Anatomy Flashcards
Upper Respiratory Tract
Nasal cavities, oral cavity, pharynx, larynx
Lower Respiratory Tract
Trachea, right & left main bronchus, lobar bronchi, segmental bronchi, bronchioles, alveoli
Where does the larynx become the trachea?
At the level of C6 verterbrae
Where does the pharynx become the oesophagus?
At the level of C6 verterbrae.
Lobar Bronchi
1 lobar bronchus for each of the 5 lung lobes.
Segmental Bronchi
1 segmental bronchus for each of the 10 bronchopulmonary segments
Lobes of the right lung
Upper, middle and lower
Lobes of the left lung
Upper and lower
Lung lobe
Area of the lung that each lobar bronchi supply with air
Bronchopulmonary segement
Area of lung lobe that each segmental bronchi supply with air
Fissures
Deep crevices that separate the lobes from each other
Lining on inside of bronchial tree (except for distal bronchioles & alveoli)
Respiratory epithelium
Respiratory Epithelium
Contain:
- Mucous glands secrete mucous onto epithelial surface.
- Cilia beat to sweep mucous + any foreign bodies stuck in the mucous superiorly, toward the pharynx.
Mucociliary Escalator
Cilia beat to sweep mucous _ any foreign bodies stuck in the mucous superiorly, toward the pharynx.
What interferes with normal beating of cilia?
Cooling/drying of mucosa & toxins in cigarette smoke.
Hyaline cartilage
Supports the walls of the trachea & all the bronchi & assists with maintaining airway patency
Do alveoli have cartilage?
No
Do alveoli have smooth muscle?
No
Why don’t alveoli have smooth muscle or cartilage?
Alveolar walls have to be extremely thin as smooth muscle and cartilage would impact on diffusion.
Cartilage in the respiratory tree
Cartilage gradually reduces distally in the respiratory tree
Smooth muscle in the respiratory tree
Smooth muscle becomes progressively more prominent distally in the respiratory tree
Bronchioles: smooth muscle
Smooth muscle is the most prominent feature of bronchioles => bronchioles can constrict or dilate
Requirements for gas transfer between air in alveoli & blood in pulmonary capillaries
- Sufficient functioning lung tissue.
- Sufficient O2 in inspired air.
- No CO2 in inspired air.
- Minimal thickness of walls of alveoli.
- Minimal tissue fluid in tissue spaces around the alveolar capillaries.
Dangers to respiratory tract
- Resp tract may become narrowed: Bronchiole constriction, swelling of mucosa/overproduction of mucous, growing tumour may compress tract.
- Foreign bodies being inhaled into resp tract.
What separates the 2 nasal cavities
Nasal septum
Nasal septum
- Bony Part (Posterior): Ethmoid bone & vomer.
- Cartilaginous Part (Anterior)
Skeleton of larynx
Epiglottis, thyroid cartilage, cricoid cartilage, 2 arytenoid cartilages
Functions of larynx
- Cartilages help to maintain patency of URT.
- Helps prevent entry of foreign bodies into the LRT (vocal cords)
- Produces sounds (vocal sounds)
Trachea
Inferior continuation of larynx
Narrowest part of the larynx
Rima glottidis
Function of Vocal cords
- Airway protection.
2. Voice production
Voice Production
- Phonation: Expire air across vocal cords, cords vibrate to produce sound.
- Articulation: Sound is modified in nose or mouth to produce vowels and consonants.
Airway Protection by Vocal Cords
Vocal cords can approximate in the midline, closing the rima Glottidis & preventing a foreign body inhaled into the trachea => stimulates cough reflex to expel foreign body via pharynx and oral cavity.
Heimlich manoeuvre
Raises abdominal pressure, forces diaphragm superiorly, raises pressure in chest & lungs, forces air from lungs into trachea, forces air through rima glottidis to expel foreign body out of URT.
Dangers of breathing in cold/dry air
Cooling & drying out of respiratory tract => damages the mucocili]ary escalator & predisposes to infection.
Dangers of breathing in unclean air
Breathing in infected foreign bodies or bacteria/viruses etc. => infection.
How do we warm air?
Respiratory mucosa lining the walls of the nasal cavities has a very good arterial blood supply providing warmth
How to de humidity air?
Respiratory mucosa produces mucous providing moisture
How do we clean air?
Sticky mucous traps potentially infected particles & tonsils produce white blood cells in defence against infection.
Chest wall
- Skin & Fascia.
- Bones.
- Skeletal muscles.
- Diaphragm.
- Parietal pleura.
Thoracic Skeleton
- 12 Pairs of Ribs (True 1-7, False 8-10, Floating 11-12)
- Intercostal spaces
- Costal margin.
- 12 thoracic vertebrae.
- clavicle & scapula
- sternum
Bones of chest wall
- Sternoclavicular joint.
- Sternocostal articulation with costal cartilage of rib 1
- Manubrium
- Sternal angle (at level of rib 2)
- Body
— Xiphoid process
Joints of thoracic skeleton
Sternocostal joints & costochondral joints
Sternocostal joints
Synovial
Costovertebral joints
Limited movement at these joints
Muscles of breathing
- Intercostal muscles: make chest wall expand during breathing by pulling adjacent ribs upwards and outwards.
- Diaphragm.
Intercostal muscles
3 layers of skeletal muscles are located between ribs in intercostal spaces:
- external intercostal muscles.
- Internal intercostal muscles.
- innermost intercostal muscles.
Parietal pleura
Internal lining of the chest wall
Visceral pleura
Skin attached lung lobes
Pleural cavity
Space that surrounds the lung in 3D apart from where main bronchus enters it
- Between parietal & visceral layers of pleura
At level of C6 vertebrae
Larynx becomes trachea & pharynx becomes oesophagus.
Where can you palpate the trachea
At the jugular notch of the manubrium
Isthmus of thyroid gland
Anterior to tracheal cartilages 2-4.
2 parts of Thorax
Chest walls & chest cavity
Function of chest walls
- Protect heart & lungs.
- Make movements of breathing.
- Breast tissue: lactation.
Chest cavity
Within chest wall, consists of mediastinum & right & left pleural cavities, contains vital organs, major vessels and nerves.
Lung development
Embryo: Lung bud pushes out from mediastinum, covered in pleura.
Adults: Pleural cavity: potential space, pleural fluid.
Both: Parietal pleura on wall, visceral pleura on lungs, reflect at lung roots.
Pleural fluid
Lubricant that provides surface tension - secreted by pleurae into pleural cavity.
Intercostal spaces
11 pairs, each carrying a neuro-vascular bundle between internal and innermost intercostal muscle layers.
Diaphragm
- Forms floor of chest cavity & roof of abdominal cavity.
- Contains openings to permit structures to pass between the 2 cavities.
- Skeletal muscle with unusual central tendon.
- Left and right domes, right more superior due to presence of liver.
- Muscular part attaches peripherally to: Sternum, lower 6 ribs, costal cartilages & L1-L3 vertebral bodies.
- Muscle part supplied by phrenic nerve.
What is supplied by phrenic nerve (C3, 4 & 5 anterior rami)
Muscular part of diaphragm
Why is the right dome of diaphragm higher?
Presence of liver inferiorly.
What does the muscular part of the diaphragm attach peripherally to?
Sternum, lower 6 ribs &costal cartilages & L1-L3 vertebral bodies
Phrenic nerves
Combined anterior rami of cervical spinal nerves C3, 4 & 5.