Anatomy (pie for finals) Flashcards
In general terms describe how we get O2 into the blood & CO2 out?
- We breathe air in via our nose (or our mouth)
- Air travels through the “respiratory tree”: a set of tubes which connect the nose/mouth with the millions of alveoli (air sacs) within the 2 lungs
- The surface of the very thin walled alveoli is covered with many thin walled capillaries
- This histological arrangement allows oxygen to be transferred by diffusion into the blood
- This, now oxygenated blood, is then returned to the heart to be pumped to all the other cells of the body
- This system also allows for the diffusion of CO2 from the blood into the alveoli to be breathed out of the body
What 4 anatomical structures comprise the upper respiratory tract (URT)?
- Nasal cavities
- Oral cavity
- naso- oro- & laryngo- Pharynx
- Larynx
Label all the anatomical structures shown in the pic
What is the anatomical importance of the level of the C6 vertebrae
- The larynx becomes the trachea
- The pharynx becomes the oesophagus
Where can the trachea be palpated ?
At the jugular notch of the manubrium
Label the anatomical structures shown in the pic
Define what is meant by the term ‘respiratory tree’
This describes the anatomy of the LRT airways from trachea to alveoli
What makes up the LRT?
- Trachea
- Right & left main bronchi
- Lobar bronchi
- Segmental bronchi
- Bronchioles
- Alveoli
Define what a lung lobe is and state how many there is
- The area of lung that each of the lobar bronchi supply with air is a lung lobe
- Remeber it as the word right has more letters so the right lung has more lobes
Name the lung fissures
Define what a bronchopulmonary segment is and state how many there is
- The area of lung lobe that each one of the segmental bronchi supply with air is a bronchopulmonary segment
- Each lung has 10 bronchopulmonary segments
Each lung lobe and each bronchopulmonary segment has its own what?
- Own air supply (lobar or segmental bronchus)
- Blood supply
- Lymphatic drainage
- and nerve supply
Define what the bronchial tree is
The bronchial tree is the branching system of trachea, bronchi, bronchioles, alveolar ducts, alveolar sacs, and alveoli that conducts air from the windpipe into the lungs.
Label the structures of the bronchial tree shown
What is the lining of the bronchial tree (except for the distal bronchioles & alveoli)?
Respiratory epithelium
Describe the function in relation to the mucociliary escalator and structure of respiratory epithelium
Ciliated columnar epithelium which have:
- Mucous glands secrete mucous onto the epithelial surface
- And cilia (“eye lashes”) beat to sweep the mucous (plus any foreign bodies stuck in the mucous) superiorly, towards the pharynx, to be swallowed - known as the mucociliary escalator
Describe, in general terms, the arrangement of hyaline cartilage and smooth muscle within the walls of the respiratory tree
Hyaline cartilage:
- It supports the walls of the trachea & all the bronchi. The amount of cartilage gradually reduces distally in the respiratory tree until, the most distal bronchioles and of the alveoli do not contain any cartilage
Smooth muscle:
- Smooth muscle in the walls of the airways becomes progressively more prominent distally
- Smooth muscle is the most prominent feature of the walls of the bronchioles
What is the function of hyaline cartilage ?
To support the walls of the trachea & all the bronchi which assists with maintaining the patency of the airways (holding them open)
Why must alveoli have neither cartilage nor smooth muscle?
Because this would impact on diffusion alveolar walls have to be extremely thin
What is the function does smooth muscle in the walls of bronchioles enable ?
It allows bronchioles to constrict (become narrower) or dilate (become wider)
State and explain the 5 main requirements for adequate diffusion of respiratory gases at the level of the alveolar wall
- Sufficient functioning lung tissue
- Sufficient O2 in the air we breathe in
- No CO2 in the air we breathe in
- Minimal thickness of the walls of the alveoli (air sacs) to facilitate gaseous diffusion
- Minimal tissue fluid in the tissue spaces around the alveolar capillaries to facilitate gaseous diffusion
Summarise the main dangers to air moving freely through the upper and lower respiratory tracts i.e. the main things that may obstruct free movement of air in the resp tracts
The respiratory tract may become narrowed:
- The bronchioles may constrict (E.g. asthma)
- Swelling of the mucosa lining the inside of the respiratory tree & overproduction of mucous (E.g. asthma)
- A growing tumour may externally compress the tract at any point
Foreign bodies being inhaled into the respiratory tract - may partially or completely stop breathing
Explain how the patency of the upper respiratory tract is maintained
- Bones forming the nasal cavities
- The nasal septum
- Skeleton of the larynx
The 2 nasal cavities are separated from each other by an internal wall called the nasal septum, what forms the nasal septum ?
- Bony (posterior) part of the nasal septum ethmoid bone (superiorly) & vomer (inferiorly)
- Cartilaginous (anterior) part of the nasal septum
Describe what forms the nasal cavity
Each nasal cavity has:
- A relatively featureless medial wall
- An interestingly featured lateral wall
- A floor (formed from the palate)
- A roof (formed by the midline part of the floor of the anterior cranial fossa)
The skeleton of the larynx (voice box) is made up of what?
Several cartilages:
- The epiglottis
- The thyroid cartilage
- The cricoid cartilage
- The 2 arytenoid cartilages (posteriorly)
Label the anatomical structures shown in the pic
What are the 3 main functions of the larynx ?
- Cartilages help to maintain the patency of the URT
- Helps to prevent the entry of foreign bodies into the LRT (the vocal cords)
- Produces sound (the vocal cords)
What is the inferior continuation of the larynx known as ?
The trachea
Label the anatomical structures shown in the pic
What is the narrowest part of the larynx and what is the clinical significance of it ?
- Narrowest part of the larynx = the rima glottis
- Clinical significance = large foreign bodies tend to block the URT at the rima glottidis
Label the anatomical structures shown in the pic
How do the vocal cords provide airway protection ?
- The vocal cords can approximate in the midline, closing the rima glottidis & preventing a foreign body being inhaled into the trachea
- A Cough reflex is then stimulated to expel the foreign body via the pharynx and oral cavity
How do the vocal cords (ligaments) influence voice production
Through Phonation (producing sound):
- Expire air across the vocal cords
- The cords vibrate to produce sound
Describe what the second phase of voice production is after phonation
Articulation (producing speech) = The sound is modified in the nose or mouth to produce vowels and consonants
How does the Heimlich manoeuvre aims to expel a foreign body out of the URT ?
- It raises abdominal pressure which forces the diaphragm superiorly
- Which will raise the pressure in the chest
- Which will raise the pressure in the lungs
- Which will force air from the lungs into the trachea
- Which will force air through the rima glottidis to expel the foreign body out of the URT
How do we warm, humidify & “clean” the air we breathe in?
Warmed:
- The respiratory mucosa lining the walls of the nasal cavities has a very good arterial blood supply providing warmth
Humidified:
- The respiratory mucosa produces mucous providing moisture
Cleaned:
- The “sticky” mucous traps potentially infected particles whilst the cilia of the mucosa waft the mucous to the pharynx to be swallowed (into gastric acid)
- Additionally the tonsils located within the mucosa lining the pharynx produce white blood cells in the defence against infection
What anatomical structures greatly increase the surface area of the lateral walls of the nasal cavities and in doing so help bring the air breathed in, in contact with the walls and hence the respiratory epithelium for warming, humidification and cleaning ?
The conchae - through increasing surface area and producing turbulent flow
What is the main danger to the lungs via the chest wall?
Penetrating injuries
What comprises the chest wall?
- skin & fascia of the chest wall
- bones of the chest wall
- skeletal muscles of the chest wall
- the diaphragm (an internal chest wall)
- parietal pleura of the chest wall
What are the bones which make up the thoracic skeleton ?
- 12 pairs of ribs
- Intercostal spaces
- Costal margin
- 12 thoracic vertebrae
- Clavicle and scapula
- Sternum
- Manubrium, body, xiphoid, sternal angle
Of the 12 ribs which make up part of the thoracic skeleton, which are known as the true ribs, false ribs and floating ribs ?
- True ribs: 1-7 (attach via their costal cartilage to the sternum)
- False ribs: 8-10 (attach via their costal cartilage above to the sternum)
- Floating ribs: 11 & 12 (no attachment to sternum)