrent laryngeal nerve (from the vagus nerve)
- it is sensory to the larynx below the vocal folds
332
What are the three main salivary glands that secrete saliva into the oral cavity?
- the parotid
- submandibular
- sublingual salivary glands
333
What is glandular secretion stimulated by?
parasympathetic fibres
334
The Parotid Gland
- largest of the three
- overlies the posterior part of mandible
- saliva empties into mouth via parotid duct (which opens adjacent to upper second molar tooth)
- closley related to facial nerve, as after it exits the skull it enters the deep surface of the parotid gland
- with in the gland, the facial nerve divides into five branches which emerge to innervate the muscles of facial expression
- gland also closely related to external carotid artery
- secretion stimulated by GLOSSOPHARNYGEAL nerve (IX)
335
Submandibular glands
- smaller
- part of gland lies within the mouth and part lies outside
- submandibular duct open into the floor of the mouth under the tongue
- secretion of saliva is stiulated by parasympathetic fibres in the facial nerve (VII)
336
Sublingual glands
- small and lie in the floor of the mouth
- they open via several small ducts into the floor of the mouth
- secretion is stimulated by parasympathetic fibres in the facial nerve (VII)
337
Vocal cord palsy
- recurrent laryngeal nerve lies close to inferior thyroid artery whic is ligated during thyroidectomy
- nerve innervated all but ones of intrinsic muscles of larynx
- if injured: intrsinic muscles of ipsilateral side do not function and subsequently the vocal cords on affected side cannot move
- when vocal cords on one side are unable to adduct, hoarseness results
338
Laryngeal cancer
- malignancy of larynx typicaly presents with a chnage in the quality of the voice such as hoarseness
- visualisation of the larynx - laryngoscopy - is used to examine the larynx and vocal cords
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Endotracheal intubation
- the passage of a semi-rigid tube into the trachea for ventilation
- commonly performed when patients have a general anaesthetic for surgery, or when patients are sedated in intesive care
- laryngoscope is used to lift the tongue or epiglottis so that the vocal cords can be directly seen and the tube is passed between them ito the trachea
- correct placement into the trachea (rather than oesophagus) is confirmed by a CO2 reading on the anaesthetic machine (expired air from the patient) and asculting both lungs to ensure the tube is in the trachea and not one of the bronchi
340
Pathology of parotid gland
- disease of parotid gland, trauma or surgery on the gland risks injury to the facial nerve and its branches
- injury to the nerve may result in paralysis of some or all the ipsilateral facial muscles
- mumps is a viral infection that causes painful inflammation and swelling of the parotid gland
