Neuro Recap Flashcards
What do oligodendrocytes myelinated?
Brain
What do Schwann cells myelinate?
PNS
Define nuclei
Collection of nerve cell bodies within the CNS
Define ganglia
Collection of nerve cell bodies outside the CNS and some in the CNS (In a capsule)
What sort of information is carried on afferent fibres?
Sensory fibres towards CNS
What sort of information is carried on efferent fibres?
Motor fibres away from the CNS
What is the function of the frontal lobe?
Voluntary movement on opposite side of the body
Dominant frontal lobe controls speech and writing
Intellectual functioning, thought processes, reasoning and memory
What is the function of the parietal lobe?
receives and interprets sensations including pain, touch, pressure and proprioception
What is the function of the temporal lobe?
understanding spoken word (Wernicke’s)
Memory and emotion
What is the function of the occipital lobe
Understanding visual images and meaning of written words
What are the components of the basal ganglia?
Caudate nucleus
Putamen
Globus Pallidus
What are the components of the striatum
Caudate nucleus and putamen
What are the components of the lentiform nucleus
Globus pallidus and the putamen
What is the function of the cerebellum?
Co-ordinates movement and balance
Describe the function of the hippocampus
Episodic memory
Construction of mental images
Short term memory
spatial memory and navigation
How many axons can oligodendrocytes myelinate?
Multiple
How many axons can Schwann cells myelinate
Single
What is the function of ependymal cells?
Line ventricles of the brain and regulate the production and flow of CSF
Which cells make up the BBB?
Endothelial cells, pericytes and astrocytes
What are the features of the blood brain barrier
Endothelial tight junctions
Astrocyte end feet
Pericytes
Continuous basement membrane
What is the name given to areas of the brain that lack a BBB?
Circumentricular organs ie. posterior pituitary
Where does the CSF circulate
Subarachnoid space
What is the volume of the CSF?
120mls
What is found in the CSF?
Protein, urea, glucose and salts
Where is the CSF produced?
By ependymal cells in the choroid plexus
How is CSF reabsorbed?
Via arachnoid granulations into the superior sagittal sinus
Describe what happens in hydrocephalus?
Abnormal accumulation of CSF in the brain which leads to a build up of pressure often due to a blocked cerebral aqueduct
Describe the passage of CSF
Produced by the ependymal cells of the choroid plexus then from the lateral ventricles it travels to the 3rd ventricle via the intraventricular forum and then from the 3rd to the 4th ventricle by the cerebral aqueduct. From the 4th it communicates with subarachnoid space via the foramen of magendie and the foramen of Luschka
What are the 5 processes of synaptic transmission
- Manufacture (intracellular biochemical processes)
- Storage - vesicles
- Release - AP
- Interact with post synaptic receptors
- Inactivation
What are the two main acetylcholine receptors
muscarinic
Nicotinic
What enzyme is responsible for the breakdown of acetylcholine in the synaptic cleft
Acetylcholinesterase into choline and acetate
What functional area of the brain surrounds the primary auditory cortex?
Wernicke’s area
What is the function of Wernicke’s area
processing of language
Inferior colliculus and medial geniculate body are important for what sense
Hearing
The superior colliculus and lateral geniculate body are important for what sense?
Vision
Which part of the eye is involved in the accommodation reflex?
Cilliary muscle
What does the iris do?
Controls the size of the pupil which lets light into the eye
What does the dilator papillae muscle do?
Dilates the pupil (Sympathetic)
What does the spinchter papillae do?
Constricts the pupil (Parasympathetic)
What are the two muscles attached to the tarsal plate?
Levatator palpibra superioris
Obicularis oculi
Which fibres cross at the optic chiasm
Nasal portion of the retina, carrying the temporary visual field
Where in the thalamus do optic tracts join too?
Lateral geniculate nucleus
Outline the order of the visual pathway from eye to visual cortex
Eye Optic nerve Optic chiasm Optic tract lateral geniculate body Optic radiation Visual cortex
What is the name of the optic radiation that passes through the parietal lobe?
Baums loop
What is the name given to optic radiation that passes through the temporal lobe?
Meyer’s Loop
What information do the superior retinal fibres of the optic radiation carry
inferior portions of the retina
What information do the inferior retinal fibres of the optic radiation carry?
Superior portions of the retina
Which lobe of the brain do the superior retinal fibres pass through?
temporal lobe
Which lobe of the brain do the inferior retinal fibres of the optic radiation pass through?
Parietal lobe
What is the effect of a lesion on the right optic nerve
Right anopia
Right monocular blindness
What is the effect of a lesion on the left optic nerve?
Left anopia
Left monocular blindness
What is the effect of a lesion at the optic chiasm?
Loss of temporal visual fields = Bitemporal hemianopia
What is the effect of a lesion on the right optic tract?
Loss of temporal field of left eye and nasal field of right eye
= Right homonymous hemianopia
What is the effect of a lesion on left Meyer’s Loop?
Carries information from inferior retina on superior visual field so causes of loss of vision in superior nasal field of left eye and superior temporal field of right eye
What is the effect of a lesion to left Baum’s Loop?
Carries information from superior retina on inferior visual field resulting in loss of vision in inferior temporal field of right eye and inferior nasal field of left eye
What is the name given to internal rotation of the eye? (Towards the midline)
Intorsion
What is the name given to external rotation of the eye?(Away from the midline)
Extorsion
What are the 6 ocular eye muscles
Superior rectus Inferior rectus Lateral rectus Medial rectus Superior oblique Inferior Oblique
Which muscles of the eye are supplied by oculomotor nerve?
Superior rectus
Medial Rectus
Inferior rectus
Inferior oblique
Which muscles of the eye are supplied by abducens nerve?
Lateral rectus
Which muscle of the eye is supplied by the trochlear nerve?
Superior Oblique
What does the somatic nervous system innervate?
Skeletal muscle
Do neurones of the somatic nervous system synapse before the skeletal muscle?
No
What is the only neurotransmitter involved in the somatic nervous system?
Acetylcholine
What does the autonomic nervous system innervate?
Smooth and cardiac muscle, glands, neurones in the GIT
Where is the first synapse of an autonomic nerve
First nerve synapses outside the CNS in a cell cluster called autonomic ganglion
Whats the name of autonomic nerve between the CNS and the ganglia?
Preganglionic fibres
Whats the name of the autonomic nerve between the ganglion and the effector cells?
Postganglionic fibres
What are the two divisions of the autonomic nervous system?
Sympathetic and Parasympathetic
Where do the sympathetic nerves leave the spinal cord?
Between T1 and L2
Where do the ganglia of the sympathetic neurones lie?
Close to the spinal cord = sympathetic chain
What neurotransmitter is used by the preganglionic sympathetic fibres?
Acetylcholine acts at nicotinic receptors
What neurotransmitter is is used at the effect cell synapse in sympathetic fibres?
Noradrenaline acts at adrenergic receptors
What are the effects of the sympathetic nervous system?
Increased HR Increased force of contraction Vasoconstriction bronchodilation Reduced gastric secretion Male ejaculation Reduced gastric motility Sphincter contraction
Where do parasympathetic nerves leave the spinal cord?
Brainstem and sacral regions of spinal cord
Which cranial nerves are parasympathetic
3, 7, 9 and 10 (1973)
Where do the ganglia of parasympathetic nerves lie?
Close to the organs that the postganglionic fibres innervate
What is the neurotransmitter used by preganglionic parasympathetic fibres
Acetylcholine at nicotinic receptors
What is the neurotransmitter used by postganglionic parasympathetic fibres
Acetylcholine at muscarinic receptors
What are the effects of the parasympathetic nervous system?
Decreased heart rate Decreased force of contraction Vasodilation Bronchoconstrition Increased gastric motility Increased gastric secretion Male erection Sphincter relaxation
Define CNS
Consists of the brain and the spinal cord
Define PNS
Nerves and ganglia outside the brain and the spinal cord
How many vertebra are their
33 in total 7 cervical 12 thoracic 5 lumbar 5 sacral 4 coccyx
How many spinal nerves are there
31 pairs of spinal nerves
- Cervical = 8 nerves (One vertebra higher than the corresponding vertebra except C8 which is one below)
- 12 thoracic nerves (one to two vertebra below corresponding vertebra)
- 5 lumbar nerves (3-4 vertebra below)
- 5 sacral (5 vertebra below)
1 coccyx nerve
Define dermatome
Area of skin supplied by a single spinal nerve (Sensory)
Define Myotome
A volume of muscle supplied by a single spinal nerve
What are the two divisions of the descending motor pathways
Pyramidal and Extrapyramidal
Describe the corticospinal pathway
Controls voluntary muscles
- Starts in the Cortex and runs through the internal capsule and the crura cerebri
- 85% decussate in the medulla through the anterior white commissure to the lateral side
- 15% stay on the same side (Anterior)
Describe the extrapyramidal pathways
Originate in the brainstem an carry motor fibres to the spinal cord - responsible for the involuntary autonomic control of all musculature
What are the extrapyramidal pathways
Rubrospinal
- Facilitates flexors and inhibits extensors
- originate in red nucleus
- Decussates in midbrain and is contralateral
Tectospinal
- Head turning in response to visual stimuli
- Originates from tectum - superior colliculus
- Decussates in midbrain
Vestibulospinal
- Muscle tone, balance and posture
- originate from the vestibular uncles
- Non decussating
What are the ascending sensory tracts
Dorsal/medial lemniscus pathway
Spinothalamic pathway
Spinocerebellar pathway
Dorsal medial lemniscus column consists of what and carries what sensations
Fasciculus cuneatus and gracilis
Ascend to the medulla and then decussate to become the medial lemniscus which ascends to the thalamus and then somatosensory cortex
Proprioception, vibration and fine touch
What does the fasciculus cuneatus carry
lateral and carries information from the upper body to the cuneate tubercle in the medulla
What does the fasciculus gracilis carry
medial and carries information from the lower body to the gracile tubercle in the medulla
Describe the spinothalamic tract
Lateral = pain and temperature
Medial/Anterior = Crude touch
Ascend on the same side then decussates before ascending to the thalamus
Describe the spinocerebellar tract
Posterior spinocerebellar = carries proprioception to the ipsilateral inferior cerebellar peduncle
Anterior spinocerebellar = carries proprioception to the contralateral superior cerebellar peduncle
Describe brown sequard disease
- Hemi section of the spinal cord
- Ipsilateral weakness below the lesions due to damage to the ipsilateral descending motor corticospinal tract which has already decussated at the medulla (loss of vibration and proprioceptive sensation)
- Contralateral Loss of spinothalamic pain and temperature below the lesion as spinothalamic fibres decussate after entering the spinal cord
What is the basal ganglia
Group of nuclei lying deep within the cerebral hemisphere
What are the main components of the basal ganglia?
Striatum (Putamen and caudate)
Globus pallidus
Subthalamic nucleus
Substantia nigra
What are the main functions of the basal ganglia?
Purposeful behaviour and movement
Inhibits unwanted movements
Controls posture and movement
Facilitation, integration and fine tuning of movements
What are the three coverings of the spinal cord from outermost to innermost
Dura
Subarachnoid
Pia
Where are the two enlargements of the spinal cord?
Cervical (Segments C3-T1) = upper limbs
Lumbar L1-S3 = lower limbs
Describe the anatomy of the spinal cord after it ends at L1/2
Tapers into a cone (Conus medullaris) and ends in a strand of tissue called filum terminale
The fascicles cuneatus carries information about what limb
Upper
The fasciculus cuneatus carries information about what limb
Lower
What information does the lateral spinothalmic tract carry
Pain and temperature
What information does the medial spinothalamic tract carry
Crude touch
What is the somatic motor function of the facial nerve?
Muscles of facial expression
What is the visceral motor function of the facial nerve?
Lacrimal glands
Submandibular and sublingual glands
What are the two motor functions of the glossopharyngeal nerve?
Elevate the pharynx by supplying stylopharyngeus
Secretion of the parotid gland
What are the sensory functions of the glossopharyngeal nerve
Sensation to external ear Posterior 1/3 of tongue - touch, pain, temp Pharynx - touch, patn, temp Eustachian tube - touch, pain, temp Carotid sinus, baro and chemoreception
What are the functions of the vagus nerve
Taste - posterior pharynx Swallowing- muscles of pharynx and larynx except stylopharngeus CV and GI regulation Hunger Fullness Decreased HR and BP
What does the accessory nerve supply?
Sternocleidomastoid
Trapezius
What does the hypoglossal nerve supply?
The intrinsic and extrinsic muscles of the tongue
What is the sensory and taste innervation of the posterior 1/3 of tongue?
Glossopharyngeal nerve
What is the sensory sensation of the anterior 2/3 of tongue?
Lingual branch of the V3 from trigeminal
What is the taste sensation of the anterior 2/3 of tongue?
Chorda tympani branch of facial nerve carried by lingual branch
What passes through the cavernous sinus
Oculomotor Trigeminal Ophthalmic trigeminal Maxillary trigeminal Carotid (internal) Abducens Trochlear
Damage to Broca’s area results in what sort of aphasia
Expressive aphasia where they understand what is being said and know what they want to say but can’t express it in meaningful words
Damage to Wernicke’s area results in what sort of aphasia
Comprehension aphasia where they have difficulty understanding written or spoken language but hearing and vision not impaired
Have fluent speech but may scramble words
What is the most common artery for a berry aneurysm to occur?
Anterior cerebral artery
What are the functions of the ophthalmic division of the trigeminal nerve
Sensation to the anterior of head and face (Superior 1/3) including scalp, forehead, cornea and tip of nose
What are the functions of the maxillary division of the trigmeninal nerve
Sensation to middle 1/3 of face including cheek, nose, upper lip, upper teeth and palate
What are the functions of the mandibular division of the trigeminal nerve?
Senesation to inferior 1/3 of face including lower Lip, lower teeth, chin, jaw and anterior 2/3 of tongue
Motor to muscles of mastication and tensor tympani muscle
What are the functions of the facial nerve?
Motor to facial movement Salivation (Submandibular and sublingual) lacrimation Sensation from external ear Taste from anterior 2/3 of tongue
What is the criteria for brainstem death
Pupils Corneal reflex Caloric vestibular reflex Cough reflex Gag reflex Respirations Response to pain
Describe the branches of the aortic arch
Brachiocephalic trunk divides into the right common carotid and the right subclavian
Left common carotid
Left subclavian artery
Where does the right and left common carotid arise from
Right = brachiocephalic trunk
Left = Directly from aortic arch
Do the carotid arteries branch
No
Where do the carotid arteries bifurcate into internal and external
C4
What are the 4 segments of the internal carotid artery
Cervical
Petrous
Cavernous
Supraclinoid
Where does the cervical section of the ICA lie
Anterior and medial to the internal jugular vein and posterior and lateral to the external carotid artery
Does the cervical section of the ICA branch
NO
The petrous portion of the ICA penetrates what bones and runs in which canal
Temporal bone and runs horizontal in the carotid canal
What is the small branch of the ICA that connect to the middle/inner ear called
Carticotympanic artery
What is the name of the potential connection between the petrous ICA and the ECA
Vidian Artery
The cavernous portion of the ICA enters the skull where
Foramen lacerum into the carotid canal and then into the cavernous sinus
Small branches of the cavernous ICA supply what?
Dura
CN3-6
Posterior pituitary (Meningio-hypophyseal artery
Inferolateral trunk
What are the name of the potential connections between the cavernous ICA and the ECA
Inferolateral trunk
What are the 4 branches of the supraclinoid ICA
Ophthalmic artery
Superior hypophyseal artery
Posterior communicating artery
Anterior Choroidal artery
What does the superior hypophyseal artery supply
Pituitary gland
Stalk
Hypothalamus
Optic chiasm
What does the posterior communicating artery supply
Runs backwards above CN3 to connect the anterior (cerebral vascular supply of head and posterior (Brainstem) supply
What does the anterior choroid artery supply
Choroid plexus Optic tract Cerebral peduncles Internal capsule Medial temporal lobe
Which is the lager of the terminal ICA branches
Middle cerebral artery
What are the segments of the middle cerebral artery
M1 - lateral lenticulostriate arteries (Supplies basal ganglia and internal capsule)
M2 - runs near insular cistern
M3 - Emerge onto brain surface
M4 - vessels on brain surface
What are the branches of the anterior cerebral arteries
A1 - runs medially to connect with contralateral ACA via anterior communicating artery to supply the head of caudate nucleus and internal capsule
A2 - runs in the inter hemispheric tissues to genu of corpus callosum
A3 - Cortical branches from callosomarginal and pericallosal arteries
Vertebral arteries arise from where
Subclavian arteries
Where do the vertebral arteries enter the skull
Foramen magnum
The extra cranial vertebral branches supply what
Neck muscles
Spinal meninges
Spinal cord
What are the inter cranial vertebral artery branches
Anterior spinal artery
Small medullary perforators
Posterior inferior cerebellar artery
The vertebral arteries combine to form what
Basilar artery
What are the branches of the basilar artery
Anterior inferior cerebellar arteries
Superior cerebellar arteries
Posterior cerebellar arteries
What does the posterior cerebral artery supply
Thalamus
Geniculate bodies
Cerebral peduncles
Tectum
Define dermatome
Area of skin supplied by a single spinal nerve
Define myotome
A volume of muscle supplied by a single spinal nerve
The dorsal column medial lemniscus pathway carries what sensory information
Proprioception, vibration and fine touch
The lateral spinothalamic tract carries information about what
Pain and temperature
the anterior spinothalamic tract carries information about what
Crude touch
What areas of the brain does the ACA supply
Motor cortex and top of the brain
What areas of the brain does the MCA supply
Outer surface of the brain
What areas of the brain does the PCA supply
Peripheral vision
What are the branches of the aortic arch
Brachiocephalic trunk divides into right common carotid and right subclavian
Left common carotid
Left subclavian
Wheree does the optic tract synapse
At the lateral geniculate nucleus of the thalamus
Fibres carrying information from the lower portions of the retina (Superior visual fields) travel through which lobe
Temporal lobe to the visual cortex = Meyer’s Loop
Fibres carrying information from the superior portions of the retina (Inferior visual fields) travel through which lobe
Loop superiorly through the parietal lobe to the visual cortex = Baum’s Loop
Inferior colliculus and medial geniculate body are important structures in which sense
Auditory
Superior colliculus and the lateral geniculate body are impotent structures in which sense
Visual
Damage to the left optic nerve causes what
Left anopia - left blindness
Damage to the optic chiasm leads to what
Causes loss of the temporal visual fields = hemianopia
Damage to the right optic tract causes what
Loss of temporal field of the left eye and the nasal field of the right eye = hemianopia
Damage to the left Meyer’s loop causes what
Damage to Meyers loop carrying information from the inferior retina and thus the superior visual field resulting in loss of vision in the superior nasal field of the left eye and the superior temporal field of the right eye