Anatomy of Breathing Flashcards
Week 1 Resp
What route does air take when it enters the body?
The upper respiratory tract- Nasal cavaties Oral cavity Pharynx - voice box Larynx The lower respiratory tract- Trachea Right and left main bronchus Lower bronchi Segmental bronchi Bronchioles Alveoli
What happens at the level of the C6 vertebrae?
The larynx becomes the trachea
The pharynx becomes the oespohagus
What is the respiratory tree?
This describes the anatomy of the lower respiratory tract airways from the trachea to the alveoli.
How many lobar bronchi are there?
There are 5 lobar bronchus, one for each of the lung lobes.
How many segmental bronchi are there?
There are 10 segmental bronchi, one for each of the bronchopulmonary segments
What is a bronchopulmonary segment?
This is a portion of the lung supplied by a specific segmental bronchus and its respective vessels
What is a lung lobe?
This is an area of the lung that each of the lobar bronchi supply with air.
What are the names of the lung lobes?
Right - upper lobe, middle lobe and lower lobe.
Left - upper lobe and lower lobe
What is a fissure?
These are the deep crevices that separate the lobes form each other
What is the lingula?
This is an extension of the left upper lobe. It is thought to be the replacement for the middle lobe on the left hand side.
What lines the proximal areas of the respiratory tree?
This is known as respiratory epithelium. Mucous glands secrete mucous onto the epithelial surface. Cilia beat the mucous and foreign bodies superiorly towards the pharynx.
What is the mucociliary escalator?
This is the action of the cilia moving mucous up the respiratory tract.
What supports the walls of the trachea and bronchi?
Hyaline cartilage assists with the patency of the airways meaning that it keeps them open. The amount of hyaline cartilage in the airways gradually reduces as we get more distal.
Describe the cartilage within the walls of the of the distal bronchioles and alveoli.
There is no cartilage within their walls as this would restrict gas exchange
Describe the walls of the alveoli.
Alveoli must have neither cartilage or smooth muscle in their walls. This would reduce diffusion rates as their walls must be extremely thin.
What happens to the amount of smooth muscle as we move down the respiratory tract.
The amount of smooth muscle increases with the exception of the alveoli. The smooth muscle allows the bronchioles to constrict or dilate
What are the 4 principles of respiration?
- We must ensure that enought O2 and CO2 can diffuse between alveolus and blood at the pulmonary capillary beds.
- We must ensure that we can move air freely into and out of our lungs
- We must ensure that we move warm, moist clean air into and out of our lungs.
- We must protect our lungs.
What are the main requirements that allow for gas diffusion in the lungs?
- Sufficient functioning lung tissue.
- Sufficient oxygen in the air that we breathe
- No CO2 in the air we breathe.
- Minimal thickness of the walls of the alveoli to facilitate gaseous diffusion.
- Minimal tissue fluid in the tissue spaces around the alveolar capillaries to facilitate gaseous diffusion.
What is an oedema?
Build up of tissue fluid that would prevent or reduce gas exchange
What are the main dangers that would prevent air moving freely in and out of the lungs?
- The respiratory tract can become narrowed by bronchiole constriction, the mucosa lining can swell and overproduce mucous or a tumour may grow and compress the respiratory tract.
- Foreign bodies may be inhaled.
How do we keep our upper respiratory tract patent?
There are two nasal cavaliers in the skull that are separated by an internal wall called the SEPTUM. The posterior part of the nasal septum is bone and the anterior part is cartilage.
There are also several cartilages in on the larynx
What are the bones that make up the nasal septum?
The superior ethmoid bond and the inferior vomer bone
What are the names of the cartilages that make up the larynx?
The epiglottis, the thyroid cartilage, the cricoid cartilage and the 2 arytenoid cartilages.
What are the functions of the larynx?
Cartilages help to maintain the patency of the URT.
The larynx helps to prevent entry of foreign bodies to the LRT.
The vocal cords produce sounds.
What is the rima glottidis?
The narrowest part of the larynx. The vocal cords are on either side. Large foreign bodies tend to block the URT at the rima glottidis.
What is the cough reflex used for?
To expel foreign bodies that have been inhaled into the trachea. It is stimulates to remove these via the pharynx and oral cavity.
What is phonation?
The is the mechanism of producing sound. Air is expired across the vocal cords and the cords will vibrate to produce sound. The cords will also change shape.
What is articulation?
This is when the sound that is produced from the vocal cord is modified in the nose or the mouth to produce vowels and consonants.
What is the heimlich manoeuvre?
This is a manoeuvre that involves using abdominal pressure to force foreign bodies out of the respiratort tract.
What are the dangers of cooling or drying the respiratory tract?
This can lead to damage in the mucociliary escalator and will predispose to infection.
What are nasal conchae?
Nasal concha are several thin, scroll-shaped bony elements forming the upper chambers of the nasal cavities. They produce turbulent flow bringing air into contact with the walls.
How do we warm, humidify and clean the air that we breathe in?
- The nasal cavity has very good arterial blood supply that provides warmth.
- The respiratory mucosa produces mucous providing moisture.
- The sticky mucosa traps potentially infected particles.
- The cillia of the mucosa waft the mucous to the pharynx to be swallowed.
- The tonsils produce white blood cells in defence against infection.
What is the chest wall composed of?
Skin, fascia, bones, skeletal muscle, the diaphragm and the parietal pleura
What is the main danger to the chest wall?
Penetrating injuries.
Describe the bones of the chest wall.
- The STERNOCLAVICULAR JOINT at the top of the sternum where is meets the CLAVICLE.
- MANUBRIUM is the top of the sternum.
- THE STERNAL ANGLE is where the sternum meets the second rib.
- THE BODY is the central portion of the sternum.
- XIPHOID PROCESS is the bottom tip of the sternum.
- COSTAL MARGIN joins up the false ribs to attach them to the sternum.
Describe the joints of the thoracic skeleton.
- The COSTOVETEBRAL JOINTS are where the head of the rib and articulates with the body of the vertebrae above and the tubercle of the rib articulates with the same numbered vertebrae.
- The STERNOCOSTAL (SYNOVIAL) JOINTS are where the costal cartilage articulates with the sternum
- The COSTROCHONDRAL JOINTS are where the ribs articulate with the costal cartilage.
(These joints permit very little movement)
What is the costal groove?
This is a groove inferior on the deep surface of the ribs. This houses the neurovascular bundle.
Name the intercostal muscles of breathing.
- External intercostal muscles.
- Internal intercostal muscles
- Innermost intercostal muscles
What are the main muscles of respiration?
The diaphragm and the intercostal muscles.
What is pleural fluid?
This is fluid secreted by the parietal pleura into the pleural cavity. It is a lubrican the provides surface tension.
What is visceral pleura in the chest cavity?
This is pleura that covers the lungs.
What is parietal pleura?
This is pleura that covers the chest wall.
What is the potential space in the lung cavity?
This is an area of vacuum between the lung and the chest wall that allows the lungs to expand.
What direction do the intercostal muscles pull the chest wall?
They make the chest wall expand and pull the adjacent ribs upwards and outwards
Describe the intercostal spaces.
There are 11 pairs of intercostal spaces. Each contain a neurovascular bundle.
What is contained within the neurovascular bundle?
A nerve, vein and an artery.
Which nerve supplies the intercostal spaces?
Anterior ramus of spinal nerve - intercostal nerve
Name the posterior blood vessels to the intercostal spaces.
Arterial supply = Thoracic aorta
Venous drainage = Azygous vein
Name the anterior blood vessels to the intercostal spaces.
Arterial supply = Right and left internal thoracic artery
Venous drainage = Internal thoracic vein
Whereabouts do the arteries anastomose in the intercostal spaces?
At the midpoint of the intercostal spaces
Where is the diaphragm?
The diaphragm forms the floor of the chest cavity and the roof of the abdominal cavity.
Why does the diaphragm have openings?
This permits structures to pass between the two cavities.
What type of muscle is the diaphragm?
This is a skeletal muscle with an unusual central tendon.
What does the muscular part of the diaphragm attach to?
- The sternum
- The lower 6 ribs and costal cartilages
- L1-L3 vertebral bodies posteriorly
What nerves supply the diaphragm?
The phrenic nerve
What is the phrenic nerve>
This is the combined anterior rami of cervical spinal nerves C3, 4, 5.
It is found in the neck on the anterior surface of scalenus anterior muscle. It is found in the chest and descends over the lateral aspects of the heart and anterior to the root of the lung.
What does the phernic nerve supply?
It supplies the somatic sensory and the sympathetic axons to the diaphragm and fibrous pericardium.
It also supplies somatic motor axons to the diaphragm
Describe the process of inspiration mechanics.
- Diaphragm contracts and descends to increase vertical chest dimension.
- Intercostal muscles contract elevating the ribs to increase lateral chest dimensions.
- The chest walls pull the lungs outwards with them allowing air to flow into the lungs by the production of -ve pressure.
Describe the process of expiration mechanics.
- Diaphragm relaxes and rises to decrease vertical thoracic dimension.
- Intercostal muscles relax lowering the ribs to decrease lateral chest dimensions.
- Elastic tissue of the lungs recoil to allow air to flow out of the lungs.
Where is the midsternal line?
This is a surface anatomy term that runs directly through the sternum to divide the body into left and right.
Where are the midclavicular lines?
This is a surface anatomy term that runs directly through the middle of the clavicle. There are right and left midclavicular lines.
Name the four quadrants of the female breast.
- Superolateral quadrant
- Superomedial quadrant
- Inferomedial quadrant
- Inferolateral quadrant
What is the midaxillary line?
This is a surface anatomy term that runs directly down the side of the body, dividing it into front and back. This is the coronal line.
What is the anterior and posterior axillary lines?
These are surface anatomy terms that refer to the lines that lie on either side of the midaxillary lines. They are determined by the position of the axillary folds.
What is the nipple of the chest?
This is the centremost area of the breast.
What is the areola?
This is the area that surrounds the nipple on the breast.
What is the axillary tail?
This is an extension of the tissue of the breast towards the
Which arteries and veins supply the female breast?
The subclavian and internal thoracic artery and vein.
Describe the lymph drainage from the breast?
There is unilateral drainage from the lateral quadrants to axillary nodes.
There is bilateral drainage from the medial quadrants to the parasternal nodes.
Where is the jugluar notch?
This can be palpated at the top of the manubrium.
Name the descending layers of the anterolateral chest wall.
- Skin
- Superficial fascia
- Deep fascia
- Skeletal muscles
- Sensory nerves
Describe the superficial fascia of the chest wall.
This is composed of adipose tissue. It is used for insulation of the chest.
Describe the deep fascia of the chest wall.
This is fibrous and tough. It is used for protection of the chest.
Name the muscles of the anterolateral chest wall.
Pectoralis major, serratus anterior, latissimus dorsi
Which vein lies in the delto-pectoral groove (between the deltoid and pectoralis major muscles)?
Cephalic vein
What is the brachial plexus?
This is a network of nervesormed by the anterior rami of the lower four cervical nerves and first thoracic nerve C5, C6, C7, C8, and T1). Itsupplies the skin and musculature of the upper limb.
What is the parietal pleura?
This is a collective term that includes cervical, costal, diaphragmatic and mediastinal parietal pleura.
What is the cervical parietal pleura?
This is in the region of the cervical vertebrae and extends from the apex of the lung into the top of the neck.
What is the costal parietal pleura?
This lines the inner surfaces of the ribs and the intercostal muscles and is separated from them by endothoracic fascia.
What is diaphragmatic parietal pleura?
This is the pleura that overlies the diaphragm at the bottom of the lungs.
What is the mediastinal pleura?
This separated the pleural cavity from the mediastinum and is at the centre of the chest cavity.
What is the costophrenic angle?
This is the point where the diaphragm meets the ribs. This can be visualised on a chest x-ray.
What is the costodiaphragmatic recess?
This is the potential space at the bottom of the chest cavity between the diaphragmatic parietal pleura and the costal parietal pleura
Name the structures in the root of the lungs.
1 main bronchus 1 pulmonary artery 2 pulmonary veins Lymphatic vessels Visceral afferents - sensory nerves Sympathetic nerves Parasympathetic nerves
What is auscultation?
This is a technique of listening to the sound of air moving through the larynx.
All 5 lung lobes, the apices and the bases must be auscultated.
How is auscultation carried out?
When air is passed through the bronchial tree and the alveoli, the sound is altered.
This change can be heard with a stethoscope.
Normal breath sounds are rustling in nature.
Summarise the anatomy of coughing.
- Stimulation of sensoty receptors in the mucosa of the oropharynx, laryngopharynx, larynx and the respiratory tree.
- The CNS responds by rapidly.
What does the CNS do in response to stimulus in the respiratory tract?
- A deep inspiration using the diaphragm, intercostal muscles and accessory muscles of inspiration.
- Adduction of the vocal cords to close the rima glottidis.
- Contraction of the anterolateral abdominal wall muscles to build up abdomnial pressure which pushes the diaphragm superiorly and builds up pressure in the chest and respiratory tree inferior to the adducted vocal cords.
- The vocal cords suddenly abduct to open the rima glottides
- The soft palate tenses and elevates to close off the entrance to the nasopharynx and direct the stream of air through the oral cavity as a cough.
Which sensory receptors are stimulated in sneezing?
CN V or the CN IX are stimulated.
Which sensory receptors are stimulated in coughing?
CN IX or CN X are stimulated.
What are the carotid sheaths?
These are protective tubes of cervical deep fascia.
They attach superiorly to the bones of the base of the skull.
They blend inferiorly with the fascia of the mediastinum
What is contained within the carotid sheaths?
The vagus nerve (CN X), internal carotid artery, common carotid artery and the internal jugular vein.
The glossopharangeal nerve (CN IX) isn’t fully in the carotid sheath.
Where do the motor axons to the respiratory tract move along?
They travel from the tracheal bifurcation along the branches of the respiratory tree to supply all mucous glands and all bronchiolar smooth muscles.
Where do the pulmonary visceral afferents to the respiratory tract move along?
They travel from visceral pleura and respiratory tree to the plexus then follow the vagus nerve to the medulla of the brain
Describe the action potentials in a deep inspiration.
There is a greater outflow of action potentials of longer duration via the phrenic nerve causing the diaphragm to flatten then descend maximally
What are the accessory muscles of forced inspiration?
Pectoralis major, pectoralis minor, sternocleidomastoid and the scalenus anterior, medius and posterior
Describe the pectoralis major.
This attaches between the sternum/ribs and humerus.
It adducts and medially rotates the humerus.
The muscle can pull the ribs upwards and outwards
Describe the pectoralis minor.
This can pull ribs 3-5 superiorly towards the coracoid process of the scapula.
Describe the sternocleidomastoid.
This attaches between the sternum/clavicle and the mastoid process of temporal bone of the base of the skull.
Describe the scalenus anterior, medius and posterior.
These attach between cervical vertebrae and ribs 1 and 2.
Describe the intrinsic muscles of the larynx.
They attach between the cartilages of the larynx.
they are skeletal muscles and are therefore voluntary.
There move the cartilage therefore resulting in movement of vocal cords.
They are supplied by somatic motor branches of the vagus nerves.
They addict the vocal cords during the cough reflex.
Describe course of the right and left vagus nerves (CNX).
They are mixed cranial nerves.
They connect with the CNS at the medulla of the brainstem.
They then pass through the jugular for amen in the base of the skull.
They descend through the the neck within the carotid sheath.
Int he chest they descend posterior to the lung root.
They pass through the diaphragm on the oesphagus.
On the surface of the stomach they finally divide into many parasympathetic branches for the foregut and midgut organs.
Describe some of the functions of the vagus nerve
It supplies somatic sensory axons to the mucosa lining the larynx and somatic motor axons to the intrinsic muscles of the larynx.
It supplies parasympathetic axons to the chest organs
What are the anterolateral abdominal wall muscles?
The left and right rectas abdominis
The left and right external oblique
The left and right internal oblique
The left and right transversus abdominus
Describe the external oblique
It attaches superiority to the superficial aspects of the lower ribs.
It attaches inferiority to the anterior part of the iliac crest and the pubic tubercle.
Describe the course of the right and left vagus nerve
- They connect with the CNS at the medulla of the brainstem.
- They pass through the base of the skull through the jugular foramen.
- They descend through the neck within the carotid sheath.
- In the chest they descend posterior to the lung root.
- They then pass through the diaphragm on the oesophagus.
- One the surface of the stomach they finally divide into many parasympathetic branches for the foregut and midgut of the stomach.
Name some important functions of the vagus nerve in the respiratory system
They supply somatic sensory axons to the mucosa lining in the larynx.
They supply somatic motor axons to the intrinsic muscles of the larynx.
They supply parasympathetic axons to the chest organs.
What are the anterolateral abdominal wall muscles?
Rectus abdominus External oblique - fibres go anteriorly Internal oblique - fibres go posteriorly Transversus abdominus - fibres go transversely (There are both left and right of these)
Where do the external oblique muscles attach?
Attaches superiorly to the superficial aspects of the lower ribs.
Attaches inferiorly to the anterior part of the iliac crest and the pubic tubercle
What is the linea semilunaris?
This is where the muscle fibres of the external oblique end and the aponeurosis begins.
What is the linea alba?
It is a midline fibrous line in the anterior abdominal wall formed by the median fusion of the layers of the rectus sheath medial to the bilateral rectus abdominis muscles.
Where do the internal oblique muscles attach?
Attaches superiorly to the inferior border of the lower ribs.
Attaches inferiorly to the iliac crest and the thoracolumbar fascia of the lower back.
Where do the transversus abdominus attach?
Attaches superiorly to the deep aspects of the lower ribs.
Attaches inferiorly to the iliac crest and the throacolumbar fascia of the lower back
What separates the rectus abdominus into compartments?
Tendinous intersetctions
What are the functions of the abdominal muscles?
- Maintain posture
- Produces movements
- Protects the abdominal viscera
- Increases intra-abdominal pressure
- Aid forced expiration
Name the four sections of the mediastinum.
Superior mediastinum
Anterior mediastinum
Middle mediastinum
Posterior mediastinum
When does a pneumothorax form?
When there is a breach in the visceral pleura or parietal pleura that permits alveolar air to enter the pleural cavity.
What is a small pneumothorax?
When a small amount of air enters the pleural cavity. The vacuum is lost and the elastic lung tissue recoils towards the lung root. There is a gap of <2cm between the parietal pleura and the lung.
What is a large pneumothorax?
This is the same as a small pneumothorax but the gap between the lung and parietal pleura is >2cm.
How is a pneumothorax diagnosed?
History
Examination showing reduced ipsilateral chest expansion and breath sounds and hyperresonance on percussion.
CXR showing absent peripheral lung markings and the visible lung edge
What is a tension pneumothorax?
This is where the torn pleura creates a one-way valve that allows air to enter the cavity on inspiration but it cannot leave. As this process continues, the pressure increases which puts pressure on the mediastinal structures.
What are the four sections of the mediastinum?
The superior mediastinum - sternal angle
The middle mediastinum
The anterior mediastinum
The posterior mediastinum
What are some of the consequences of mediastinal shift?
Tracheal deviation away from the side of the pneumothorax, SVC compression that causes hypotension
How do we treat a large pneumothorax?
Needle aspiration (thoracentesis) and the siting of a chest drain. There will both take place at the 4th or 5th intercostal space on the midaxillary line
How do we treat a tension pneumothorax?
Insert a large gauge cannula into the pleural cavity via the 2nd or 3rd intercostal space on the midclavicular line.
