The Brainstem, Cranial Nerves and the Visual Pathways (Neuro) Flashcards
What the brainstem connect together? What three sections is it made up of?
Connects cerebrum to spinal cord
1. Midbrain
2. Pons
3. Medulla Oblongata
What is it the most superior part of the Brainstem? Why is it hard to see?
Midbrain
Optic chiasm obstructs most of the view of the anterior brainstem
What are the two parts of the Midbrain called? Where is each one located?
Tectum (Dorsally)
Tegmentum (Ventrally)
What are the two pairs of rounded bumps called on the Brainstem?
Superior colliculi and Inferior colliculi
What are the Super colliculi involved in? (2)
Involved in regulating eye movements
Reflexes associated with visual stimuli (turning or moving the head quickly)
What are the inferior Colliculi involved in? (3)
Sound location
Pitch discrimination
Reflexes with auditory stimuli
What is the larger part of the midbrain called? Where is it located? What does it contain?
Tegmentum
Ventrally
Substantia nigra
What is the Substantia nigras function? What else does the Tegmentum contain (2)? Which surface is it on?
Dopamine production
Cerebral peduncles on the most ventral surface and red nuclei
What is the function of cerebral peduncles? What do the red nuclei do?
Large white matter bundles that connect the midbrain to the thalami
Involved in supporting motor control to limbs
The Nuclei of which three structures is found in the Midbrain?
- Oculomotor (CN 3)
- Trochlear (CN 4)
- Edinger Westphal
Name the structures
a- Superior colliculus
b- Trochlear nucleus
c- Oculomotor Nucleus
d- Edinger Westphal nucleus
e- Red Nucleus
f- Substantia Nigra
g- Cerebral Peduncle
h- Tectum
I- Tegmentum
j- Cerebral aqueduct
What is the Largest part of the Brainstem in the middle called? What lies on its Ventral surface? What lies on the Dorsal surface?
The Pons
Basilar artery
Middle cerebellar peduncles
What are the Middle cerebellar peduncles? What other structure lies dorsal to the pons? Inbetween what?
White matter connections to the cerebellum
Fourth ventricle lies posterior (shown on picture) inbetween the middle cerebellar peduncles
What four nuclei does the Pons contain?
- Trigeminal (CN 5)
- Abducens (CN 6)
- Facial (CN 7)
- Vestibulocochlear (CN 8)
What two centres do the pons contain? What are they involved in the regulation of?
Apneustic and Pneumotaxic centres
Regulation of breathing
What connects the Pons to the spinal cord? What is the groove on its ventral surface called?
The medulla oblongata
Anterior median fissure
What does the anterior median fissure separate? What is the structure of these?
Medullary pyramids
Two distinct lumps on the ventral surface
What runs through the Medullary pyramids? What structures are immediately lateral to the pyramids?
Essential motor tracts known as corticospinal tract
Medullary olives
What is the sensory pathway of nerves called on the dorsal part of the medulla? What is it made up of? Names for both these structures(2)?
Dorsal column Medial Lemniscus (DCML)
Two pairs of nerve bundles: Fasciculus gracilis and fasciculus cuneatus
What 4 nuclei of nerves does the medulla contain?
Glossopharyngeal (CN 9)
Vagus (CN 10)
Accessory (CN 11)
Hypoglossal (CN 12)
Vital centres for regulating what 4 processes are found in the medulla oblongata?
Respiration
Heart rate
BP
Initiating vomiting
Where do the Cranial nerves originate from? Why is this different to other nerves?
Brain
Other nerves originate from the spinal cord
What position do all the Cranial Nerves leave there point of origin? Which one is the exception and why?
Anteriorly
Trochlear nerve, leaves brain posteriorly
How are odour molecules detected?
Specialised nerve cells of the nasal cavity detect odour molecules
convey information superiorly through the cribriform plate to olfactory bulbs
Where is the information from the olfactory bulbs taken to? in what direction?
Olfactory cortices in temporal lobes
Posteriorly
What is the name of CN2 where does it carry nerves to and from?
Optic nerve
Retina to the optic chiasm
What are the names of CNs III, IV and VI? What is their role?
Oculomotor, Trochlear and Abducens
Control muscles for movements of eyes and diameter of pupils
Mnemonic for Sensory or motor innervation of Cranial nerves?
Some Say Money Matters But My Brother Says Big Brains Matter More
Where do the olfactory and Optic nerve originate from respectively?
Cerebrum and Diencephalon
What four functions does the Oculomotor have?
Eye movements
Eyelid opening
Pupillary constriction and accomodation
What three areas does the Trigeminal Nerve Provide sensation to?
Sensation from upper third of face (V1-opthalmic)
Sensation from middle third of face (V2- Maxillary)
Sensation from lower third of face (V3- Mandibular)
What two Muscles does the V3 branch of the Trigeminal nerve provide sensation to?
Muscles of mastication (Move the mandible)
Tensor Tympani muscle
What parts of the face does the Maxillary branch of the Trigeminal nerve provide sensation for?
Middle 1/3 of face
Internal nasal cavity, upper teeth and palate
What parts of the face does the Mandibular branch of the trigeminal nerve provide sensory and motor information for?
Anterior 2/3 of tongue
Mandibular teeth and gums
Tensor tymapni
Four muscles of Mastication
What are the four muscles of Mastication?
Temporalis
Masseter
Media pterygoid
Lateral Pterygoid
What is the motor and sensory functions of the Facial nerve? (2&1)
Motor to:
- Muscles of facial expression
- Stapedius muscle
Sensation:
- ear canal
Secretomotor and taste functions of facial nerve? (3+1)
Secretomotor:
- Submandibular gland
- Sublingual gland
- Lacrimal gland
Taste:
- anterior 2/3 of tongue
What does the first branch of the Facial nerve do? What does the next branch innervate?
Parasympathetic secretomotor function to lacrimal gland
Next branch is to the stapedius muscle (As it progresses through MEC)
After it has given off a branch to the stapedius muscle what is the next branch called and what are its functions (3)?
Chorda tympani (branch)
Taste to anterior 2/3 of tongue, parasympathetic secretomotor function to submandibular and sublingual salivary glands
Where does the facial nerve leave the skull after giving off the chorda tympani branch?
Stylomastoid foramen
When the Facial nerve passes through the Stylomastoid foramen what does it carry sensory and motor innervation to and from respectively?
(Branch of facial)
Sensory- Ear
Motor- Muscles of scalp
Where does the Facial nerve divide? What five nerves does it divide into? What do they innervate?
Parotid Gland
Temporal, zygomatic, buccal, marginal mandibular and cervical branches]
Muscles of facial expression
What are the Motor and sensation innervations of the Glossopharyngeal nerve? (1 & 4)
Motor- Stylopharyngeus muscle
Sensation:
- Pharynx
- Posterior 1/3 of tongue
- Carotid baroreceptors and chemoreceptors
What are the secretomotor and taste functions of the Glossopharyngeal nerve?
Secretomotor- Parotid gland
Taste- posterior 1/3 of tongue
Motor and sensation functions of the Vagus nerve? (3&2)
Motor:
- Muscles of soft palate
- Palatine folds
- Pharyngeal muscles (Pharyngeal constrictors)
- Internal laryngeal muscles
Sensation:
- External ear
- Ear canal
- Larynx
What taste and parasympathetic functions does the vagus nerve have?
Taste:
Epiglottis
Parasympathetic:
Thoracic and abdominal organs
Which Muscle does the glossopgaryngeal nerve supply? What is it involved in?
Stylopharyngeus
Swallowing
Which CN is the accessory nerve? Where does it originate from? Where does it provide innervation to?
CN 11
Spinal cord C1-C5
Motor signals to trapezius and sternocleidomastoid muscles
What are the functions of the Sternocleidomastoid and trapezius respectively?
Sternocleidomastoid- turning head and nodding
Trapezius- Shrugging and movement of scapula
Where does the accessory nerve enter and leave the skull?
Enter- Foramen Magnum
Leave- Jugular Foramen
What does the Hypoglossal nerve send information to? What type of information? What is not innervated by the Hypoglossal nerve?
Intrinsic and Extrinsic muscles of the tongue
Motor innervation
Palatoglossus (supplied by vagus)
What are the areas of vision we can see in each eye called? What is each area divided into? Which one is lateral and which one is medial?
Visual fields
Temporal field and nasal field
Lateral- Temporal field
Medial- Nasal field
What detects light? What is the course of visual information to the CNS?
Retina detect light
Optic nerve, optic tracts and finally the optic radiations then the primary visual cortex (Occipital lobe)
Which part of the retina receives the lateral half of the visual field? Which part receives the Medial half of the visual field?
- Nasal/ medial half of retina receive lateral half of the visual field
- Temporal/ Lateral half of retina receive medial half of visual field
Where does visual information first travel to from the retinas? Where is this structure located?
Optic chiasm
Anterior to midbrain and superior to pituitary gland
Visual information from which visual field does what at the optic chiasm?
Visual information from the temporal visual field crosses over at the optic chiasm to the opposite side
E.g. Right Temporal visual field information goes to the left optic tract
After the optic chiasm where does visual information travel along? Where most of the fibres synapse along this tract? Where is this located?
Optic tract
Lateral geniculate nucleus
Thalamus
After the lateral geniculate nucleus synapse where do the fibres move towards? What do they split into? What are they known as?
Move towards primary visual cortex
Split into superior and inferior pathways
Optic radiations
What are the names of the superior and inferior optic radiation? Why?
Superior- Parietal radiation- travels through parietal lobe
Inferior- Temporal radiation (Meyers loops)- Travels through temporal lobe
Where does the visual information from the parietal and temporal radiations come from in the retina respectively? Which visions of field is associated with each area?
Parietal (superior) radiation- Superior aspect of retina- inferior field of vision
Temporal (Inferior) Radiation- Inferior aspect of retina- Superior field of vision
