Anatomy of Coughing Flashcards
The sensory receptors that can stimulate a cough/sneeze are located in the mucosa of which areas of the respiratory tract?
Oropharynx
Laryngopharynx
Larynx
All of lower respiratory tract
What are the basic steps involved in a cough/sneeze?
Stimulation of sensory receptors
Deep inspiration using all muscles of inspiration
Adduction of the vocal cords to close rima glottidis
Contraction of anterolateral abdominal wall muscles to increase intra-abdominal pressure
Pushes diaphragm superiorly which increases thoracic pressure
Increased thoracic pressure increases respiratory tract pressure beneath rima glottidis
Vocal cords abduct to open rima glottidis which expels air through either oral cavity (cough) or nasal cavities (sneeze)
Which sensory nerves stimulate a sneeze?
CN V1
CN V2
CN IX
Which sensory nerves stimulate a cough?
CN IX
CN X
Name the nerve which provides sensory innervation in each of the numbered regions
- CN V1
- CN V2
- CN IX
- CN X
What are the carotid sheaths?
Protective tubes of cervical deep fascia in the neck which contain the vagus nerve, the common carotid artery, internal carotid artery and the internal jugular vein
What structures are contained within the carotid sheaths?
Vagus nerve
Common carotid artery
Internal carotid artery
Internal jugular vein
Where does the carotid sheath attach to superioely and inferiorly?
Superiorly- bones of the base of the skull
Inferiorly - blends into mediastinal fascia
Name the bilateral structure the arrows are pointing at
Carotid sheath
How does sensory information from the lower respiratory tract reach the brain?
Information passes from the visceral pleura/respiratory tree to the pulmonary plexus
The vagal branches of the pulmonary plexus join the vagus nerve
Information then ascends the vagus nerve in the carotid sheath to the medulla
What nerve supplies the respiratory tree and the visceral pleura with sensory fibres?
CN X
What is the pulmonary plexus?
A plexus of nerves innervating the visceral pleura and the respiratory tree. It is formed of sympathetic fibres from the sympathetic trunk and parasympathetic fibres from the vagus nerve
Where do the motor axons innervating the lungs travel?
From tracheal bifurcation along branches of respiratory tree to mucous glands/brobchiolar smooth muscle
What are the basic mechanics of inspiration?
Diaphragm contracts which increases the vertical dimension of the lung
Intercostal muscles contract which increases the anteroposterior and lateral dimensions of the lung
This increases the volume of the lungs and therefore reduces the pressure in the lungs
Air flows into the low pressure of the lungs along its concentration gradient
What innervates the diaphragm?
Combined anterior rami of C3, C4 and C5
(phrenic nerve)
Where is the phrenic nerve found in the neck?
Anterior surface of scalenus anterior muscle
Where can the phrenic nerve be found in the thorax?
Descending over the lateral borders if the fibrous pericardium anterior to the lung root
What does the phrenic nerve supply the diaphragm with?
Motor function
Sensory
Sympathetic axons
What does the phrenic nerve supply the fibrous pericardum with?
Sensory fibres
Sympathetic axons
What does a normal contraction of the diaphragm do to its shape?
Flattens it
What does a strong contraction of the diaphragm (deep inspiration) do its shape?
Descends it maximally
What are the three layers of intercostal muscle from superficial to deep?
External intercostal muscle (superficial)
Internal intercostal muscle
Innermost intercostal muscle (deep)
What are the intercostal nerves?
Anterior rami of T1-T11
What are the muscles of quiet respiration?
Diaphragm
Intercostal muscles
What are the accessory muscles of inspiration?
Pectoralis major
Pectoralis minor
Sternocleidomastoid
Scalenus anterior
Scalenus medius
Scalenus posterior
Where does the pectoralis major muscle attach?
On the sternum/ribs and humerus
How can use of the pectoralis major aid respiration?
If the upper limb position is fixed, it can pull the ribs upwards/outwards
What does the pectoralis major muscle do?
Adducts humerus
Medially rotates humerus
How can use of pectoralis minor aid respiration?
Can pull ribs 3-5 superiorly towards coracoid process of the scapula
Where does the sternocleidomastoid muscle attach?
Mastoid process of temporal bone
Sternum
Clavicle
Where do scalenus anterior, medius and posterior attach?
Between cervical vertebrae and ribs 1/2
What does use of the accessory muscles of breathing suggest?
Patient is dyspnoeic