Anatomy Flashcards
How many cartilages make up the larynx, and what are they?
Nine
X2 corniculate
X2 cuneiform
X2 arytenoid
Epiglottic
Thyroid
Cricoid
Which of the following is true of laryngeal anatomy?
A) The infrahyoid muscles alter the length of the vocal cords
B) The vallecula lies within the ventricle
C) The piriform fossa is in the vestibule
D) The epiglottis defines the border of vestibule and ventricle
E) The cricoarytenoids are suprahyoid muscles
C) The piriform fossa is in the vestibule
The larynx is divided into three regions: the vestibule which is from the epiglottis down to the vestibular folds (false cords), the ventricle between the vestibular folds and the vocal cords, and the infraglottic space beneath the cords down to the inferior cricoid cartilage.
The infrahyoid muscles (e.g. omohyoid, thyrohyoid, sternohyoid) depress the hyoid and larynx but don’t alter the length of the vocal cords. The posterior and lateral cricoarytenoids (abductors and adductors respestively) are intrinsic muscles of the larynx.
Which of the following is true of laryngeal innervation?
A) The RLN innervates palatopharyngeus
B) The superior laryngeal nerve innervates a single muscle
C) Combined internal and external laryngeal nerve palsy is an emergency
D) Vocal changes would not be expected with superior laryngeal nerve palsy
E) The RLN runs posterior to the oesophagus
B) The superior laryngeal nerve innervates a single muscle
The superior laryngeal nerve is a branch of the vagus which then branches again into internal (sensory) and external (motor). The external branch innervates only the cricothyroid (the singer’s) muscle.
Which of the following is false of the laryngeal nerves and muscles?
A) The extrinsic muscles of the larynx act via the hyoid bone
B) The internal laryngeal nerve is sensory only
C) The thyroarytenoid is the only muscle that relaxes the cords
D) Stylopharyngeus acts with the suprahyoid muscles
E) Vagus nerve supplies purely autonomic innervation to the larynx
E) Vagus nerve supplies purely autonomic innervation to the larynx
The vagus nerve supplies the internal, external, and recurrent laryngeal nerves, and therefore supplies a large amount of motor as well as sensory innervation to the larynx.
Which of the following is incorrect?
A) Baroceptors are found in carotids, aorta, and heart, but carotid bodies are most sensitive
B) The pressor centre is supero-lateral to the depressor centre in the medulla
C) The afferent pathway from baroceptor to pressor centre is mixed IX & X cranial nerves, but share a common nucleus (tractus solitarius) in the medulla
D) Sympathetic pre-ganglionic fibres are short, myelinated, and cholinergic
E) The Cushing reflex is triggered by carotid bodies via CNIX
E) The Cushing reflex is triggered by carotid bodies via CNIX
The Cushing reflex is a direct response of cells in the pressor centre (ventrolateral medulla) to ischaemia.
Which of the following is false?
A) Of 1L 0.9% NaCl transfused rapidly into a euvolemic subject, ~25% will remain intravascular
B) The carotid bodies are chemoceptors
C) Voluceptors are more sensitive to transfusion than osmoceptors in a healthy adult
D) Sweat glands and skeletal muscle vessels receive post-ganglionic cholinergic sympathetic input
E) Adrenergic innervation is via long unmyelinated post-ganglionic fibres, or release of adrenaline systemically
C) Voluceptors are more sensitive to transfusion than osmoceptors in a healthy adult
Describe the sequence of events with respect to cardiac output on standing from lying
Initially the influence of gravity causes blood to pool in venous capacitance vessels, reducing return to the heart thus preload thus cardiac output thus MAP.
This reduces firing rate of baroceptors (mostly in the carotid sinus) to the pressor centre via CNIX and the nucleus tractus solitarius, which increases sympathetic outflow via paravertebral ganglions and the adrenals, resulting in:
- Venoconstriction
- Capacitance vessels in splanchnic circulation, skin, lungs, skeletal muscle constrict to increase return to right heart
- Vasoconstriction
- Increased adrenergic stimulation of vessels to raise systemic vascular resistance
- Inotropy
- Increased calcium influx via L-type channels in cardiac sarcolemma potentiates CICR and force of contraction.
- Chronotropy
- Accelerated decay of pre-potential/ phase 4 in pacemaker cells due to increased membrane permeability to sodium, and reduced permeability to potassium
Describe the physiological response to haemorrhage
Divided into immediate and delayed
Immediate:
- Cardiac
- Vascular
- Systemic vasoconstriction reduces blood flow peripherally e.g. to skeletal muscle, and renal vasoconstriction reduces the usually very high CO to the kidneys
- Venoconstriction mobilises blood from capacitance vessels in the splanchnic circulation, skin, lungs, and skeletal muscle
- Renal
- Reduced renal blood flow stimulates renin release from the juxtglomerular apparatus. This activates the RAAS system releasing angiotensin II (vasoconstrictor) and aldosterone (sodium retention and thus fluid retention)
- Neurological
- Autoregulation serves to preserve cerebral blood flow longer than for other organs
- ADH is released from neurohypophysis in response to reduced atrial stretch, stimulating thirst, increasing water reabsorption in the collecting ducts via aquaporin, and vasoconstricting
Delayed:
- Renal
- Increased EPO synthesis
- Haematological
- Release of reticulocytes
- Hepatic
- Increased synthesis of plasma proteins
Describe the four phases of a Valsalva manouevre
x
What would be the effect of each of the following on the physiology of a Valsalva manouevre?
- Increased age
- Alpha blockade
- Beta blockade
- Increased age - reduced Valsalva ratio (i.e. less bradycardic response) due to blunted autonomic responsiveness
- Alpha blockade - more tachycardia in phase 2 as the heart compensates for poor peripheral vasoconstriction to increase output. There is then an overshoot in blood pressure due to the tachycardia in phase 4, when venous return to the heart is restored
- Beta blockade - blunted tachycardic response in phase 2 due to beta blockade, so less BP overshoot in phase 4.
