Phase 1 - Week 11 (Ear, ear infection, temperature control, paracetamol), Phase 1 - Week 12 (Mock MILE - Eyes) Flashcards

Question

List the parts of the external ear

Answer 1

1. Auricle (or pinna) | 2. External acoustic meatus (auditory canal)

Answer 2

- Visible part - On side of head - Made of elastic cartilage covered by skin - Shape causes sound to be directed into external acoustic meatus Parts: 1. Helix - outer curved margin of auricle 2. Tragus - flat triangular prominence, partially occludes entrance to external acoustic meatus 3. Lobule - highly vascularised flap of skin, most inferior part of auricle, no cartilage

Answer 3

- S-shaped passage - Begins as opening in the auricle -> tympanic portion of temporal bone -> terminate at tympanic membrane - Lined w/ mucous membrane containing sebaceous glands + modified sweat glands - ceruminous glands - Directs sound waves to tympanic membrane

Answer 4

Secretory ducts can open independently into external auditory meatus

Answer 5

= Cerumen (ear wax) - Prevents entrance of foreign particles - Reduces risk of bacterial + fungal infection

Answer 6

1. Tympanic membrane 2. Tympanic cavity 3. Tensor tympani 4. Stapedius 5. Ossicles 6. Eustachian tube 7. Oval window

Answer 7

- Ear drum - Separates external ear from middle ear - Thin, semi-transparent, concave sheet composed of epithelium and collagen fibres - Fixed within ring in temporal bone - Vibrates in response to sound, transmits vibrations to malleous

Answer 8

Pharyngotympanic (Eustachian) tube

Answer 9

- Small muscle of middle ear - Originates from pharyngotympanic tube + greater wing of sphenoid bone - Inserts into malleus, works w/ stapedius to tense tympanic membrane (response to abrupt noise - in anticipation of loud vocalisation)

Answer 10

- Small muscle of middle ear - Attached to temporal bone + neck of the stapes - Dampens vibrations of ossicles - contracts in response to high intensity sounds

Answer 11

Allows equalisation of pressure between tympanic cavity and the local barometric pressure

Answer 12

- Bony labyrinth - Scala vestibuli - Scala tympani

Answer 13

- Tube of bone coiled around a central pillar (modiolus) - Resembles a snail shell - Between bony + membranous labyrinth = 2 fluid filled spaces - scala vestibuli + scala tympani

Answer 14

- Upper triangular canal - Bound by roof of bony cochlea above and vestibular membrane below - Passes through entire length of cochlea - Oval window at base of canal - connects to tympanic cavity - Helicotrema joins scala vestibuli to scala tympani - Contains perilymph - maintained by secretory epithelial cells lining the canal

Answer 15

- Lower triangular canal - space beneath basilar membrane - Passes entire length of cochlea - Round window at base - connects it to tympanic cavity - Helicotrema joins it to scala vestibuli - Contains perilymph

Answer 16

- Coiled tube containing cochlear duct (or scala media) - Cochlear duct (scala media) - middle triangular canal, houses organ of corti - Roof = vestibular membrane - Floor = basilar membrane - Blind tube, ductus reuniens is only outlet, connects it to saccule - Contains endolymph

Answer 17

- Central part of bony labyrinth - Contains oval window in lateral wall - Connects inner ear w/ middle ear - Supports membraneous saccule + utricle within it - contain endolymph + some of the mechanoreceptors responsible from balance

Answer 18

- Modiolus - cone-like central pillar of bone, forms centre of bony labyrinth which spiral canal of cochlea runs around, contains spiral ganglia of vestibulocochlear nerve (CN VIII) in Rosenthal's cavitus - Vestibular membrane - thin transparent membrane which separates cochlear duct from scala vestibuli - Basilar membrane - supports organ of Corti, separates cochlear duct from scala tympani - Spiral ganglion - in modiolus, contains cell bodues of cochlear branch of vestibulocochlear nerve (VIII), supplies hair cells of organ of Corti - Cochlear nerve - branch of vestibulocochlear nerve (VIII), fibres pass from hair cells of organ of Corti, through the modiolus as spiral ganglia, continuous onto internal auditory meatus

Answer 19

- Sensory epithelium on top of the basilar membrane - Hair cells = sensory transducers of organ of Corti, rest on basilar membrane w/ their stereocillia (hairs) embedded in the underside of the tectorial membrane - Two layers - outer (3/4 rows) + inner (1 row), separated by rows of supporting cells

Answer 20

- Pear-shaped - Curve slightly towards surface of organ of Corti - Not much movement in response to vibrations - due to position on basilar membrane - Each inner hair cell has 3/4 rows of stereocillia - make contact w/ tectorial membrane

Answer 21

- Sensory tranducers - mechanical energy -> neural energy | - Detect + send signals to brain - info about amplitude and frequency of sound waves

Answer 22

- Long, cylindrical cells - twice as tall as inner hair cells - Arranged by size in a gradient - outermost and closest to apex = tallest - Each has flat apical surface - 3 rows of stereocillia protrude through

Answer 23

- Key to high sensitivity + sharp tuning ability of organ of Corti - When stereocillia are displaced, entire cell shortens and elongates causing displacement of stereocillia - Outer hair cells then push up against tectorial membrane amplifying the vibrations felt by the basilar membrane at specific points - enabling us to hear quieter sounds

Answer 24

- 'Hairs' - Membrane-bound cellular projections of inner + outer hair cells - Arranged in unique patterns on apical surface of both types of hair cells - Vital role in sound transduction - Protrude through hair cell's reticular membrane, point towards the tectorial membrane above - only tallest make contact w/ tectorial membrane

Answer 25

- Bend forwards and backwards in response to shearing force created by movement of tectorial and basilar membranes - also created streaming movement in surrounding fluid - Movements cause stereocillia to depolarise - sending info to rest of hair cell - mechanical energy -> neural signal

Answer 26

- Semi-transparent, fibrogelatinous structure that overlies the hair cells of organ of Corti - Indented by stereocillia of outer hair cells in a W or V shaped pattern along Hensen's striped

Answer 27

- Purely mechanical role - Withstands mechanical stresses of cochlear fluid vibrations - As basilar membrane moves in response to sound waves from middle ear, shearing forces move stereocillia + depolarises them causing neural signals to be sent to the brain

Answer 28

Series of specialised epithelial cells that provide mechanical support to sensory cells they surround

Answer 29

1. Auditory transmission 2. Auditory transduction 3. Auditory pathway

Answer 30

Oscillations of pressure in a medium (air or liquid)

Answer 31

1. External sound waves 2. Auricle 3. External acoustic meatus 4. Tympanic membrane (vibration) 5. Malleus 6. Incus 7. Stapes 8. Membrane covering oval window 9. Cochlea 10. Scala vestibuli (perilymph) Cochlear duct (endolymph), separated by vestibular + basilar membrane 11. Scala tympani (perilymph) 12. Round window

Answer 32

1. Vestibular membrane vibrates in response to pressure waves travelling up perilymph of the scala vestibuli 2. Vibration transmitted through endolymph to the basilar membrane 3. When basilar membrane vibrates stereocillia on organ of corti move against tectorial membrane 4. Movement of hair cells initiates sound waves -> electrical impulses (sound transduction)

Answer 33

Inner hair cells of the organ of Corti

Answer 34

1. At apex of each stereocillia is a mechanically-gated ion channel, connected to taller neighbouring stereocillium by a tip-link protein 2. Displacement of stereocillia increases tension on the tip-link protein, opening the mechanically gated ion channels 3. Cations flood into inner hair cells, depolarising them 4. This causes voltage-gated calcium channels to open and calcium ions to enter the inner hair cells 5. Increase in calcium ion levels cause the release of of a neurotransmitter from the base of the inner hair cells 6. Neurotransmitter stimulates afferent neurons innervating the inner hair cells to fire action potentials, which are conveyed via the vestibulocochlear nerve to the brain 7. Basilar membrane moves downwards, it displaces stereocillia in the opposite direction 8. Reduces tension on the tip-link proteins, mechanically-gated ion channels close 9. Cations can no longer enter the inner hair cell - become hyperpolarised 10. Voltage-gated calcium channels close, calcium doesn't enter the inner hair cell, stop releasing neurotransmitter

Answer 35

Different frequencies of sound make different regions of the basilar membrane vibrate and different amplitudes of sound make the basilar membrane vibrate at different intensities

Answer 36

1. Hair cells 2. Spiral ganglia 3. Vestibulocochlear nerve: cochlear branch 4. Cochlear nucleus 5. Lateral lemniscus 6. Superior olivary nucleus 7. Inferior collicus 8. Medial geniculate nucleus 9. Primary auditory cortex

Answer 37

Thermoregulatory centre in the hypothalamus - 1. Thermoreceptors in hypothalamus monitor temp. of blood through brain (core temp.) 2. Thermoreceptors in the skin (esp. on trunk) monitor the external temp.

Answer 38

- Heat conservation centre in hypothalamus stimulated - Skeletal muscles activated - shivering - Blood vessels in skin constrict - divert blood from skin to core, reducing heat loss from skin surface - Body temp. increases - Heat conservation centre 'shut off'

Answer 39

- Heat loss centre in hypothalamus activated - Blood vessels in skin dilate - heat lost from skin surface - Sweat glands activated - evaporative cooling - Body temp. decreases - Heat loss centre 'shut off'

Answer 40

- Smooth muscles in arterioles in skin - Sweat (eccrine) glands - Errector pilli muscles in skin (attached to hairs) - Skeletal muscles - Adrenal and thyroid glands

Answer 41

a) Vasoconstriction. Less heat lost from surface of body, maintains core temp. Extremities turn blue and feel cold b) Vasodilation. More heat carried from core -> surface of skin. Lost by convection and radiation. Skin turns red.

Answer 42

a) No sweat produced | b) Glands secrete sweat onto surface of skin - evaporates, causing heat loss

Answer 43

a) Muscles contract, raising hairs and trapping an insulating layer of warm air. Causes goosebumps. b) Muscles relax, lowering hairs and allowing air to circulate over the skin, encouraging convection and evaporation

Answer 44

a) Shivering - muscles contract and relax repeatedly generating heat by friction + metabolic reactions b) No shivering

Answer 45

a) Glands secrete adrenaline + thyroxine - increase metabolic rate in different tissues, esp. liver b) Glands stop secreting adrenaline + thyroxine

Answer 46

Body temperature >38 degrees

Answer 47

1. Infection 2. Neurological conditions 3. Cancer 4. Dehydration 5. Pulmonary embolism 6. After transfusion of incompatible blood

Answer 48

- Pyrogens - Phagocytes secrete cytokines: 1. IL-1, IL-6, tumour necrosis factor alpha (TNF-alpha) 2. Reach hypothalamus via circumventricular organs adjacent to 3rd ventricle where blood-brain barrier is relatively permeable to large molecules 3. Increased production of prostaglandin E2 - acts on neurones in preoptic area to initiate febrile response

Answer 49

- Heat conserved inappropriately through thermoregulatory responses of body - Increased temperature but feel cold + shiver + peripheral vasoconstriction - When PGE2 synthesis returns to normal, set point returns to normal, patient feels hot - peripheral vasodilation + sweating occur - Kills bacteria, inhibits viruses

Answer 50

- Middle ear infection - Presence of inflammation in middle ear associated with an effusion, accompanied by rapid onset of symptoms of ear infection - Causes by viruses/bacteria - Very common in children

Answer 51

- Children - Especially those exposed to passive smoking, attend nursery etc., are formula fed, have craniofacial abnormalities (Down syndrome or cleft palate) - More common in males than females

Answer 52

- Recurrence of infection - Hearing loss - Tympanic membrane perforation - Mastoiditis - Meningitis - Intercranial abscess - Sinus thrombosis - Facial nerve paralysis

Answer 53

- Earache - Younger children - pull/rub ear, irritability, crying, poor feeding, restlessness at night - Rhinorrhoea (runny nose) - Fever - Tympanic membrane - red/yellow + cloudy + bulging - Air/fluid level behind tympanic membrane - Perforation of tympanic membrane and/or discharge in external auditory meatus

Answer 54

Admit for immediate paediatric/specialist assessment: - Children <3 months, >38 degree temp. - Adults/children w/ suspected acute complications e.g. meningitis, mastoiditis or facial nerve paralysis Other treatment: - Treat pain + fever w/ paracetamol or NSAIDs e.g. ibuprofen - No antibiotic or delayed antibiotic prescribing (majority viral) - Antibiotics - systemically unwell, high risk of serious complications, immunocompromised, symptoms last more than 4 days - Long-term - hearing aids, grommets, adenoidectomy

Answer 55

Tubes inserted to drain fluid + keep eardrum open

Answer 56

- Commonly used for its analgesic and antipyretic effects - Lacks anti-inflammatory, anti-platelet + gastric ulcerative effects - Used for the relief of fever, headaches and other minor aches + pains

Answer 57

- Acetaminophen - Extremely safe in standard doses, deliberate or accidental overdoses not uncommon - No problems w/ addiction, dependence, tolerance or withdrawal

Answer 58

- Primarily in CNS - Increases pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2 and COX-3 enzymes involved in prostaglandin synthesis - Doesn't inhibit cyclooxygenase in peripheral tissue so has no peripheral anti-inflammatory effects - Reduces fever by affecting hypothalamic heat-regulating centre

Answer 59

- Substance which induces fever | - Can be either internal (endogenous) or external (exogenous) to the body

Answer 60

- Cytokines produced by activated immune cells - Cause increase in the thermoregulatory set point in the hypothalamus - Main endogenous pyrogens = interleukin 1 (alpha and beta) and interleukin 6 - Also - IL-8, tumour necrosis factor-beta/alpha, macrophage inflammatory protein-alpha/beta and interferon alpha/beta/gamma - Secreted into the circulation, migrate to the circumventricular organs of the brain due to easier absorption caused by blood-brain barrier's reduced filtration action there - Cytokines then bind with endothelial receptors on vessel walls or interact with local microglial cells - When they bind, the arachidonic acid pathway is activated

Answer 61

- Cause the release of endogenous cytokine pyrogens, which activate the arachidonic acid pathway - Immunological protein called lipopolysaccharide-binding protein (LBP) binds to LPS (lipopoysaccharide) which is a cell wall component of gram-negative bacteria - LBP-LPS complex binds to CD14 receptor of machrophage, results in synthesis and release of various endogenous cytokine factors e.g. IL-1, IL-6 and TNF-alpha

Answer 62

The enzymes cyclooxygenase-1 and 2, phospholipase A2 and prostaglandin E2 synthase metabolise arachidonic acid to prostaglandin G2 and H2 which may be converted to various prostaglandins - e.g. PGE2

Answer 63

- Ultimate mediator of the febrile response - Set point temperature of the body will remain elevated until PEG2 is no longer present - Acts on neurones in the preoptic area through the prostaglandin E receptor 3 - EP3-expressing neurones in the POA innervate the dorsomedial hypothalamus, the rostral raphe pallidus nucleus in the medulla oblongata and the paraventricular nucleus of the hypothalamis - Fever signals sent to these areas lead to stimulation of the sympathetic output system - causes thermogenesis

Answer 64

- Some important immunological reactions sped up by temperature - Pathogens w/ strict temperature preferences could be hindered - Increased mobility of leukocytes - Enhanced leukocyte phagocytosis - Endotoxin effects decreased - Increased proliferation of T cells

Answer 65

National early warning score: - Bedside score and tirck and trigger system which staff calculate from routinely collected physiological observations - Aims to detect early signs of patients' deterioration and prompts more timely medical review and treatment of patients duet to the inbuilt escalation protocol - Does not replace clinical concern for the patients - Does not apply to patients in the paediatric or obstetric departments

Answer 66

1. Respiratory rate 2. Oxygen saturations 3. Temperature 4. Systolic blood pressure 5. Pulse rate 6. Level of consciousness

Answer 67

A vital sign is a sign that pertains to life, without which life would not exist - respiratory rate, pulse, blood pressure and temperature. Changes in these reflect an increased risk of death, hence the importance of detecting, observing and recording these vital signs early, thereby allowing staff to deliver timely treatment and normalise these vital signs.

Answer 68

2 Types : - AVPU - Glasgow coma scale

Answer 69

``` A = the patient is awake V = the patient responds to verbal stimulation P = the patient responds to painful stimulation U = the patient is completely unresponsive ```

Answer 70

- Eyes: 1. Does not open eyes 2. Opens eyes to painful stimuli 3. Opens eyes in response to voice 4. Opens eyes spontaneously - Verbal: 1. Makes no sounds 2. Incomprehensible sounds 3. Utters incoherent words 4. Confused, disoriented 5. Oriented, converses normally - Motor: 1. Makes no movements 2. Extension to painful stimuli 3. Abnormal flexion to painful stimuli 4. Flexion/withdrawal to painful stimuli 5. Localises to painful stimuli 6. Obeys commands

Answer 71

- White of eye - Avascular - Limits light entering eye, supports shape of eyeball

Answer 72

- Transparent dome over anterior of eye | - Refracts light towards pupil

Answer 73

- Layer of blood and and lymphatic vessels - Blood vessels supply nutrients to eye - Lymphatic vessels drain fluid from posterior cavity

Answer 74

- Anterior part of choroid, posterior to iris - Smooth muscle forming ring around lens - Has suspensory ligaments attached which change shape of lens

Answer 75

- Two pigmented rings of smooth muscle (pupillary constrictor and pupillary dilator) - Forms the pupil at its centre, changes diameter of pupil

Answer 76

- 10 layers of neural, epithelial and supporting cells - Contains rod and cone cells - Light is detected by rod and cone cells and converted into a neural signal

Answer 77

- Cranial nerve II - Passes from back of eyeball and enters the middle cranial fossa of the skull via the optic canal in the sphenoid bone - The optic nerves from each eye cross at the optic chiasma and pass posteriorly to visual structures in the brain - Relays the neural signal from the eye to the brain where it is processed

Answer 78

- Clear, watery fluid | - Maintains the intraocular pressure and provides nutrients to the cornea and sclera

Answer 79

- Transparent, avascular elliptical structure | - Refracts light onto the focal point on the retina

Answer 80

- Gelatinous mass of collagen and proteoglycans | - Supports the shape of the eye

Answer 81

Light hits the eye and passes through the cornea, which refracts it towards the pupil. The lens refracts light so that it is focussed onto the retina. Suspensory ligaments of the ciliary body can change the curvature of the lens so that light reaches a focal point on the retina.

Answer 82

Photoreceptors in rod and cone cells in the retina

Answer 83

- Contain the photopigment rhodopsin | - Sensitive to low light and provide black and white vision

Answer 84

- 3 types - blue, green and red - Provide colour vision - Sensitive to high light levels - Contain the photopigment photopsin

Answer 85

- Composed of retinal and opsin - Opsins determine the wavelength of light that a photopigment can absorb - Rod cells only have one type of opsin, cones have three types - Retinal is the light-absorbing part of the photopigment derived from vitamin A - Two form of retinal - trans-retinal and cis-retinal

Answer 86

- Rod and cone cells absorb light, which changes the shape of their photopigments - Retinal changes rom cis-retinal to trans-retinal in a process called isomerisation - This leads to generation of a receptor potential - In darkness, sodium ions flow into the outer segments of the photoreceptors through channels gated by the ligand cyclic guanosine monophosphate (cGMP) - This inflow partially depolarises the photoreceptor, stimulating the release of glutamate, an inhibitory neurotransmitter - Glutamate hyperpolarises bipolar cells so they do not send neural signals to ganglion cells - When the retina absorbs light, enzymes which break down cGMP are activated, decreasing the inflow of sodium ions and glutamate released - This produces a neural signal in bipolar cells, which passes through ganglion cells and the optic nerve to the primary visual cortex in the brain where the information is processed

Answer 87

Condition which occurs when there is a deterioration of complete loss of peripheral vision. Caused by several diseases.

Answer 88

1. Damage to the optic nerve 2. Damage to the brain 3. Damage to the retina 5. Temporary loss of peripheral vision

Answer 89

Glaucoma: - Common eye disease - Damage to optic nerve occurs through increased intraocular pressure - Normal IOP = 10-21mmHg, glaucoma can increase to 70mmHg - Two types - primary open angle glaucoma and acute angle-closure glaucoma - Primary open angle glaucoma causes gradual, painless loss of peripheral vision and is treated through reducing the IOP by reducing the aqueous production or increasing its drainage - Acute angle-closure glaucoma is an ophthalmic emergency in which the IOP suddenly increases to over 50mmHg

Answer 90

Retinitis pigmentosa: - Common, inherited degenerative disease of the retina - Can lead to tunnel vision - No treatment - Vitamin A supplementation may slow the progression

Answer 91

Stroke: A stroke may damage parts of the brain where images are processed which causes scotomas (an area of alteration in field vision where vision is partially diminished or entirely degenerated)

Answer 92

High levels of adrenaline (due to high stress, anxiety or anger) can cause temporary tunnel vision. Drugs and alcohol may also cause tunnel vision. Normal vision will usually return without treatment.

Phase 1 - Week 11 (Ear, ear infection, temperature control, paracetamol), Phase 1 - Week 12 (Mock MILE - Eyes) Flashcards

(116 cards)