Peerwise Notes PDF

Peerwise notes 12/12/2024 4:23 pm Endocrinology: - Kallman syndrome - characterised by hypogonadotrophic hypogonadism and anosmia, occurs due to neuron migration failure - Klinefelter syndrome - poor coordination, muscle weakness, reading difficulties, gynaecomastia, secondary s...

Peerwise notes 12/12/2024 4:23 pm Endocrinology: - Kallman syndrome - characterised by hypogonadotrophic hypogonadism and anosmia, occurs due to neuron migration failure - Klinefelter syndrome - poor coordination, muscle weakness, reading difficulties, gynaecomastia, secondary sexual characteristic development delay, taller than average, rounded body, microorchidism - Turner syndrome - short stature, widely spaced nipples, webbed neck, high-arched palate, patient appears phenotypically female due to absence of Y chromosome - Symptoms of Grave's eye disease: ○ Bulging eyes ○ Eye irritation or dryness ○ Double vision ○ Swelling around the eyes ○ Eye pain with movement - Transcortin (corticosteroid-binding globulin) is the principal serum cortisol-binding protein, but albumin binds approximately 20% of circulating cortisol in an inactive form - Bilateral adrenal hyperplasia can lead to Cushing's syndrome due to excess cortisol production - Polymyositis - characterised by proximal weakness, non-fatiguable weakness in hips and shoulders ○ Prednisolone (steroid, glucocorticoid) as first line treatment as an immunosuppressant - Cortisol: ○ Catabolic effects: § Bone resorption § Immune system suppression § Muscle proteolysis § Lipolysis ○ Anabolic effects: § Gluconeogenesis - ADH is released from the posterior pituitary gland via neural cells (magnocellular neurons) which extend from the hypothalamus, and is stored in Herring bodies within the posterior pituitary - CYP11b1 codes for 11b-OH - CYP11B2 codes for aldosterone synthase - Somatostatin and pegivsomant are used to treat acromegaly which enhances the secretion and action of GH - Secondary adrenal insufficiency = due to chronic low ACTH stimulation ○ Low ACTH, delayed cortisol recovery and delayed rise in cortisol after synacthen test § Addison's disease shows no significant cortisol rise in Synacthen test - Dopamine inhibits prolactin - Hypopituitarism = partial or complete loss of anterior lobe pituitary function due to tumour/pituitary apoplexy/suppression by long term corticosteroids ○ Lack of ACTH secretion affects zona fasciculata and reticularis ○ Low cortisol - lack of ADH inhibition on posterior pituitary ○ High vasopressin causes ECF expansion, low Na+ and low K+ (dilutational hyponaetraemia) - 5a-reductase converts testosterone into DHT, which is a more potent androgen involved in the development of male secondary sexual characteristics - PTH = increases bone resorption, increases renal absorption of calcium, increases synthesis of active vitamin D - Endometriosis symptoms - dysmenorrhea, dyspareunia, infertility, chocolate cyst on imaging - PCOS symptoms - irregular periods, hyperandrogenism - Elevated FSH and LH with low estradiol indicate primary ovarian insufficiency - A rise in estrogen levels mid-cycle triggers a surge in LH, leading to ovulation - Turner syndrome (45,X) leads to primary ovarian insufficiency, resulting in hypergonadotrophic hypogonadism due to failure of ovarian development - Spironaloctone = mineralocorticoid antagonist with anti-androgen effects, can be used to manage hirsuitism - Adapalene used to treat acne - Bromocriptine is a dopamine agonist used to treat infertility in patients with prolactinaemia - Clomifene citrate used to treat female infertility due to ovulatory dysfunction e.g. for PCOS patients - Co-cyprindiol is used to treat acne - Kallman syndrome - genetic mutation affecting GnRH secretion, associated with anosmia and leading to delayed or absent puberty - Adrenal venous sampling = used to diagnose between unilateral and bilateral aldosterone overproduction, to diagnose Conn's disease or BAH - Renal artery Doppler ultrasound - used to detect renal artery stenosis, i.e. secondary hyperaldosteronism - Adrenal MRI = can detect adrenal masses - 24 hour urinary metanephrines = used to diagnose pheochromocytoma - Turner syndrome: ○ Elevated FSH and LH - characteristic of hypergonadotrophic hypogonadism ○ Short stature ○ Webbed neck ○ Widely spaced nipples ○ Due to primary ovarian insufficiency, estradiol levels are low, leading to a lack of negative feedback to the pituitary - GnRH agonists = downregulate the HP-ovarian axis, reducing estrogen prodcution ○ Since endometriosis is estrogen-dependent, this helps control the growth of ectopic endometrial tissue and reduces symptoms - Keto diet = high fat, low carb - Metabolic syndrome = clustering of CVD risk factors, underlying pathophysiology is related to insulin resistance and visceral/central obesity ○ Criteria: increased waist circumference of BMI > 30, dyslipidaemia with raised triglycerides or reduced HDL cholesterol, hypertension, impaired glucose tolerance - Patients on long-term steroids have suppressed production of endogenous steroids and should have doses doubled during intercurrent illness to combat infection - Immediate hydrocortisone IM injection can be used to treat adrenal crisis - Stopping long-term steroids during illness can precipitate Addisonian crisis - Steroidal medications: Minimal Glucocorticoid Predominant HIGH glucocorticod, HIGH activity, HIGH GLUCOCORTICOID. GLUCOCORTICOID, MINERALOCORTICOI MINERALOCORTICOI Low mineralocorticoid minimal D D mineralocorticoid Fludrocortisone Hydrocortisone Prednisolone Dexamethasone Betamethasone - Polymyositis = autoimmune inflammatory myopathy presenting with proximal muscle weakness and elevated CK levels - Myaesthenia gravis causes fatiguable weakness without CK elevation - Rhabdomyolysis causes weakness associated with acute muscle damage, not chronic progression - Endocrine conditions: ○ Addison's = destruction of adrenal gland causing primary adrenal insufficiency = low aldosterone, low Na+, high K+, low cortisol, low glucose, high ACTH, high urea ○ Acromegaly = 75% due to pituitary macroadenoma, increased IGF-1, random GH level inappropriate due to pulsatile release, gluocse tolerance test suppresses GH in normal individuals but NOT those with acromegaly ○ Laron syndrome = GHR mutation causing postnatal growth failure = short limbs, small head circumference, saddle nose, delayed skeletal maturation, osteopenia, obesity, normal/high GH, low GH binding protein and low IGF-1, reduced cancer susceptibility ○ Cushing's disease = pituitary tumour causing cortisol overproduction = hypertension, high ACTH, high cortisol, high Na+, low K+, low renin and aldosterone, high plasma glucose ○ Cushing's syndrome - can be due to unilateral adrenal adenoma which secretes cortisol, and in this case ACTH would be low due to negative feedback ○ Hashimoto's = primary hypothyroidism = high TSH, low T3 and T4, TPO antibody positive ○ Conn's syndrome = unilateral aldosterone producing tumour presenting with low renin and high aldosterone Neurology: - Broca's area is supplied by the superior division of the left middle cerebral artery ○ Broca's aphasia due to a lesion of the inferior frontal gyrus - Wernicke's area is supplied by the inferior division of the left middle cerebral artery ○ Wernicke's aphasia due to lesion of superior temporal gyrus - Lesion in arcuate fasciculus causes conduction aphasia - normal comprehension, fluent speech, poor repetition and individual is aware of errors they are making - Frontal lobe lesion - Broca's aphasia, anosmia - Temporal lobe lesion - superior homonymous quadrantanopia - Parietal lobe lesion - sensory inattention, inferior homonymous quadrantopia - Occipital lobe lesion - vision issues - Cerebellar lesion - DANISH - Amygdala lesions cause Kluver-Bucy syndrome - hypersexuality, hyperorality, hyperphagia, visual agnosia - External carotid arteries supply the face and neck - Occlusion of an internal carotid artery causes amaurosis fugax - temporary loss of vision in one or both eyes that occurs when blood flow to the retina is disrupted - Brown-Sequard syndrome = affects one whole side of spinal cord. AFFECTED side has loss of motor, vibration and proprioception, but contralateral side experiences loss of pain and temperature sensation - Spinothalamic tract decussates in the spinal cord one level above where the stimulus enters - this means loss of pain sensation on the opposite side of the body if one side of the spinal cord is injured - Trochlear nerve palsy CNIV - defective downward gaze and vertical diplopia - Abducens nerve palsy CNVI - horizontal diplopia with inward deviation of affected eye - Oculomotor nerve palsy CNIII - ptosis, down and out eye - Optic nerve palsy CNII - visual agnosia - S2,3,4 keeps poo off the floor - pudendal nerve - Internuclear opthalmoplegia ○ Lesion in the medial longitudinal fasciculus ○ Affects coordination between the eyes during horizontal gaze ○ Inability to adduct the affected eye while the other eye abducts ○ Seen in MS or brainstem conditions - Posterior circulation stroke means patient is most likely to lose consciousness - Facial sensation provided by CNV (trigeminal nerve) and the muscles of mastication - Phonation, breathing and pharynx are controlled by CNIX and CNX - glossopharyngeal and vagus - Neisseria meningitidis is most common cause of bacterial meningitis, causes non blanching rash ○ Haemophilus influenza causes bacterial meningitis in young children - Parasympathetic innervation: ○ Oculomotor - CNII - pupil constriction ○ Facial - CNVII - lacrimal gland and salivary production ○ Glossopharyngeal - CNIX - salivary production ○ Vagus - CNX - thorax and abdomen - Sympathetic nervous system (fight or flight) ○ Originates from thoracolumbar region of spinal cord - T1-L2 ○ Postganglionic noradrenaline binds to adrenergic receptors ○ SNS binds to beta 2 receptors, causing bronchodilation ○ Preganglionic sympathetic fibres release AcH at adrenal medulla, causing adrenaline secretion - Optic neuritis - unilateral blurred vision and pain upon movement - MS plaque in spinal cord would cause sensory paraesthesia - Vascular dementia = vascular damage and impaired blood supply to the brain - Alzheimer's = amyloid plaque buildup - Lewy body dementia = abnormal deposits of alpha-synuclein - Frontotemporal dementia = accumulation of tau proteins and TDP-43 - Alzheimer's = cholinergic system degradation - MND = TDP-43 alteration leading to bunina body formation - Parkinson's - alpha synuclein missfold leads to Lewy body formation within neurones - Radiculopathy - results from compression or irritation of a nerve root, due to herniated disc - leads to dermatomal sensory loss, sharp pain, absent/reduced reflexes - Guillain Barre syndrome - causes diffuse or glove and stocking sensory loss - Polymositis - causes proximal muscle weakness without sensory loss or radicular pain - Stroke affecting sensory cortex - causes broader sensory or motor deficits without radicular pain or reflex changes - MRI findings in MS of brainstem atrophy without new enhancing lesion support a progressive phase rather than active inflammation - Ulnar nerve compression = Guyon's canal and cubital tunnel, results in tingling of 2 most medial fingers of the hand - Median nerve compression - carpal tunnel, thumb and two most lateral fingers and half of ring finger are affected - Radial nerve = compression likely at axilla and spinal groove of humerus, symptoms include loss of sensation of the back of the hand on the lateral side of the thumb - Lateral cutaneous = vulnerable to compression at the inguinal ligament - symptoms include paraesthesia to the outer thigh - Common peroneal nerve compression = vulnerable to compression at the fibular neck, symptoms include paraesthesia to outer part of leg and foot drop ○ Causes slapping gait = where foot falls and slaps the ground - Cauda equina syndrome - causes saddle anaesthesia (loss of sensation to the perianal region), innervated by S2-S4 - Postural hypotension in Addision's due to low ECF - MAO-B inhibitors e.g. rasagiline - prevents breakdown of dopamine into metabolites - Dopamine agonists - bind to dopamine receptors to stimulate them - Cushing's and renal artery stenosis cause high Na and low K - Corticospinal tract is affected in UMN lesions, leading to hyperreflexia, spasticity and clonus - Peripheral nerves and anterior horn cells are affected in LMN lesions - Neuroanatomy of vision: ○ Two layers of retina: neurosensory retina and retinal pigment epithelium ○ Photoreceptors = specialised neuronal cells for phototransduction § Rods = high sensitivity, good for night vision, low acuity and no colour § Cones = low sensitivity, high acuity (sharpness), sense green and red light § Ganglion = sense blue light and are involved in Circadian rhythym ○ Retinal pigment epithelium sits below the photoreceptors of the neurosensory retina and maintains the overlying neurosensory, absorbs scattered light and forms the blood eye barrier ○ Choroid layers - contain blood vessels supplying the retina - Dorsal column disease can be caused by syphilis, compression, Friedreich ataxia and B12 deficiency - OCULOMOTOR PALSY - ptosis, dilated, fixed pupil, down and out eye in affected eye - Bitemporal hemianopia - caused by lesion in optic chiasm e.g. pituitary adenoma - Horizontal diplopia - problem with abducens nerve - Vertical diplopia - problem with trochlear nerve - Autonomic dysreflexia only occurs if spinal cord injury occurs above the T6 level ○ Autonomic dysreflexia = headache, sweating, hypertension and bradycardia - can be triggered by any afferent sympathetic signal such as urinary retention or faecal impaction - Nervous system embryology: ○ Telencephalon = cerebral cortex, lateral ventricles, basal ganglia ○ Dicephalon = thalamus, hypothalamus, optic nerves, third ventricle ○ Mesencephalon = midbrain, cerebral aqueduct ○ Metencephalon = pons, cerebellum, superior part of 4th ventricle ○ Myelencephalon = medulla, inferior part of 4th ventricle ○ Alar plate = sensory neurons ○ Basal plate = motor neurons - Dominant temporal lobe lesion = receptive aphasia, dyslexia, impaired verbal memory - Non-dominant temporal lobe lesion = impaired non-verbal memory, impaired tonal perception (musical skills) - Dominant parietal lobe lesion = dysphasia, acalculia, dyslexia, apraxia, agnosia - Non-dominant parietal lobe lesion = neglect of contralateral side, spatial disorientation, constructional apraxia, dressing apraxia - Acute disseminating encapholomyelitis: ○ Sudden inflammation and demyelination at multiple sites of the brain and spinal cord ○ T cells cross BBB, changing BBB cells to express receptors and more immune cells enter the brain ○ Immune cells bind and are activated by myelin, myelin specific T cells release cytokines and this dilated blood vessels allowing more immune cells to get into the brain ○ Cytokines attack B cells and macrophages as part of the inflammatory reaction - antibody markers mark myelin sheath proteins and macrophages engulf and destroy oligodendrocytes, leading to demyelination ○ Causes = molecular mimicry, viruses, bacterial infections ○ Symptoms = sudden onset, system inflammation, fever, headache, nausea, vomiting § Demyelination can cause visual problems, seizures and weakness typically in children - Opioid OD = constricted pupils and hypotension - Diazepam = pupil dilation, respiratory depression, slurred speech, poor co-ordination, bradycardia, hypotension, apnoea - Phenytoin = sodium channel blockage causes ataxia, dysarthria, nystagmus, cardiac dysrhythmia - Amitryptyline = blocks Na+ channels, inhibits serotonin and noradrenaline reuptake, arrythmia, seizure, coma - administer sodium bicarb to reverse acidosis - Sertraline = 'serotonin syndrome' nausea, vomiting, agitation, tremor, nystagmus, dilated pupils, tachycardia, neuromuscular hyperactivity, hyperthermia - Thrombolysis needs to be completed within 4.5 hours of ischaemic stroke - Amitryptyline as prophylaxis for chronic tension-type headaches - Verapamil as prophylaxis for cluster headaches - Topiramate/propanolol as migraine prophylaxis - Indomethacin for paroxysmal hemicrania - Root lesion at L3/L4 = radicular pain, dermatomal sensory loss, loss of knee reflex, areflexia and wasting (common LMN signs) - Cauda equina syndrome = acute lower limb pain and weakness, sphincter disturbance - Root lesion at L4/L5 = loss of ankle dorsiflexion and inversion - Root lesion at L5/S1 = plantar flexion and absent ankle reflex - Thoracic cord lesion = lower limb weakness, UMN signs including spasticity, brisk reflexes, upgoing plantars and pyramidal weakness - Signs of MS: ○ Lhermitte's sign = electric shock like sensation due to flexion of the neck - Signs of meningitis : ○ Kernig's sign = patient lies on their back with hips and knees flexed at 90 degrees, examiner attempts to straighten patients knee § Positive test = pain/resistance ○ Brudzinski = patient lies flat on their back and examiner gently flexes patient's neck forward - if this action causes patient's hips and knees to flex involuntarily, it is considered a positive Brudzinski sign - Babinski sign suggest UMN palsy = upgoing plantar reflex - Parietal lobe seizure: ○ Numbness, tingling, prickling, crawling or electric shock like sensations spread along the effected body part ○ Sensations or burning or cold or pain ○ Feeling like part or all of your body is moving or floating ○ Feeling like a body part has shrunk or become bigger or is missing ○ Sexual sensations ○ Difficulty understanding language or reading or writing or doing simple maths ○ Seeing things as bigger or smaller than they are ○ Seeing things that aren't there ○ Neglect of contralateral side - Temporal lobe seizure: ○ Feeling frightened ○ Déjà vu ○ Auditory hallucinations ○ Experiencing an unpleasant taste or smell ○ Rising sensation in stomach ○ Lip smacking or repeated swallowing or chewing ○ Changes to skin tone or HR ○ Automatic behaviours like fidgeting, undressing, running or walking - Frontal lobe seizure: ○ Jacksonian movement - clonic movements travelling proximally ○ Pelvic thrusting or kicking or pedalling or thrashing or rocking movements ○ Screaming or swearing or laughing ○ Unintentionally passing urine ○ Head or eyes turning to one side ○ Unusual body movements e.g. stretching one arm while the other bends ○ Twitching or jerking or stiffening of muscles in one area of body - Occipital lobe seizure: ○ Seeing flashing lights, colour or simple patterns ○ Seeing more complex images such as pictures of people or animals or scenes ○ Not being able to see as well as usual or not being able to see at all ○ Having eye movements you can't control such as eyes closing or moving to one side or quickly from side to side ○ Repeated blinking - MS pathology (focal demyelinating lesions) ○ Perivascular lymphocytic infiltrate and macrophages attack oligodendrocytes ○ Leads to focal lesions degrading the myelin sheath ○ Causes decreased fidelity and speed of transmission in CNS neurons - Myaesthenia gravis (Ach receptor destruction) ○ AChR antibodies attack post-synaptic Ach receptor at NMJ ○ Ach at NMJ is unable to bind to receptors on skeletal muscle ○ Causes fatiguable weakness - NMO (on-target damage) ○ Autoantibodies bind to and destroy aquaporin channels on astrocytes ○ Loss of the water channel causes impaired astrocyte function ○ Cell death via complement dependent cytotoxicity - NMO (off-target damage) ○ Astrocyte death causes blood brain barrier disruption due to impaired water balance in brain ○ Impaired water balance causes swelling and oedema ○ Oedema causes secondary damage to other cell types, including neuronal axon swelling which impairs fidelity and transmission of signals - Focal demyelinating lesions ○ In acute attacks, T cells and MOG antibodies cross the blood-brain barrier ○ This leads to confluent lesions where the myelin sheath is degraded ○ Most axonal damage happens in the initial attack whereas relapses are associated with increased myelin damage ○ Causes inflammation in spinal cord (vertical lesions) optic nerve and brain - Subacute combined degeneration of the spinal cord - affects the dorsal columns (causing loss of proprioception and vibration sense) and the lateral corticospinal tracts (causing spasticity and weakness) - SAH CT shows hyperdense areas in basal cistersn - adminster nimodipine (a calcium channel blocker) to prevent cerebral vasospasm - Dorsal column == fine touch, vibration, proprioception ○ Vitamin b12 deficiency resulting in dorsal column lesion = subacute combined degeneration of the spinal cord - Spinocerebellar tract = coordination - Spinothalamic tract = pain sensation - Trochlear CNIV = defective downward gaze and vertical diplopia - 21-alphahydroxylase defiency causes XX females to appear male at birth - 5 alpha reductase deficiency causes XY males to have external female genetalia - SAH occurs between pia and arachnoid space - Lesion in parietal lobe can cause astereognosis = inability to recognise objects by touch - Wallerian degeneration = process occuring when a nerve is cut or crushed ○ Occurs when part of the axon is seperated from the neuron's cell nucleus degenerates ○ Begins 24h following neuronal injury and distal axon remains excitable up until this time ○ Degeneration of the axon is following breakdown of myelin sheath, a process that occurs by infiltration of the site with macrophages ○ Regeneration of the nerve may occur eventually although recovery will depend on the extent and manner of injury - Subdural haemorrhage results from bleeding of damaged bridging veins between the cortex and venous sinuses - CT will show a crescent shaped hyperdensity over cerebral hemispheres - Wernicke's aphasia - fluent, incoherent speech - inferior division of left MCA ○ Lesion in temporal lobe - Broca's aphasia - non-fluent, broken speech - superior division of left MCA ○ Lesion in frontal lobe - Hemiballism - rare hyperkinetic movement disorder resulting from a lesion to the subthalamic nucleus of the basal ganglia (characterised by intense, flailing movements of the limbs that originate in the proximal area of the limb, and can be distinguished from chorea which originates in the distal area of the limb) - Amygdala lesion - Kluver-Bucy syndrome = hypersexuality, hyperorality, hyperphagia, visual agnosia - Midline cerebellar lesion = gait ataxia (unsteady, uncoordinated gait) Transitions: - DEXA scans: ○ Normal = -1 to +1 ○ Osteopenia = -1 to -2.5 ○ Osteoporosis = -2.5 and below - Bone remodelling: ○ Quiescence ○ Activation ○ Resorption ○ Reversal ○ Formation ○ Mineralisation - Autoimmune encephalitis - can follow 1-2 months after an episode of viral, due to sensititsation during infection to brain antibodies - OPG, oestrogen and calcitonin all inhibit osteoclast activity whereas RANKL causes osteoclast precursor cells to activate and bind to the site of bone resorption - Secretory/luteal phase of menstrual cycle: ○ Low gonadotrophs due to negative feedback from progesterone production by corpus luteum ○ High progesterone as granulosa cells in corpus luteum secrete progesterone to promote decidualisation ○ Medium oestrogen as oestrogen is produced by the antral follicle, which degenerates after ovulation ○ Corpus luteum eventually takes over oestrogen productoin but a drop in levels is observed immediately after ovulation - Luteal phase histology: ○ Complex, coiled gland ○ Maximum thickness ○ Saw-toothed glands ○ Decidualisation ongoing - Follicular phase histology: ○ Thickening of lining ○ Vascularisation ongoing ○ Enlargement of uterine glands ○ Endometrial stromal cell proliferation Anatomy: - Muscles of the eye: ○ Levator palppebrae superioris = raises eyelid, supplied by CNIII ○ Superior rectus - look up, CNIII ○ Inferior rectus - look down, CNIII ○ Medial rectus - adducts eye, CNIII ○ Lateral rectus, abducts eye, CNVI ○ Inferior oblique - up and in, CNIII ○ Superior oblique - down and in, CNIV - Spinothalamic pathway - PAIN, NON-DISCRIMINATIVE TOUCH AND TEMPERATURE ○ 3 neuron pathway from body up to contralateral primary somatosensory cortex ○ Enters dorsal grey column and 1st order neuron immediately synapses in substantia gelatinous and decussates via the ventral white commissure to spinothalamic tract on the contralateral side ○ 2nd order neuron ascends via spinothalmic tract through the spinal lemniscus of the rostral midbrain to the VPL nucleus of the thalamus where it synapses with 3rd order neuron ○ 3rd order neuron travels via the internal capsule (posterior limb) to the primary somatosensory cortex - Ventral horn carries cell bodies of motor tracts - Dorsal horns carry sensory cell bodies - Lateral horns carry autonomic cell bodies - Prolapsed disc protruding onto the spine is most likely to affect the ventral horn of the spinal cord - Bicep reflex - C5 - Supinator reflex - C6 - Tricep reflex - C7 - Finger jerk - C8 - Knee reflex L3/L4 - Stroke ○ Anterior cerebral artery = contralateral hemiparesis and sensory loss, lower > upper ○ Middle cerebral artery = contralateral hemiparesis and sensory loss, upper extremity > lower, contralateral homonymous hemianopia, aphasia ○ Posterior cerebral artery = contralateral homonymous hemianopia with macular sparing, visual agnosia (inability to recognise and identify familiar objects) ○ Branches of the posterior cerebral artery that supply the midbrain (Weber's syndrome) = ipsilateral CNIII palsy, contralateral weakness of upper and lower extremity ○ Posterior inferior cerebellar artery (lateral medullary syndrome, Wallenberg syndrome) = ipsilateral facial pain and temperature loss, contralateral limb/torso pain and temperature loss, ataxia, nystagmus ○ Anterior inferior cerebellar artery = ipsilateral facial paralysis and deafness - Free nerve endings = detect pain/temperature - Messiner's corpuscle = fine touch, concentrated in the fingertips - Ruffini endings = stretch of skin - Pacianian corpuscles = detect vibration, deep pressure and play a role in proprioception - Corpus lueteum: ○ Formed by granulosa cells ○ Secretes progesterone ○ Maintained by LH ○ Formed by theca cells ○ hCG maintains corpus luteum during pregnancy - Exit foramen of trigeminal nerve branches: ○ Mandibular branch = foramen ovale ○ Maxillary branch = foramen rotundum ○ Opthalmic branch = superior orbital fissure - Facial and vestibulocochlear nerve exit cranium via internal auditory meatus - Common peroneal nerve bifurcates at the lateral aspect of the neck of the fibula - Amaurosis fugax is a form of TIA affecting the opthalmic/retinal artery - presents as transient, monocular vision loss that appears as a rising curtain - Optic nerves leaves the cranium via the optic canal - Cranial nerve reflexes Reflex Afferent limb Efferent limb Corneal Opthalmic (CNV1) Facial (CNVII) Jaw jerk Mandibular nerve (CNV3) Mandibular nerve (CNV3) Gag Glossopharyngeal (CNIX) Vagus (CNX) Carotid sinus Glossopharyngeal (CNIX) Vagus (CNX) Pupillary light Optic nerve (CNII) Oculomotor nerve (CNIII) Lacrimation Opthalmic nerve (CNV1) Facial nerve (CNVII) - Facial nerve runs through parotid gland and divides into 5 branches: temporal branch, zygomatic branch, buccal branch, marginal mandibular branch and cervical branch - Tibial nerve injury results in loss of plantar flexion and inversion of foot - Thalamus nuclei: Nuclei Function Lateral geniculate nucleus Visual signals Medial geniculate nucleus Auditory signals Medial portion of the ventral posterior Facial sensation nucleus Ventral anterior/lateral nuclei Motor function Lateral portion of the ventral posterior Body sensation - touch, pain, proprioception, nucleus pressure, vibration - Inferior vena cava passes through the diaphragm through T8 - Thoracic cord lesion effects = spastic paraperesis, hyperreflexia, extensor plantar responses, incontinence, sensory loss below the lesion and sensory ataxia - these features typically manifest several weeks later once spinal shock (in which areflexia predominates) has resolved - Autonomic dysreflexia (headache, sweating, hypertension and bradycardia) only occurs in spinal cord injury occurs above T6 - Cerebellum is supplied by branches of basilar and vertebral arteries - Anterior cord lesions cause motor defects because the ventral (anterior) horns contain motor neurone cell bodies - Right recurrent laryngeal nerve originates under the subclavian artery so crosses the neck at a diagonal and is more likely to be injured than the left during neck surgery Memory aid common reflexes: S1-S2 buckle my shoe (ankle) L3-L4 kick the door (knee) C5-C6 pick up sticks (biceps) C7-C8 shut the gate (triceps)