Cardiorespiratory Flashcards

1
Q

Tunica intima structure

A

Endothelium layer
Loose CT
Internal elastic lamina

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2
Q

Tunica intima structure

A

Endothelium layer
Loose CT
Internal elastic lamina

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3
Q

Tunica media structure

A

Circularly arranged smooth muscle
Supporting ECM with collagen and elastic fibres
External elastic lamina

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4
Q

Tunica adventitia

A

Loose CT

Vaso vasorum

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5
Q

Endocardium structure

A

Inner endothelium lining

Supporting highly elastic fibrocollagenous CT

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6
Q

Myocardium structure

A

Cardiac myocytes linked by intercalated discs

Supporting fibrocollagenous CT

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7
Q

Epicardium structure

A

Outer fibrocollagenous tissue
Large amounts of adipose tissue
Outer mesothelium - visceral pericardium

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8
Q

Elastic arteries

A

Predominance of elastin and little smooth muscle in tunica media
Found in large arteries just downstream of the heart
Function to smooth out large pressure fluctuations

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9
Q

Muscular arteries

A

Medium to small sized arteries

Have the basic arterial structure

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10
Q

Which types of cells form foam cells

A

Macrophages and smooth muscle cells

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11
Q

What does the fibrous cap consist of?

A

Smooth muscle cells with an ECM with dense collagen, elastic fibres and proteoglycans

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12
Q

Upper respiratory tract

A

Mouth –> larynx

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13
Q

Lower respiratory tract

A

Trachea –> terminal bronchioles

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14
Q

Classic respiratory epithelium

A

Pseudostratified columnar, ciliated epithelium with mucous secreting goblet cells

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15
Q

How does the epithelium change throughout the lungs?

A

Gradual transition from pseudostratified to columnar to cuboidal epithelium
Gradual decrease in number of goblet cells

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16
Q

Epithelium in the pharynx

A

Stratified squamous

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17
Q

Immune properties of the respiratory tract

A

Mucociliary escalator

MALT

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18
Q

Trachea layers

A
Respiratory epithelium
Lamina propria - with elastin and lymphoid tissue
Submucosa - with many glands
C shaped rings of hyaline cartilage
Adventita
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19
Q

Bronchi structure

A
Shorter epithelial cells 
Lamina propria contains more elastic tissue
Muscularis mucosae begins to form 
Fewer submucosal glands
Cartilage in plates rather than rings
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20
Q

Tertiary bronchi structure

A

Simple columnar epithelium
Prominent muscularis mucosae
Few cartilage plates
Few mucous glands

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21
Q

Bronchiole structure

A
Ciliated columnar epitehlium
Few goblet cells 
Clara cells 
Prominent muscularis mucosae
No cartilage 
No mucous glands
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22
Q

Respiratory bronchiole structure

A

Occasional alveoli in their walls
Ciliated cuboidal epithelium
Smooth muscle in their walls

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23
Q

Alveolar cell types

A

Type I pneumocyte - simple squamous lining cell
Type II pneumocyte - cuboidal cells that produce surfactant
Pulmonary macrophages - immune surveillance

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24
Q

Blood-air barrier

A

Type I pneumocyte
Basement membrane
Capillary endothelium

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25
Q

Functions of platelet factors

A

Promote aggregation with other platelets
Alter local blood flow
Initiate coagulation cascade
Encourage vascular repair

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26
Q

Neutrophils

A

60-70% of blood WBCs
First line of defence against pathogens
Highly phagocytic
Role in inflammation

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27
Q

Eosinophils

A

1-4% of blood WBCs
Defence against parasites and helminths
Increased levels in allergic responses

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28
Q

Basophils

A
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29
Q

Monocytes

A

2-6% of blood WBCs
Mature into macrophages when they enter the tissues
Main roles in phagocytosis, antigen presentation and cytokine production

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30
Q

Lymphocytes

A

20-40% of blood WBCs
B cells and T cells
Can form memory cells - longest WBC lifespan

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31
Q

CCBs

A

Amlodipine, dilatiazem
Blocks calcium entry into smooth muscle cells
Vasodilators and reduce heart rate and contractility
May worsen heart failure

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32
Q

CCBs

A

Amlodipine

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33
Q

Tunica media structure

A

Circularly arranged smooth muscle
Supporting ECM with collagen and elastic fibres
External elastic lamina

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34
Q

Tunica adventitia

A

Loose CT

Vaso vasorum

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35
Q

Endocardium structure

A

Inner endothelium lining

Supporting highly elastic fibrocollagenous CT

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36
Q

Myocardium structure

A

Cardiac myocytes linked by intercalated discs

Supporting fibrocollagenous CT

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37
Q

Epicardium structure

A

Outer fibrocollagenous tissue
Large amounts of adipose tissue
Outer mesothelium - visceral pericardium

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38
Q

Elastic arteries

A

Predominance of elastin and little smooth muscle in tunica media
Found in large arteries just downstream of the heart
Function to smooth out large pressure fluctuations

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39
Q

Muscular arteries

A

Medium to small sized arteries

Have the basic arterial structure

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40
Q

Which types of cells form foam cells

A

Macrophages and smooth muscle cells

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41
Q

What does the fibrous cap consist of?

A

Smooth muscle cells with an ECM with dense collagen, elastic fibres and proteoglycans

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42
Q

Upper respiratory tract

A

Mouth –> larynx

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43
Q

Lower respiratory tract

A

Trachea –> terminal bronchioles

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44
Q

Classic respiratory epithelium

A

Pseudostratified columnar, ciliated epithelium with mucous secreting goblet cells

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45
Q

How does the epithelium change throughout the lungs?

A

Gradual transition from pseudostratified to columnar to cuboidal epithelium
Gradual decrease in number of goblet cells

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46
Q

Epithelium in the pharynx

A

Stratified squamous

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47
Q

Immune properties of the respiratory tract

A

Mucociliary escalator

MALT

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48
Q

Trachea layers

A
Respiratory epithelium
Lamina propria - with elastin and lymphoid tissue
Submucosa - with many glands
C shaped rings of hyaline cartilage
Adventita
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49
Q

Bronchi structure

A
Shorter epithelial cells 
Lamina propria contains more elastic tissue
Muscularis mucosae begins to form 
Fewer submucosal glands
Cartilage in plates rather than rings
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50
Q

Tertiary bronchi structure

A

Simple columnar epithelium
Prominent muscularis mucosae
Few cartilage plates
Few mucous glands

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51
Q

Bronchiole structure

A
Ciliated columnar epitehlium
Few goblet cells 
Clara cells 
Prominent muscularis mucosae
No cartilage 
No mucous glands
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52
Q

Respiratory bronchiole structure

A

Occasional alveoli in their walls
Ciliated cuboidal epithelium
Smooth muscle in their walls

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53
Q

Alveolar cell types

A

Type I pneumocyte - simple squamous lining cell
Type II pneumocyte - cuboidal cells that produce surfactant
Pulmonary macrophages - immune surveillance

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54
Q

Blood-air barrier

A

Type I pneumocyte
Basement membrane
Capillary endothelium

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55
Q

Functions of platelet factors

A

Promote aggregation with other platelets
Alter local blood flow
Initiate coagulation cascade
Encourage vascular repair

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56
Q

Neutrophils

A

60-70% of blood WBCs
First line of defence against pathogens
Highly phagocytic
Role in inflammation

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57
Q

Eosinophils

A

1-4% of blood WBCs
Defence against parasites and helminths
Increased levels in allergic responses

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58
Q

Basophils

A
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59
Q

Monocytes

A

2-6% of blood WBCs
Mature into macrophages when they enter the tissues
Main roles in phagocytosis, antigen presentation and cytokine production

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60
Q

Lymphocytes

A

20-40% of blood WBCs
B cells and T cells
Can form memory cells - longest WBC lifespan

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61
Q

ACEIs

A

Ramipril, captopril
Lower blood pressure
Used after MIs in diabetics
Side effects = K+ retention, cough

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62
Q

CCBs

A

Amlodipine

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63
Q

Thiazide diuretic

A

Bendoflumethiazide

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64
Q

Loop diuretic

A

Furosemide

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65
Q

Beta blockers

A

Propanolol, atenolol
Reduce sympathetic tone
Used in heart failure and after MI

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66
Q

Aldosterone blockers

A

Spironolactone

Used in heart failure

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67
Q

Angiotensin II receptor antagonists

A

Losartan

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68
Q

Digoxin mechanism of action

A
Inhibits Na/K ATPase in cardiac myocytes
Myocyte Na+ rises
Increased IC calcium 
Improved contractility 
Slows heart rate at AV node
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69
Q

Hypertension treatments

A

ACEI, CCBs, diuretics

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70
Q

Heart failure treatments

A
Reduce preload and afterload 
Diuretics
ACEIs
Beta blockers 
Digoxin
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71
Q

Angina treatments

A

Nitrates
Beta blockers
CCBs

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72
Q

Short term beta2 agonist

A
Salbutamol
Receptor activates adenylyl cyclase 
ATP --> cAMP 
Lowers IC calcium 
Relaxes smooth muscle
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73
Q

Long term beta2 agonist

A

Salmeterol, formoterol

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74
Q

Anti-muscarinic

A

Ipratropium = short term
Tiotropium = long term
Mainly act on M3 receptors

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75
Q

Superior mediastinum contents

A
Thymus
Large veins
Large arteries
Trachea
Oesophagus 
Thoracic duct
Sympathetic trunks
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76
Q

Path of the right vagus nerve

A

Enters lateral to the right common carotid and passes Anterior to the subclavian artery
Here it gives of the right recurrent laryngeal
Passes posterior to subclavian vein and SVC
Joins course of oesopahgus

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77
Q

Path of left vagus nerve

A

Enters lateral to the left common carotid
Anterior to the subclavian artery and posterior to brachiocephalic vein
Passes over the aortic arch and gives off left recurrent laryngeal
Passes posterior to the lung root and gives off branches to the pulmonary and cardiac plexuses

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78
Q

How do the phrenic nerves enter the mediastinum?

A

Between the subclavian artery and vein

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79
Q

Where does the right phrenic nerve travel?

A

Over pericardium and right atrium

Anterior to the lung root

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80
Q

Where does the left phrenic nerve travel

A

Over the aortic arch and left atrium and ventricle

Anterior to the lung root

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81
Q

Trachea length and spinal levels it extends from and to

A

13cm

C6–> T4

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82
Q

Where does the thoracic duct cross the midline?

A

T4/5

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83
Q

Azygous vs hemiazygous

A

Azygous drains right side

Hemiazygous drains left side

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84
Q

Where does the hemiazygous vein cross and empty into the azygous vein?

A

T7-8

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85
Q

Where does the azygous vein empty into?

A

SVC just before it enters the right atrium

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86
Q

Left coronary arteries

A

LAD
Circumflex
Left marginal

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87
Q

Right coronary arteries

A

Right marginal

Posterior descending

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88
Q

Where does the great cardiac vein run?

A

Anterior IV sulcus

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89
Q

Where does the middle cardiac vein run?

A

Posterior IV sulcus

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90
Q

Where does the small cardiac vein run?

A

With the right marginal artery

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91
Q

What divides the pectinate and smooth muscle of the atria?

A

Cristae terminalis

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92
Q

Where is the moderator band found?

A

Right ventricle

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93
Q

What happens when the papillary muscles contract/

A

Chordae tendinae pulled taut

Valve cusps close

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94
Q

Blood supply to thoracic wall

A

Anterior intercostals from internal thoracic artery

Posterior intercostals from thoracic aorta

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95
Q

Venous drainage of thoracic wall

A

Anterior intercostals drain into the internal thoracic vein

Posterior intercostals drain to the azygous and hemiazygous veins

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96
Q

Where is the intercostal bundle found?

A

Inferior to the superior rib

Between innermost and internal intercostals

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97
Q

External intercostal fibre direction

A

Inferomedially

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98
Q

Internal and innermost intercostal fibre direction

A

Inferolaterally

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99
Q

What passes through the diaphragm at T8?

A

Interior vena cava

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100
Q

What passes through the diaphragm at T10?

A

Oesophagus

Vagus nerve

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101
Q

What passes through the diaphragm at T12?

A

Aorta
Azygous vein
Thoracic duct

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102
Q

Site of referred pain from mediastinal and diaphragmatic parietal pleura

A

Neck and shoulders

C3,4,5

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103
Q

What forms the nasal septum?

A

Ethmoid bone
Vomer
Hyaline nasal cartilage

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104
Q

What forms the floor of the nasal cavity?

A

Palatine process of maxilla

Horizontal process of palatine bone

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105
Q

Paranasal sinus functions

A
Decrease weight of skull
Increase vocal resonance 
Humidifying air 
Regulation of gas pressure
Immunological defence
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106
Q

Intrinsic laryngeal muscles

A

Cricothyroid
Crico-arytenoids
Vocalis

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107
Q

Membranes of the larynx

A

Cricothyroid membrane
Vocal fold
Vestibular fold
Thyrohyoid membrane

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108
Q

Internal laryngeal nerve

A

Sensory to the larynx above the vocal fold

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109
Q

External laryngeal

A

Motor to cricothyroid to provide tone to the voice

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110
Q

Recurrent laryngeal

A

Sensory to larynx below the vocal fold

Motor to all muscles of the larynx except the cricothyroid

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111
Q

Larynx blood supply

A

Superior and inferior thyroid arteries from ECA

Drainage from thyroid veins to IJV

112
Q

Organisation of the lung hilum

A

Bronchi lie posteriorly
Pulmonary arteries lie superior
Pulmonary veins lie below and infront

113
Q

Where do inhaled foreign objects often lodge?

A

Right main bronchus - straighter course

114
Q

Which X-ray angle gives cardiac enlargement?

A

AP

115
Q

Which heart chamber has more pectinate muscle?

A

Right

In left only in the auricle

116
Q

What are trabeculae carnae?

A

Ridges of muscle projecting out from the ventricle walls

117
Q

What empties into the right atrium

A

SVC
IVC
Coronary sinus

118
Q

Muscles of quiet inspiration

A

Diaphragm
External intercostals
Interchondral part of internal intercostals

119
Q

Accessory muscles of inspiration

A

Scalenes
SCM
Pec major

120
Q

Muscles of forced expiration

A

Interosseous part of internal intercostals
Abdominal muscles
Serratus posterior inferior

121
Q

External carotid artery branches

A
Superior thyroid
Ascending pharyngeal
Lingual 
Facial 
Occipital 
Posterior auricular 
Superficial temporal 
Maxillary
122
Q

Where do thyrocervical arteries come from?

A

Subclavian artery

123
Q

Pharyngeal arches

A

Palatoglossus anteriorly

Palatopharyngeal posteriorly

124
Q

What divides the superior and inferior mediastinum?

A

Sternal angle

125
Q

Where do the humeral circumflex arteries branch from?

A

Axillary artery

126
Q

Which artery gives off the common interosseous artery?

A

Ulnar artery

127
Q

What drains into the superior meatus?

A

Posterior ethmoid sinuses

128
Q

What drains into the middle meatus?

A

Frontal, maxillary and anterior ethmoid sinuses

129
Q

What drains into the inferior meatus?

A

Nasolacrimal duct

Auditory (eustachian) tube - at the posterior aspect

130
Q

Central chemoreceptors

A

Specialised neurones on the surface of the ventral medulla that are sensitive to the pH of the CSF

131
Q

What is the action of carbonic anhydrase?

A

Convert carbonic acid into bicarbonate and protons

132
Q

What happens when the acidity of CSF is increased?

A

Increases stimulation of central chemoreceptors
Stimulates neurones in the respiratory centre in the medulla
Drives increased ventilation to expel more CO2 from the lungs so reduce pH

133
Q

Normal pH of CSF

A

7.32-33

134
Q

Lung based mechanoreceptors

A

Pulmonary stretch receptors - prevent overinflation of the lungs
Irritant receptors - activate cough reflex
J receptors - respond to pulmonary oedema, pneumonia, emboli to increase ventilation and respiration

135
Q

How does hypoxia affect ventilation?

A

Increases the sensitivity to CO2

136
Q

Peripheral chemoreceptors

A

In the carotid body
Respond to reduced PaO2, low pH and high PCO2
Afferents travel in glossopharyngeal and vagus nerves

137
Q

Cells of the carotid body

A

Glomus type I chief cells - release NTs to stimlate afferent nerves
Glomus type II substentacular cells - resemble glia and act as supporting cells

138
Q

How do type I glomus cells detect hypoxia?

A

Decrease in arterial pH causes depolarisation of the cell membrane
Opens calcium channels
Causes release of NTs

139
Q

Where is the respiratory centre?

A

Groups of neurones in the pons and medulla

Medullary centres found in the reticular formation

140
Q

Where does the respiratory centre project to?

A

Reticulospinal tract

141
Q

Where does the reticulospinal tract run?

A

Around the margin of the ventral horn

142
Q

Sensory integrating centre of the respiratory centre

A

Nucleus of the solitary tract

Dorsal medulla

143
Q

Motor output centre of the respiratory centre

A

Nucleus ambiguus

More ventrally positioned

144
Q

Amount of haemoglobin in a typical erythrocyte

A

270 million molecules

145
Q

How do RBCs produce energy?

A

No mitochondria
ATP by glycolysis
High lactate levels
Low IC pH

146
Q

What are the 6 outer electrons in iron bonded to?

A

4 to the porphyrin ring
5th to histadine amino acid
6th free to bond to oxygen

147
Q

Haemoglobin strecture

A

4 subunits

Each with a haem group attached

148
Q

Methaemoglobin

A

Oxidised haemoglobin
Can be reversed by methaemoglobin reductase
Reason why red cells have a short lifespan

149
Q

How does methaemoglobin formation lead to the cell being destroyed?

A

Changes markers on the RBC surface
Detected by liver and spleen cells
Cells are removed

150
Q

Adult vs foetal haemoglobin

A
Adults = a2b2
Foetal = a2g2
151
Q

Sickle cell disease

A

Defective form of haemoglobin, HbS, formed
HbS is a mutant form of one of the beta subunits
HbS aggregates and causes RBCs to change shape

152
Q

Thalassaemia

A

Reduced rate or no synthesis of one the globin chains making up haemoglobin
Reduced oxygen transport
Can affect a or b subunits

153
Q

What causes the oxygen dissociation curve to shift to the right?

A

Increased temperature

Decreased pH

154
Q

Myoglobin

A

Single subunit
Greater affinity for oxygen than Hb
Acts as oxygen buffer store in muscles

155
Q

How is carbon dioxide carried in the blood?

A

Converted to bicarbonate by carbonic anhydrase
Bicarbonate pumped out and exchanged for Cl- ion
Bicarbonate carried in venous blood to the lungs

156
Q

How is carbon dioxide exhaled?

A

Bicarbonate re-enters the cell by exchange of Cl-

Converted back to CO2 by carbonic anhydrase

157
Q

When can CO2 displace oxygen from haemoglobin?

A

In acid conditions

158
Q

Neuronal sensors for blood pressure

A

In carotid sinus and aortic sinus

159
Q

What does an increase in blood pressure cause?

A

Increase stretch of baroreceptors
Increased frequency of firing to vasomotor centre of medulla
Inhibits the vasomotor centre to reduce sympathetic outflow
Lowers heart rate and TPR
Lowers BP
Excitatory response to the cardioinhibitory centre
Increases vagal outflow to the heart

160
Q

What does a decrease in blood pressure cause?

A

Decreased frequency of action potentials from baroreceptors
Increased output of vasomotor centre
Impulses down reticulospinal tract
Stimulate preganglionic sympathetic neurones to increase sympathetic outflow
Increases HR and TPR
Increases BP

161
Q

Action of angiotensin II

A

Causes vasoconstriction to increase TPR to increase BP

Acts on the adrenal cortex to stimulate aldosterone release

162
Q

Poiseuille’s law

A

Small changes in diameter produce large changes in flow

163
Q

Why does stagnant blood lead to clots?

A

When blood moves over the enodthelium it deflects polypeptide chains and causes nitric oxide release which relaxed and dilates the walls
With stagnant blood this doesn’t happen so more likely to clot

164
Q

Polycythemia

A

Increased haematocrit
Flow through vessels very slow
Can lead to end organ failure

165
Q

Laplace’s law

A

The smaller the radius of a vessel, the greater the pressure the wall can withstand

166
Q

Mean pulmonary circulation pressure?

A

25/8

167
Q

Starling’s law

A

Ventricular contractile force increases with end diastolic volume

168
Q

Preload

A

Degree of stretch in the ventricles during diastole

169
Q

Afterload

A

Effective flow impedance of the aorta and large vessels that must be overcome for blood to be ejected from the heart

170
Q

Isovolumetric contraction

A

When the ventricles contract but with no volume change

Occurs before valves often

171
Q

Age and length of isovolumetric contraction

A

Longer
Results in smaller stroke volume
Due to reduced compliance of aorta due to loss of elasticity

172
Q

3 main JVP waves

A
a = due to atrial contraction 
c = tricuspid valve closing and bulging back slightly
v = valve bulging as ventricles contract
173
Q

Cardiac pacemaker cell action potential

A

Constant inward sodium leak
Outward potassium leak with a rate that decays
Membrane slowly depolarises
Reaches the threshold value and triggers sodium influx and action potential fires

174
Q

Effect of ANS on potassium leak

A

Parasympathetic - inhibits closure of potassium channels to slow down HR
Sympathetic - increases closure of potassium channels to increase HR

175
Q

How long is the AVN delay

A

60ms

176
Q

What is the normal PR interval?

A

120-200ms

177
Q

What does a long PR interval indicate

A

First degree AV block

178
Q

Ventricular muscle action potential?

A

Begins normally
Long plateau phase
Prolonged entry of calcium due to L type channels which are slow

179
Q

Importance of cardiac refractory period

A

To ensure that the contractions do not merge into one

Keeps all the cells synchronous

180
Q

ECG limb leads

A
I = right axilla--> left axilla
II = right axilla --> left leg
III = left axilla --> left leg
181
Q

QRS complex length

A
182
Q

P wave

A

Atrial depolarisation
Positive in I, II
Notched or peaked P waves seen in COPD and CHF

183
Q

ST segment

A

When all ventricular muscles are contracting

Changes seen in MI

184
Q

T wave

A

Repolarisation of the ventricles

185
Q

Characteristic of aVR

A

Large Q wave with small R wave

186
Q

Characteristic of aVL

A

Very small

187
Q

Characteristic of V1

A

Mainly negative with large S wave

188
Q

Characteristic of V5 and V6

A

Mainly positive with large R wave

189
Q

Which leads give an anterior view of the heart?

A

V3,4

190
Q

Which leads give an inferior view of the heart?

A

II, III, aVF

191
Q

Which leads give a lateral view of the heart?

A

I, aVL, V5, V6

192
Q

Which leads give a septal view of the heart?

A

V1, V2

193
Q

ECG of AF

A

No P wave

Irregular R-R intervals

194
Q

ECG of atrial flutter

A

Extra P waves

195
Q

ECG of ventricular fibrillation

A

No clear QRS complexes

196
Q

Proteins found in plasma

A

60% albumin
36% globulin
4% fibrinogen

197
Q

Hb results in anaemia

A
198
Q

Microcytic anaemia

A

MCV

199
Q

Normacytic anaemia

A
MCV 80-100fL
Acute blood loss 
Chronic disease
Renal failure 
Leukaemia
Sickle cell anaemia
200
Q

Macrocytic anaemia

A

MCV >100fL
B12/folate deficiency
Liver disease

201
Q

Where are continuous capillaries found?

A

Throughout the body

202
Q

Where are fenestrated capillaries found?

A

Exocrine glands
Intestines
Pancreas
Glomeruli of kidney

203
Q

Where are sinusoidal capillaries found?

A

Liver
Spleen
Bone marrow

204
Q

Filtration pressure at arterial vs venous end

A

10mmHg at arterial end - water forced out

-8mmHg at venous end - water pulled back in

205
Q

What is responsible for oncotic pressure?

A

Large plasma proteins that cannot leave the blood

206
Q

Filtration pressure in the lungs

A

7mmHg

Keeps the lungs damp and moist for optimal gaseous exchange conditions

207
Q

How much lymph is returned to the circulation per day?

A

2-4L/day

208
Q

Causes of oedema

A

Increased venous HPc in heart failure
Reduced capillary oncotic pressure in liver or kidney damage
Increased capillary permeability in burns
Obstruction of lymphatic drainage in fibrosis or filiariasis

209
Q

Percent of plasma filtered through glomerulus

A

20%

210
Q

Kidney blood flow

A

1.2L/min

211
Q

Renal plasma flow

A

680ml/min

212
Q

GFR

A

120-125ml/min

213
Q

Urine flow

A

1ml/min

214
Q

Net filtration pressure

A

10mmHg

215
Q

Clearance formula

A

(urine conc x flow) / plasma conc

216
Q

What is used to measure GFR?

A

Inulin as gold standard

Creatinine clinically but overestimates by 10-20% as some active secretion

217
Q

What is used to measure RPF?

A

PAH

218
Q

How is GFR increased?

A

Afferents relax and efferents constrict
Increases filtration pressure
Increases GFR

219
Q

How is GFR decreased?

A

Afferents constrict and efferents relax
Lowers filtration pressure
Decreases GFR

220
Q

When is renin released?

A

When macula densa cells sense a decrease in sodium concentration in the distal tubule fluid

221
Q

What does renin do?

A

Cleaves angiotensinogen in the liver to angiotensin I

222
Q

Where is angiotensin I converted to angiotensin II and by what?

A

In the lungs

By angiotensin converting enzyme

223
Q

Neuronal volume sensors

A

Right and left atrium
Act as stretch receptors
Send signals via vagus nerve to the brainstem
In high blood pressure it inhibits sympathetic outflow

224
Q

Hormonal volume sensors

A

Right atrium and IVC

Release ANP in response to stretching

225
Q

Action of ANP

A

Decreases Na+ reabsoprtion in the distal tubule of the kindey

226
Q

When is BNP released?

A

If the ventricles are very overstretched

Such as in heart failure

227
Q

Which nuclei are responsible for ADH secretion

A

Supraoptic

Paraventricular

228
Q

If osmoreceptors detect hypo-osmolarity…

A

Triggers renin release

Inhibits ADH release

229
Q

If osmoreceptors detect hyper-osmolarity…

A

Stimulates ADH release

230
Q

Water diuresis

A

Due to drinking too much water
ADH release inhibited
High volume of dilute urine

231
Q

Osmotic diuresis

A

Sugars not completely reabsorbed in the proximal tubule
Glucose provides osmotic force pulling water into the urine
High volume of sugary urine

232
Q

Pre vs post ganglionic neurones

A
Pre = small myelinated type B axons
Post = unmyelinated type C axons
233
Q

Synapse between pre and postganglionic sympathetic neurones

A

Nicotinic ACh receptor

234
Q

Adrenal gland as an exception to the rule

A

Gland acts as the postganglionic neurone
Receives stimulation by nicotinic receptors and ACh
Secreted adrenaline directly into the blood

235
Q

Sweat glands as an exception to the rule

A

Use ACh as their postganglionic NT

236
Q

Where are there no alpha adrenoreceptors?

A

In the heart or brain

Ensures constant blood flow to these organs

237
Q

Alpha 1 adrenoreceptors

A

Increases vascular smooth muscle contraction

Contraction of ureter, vas deferens, uterus, urethral sphincter

238
Q

Alpha 1 antagonists

A

Prazosin

Antihypertensives

239
Q

Alpha 2 adrenoreceptors

A
Found in presynaptic sympathetci nerve terminals 
Reduce NA release by negative feedback
Inhibit insulin release
Stimulate glucagon release
GI sphincter contraction
240
Q

Alpha 2 agonists

A

Clonidine

Antihypertensives

241
Q

Beta 1 adrenoreceptors

A

Increase heart rate and force of contraction

Increase renin and ghrelin secretion

242
Q

Beta blockers

A

Propanolol, atenolol
Reduce heart rate and contraction force
Antihypertensives

243
Q

Beta 2 adrenoreceptors

A

Relax bronchial smooth muscle
Decrease GI motility
Relaxation of detrusor muscle
Stimulate gluconeogenesis and glycogenolysis

244
Q

Beta 2 agonists

A

Relax bronchial smooth muscle

Given to asthmatics

245
Q

Beta 3 adrenoreceptors

A

Stimulate lipolysis

Found in adipose tissue

246
Q

Sympathetic activity during exercise

A

Beta 2 and 3 stimulation increases glucose release from the liver and increases muscle uptake

247
Q

HPA axis

A

CRH from hypothalamus
ACTH release from pituitary
Cortisol from adrenal cortex
Cortisol stimulates adrenaline and noradrenaline synthesis

248
Q

How are cardiac myocytes joined?

A

By gap junctions and desmosomes

249
Q

Define automaticity

A

Ability to initiate their own action potentials without the need of external stimuli

250
Q

Cardiac calcium signalling

A

Depolarisation opens calcium channels
Influx of calcium through L type calcium channels
Rise in IC calcium triggers further release from the sarcoplasmic reticulum by ryanodine receptors
Calcium associates with troponin C to displace tropopmyosin
Allows actin-myosin cross bridges to form
Reuptake of calcium by SERCA

251
Q

Multiunit smooth muscle

A

Each muscle receives its own synaptic input
Little electrical coupling
Allows for fine control and gradual responses
e.g. eyes

252
Q

Single unit smooth muscle

A

Single cell within a sheet or bundle innervated
Action potential spreads through cells through gap junctions
Whole bundle/sheet contracts together
Found in walls of visceral organs

253
Q

Calcium signalling in smooth muscle

A

Depolarisation opens voltage gated calcium channels and leads to calcium influx
Agonist induced calcium release via IP3
Calcium binds to calmodulin and activates myosin light chain kinase
MLCK phosphorylates myosin light chain regulatory region
Increases ATPase activity to allow cross bridge cycling

254
Q

How many divisions are there in the airway tree?

A

23
First 16 divisions make up the conducting airways
Last 7 divisions make up the respiratory zone

255
Q

What two forces hold the lungs and thoracic walls together?

A

Intrapleural fluid cohesiveness

Negative intrapleural pressure

256
Q

Boyle’s law

A

As the volume of gas increases the pressure decreases

257
Q

Factors contributing to lung recoil

A

Elastic connective tissue

Alveolar surface tension

258
Q

Anatomical dead space

A

Volume of conducting airways

259
Q

Functional/physiological dead space

A

Anatomical dead space + non-perfused volumes of the respiratory airways

260
Q

Alveolar oxygen partial pressure

A

100mmHg

261
Q

Alveolar carbon dioxide partial pressure

A

40mmHg

262
Q

Differences in lung flow at different levels

A
Apices = intermittent flow - during systole only
Centres = pulsatile flow - high during systole
Bases = continuous flow
263
Q

Alveolar vs arterial vs venous pressures at lung levels

A
Apices = PA>Pa>Pv
Centres = Pa>PA>Pv
Bases = Pa>Pv>PA
264
Q

What element is used to measure lung perfusion?

A

Xenon

265
Q

Compliance formula

A

= dV/dP

266
Q

Differences in compliance at different lung levels

A

Highest in the bases
Lowest in the apices
This means the bases are better ventilated

267
Q

VQ ratios throughout the lung

A

Apices –> V/Q = 3.3
3rd rib –> V/Q = 1
Bases –> V/Q = 0.6

268
Q

Decline in blood flow vs ventilation

A

Blood flow has a steeper decline than ventilation

269
Q

Effect of pulmonary hypoxia

A

Vasoconstriction

Diverts blood away from under-ventilated areas of the lung

270
Q

What happens to the pulmonary arterial resistance during exercise?

A

Decreases
Stretching due to high cardiac output generates a reflex relaxation
Increased ventilation increases arteriolar dilation

271
Q

Causes of reduced lung compliance

A

Pulmonary fibrosis
Lung collapse
Increased pulmonary venous pressure

272
Q

Causes of increased lung compliance

A

Age

Emphysema

273
Q

Hysteresis

A

Inflation and deflation pressure/volume curves are different

Greater pressure required to reach a given volume during inflation compared to deflation

274
Q

Average tidal volume

A

500ml

275
Q

Average vital capacity

A

4-6L