Neuro Physiology

Front 1

What do the eyes form from?

Back 1

The optic vesicles of the diencephalon

Front 2

How is transparency maintained in the cornea?

Back 2

There is regular arrangement of collagen in the stroma, no blood vessels and endothelium pump keeps aqueous humour out.

Front 3

How many layers are in the retina?

Back 3

10

Front 4

Where are the nerve fibres in the retina?

Back 4

Near the top

Front 5

What the optic disc?

Back 5

Blind spot, as its where the optic nerve leaves the eye

Front 6

Where is the highest visual acuity?

Back 6

Fovea/Macula - highest density of rods and cones

Front 7

What ensures the lens is transparent?

Back 7

It doesn't have blood vessels

Front 8

What is the difference between the segments and chambers of the eye?

Back 8

Segments - in front of/behind the lens

Chamber - iris

Front 9

Where is aqueous humour produced?

Back 9

In the posterior chamber by the ciliary bodies

Front 10

Where does AH get filtered? And what drains it?

Back 10

Filtered through the trabecular meshwork and drained by schlemm's canal

Front 11

What is the conjunctiva?

Back 11

Thin vascular membrane that covers inner surface of eyelid and sclera

Front 12

What is the autonomic innervation of the lacrimal apparatus?

Back 12

Parasympathetic

Front 13

Where do tears drain?

Back 13

Into lacrimal sac and then into the inferior meatus of the nasal cavity

Front 14

What is the role of tears?

Back 14

Keeps cornea moist, washes away foreign bodies, kill microbes and provides smooth surface for refraction

Front 15

What parts of eye refract light?

Back 15

Cornea, lens, AH and VH

Front 16

What 3 things allow accommodation?

Back 16

Lens can change shape, pupil can constrict and eyes can converge

Front 17

How does the lens change shape?

Back 17

Paraympathetic nerevs cause ciliary muscles to contract, ligments slacken and lens becomes thicker

Front 18

How does the pupil constrict?

Back 18

PS innervation from oculomotor n (III) causes sphincter pupillae to contract

Front 19

How do the eyes converge?

Back 19

Medial recti contract due to PS innervation from CN III

Front 20

How do we see?

Back 20

Energy from visible light stimulates photorecepter cells on the retina. Rods and cones generate an AP using the energy from the light

Front 21

What is phototransduction?

Back 21

The conversion of light energy to an electrochemical response by photoreceptors

Front 22

What are the visual pigments in rods and cones?

Back 22

Rhodopsin and S, M and L cone opsin

Front 23

What is rhodopsin made up of?

Back 23

Opsin and 11-cis retinal

Front 24

How does light energy affect rhodopsin?

Back 24

It causes 11 cis retinal to change to all-trans retinol, which causes rhodopsin to split. This results in bleaching of the visual pigment and the start of the phototransduction cascade

Front 25

What happens in the pigment epithelial cells?

Back 25

All trans retinol is regenerated into 11 cis retinal

Front 26

How does Vitamin A play a part?

Back 26

AT retinol can be formed from Vit A in the diet so can help prevent blindness

Front 27

What rhyme is used to remember the actions of the extrinsic eye muscles?

Back 27

RADSIN - Recti adduct, superiors intort

Front 28

What is the visual pathway?

Back 28

Retina

Optic nerve

Optic chiasma

Optic tracts

Lateral geniculate body

Optic radiation

Primary visual cortex

Front 29

What would occur if the right optic nerve is damaged?

Back 29

Blindness in right eye

Front 30

What would happen if optic chiasma is disrupted in the middle? What can cause this?

Back 30

Bitemporal hemianopia

Pituitary tumour

Front 31

What would happen if right optic tract or optic radiation is damaged?

Back 31

Contralateral homonymous hemianopia

Front 32

What is the pathway of the PS fibres that elicit the pupillary reflex?

Back 32

Sensory fibres leave the optic tract to go to the mid-brain and synapse with CN III via EWN. The pre-ganglionic fibres synapse then in the ciliary ganglion.

Front 33

What syndrome causes unequal pupil size, ptosis (eyelid drooping) and loss of sweating on affected side?

Back 33

Horner's Syndrome - caused by pancoast tumour of the lung

Front 34

Which glial cells are found in the CNS?

Back 34

Ependymal - line ventricles

Microglia - phagocytosis

Oligodendrocytes - myelination

Astrocytes - surround synapses and capillaries

Front 35

Which glial cells are found in the PNS?

Back 35

Schwann - Myelination

Satellite - Surround neuronal cell bodies

Front 36

What disease can cause loss of the myelin sheath?

Back 36

Multiple Sclerosis

Front 37

What three parts does the neural tube split into after 4 weeks?

Back 37

Prosencephalon - Forebrain

Mesencephalon - Midbrain

Rhombencephalon - Hindbrain

Front 38

What structures does the pronsencephalon form?

Back 38

Cerebral cortex, basal ganglia, thalamus, hypothalamus

Front 39

What does the mesencephalon form?

Back 39

The midbrain

Front 40

What does the rhombencephalon form?

Back 40

Pons, cerebellum and medulla

Front 41

Where is CSF found in the spinal cord?

Back 41

Subarachnoid space

Front 42

Where is CSF produced? And where is it absorbed?

Back 42

Produced by choroid plexus and absorbed by arachnoid villi

Front 43

Where is there no blood brain barrier?

Back 43

Vomiting center of the medulla and the hypothalamus

Front 44

What does the brainstem contain?

Back 44

The midbrain, pons and medulla

Front 45

What functions are contolled in the medulla?

Back 45

Blood pressure, breathing, swallowing and vomiting

Front 46

What tracts are found in the medulla?

Back 46

Ascending somatosensory tracts and descending corticospinal tracts

Front 47

What is the function of the pons?

Back 47

Acts as a relay station for information transfer between the cerebrum and cerebellum and also helps coordinate control of breathing

Front 48

What is the function of the midbrain?

Back 48

Controls eye movement and also relays signals for auditory and visual reflexes

Front 49

What is the function of the cerebellum?

Back 49

To process sensory information and coordinate the execution of movement

Front 50

Where does the cerebellum receive sensory input from?

Back 50

Somatic receptors in the periphery of the body and receptors for balance located in the inner ear

Front 51

What does the diencephalon contain?

Back 51

Thalamus, hypothalamus, pituitary and pineal glands

Front 52

What does the thalamus do?

Back 52

Acts as a relay station for sensory information for lower parts of the CNS

Front 53

What does the hypothalamus do?

Back 53

It is a center for homeostasis and contains centers for behavioural drives such as hunger and thirst

Front 54

What does the pineal gland secrete?

Back 54

Melatonin

Front 55

What Brodmann areas are found in the frontal lobe?

Back 55

Area 4 - Precentral gyrus - Primary Motor Cortex

Area 44/45 - Inferior frontal gyrus - Broca's Area of motor speech

Prefrontal cortex

Front 56

What is the motor homunculus?

Back 56

Somatotopic representation of contralateral half of body

Front 57

What does a frontal lesion cause?

Back 57

Intellectual impairment, personality change, urinary incontinence, monoparesis or hemiparesis.

Left sided lesions cause Broca's Aphasia

Front 58

What is broca's aphasia?

Back 58

Can't construct sentences, but know what they want to say.

Front 59

What brodmann's areas are found in the parietal lobe?

Back 59

Area 3/1/2 - Post central gyrus - Primary sensory area

Superior parietal lobule - interpretation of general sensory info and conscious awareness of other half of body

Inferior parietal lobule

Front 60

What does a parietal lesion cause?

Back 60

Contralateral sensory loss/neglect

Agraphaethesia

Homonynous field defect

Right - Dressing apraxia, failure to recognise faces

Left - Limb apraxia

Front 61

What areas are found in the temporal lobe?

Back 61

Primary auditory complex

Wernicke's area - key for understanding speech

Inferior surface - used to understand smellq

Front 62

What would a temporal lesion cause?

Back 62

Left - Acalculia, alexia (can't read), agraphia, wernicke's aphasia, right-left disorientation and homonymous field defect

Right - Confusion, failure to recognise faces and homonymous field defect

Front 63

What is main function of the occipital lobe?

Back 63

Contains primary visual cortex

Front 64

What would an occipital lesion cause?

Back 64

Visual field defects and visuospatial defects

Front 65

What types of fibres are found in the white matter of the brain?

Back 65

Commisural - connect 2 hemispheres

Association - connect one part of cortex to another

Projection - Run between cerebral cortex and subcortical areas

Front 66

What fibres make up the internal capsule?

Back 66

Projection fibres

Front 67

What three make up the Basal Ganglia?

Back 67

Caudate nucleus, putamen and globus pallidus

Front 68

What is the major function of the BG?

Back 68

Initiation and Termination of movements

Front 69

What sensations does the posterior column associate with?

Back 69

Touch, pressure and proprioception

Front 70

Touch, pressure and proprioception

Back 70

Moves up posterior column and synapses in medulla. Switches to other side here and then synapses in thalamus. Then moves up to the primary sensory cortex

Front 71

What tract is associated with pain and temperature?

Back 71

The lateral spinothalamic tract

Front 72

The lateral spinothalamic tract

Back 72

1st order neurons enter spinal cord and synapse in grey matter. They cross over to other side and move up LS tract. They synapse in medulla and move up to primary sensory cortex

Front 73

Where do motor/descending tracts switch over?

Back 73

In the medullary pyramids

Front 74

What is an example of a descending tract?

Back 74

Corticospinal tract

Front 75

What happens to the muscle tone and reflexes if the UMN becomes damaged?

Back 75

They become exaggerated as the inhibitory action of the UMN is lost

Front 76

What type of receptors are used to detect touch, pain, deep pressure and warmth?

Back 76

Touch - tactile corpuscle

Pain - free nerve ending

Deep pressure - lamellated corpuscle

Warmth - Ruffini corpuscle

Front 77

What type of fibres mediate cutaneous sensation?

Back 77

A beta

A gamma

C

Front 78

Talk about A beta fibres

Back 78

They are large myelinated fibres for touch, pressure and vibration

Front 79

Talk about A gamma fibres

Back 79

They are small myelinated fibres for cold, fast pain and pressure

Front 80

Talk about C fibres

Back 80

They are unmyelinated fibres for warmth and slow pain

Front 81

What activates signal transduction in nociceptors?

Back 81

pH, heat and local chemical mediators such as bradykinin, histamine and prostaglandins

Front 82

What is the gate control theory of pain receptors?

Back 82

Activity in A beta neurons activate inhibitory interneurones which inhibit a gamma and C fibres. Descending pathways also activate the inhibitory interneurones.

Front 83

How do the inhibitory interneurones work?

Back 83

When activated they release opioid peptides (endorphins) that inhibit transmitter release from the A gamma and C fibres

Front 84

How do NSAIDs work?

Back 84

They inhibit prostaglandin formation, which reduces the sensitivity of nociceptors to bradykinin

Front 85

How do local anaesthetics work?

Back 85

They block Na+ action potentials

Front 86

How does Trans cutaneous electric nerve stimulation work?

Back 86

Using the gate control method as it activates A beta fibres

Front 87

How do opiates work?

Back 87

It reduces sensitivity of nociceptors, blocks transmitter release and activates descending inhibitory pathways

Front 88

What are the 12 Cranial nerves?

Back 88

Olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal, vagus, accessory and hypoglossal

Front 89

What is the pathway of the olfactory nerve?

Back 89

Olfactory epithelium in nose --> nerve fibres pass through cribriform plate --> enter olfactory bulb

Front 90

What type of nerve is the olfactory?

Back 90

Special sensory

Front 91

How can the olfactory nerve be affected clinically?

Back 91

A fractured cribriform plate can tear the fibres and cause anosmia

Front 92

How can the optic nerve be affected clinically?

Back 92

Increased CSF pressure can cause papilloedema

Sections of optic tract -

Front 93

What does the oculomotor nerve do?

Back 93

Innervates extraocular muscles and eyelid. Also brings PS fibres to pupil and ciliary muscles

Front 94

How can CN III be affected clinically?

Back 94

Eyelid drooping (ptosis)

No pupillary reflex

Eyeball abducted and pointing down

No accommodation of the lens

Front 95

What does trochlear nerve palsy occur as?

Back 95

Diplopia when looking down

Front 96

Which of the trigeminal branches is both sensory and motor?

Back 96

Mandibular

Front 97

What the symptoms of damage to a branch of the trigeminal nerve?

Back 97

Paralysis of the muscles of mastication

Loss of corneal reflex

Loss of sensation in face

Trigeminal neuralgia

Front 98

What are the symptoms of abducens palsy?

Back 98

Medial deviation of the affected eye, which causes diplopia

Front 99

What is facial palsy also known as?

Back 99

Bell's Palsy?

Front 100

What are the symptoms of bell's palsy?

Back 100

Cannot frown, close eyelid or bare teeth

Front 101

What are the symptoms of VIII damage?

Back 101

Tinnitus, deafness, vertigo and nystagmus

Front 102

What are the symptoms of glossopharyngeal damage?

Back 102

Loss of gag reflex and taste from back of tongue. Often present with symptoms of X and XI damage

Front 103

What are the symptoms of vagus damage?

Back 103

Difficulty in swallowing or difficulty in speaking

Front 104

What does accessory damage present as?

Back 104

Weakness in turning head and shrugging shoulders

Front 105

What are the clinical aspects to consider with the hypoglossal nerve?

Back 105

Can be damaged during tonsillectomy. Presents as paralysis and atrophy of ipsilateral side of tongue.