HNN Week 2 Flashcards
Describe the muscles in the face and their function:
See drawing p4 HNN stripy notes
MAIN MUSCLES
- frontalis - moves scalp and wrinkles forehead (has a posterior belly called occipitalis at posterior of head and the two are connected by aponeurosis)
- platysma - tenses skin of lower face and neck
- corrugator supercili - draws eyebrows medially making the vertical forehead wrinkles
EYE MUSCLES
- obicularis occuli (palpebral and orbital part)
NASAL MUSCLES
- nasalis - flares nostrils
- procerus - depresses medial end of eyebrow
ORAL MUSCLES
- obicularis oris - closes mouth and puckers lips
- buccinator - draws cheeks in
UPPER ORAL MUSCLES
- risorius - moves corner of mouth lateral and superior
- zygomaticus minor - smiling
- zygomaticus major - smiling
- levator labii superioris - elevates upper lip AND deepens furrow between nose and mouth when sad
- levator labii superioris alaeque nasi (Little Ladies Snore All Night) - lifts upper lip and flares nostrils
- levator anguli oris - for smiling and deepening furrow between nose and mouth when sad
LOWER ORAL MUSCLES
- depressor anguli oris - moves corners of mouth down
- depressor labii inferioris - depresses lower lip
- mentalis - protrudes lower lip and wrinkles chin
Describe the three muscles surrounding the ear and their function:
- posterior auricular muscle (retracts and elevates ear)
- superior auricular muscle (elevates ear)
- anterior auricular muscle (elevates and moves ear anteriorly)
Describe the 4 muscles of mastication and their innervation:
1 - masseter (most superficial and largest, elevates mandible)
2 - temporalis (elevates mandible)
3 - medial pterygoid (elevates mandible, quadrangular with two heads)
4 - lateral pterygoid (moves jaw side to side and protracts mandible, triangular with two heads)
All receive motor innervation from the trigeminal nerve
What is the innervation of each of the facial muscles?
MAIN MUSCLES (3)
- frontalis (temporal branch)
- platysma (cervical branch)
- corrugator supercili (temporal branch)
EYE MUSCLES (1) - obicularis occuli (palpebral and orbital part) (temporal and zygomatic branches)
NASAL MUSCLES (2)
- nasalis (buccal branch)
- procerus (buccal branch)
ORAL MUSCLES (2)
- obicularis oris (buccal branch)
- buccinator (buccal branch)
UPPER ORAL MUSCLES (6)
- risorius (buccal branch)
- zygomaticus minor (buccal branch)
- zygomaticus major (buccal branch)
- levator labii superioris (buccal branch)
- levator labii superioris alaeque nasi (buccal branch)
- levator anguli oris (buccal branch)
LOWER ORAL MUSCLES (3)
- depressor anguli oris (marginal mandibular branch)
- depressor labii inferioris (marginal mandibular branch)
- mentalis (marginal mandibular branch)
Describe the arterial supply of the face:
brachiocephalic trunk -> common carotids -> EXTERNAL carotid (supplies everything outside the skull) :
BRANCHES:
- facial artery -> superior and inferior labial artery
- occipital artery
- posterior auricular artery
- maxillary artery
- superficial temporal artery
Describe the venous drainage of the face:
- superficial temporal vein and maxillary vein join forming retromandibular vein
- retromandibular vein + posterior auricular vein + facial vein = external jugular vein
Describe the nervous supply of facial structures:
Facial nerve branches: supply all muscles (Two Zebras Bit My Carrot) - temporal branch - zygomatic branch - buccal branchES - marginal mandibular branch - cervical branch (- also posterior auricular branch)
Trigeminal branches: supply sensation and motor supply to muscles of mastication
- ophthalmic branch = V1
- maxillary branch = V2
- mandibular branch = V3
What is the physiology of salivary glands and the composition of saliva?
- ~1.5L produced per day
- pH 6-7
- dissolves food so that particles can react with chemoreceptors in the mouth
Contents:
- mucous
- amylase
- lysozyme
Why is salivary a-amylase important if pancreatic a-amylase has the same digestive function?
Salivary a-amylase dissolves food that is stuck in teeth
How does the nervous system control saliva secretion?
Controlled by sympathetic and parasympathetic division of the ANS.
Both divisions stimulate salivate SECRETION but the the parasympathetic division stimulates saliva secretion more so.
Increased parasympathetic activity -> increased blood flow to glands -> increased secretion.
Describe the physiological process behind saliva secretion including ion movement:
- the acini cells in each of the salivary glands secrete a PRIMARY SECRETION that has an ion composition similar to extracellular fluid
- as the secretion flows through the duct system of the glands, active transport occurs and the composition changes
- > Na/K pump actively transports Na out of saliva
- > K+ ions are actively pumped into
- > as a consequence, Cl moves out also, following the Na
- > HCO3- is actively secreted into saliva
- as the rate of salivation increases, the pH increases as more HCO3- is added
- pH increases from 6.2-7.4
Describe the anatomy and physiology of the parotid gland:
- produces serous saliva that is rich in enzymes
- the facial gland passes through the parotid gland and separates it into a deep and superficial lobe
- 4 bordering structures:
- > zygomatic arch superiorly
- > mandible inferiorly
- > masseter anteriorly
- > ear and sternocleidomastoid muscle posteriorly
- secretions transported by STENSEN DUCT from the anterior surface of the gland through the masseter muscle, pierces buccinator muscle and enters the oral cavity near the 2nd MOLAR
Describe the anatomy and physiology of the submandibular salivary gland:
- mixed mucous and serous secretions
- 3 boundaries:
- > inferior body of mandible superiorly
- > anterior belly of digastric anteriorly
- > posterior belly of digastric posteriorly
- gland is J shaped and hooks round the mylohyoid muscle
- secretions excreted though 5cm long submandibular duct which opens at base of lingual frenulum
Describe the anatomy and physiology of the sublingual salivary gland:
- smallest and deepest of the three glands
- contributes 5% of all secretions and is mainly mucous
- found in sublingual fossae on the medial surface of the mandible under the tongue
- the secretory glands (leaving each sublingual gland) unite anteriorly in a horse-shoe shape and open at sublingual caruncle (small lump either side of lingual frenulum)
- each gland also has 8-20 excretory ducts (ducts of rivinus) which open out on top of sublingual folds (mucous membrane anterior to glands in bottom of mouth)
Describe the innervation of each of the salivary glands:
SUBMANDIBULAR AND SUBLINGUAL:
- facial nerve supplies parasympathetic
- superior cervical ganglion supplies sympathetic
PAROTID:
- glossopharyngeal nerve supplies parasympathetic
- superior cervical ganglion supplies sympathetic
How would you test the trigeminal nerve?
SENSORY
- cotton wool ball on face, repeat with pin
MOTOR
- place fingers on temples, patient clenches teeth and test temporalis muscle
- place fingers on cheeks and patient clenches teeth feeling masseter muscles
- test jaw jerk
CORNEA (sensory supply of cornea is trigeminal nerve)
- lightly touch cornea with cotton wool wisp while patient looks away and there will be reflex shutting of eyelids
How would you test the facial nerve?
MOTOR - test muscle control:
- raise eyebrows
- frown
- smile
- puff out cheeks
- tightly close eyes and resist gentle opening
What may be the clinical effects if a patient receives a slash to the side of the face?
- parotid gland swells
- leaking saliva may form fistula
- blood spurts from 3 places:
- > superior temporal artery
- > facial artery
- > superior labial artery
- if facial nerve branches damaged = tarrsorephy
- > cornea drys out as eyelids cannot close
What is tarrsorephy?
Surgical procedure where the eyelids are partially sewn together to prevent drying out of cornea
What is the violence reduction unit?
- part of Police Scotland, which is a national centre of expertise on violence
- tries to reduce violence
- teams up with agencies in fields of health, education and social work and targets violence in school/workplaces/on streets
- trains hairdressers, vets, dentists and firefighters to look for signs of domestic abuse
- has managed to increase the sentence time for carrying a knife
- runs various programmes to help reduce and contain violence
Describe the ‘medics against violence’ programme run by the violence reduction unit:
- charity set up by 3 surgeons in 2008 to prevent young people being killed or being victims of life-changing injuries
- secondary school education programmes
- NHS professionals volunteer with the charity and educate school pupils
- beneficial as incidents of youth crime are falling
What is spinal shock and why does it occur?
- long term depression of all spinal reflexes
- spinal cord functions and reflexes become depressed to the point of total silence
- amount of disability and duration depends on level and degree of injury
- there is temporary suppression of all reflex activity below level of injury and spinal neurons gradually regain their exciteability over time from hrs -> weeks -> months
What are the phases of spinal shock and its recovery?
- Areflexia
- Initial reflex return
- Increased muscle tone
- Hyperreflexia and spasticity
What are clinical symptoms of spinal shock?
- paralysis
- areflexia
- loss of sensation
- loss of bladder and bowel reflexes
What are complications that can arise depending on the level of spinal injury and spinal shock?
- low BP -> hypotension -> loss of sympathetic stimulation of blood vessels
- impaired breathing -> hypoxia
- lack of sympathetic input to the heart -> bradycardia
- hypothermia -> cannot shiver and heat loss from the dilated blood vessels causing low BP
In the dorsal medial lemniscus pathway, what are the two areas that receive different signals in the thalamus and where do they receive signals from?
1) ventroposterolateral (VPL) nucleus = receives sensory information from the body
2) ventroposteromedial (VPM) nucleus = receives sensory information from the head
What is the rubrospinal tract?
- descending tract
- non-pyramidal
- allows the motor cortex and cerebellum to influence motor activity and control the tone of limb FLEXORS
What is the tectospinal tract?
- mediates REFLEX movements in response to VISUAL STIMULI
What is the vestibulospinal tract?
- control EXTENSOR muscle tone in antigravity maintenance of posture
What is the reticulospinal tract?
- controls muscle tone, voluntary movement, reflexes and is involved in the control of breathing
Draw the locations of the main ascending/descending tracts on a cross section of the spinal cord:
See stripy notes HNN p4
Although most organs receive both P and S input from the ANS, which organs receive parasympathetic only?
- ciliary muscles which focus the eye
- iris sphincter muscle
Although most organs receive both P and S input from the ANS, which organs receive sympathetic only?
- adrenal medulla
- hair follicles and sweat glands
- spleen
- iris dilator muscle
Describe the ANS:
- autonomic nervous system
- regulates organs and maintains homeostasis
- requires CNS input
- consists of pre-ganglionic and post-ganglionic fibres
Describe features of the sympathetic division of the ANS:
- T1-L2
- post-ganglionic neurons in the sympathetic trunk
- short pre-ganglionic neurons and long post-ganglionic neurons
- preganglionic neurotransmitter always cholinergic ACh
- postganglionic neurotransmitter adrenergic NA (except sweat glands are cholinergic ACh)
Describe features of the parasympathetic division of the ANS:
- CN 3, 7, 9 and 10 and S2-4
- post-ganglionic neuron in wall of viscera they innervate
- long preganglionic and short postganglionic neuron
- preganglionic neurotransmitter AND postganglionic neurotransmitters are cholinergic ACh
What is the effect of the sympathetic NS on the following:
a) viscera
b) HR
c) bronchus
d) pupils
e) genitalia
a) increases activity
b) increases
c) dilates
d) dilates
e) ejaculation
What is the effect of the parasympathetic NS on the following:
a) viscera
b) HR
c) bronchus
d) pupils
e) genitalia
a) decreases activity
b) decreases
c) constricts
d) constricts
e) erection
What is the anatomical difference between and upper and lower motor neuron?
An upper motor neuron runs from the cortex to the anterior (ventral) horn of grey matter in the spinal cord.
A lower motor neuron runs from the ventral horn of grey matter in the spinal cord to innervate skeletal muscle.
What is a upper motor neuron lesion?
A lesion of the neural pathway between the brain and the grey matter of the spinal cord (i.e. somewhere on the upper motor neuron) e.g. cerebral infarction,
What is a lower motor neuron lesion?
Affects the nerves travelling out of the spinal cord from the anterior horn of grey matter to the periphery e.g. nerve root damage or peripheral nerve damage
What signs (UMNL or LMNL) are seen if there is a lesion between C1-5?
UMNL signs seen in all limbs
What signs (UMNL or LMNL) are seen if there is a lesion between T3-12?
UMNL signs seen in lower limbs (upper limbs normal)
What signs (UMNL or LMNL) are seen if there is a lesion between T12-S2?
LMNL signs seen in lower limbs (upper limbs normal)
What is hemiparesis?
Weakness of limbs on one side
What is paraplegia?
Paralysis of the lower limbs
What is tetraplegia?
Paralysis of all 4 limbs
What are signs/symptoms of an UMNL?
- muscle weakness but NOT MUCH WASTING
- increased reflexes
- increased tone and spasticity
- clonus
- positive babinski sign
What are signs/symptoms of an LMNL?
- muscle weakness AND WASTING
- decreased reflexes
- reduced tone and spasticity
- fasciculations
- negative babinski sign
Describe the effects of a spinal injury at different segments of the spinal cord on RESPIRATION:
C3,4,5 -> contribute to the phrenic nerve, therefore if there is damage in this region then signals from the respiratory centre in the brain cannot innervate respiratory muscles. Damage above this level means there is no continuity of signals between the respiratory centres in the brain and the respiratory nerve terminal innervating the lungs.
C7+8 -> innervate intercostal muscles, diaphragm innervation still intact but paradoxial breathing occurs where the chest wall moves in on inspiration and out on expiration as the intercostals do not contract to expand the chest
Describe the effects of a spinal injury at different segments of the spinal cord on BODY MOVEMENT:
C1-4 -> most severe and paralysis of the arms, trunk and legs, limited head and neck movement
C5 -> normal shoulder and bicep control, no wrist or hand control
C6 -> normal wrist control, no hand control
C7+T1 -> arms can straighten, issues with dexterity of hands and fingers
T1 - T8 -> paraplegia, hands not affected, poor trunk control but good balance
L-S regions -> poor control of hip flexors and legs
What is the difference between a complete and an incomplete spinal cord injury?
Complete = no motor or sensory function below the level of the SCI
Incomplete = partial motor or sensory loss below the level of the SCI
Describe the effects of a spinal injury at different segments of the spinal cord on BLADDER CONTROL:
- micturition reflex depends on integrity of lumbosacral region, damage above this area (i.e. not directly in this area) means reflex should gradually return
- automatic bladder: where the bladder suddenly voids when the stretch receptors in the bladder wall reach threshold
- Indirect control of micturition can occur as when the bladder fills, distension of stretch receptors produces a reflex increase in BP (an exaggerated BP increase) and flushing of face occurs = signalling that the patient must go to the toilet
- Scratching inside thigh = sensory bombardment of the sacral region -> micturition reflex stimulated and bladder empties
- Increased emptying of bladder can be taught by compression if arm movement intact
What are the risks associated with incomplete bladder emptying in a patient with a SCI?
increased UTI risk
kidney damage
renin released
hypertension
What are other complications of SCI that must be monitored?
- loss of sensation = constant monitoring and prophylaxis as there is increased risk of DVT and pressure sores
- hyperreflexia and increased BP = headaches, dizziness
Describe the recovery and management process of a spinal cord injury patient:
- urgent assessment and decompression: surgery, metal plates to stabilise spinal cord, immobilise patient to prevent further injury
- physiotherapy and mobilisation
- supportive care (DVT / prophylaxis)
- bowel and bladder management = intermittent self-catheterisation and balanced food and fluid intake
- pain management (analgesia, opioids)
Describe the return of reflexes after a SCI:
SOMATIC FIRST
- flexor reflexes first
- extensor reflexes (knee jerk)
- exaggerated extensor reflexes may occur
(plantar reflex -> cremasteric reflex -> ankle jerk -> knee jerk)
AUTONOMIC REFLEXES SECOND
Initially there would be autonomic dysreflexia and mass reflex responses due to a large sympathetic discharge, but then these would gradually subside
What is the babinski reflex?
Negative babinski sign = normal = plantar movement of toes when sole of foot stimulated
Positive babinski response = abnormal = dosriflexion of toes when the sole of the foot is stimulated
What is the abdominal reflex?
NORMALLY if abdominal wall scratched, muscles contract to pull umbilicus towards the stimulus
