Lecture 6: How do we breathe? Flashcards
What is meant by the respiratory tree?
The set of tubes which connect the nose and mouth with the alveoli in the lungs.
What are alveoli?
Tiny air sacs located within the lungs.
What histological feature of alveoli allows oxygen to diffuse into the blood? (2)
- The alveoli have very thin walls
- The surrounding capillaries also have thin walls, and there are many of these capillaries.
Which components constitute the Upper respiratory tract? (4)
- Right and left nasal cavities (nose)
- Oral cavity (mouth)
- Pharynx (throat)
- Larynx (Voice box)
Which components constitute the lower respiratory tract? (6)
- Trachea
- Right and left main bronchus
- Lobar bronchi
- Segmental bronchi
- Bronchioles
- Alveoli
What does the larynx become at the C6 vertebra?
Trachea
What does the pharynx become at the C6 vertebra?
Oesophagus
What is meant by bifurcation of the trachea?
Division into the 2 main bronchi.
How many bronchus serve each lung?
1
How many lobar bronchi are there in each lung?
5- One for each of the 5 lung lobes.
How many segmental bronchi are there in each lung?
10- One for each of the bronchopulmonary segments
Name the three lung lobes on the right lung.
Upper, middle, lower
Name the two lobes of the left lung.
Upper and lower
What is the function of the fissures of the lung?
To separate the lobes from each other.
What kind of cells line the bronchial tree? (except the distal bronchioles and alveoli)
Respiratory epithelium
Name the branches of the respiratory tree, from trachea to lung. (6)
- Trachea
- Main bronchus
- Lobar bronchus
- Segmental bronchus
- Bronchioles
- Alveoli
What produces mucous onto the epithelial surfaces?
Mucous glands
What is the purpose of cilia?
They move (beat) mucous towards the pharynx to be swallowed. (Mucociliary escalator)
What is the function of the hyaline cartilage found supporting the walls of the trachea and bronchi?
Maintains patency of airways (Holds them open)
Which branches of the respiratory tree do no have cartilage?
- The most distal bronchioles
- The alveoli
What feature of bronchioles allows them to constrict and dilate?
Smooth muscle in the walls.
Why do alveoli not contain any cartilage or smooth muscle?
This would impact on diffusion due to the thickness that the walls would have.
Name the five main requirements for effective gas exchange in the lungs.
- Sufficient functioning lung tissue
- Sufficient O2 in the air we breathe in
- No CO2 in the air we breathe in
- Minimal thickness of alveoli walls.
- Minimal tissue fluid in the tissue spaces around the alveolar capillaries.
What causes asthma? (3)
- Constriction of the bronchioles
- Swelling of the mucosa lining of the respiratory tree
- Overproduction of mucous
What two factors cause complications in the respiratory tract?
- Narrowing of the respiratory tract
- Foreign bodies being inhaled
What is the nasal septum?
The wall that divides the nasal cavity into left and right.
What two aspects are the nasal septum divided into?
- Bony (posterior) part: The ethmoid bone superiorly and the vomer inferiorly
- Cartilaginous (anterior) part: The septal cartilage (hyaline cartilage)
What is the epiglottis?
A flap of elastic cartilage tissue which acts as a switch to allow air to enter the trachea and food to enter the oesophagus.
What are the four cartilages that make up the skeleton of the larynx?
- Epiglottis
- Thyroid cartilage
- Cricoid cartilage
- 2 Arytenoid cartilages (posteriorly)
What are the functions of the larynx? (3)
- Cartilages maintain patency of airways
- Helps to prevent foreign bodies entering LRT
- Produces sound via the vocal cords
What is the rima glottidis?
The narrowest part of the larynx.
What makes up the Glottis?
The rima glottidis and the vocal ligaments.
What are the functions of the vocal ligaments?
- Airway protection
- Voice production
What feature of the vocal cords allow for airway protection?
-Approximation of the rima glottidis.
Describe phonation.
- Production of sound
- Air is expired across the vocal cords, the cords vibrate to produce sound
Describe the aims of the Heimlich manoeuvre.
- Raise abdominal pressure
- Force the diaphragm superiorly
- Raise pressure in the chest
- Raise pressure in the lungs
- Force air from the lungs into the trachea
- Force air through the rima glottidis to expel foreign body.
What effect does cooling and drying out of the airways have?
Damages mucociliary escalator and predisposes to infection.
Which bones form the lateral wall of the nasal cavity?
Inferior, middle and superior nasal conchae.
What functions do the nasal conchae perform?
Increase surface are of lateral walls of nasal cavity
Produce turbulent flow bringing the air into contact with the walls.
What feature of the respiratory tract provides warmth?
The very good arterial blood supply to the respiratory mucosa.
What feature of the respiratory tract provides moisture?
The mucous produced by the respiratory mucosa.
What is the function of the mucous?
Trap potentially infected particles
What three parts is the pharynx divided up? (Superior to inferior)
- Nasopharynx
- Oropharynx
- Laryngopharnyx
What is the normal route of air taken when breathing in? (reverse for breathing out) (6)
- Nasal cavities
- Nasopharynx
- Oropharynx
- Laryngopharynx
- Larynx
- Trachea
Where are the tonsils located?
Within the mucosa lining the pharynx
What is the function of tonsils?
To produce white blood cells in the defence against infection.
Describe the makeup of the chest wall. (5)
- Skin and fascia
- Bones
- Skeletal muscles
- Diaphragm (internal chest wall)
- Parietal pleura
Name and describe the attachment of the ribs.
- True ribs 1-6: Attach via costal cartilage to sternum
- False ribs 7-10: Attach via costal cartilage to sternum above.
- Floating ribs 11 & 12: No attachment to sternum
What is the definition of the rib cage?
The 12 ribs, their costal cartilages, clavicles, sternum and thoracic vertebrae.
Where is the costal groove of a rib?
Inferiorly on deep surface
Where is the sternal angle?
At the level of rib 2
There are 3 layers of skeletal muscles used for breathing. Name these.
- External intercostal muscles
- Internal intercostal muscles
- Innermost intercostal muscles
What is the parietal pleura?
The internal lining of the chest wall
