Larynx Structure and Function Quiz

Recurrent laryngeal nerve damage can occur iatrogenically during thyroid surgery, or due to compression by a tumor. This damage can lead to hoarseness/vocal cord paralysis. If unilateral, the other cord can compensate for phonation, but complete bilateral damage will result in the inability to phonate. Partial damage affects abductors more than adductors, leading to median position of cords and increased dyspnea.

Laryngospasm can be triggered by stimulation of internal superior laryngeal fibers, leading to reflex closure of the airway. It can be a surgical/anaesthetic consideration, triggering inappropriate laryngeal closure reflex. Laryngospasm can also occur in neurological conditions. Additionally, compromised swallowing coordination (dysphagia) can lead to aspiration pneumonia, where food/drink is inhaled, leading to infection, sometimes requiring dietary changes e.g. thickening agents.

The epiglottic cartilage is composed of elastic cartilage.

<p>The recurrent laryngeal nerve is in close association with the thyroid gland and can be damaged during thyroid surgery. This nerve supplies intrinsic laryngeal muscles that control the vocal ligaments/cords. Damage to the recurrent laryngeal nerve therefore results in a hoarse voice or loss of voice.</p> Signup and view all the answers

<p>By the end of this lecture, time spent in the dissecting room, and further private study, students should be able to: 1. Describe the general structure and functions of the larynx 2. Describe the cartilages and membranes of the larynx 3. List the extrinsic muscles of the larynx 4. Describe the actions of the intrinsic muscles of the larynx 5. Describe (briefly) the neurovascular supply of the larynx (more detail will come in MD 4001) 6. Discuss the clinical conditions that may affect the larynx, particularly in relation to nerve lesions</p> Signup and view all the answers

<p>The larynx functions to conduct air, protect the airway from food, liquids etc., and for vocalization.</p> Signup and view all the answers

<p>The larynx is located in the anterior, median neck, with the laryngeal inlet at C3 level and the trachea beginning at C6 level. The laryngeal prominence is palpable below the skin and is mobile during function. It is higher in newborns and infants, descending around weeks 4-6.</p> Signup and view all the answers

<p>The three large unpaired cartilages of the larynx are primarily made of hyaline cartilage, and the elastic cartilage epiglottis is made of elastic cartilage.</p> Signup and view all the answers

<p>The larynx is supplied with blood by the superior laryngeal arteries from the external carotid artery and the inferior thyroid arteries from the subclavian artery.</p> Signup and view all the answers

<p>The cricothyroid muscle is innervated by the external branch of the superior laryngeal nerve, while most intrinsic laryngeal muscles are innervated by the recurrent laryngeal nerve, which branches off from the vagus nerve.</p> Signup and view all the answers

<p>The larynx is a membranous tube of cartilage, muscle, and fibrous membranes that connects the oropharynx with the trachea via the laryngeal inlet. It functions to conduct air, protect the airway from food and liquids, and enable vocalization. The larynx is located in the anterior median neck, with the laryngeal inlet at the C3 level and the trachea beginning at the C6 level.</p> Signup and view all the answers

<p>The extrinsic muscles of the larynx include the sternothyroid, thyrohyoid, omohyoid, and sternohyoid muscles. The intrinsic muscles of the larynx, such as the cricothyroid and posterior cricoarytenoid muscles, are responsible for controlling the tension and position of the vocal folds during phonation and respiration.</p> Signup and view all the answers

<p>The neurovascular supply of the larynx involves the recurrent laryngeal nerve and the superior laryngeal nerve, which provide motor and sensory innervation. Clinical conditions that may affect the larynx include nerve lesions, which can lead to vocal cord paralysis, and vascular issues such as laryngeal edema.</p> Signup and view all the answers

<p>The laryngeal prominence is palpable below the skin and is mobile during function. In newborns and infants, the laryngeal prominence is higher and gradually descends between weeks 4-6 of development.</p> Signup and view all the answers

<p>The larynx protects the airway from food and liquids by closing off the trachea during swallowing. It also plays a crucial role in vocalization by controlling the tension and position of the vocal folds to produce sound.</p> Signup and view all the answers

<p>Cricothyroidotomy allows gaining access to the airway in emergency situations. The cricothyroid membrane is relatively superficial, and a vertical incision in the skin is made to avoid the anterior jugular veins, followed by a transverse incision in the cricothyroid membrane.</p> Signup and view all the answers

<p>Recurrent laryngeal nerve damage can occur iatrogenically, for example during thyroid surgery, or due to neurological compression via a tumor. This can cause hoarseness or vocal cord paralysis. Partial damage affects abductors more than adductors, leading to a median position of cords and increased dyspnoea.</p> Signup and view all the answers

<p>Laryngospasm can be triggered by stimulation of internal superior laryngeal fibers, leading to reflex closure of the airway. It can be a surgical/anaesthetic consideration triggering inappropriate laryngeal closure reflex. Additionally, it can occur in neurological conditions and may lead to aspiration pneumonia due to compromised swallowing co-ordination.</p> Signup and view all the answers

<p>The epiglottic cartilage is composed of elastic cartilage.</p> Signup and view all the answers

<p>A patient may report a hoarse voice after thyroid surgery due to potential damage to the recurrent laryngeal nerve, which is in close association with the thyroid gland and supplies intrinsic laryngeal muscles controlling the vocal ligaments/cords.</p> Signup and view all the answers

<p>The cricothyroid muscle is innervated by the external branch of the superior laryngeal nerve. Most intrinsic laryngeal muscles are innervated by the recurrent laryngeal nerve, except for the cricothyroid muscle.</p> Signup and view all the answers

<p>The larynx is supplied by the superior laryngeal arteries from the external carotid artery and the inferior thyroid arteries from the subclavian artery.</p> Signup and view all the answers

<p>The lymphatics drain above the vocal folds into the superior deep cervical nodes and below the vocal folds into the pre and paratracheal nodes, and then into the inferior deep cervical nodes.</p> Signup and view all the answers

<p>Intrinsic and extrinsic muscles play a crucial role in protecting and closing the airway, as well as controlling the size of the rima glottidis.</p> Signup and view all the answers

<p>Clinical considerations related to the larynx include choking, anaphylaxis, laryngospasm, aspiration pneumonia, cricothyroidotomy, and recurrent laryngeal nerve damage.</p> Signup and view all the answers

<p>1 in 2000 births</p> Signup and view all the answers

<p>1 in 3000 births</p> Signup and view all the answers

<p>1 in 30,000 births</p> Signup and view all the answers

<p>Premature birth and insufficient surfactant</p> Signup and view all the answers

<p>Pseudoglandular</p> Signup and view all the answers

<p>The primitive body cavities undergo partitioning, forming pleural and pericardial cavities. The diaphragm forms to separate thoracic and abdominopelvic cavities through the fusion of pleuroperitoneal membranes.</p> Signup and view all the answers

<p>The respiratory diverticulum, or lung bud, develops as an outpouching of the foregut, with endoderm and visceral mesoderm origin.</p> Signup and view all the answers

<p>Pharyngeal arches 4 and 6 contribute to larynx development. The internal epithelium of the larynx is from endoderm, while laryngeal muscles and cartilages come from mesenchyme fusion.</p> Signup and view all the answers

<p>Lung development involves generational divisions to create the bronchial tree and four phases of development.</p> Signup and view all the answers

<p>Lung development continues after birth, with the earliest survival for a prematurely born baby at around week 24.</p> Signup and view all the answers

<p>By the end of this lecture, time spent in the dissecting room, and further private study, students should be able to describe the embryonic development of the trachea and bronchi, describe the embryonic development of the lungs and pleura, describe the embryonic development of the diaphragm, and discuss the congenital abnormalities that may affect the respiratory system and diaphragm.</p> Signup and view all the answers

<p>Chapters 7 and 14 from <a href="https://meded.lwwhealthlibrary.com/multimediaplayer.aspx.MultimediaID=19450544">https://meded.lwwhealthlibrary.com/multimediaplayer.aspx.MultimediaID=19450544</a>.</p> Signup and view all the answers

<p>All humans start as two cells that form a zygote, which undergoes divisions and implants into the mother's uterus. Implantation occurs by days 7-9, and two layers of cells form from the inner cell mass – epiblast and hypoblast. A three-layer (trilaminar) disc forms via a process termed gastrulation (day 17), and these three layers are ectoderm, mesoderm, and endoderm.</p> Signup and view all the answers

<p>A three-layer (trilaminar) disc forms, and all three layers derive from the epiblast via a process termed gastrulation. The three layers are ectoderm, mesoderm, and endoderm, and they subsequently develop into all tissues of the body.</p> Signup and view all the answers

<p>The key topics covered in the lecture include the embryonic development of the trachea and bronchi, the embryonic development of the lungs and pleura, the embryonic development of the diaphragm, and the congenital abnormalities that may affect the respiratory system and diaphragm.</p> Signup and view all the answers

<p>The diaphragm attaches to the xiphoid process, costal margin, and lumbar vertebrae. It separates the thoracic and abdominal cavities and plays a crucial role in respiration.</p> Signup and view all the answers

<p>The structures that pass through the diaphragm include the inferior vena cava (T8), esophagus (T10), and aorta (T12).</p> Signup and view all the answers

<p>During inhalation, the diaphragm contracts and moves inferiorly, while the thoracic cavity expands. During exhalation, the diaphragm relaxes and moves superiorly, and the thoracic cavity decreases in size.</p> Signup and view all the answers

<p>A pneumothorax occurs when air enters the space between the lung and the chest wall, causing the lung to collapse partially or completely.</p> Signup and view all the answers

<p>Anatomical structures in cross-sections of the thorax include the heart, lungs, trachea, bronchi, and major blood vessels such as the aorta and vena cava.</p> Signup and view all the answers

<p>The anatomical landmarks for chest tube placement include the midclavicular line (8th rib), midaxillary line (10th rib), and scapular line/midline (12th rib posteriorly). These landmarks are important for determining the appropriate insertion site for the chest tube to effectively drain air or fluid from the pleural space.</p> Signup and view all the answers

<p>Pneumothorax occurs when air enters the pleural space, causing the lung to collapse due to the loss of negative pressure. This can lead to mediastinal shift and impaired lung function. Clinically, it can present as dyspnea, chest pain, and respiratory distress, and may require chest tube insertion for management.</p> Signup and view all the answers

<p>Chest drain insertion is indicated for conditions such as pneumothorax, pleural effusion, haemothorax, and chylothorax. Complications can include perforation of the pericardium, heart, or liver if the drain is incorrectly placed.</p> Signup and view all the answers

<p>Flail chest is characterized by the fracture of more than three ribs, leading to a segment of the thoracic wall becoming 'loose' and moving paradoxically during respiration. Clinically, it can present as paradoxical chest wall motion and respiratory compromise.</p> Signup and view all the answers

<p>Chest tube placement requires precise anatomical knowledge to avoid complications such as injury to vital structures. The management of pleural conditions involves understanding the underlying pathophysiology and selecting appropriate interventions, such as chest tube insertion or drainage.</p> Signup and view all the answers

<p>The three major openings of the diaphragm are the caval opening at the level of T8, the oesophageal hiatus at the level of T10, and the aortic hiatus at the level of T12.</p> Signup and view all the answers

<p>The diaphragm is primarily innervated by the phrenic nerve, providing motor and sensory function to the central diaphragm, parietal pleura, and pericardium. In terms of the mechanics of breathing, at rest, inspiration is mostly driven by the diaphragm, with contraction increasing thoracic volume to draw air into the lungs.</p> Signup and view all the answers

<p>The surface anatomy of the lungs and pleurae includes the apex located 3cm superior to the mid clavicle, as well as specific rib levels for the midclavicular line, midaxillary line, scapular line, and midline.</p> Signup and view all the answers

<p>Gaseous exchange occurs during inspiration, and exhaling at rest is largely passive due to elastic recoil, while higher demand for O2/CO2 removal can involve accessory muscles and is aided by the pleurae.</p> Signup and view all the answers

<p>The diaphragm's inverted 'J' domed structure, its attachments to the thoracic and lumbar regions, and its role as the main muscle for breathing are key aspects of its anatomy and function.</p> Signup and view all the answers