Lecture 7- The Spinal Cord, Brainstem, Cranial Nerves And Cerebellum Flashcards
What protects the spinal cord?
Meninges
How many protections are there in meninges? And what is the name of the meninges?
Three layers of protection: Dura Mater, Pia Mater and Arachnoid Mater
What are the two types of fibres under spinal cord?
General visceral fibres and General somatic fibres
What are the two types of fibres in general somatic fibres?
- Afferent fibres (sensory information: skin)
- Efferent fibres (motor information: skeletal muscles)
What are the two types of fibres in the general visceral fibres?
- Afferent fibres (internal organs, vessel, glands)
- Efferent fibres (hearts, glands, smooth muscles)
What does dorsal root carry?
Sensory information
What is the pathway of dorsal root?
It goes all the way up to the parietal lobe in cerebrum about sensory information
What does ventral root carry?
Motor information
What is the pathway of ventral root?
It will flow down to different places through spinal cord and to muscles.
What are formed after merging dorsal root and ventral root?
Dorsal ramus and Ventral ramus
What does dorsal ramus innervantes/ connects?
The back (dorsal) part of the body
What does ventral ramus innervate/ connect?
Ventral (frontal) part of the body
What is dorsal root ganglion?
Collection of neuronal cell bodies of sensory neurons that transmit sensory impulses
Do dorsal and ventral ramus contain sensory and motor information?
They contain both sensory and motor information
What can the spinal cord mapping infer?
Humans are most likely evolved fro quadripedal
How is the internal structure of spinal cord structured?
Well-structured and organised (with ascending tract separated from descending tract)
What hosts the tracts of neural fibres?
Spinal cord
How does the spinal cord host the tracts of neural fibres?
It bridges the brain and body bi-directionally and are structurally well organised
What are the parts of spinal cord?
Cervical (C1-C7), Thoracic (T1-T12), Lumbar (L1-L5), sacral and coccyx
What are the two ascending and descending tracts separated?
Ascending sensory tracts and descending motor tracts
What is the basic cell in the nervous system for information communication and processing?
Neuron
What is neuron?
The basic cell in the nervous system for information communication and processing
What is nerve?
A general term referring to the fibre-like nervous tissue that carries information between the brain and body
What refers to the fibre-like nervous tissue that carries information between the brain and body?
Nerve
What is fibre/ nerve fibre?
A general tram for axon
What is the general term for axon?
Fibre/ Nerve Fibre
What is a bundle of axon sharing common features?
Fasciculus/ Fascicle
What is fasciculus/ fascicle?
a bundle of axon sharing common features
What is a bundle of fasciculus?
Funiculus
What is funiculus?
A bundle of fasciculus
What is a tract?
A group of nerve fibres with the same origin, course, termination and function
What is a group of nerve fibres with the same origin, course, termination and function?
Tract
What is a body structure that represents a cord (rope-like thing)?
Cord
What is a cord?
A body structure that represents a cord (rope-like thing)
What is ganglion?
An encapsulated collection of cell bodies in peripheral nervous system
What is nucleus?
An encapsulated collection of cell bodies and nucleus in the central nervous system
What are the two encapsulated collection of cell bodies?
Ganglion and Nucleus
What are the three structures of brainstem?
medulla, pons, and midbrain
Where is brainstem located at?
Located between cerebrum and spinal cord
What function is brainstem responsible for?
Responsible for automatic functions (running on their own subconsciously and cannot be controlled)
What does brainstem host?
It hosts cranial nerves (neural fibres innervating different areas in face and neck)
Where is medulla located at?
Located between spinal cord and pons
What is the function of medulla?
It integrates signals for cerebellum and spinal cord for coordinating motor movements and learning
What run through the medulla?
80% motor tracts
What does medulla host?
- Hosts the nuclei of cranial nerves IX, X, XI, and XII
- Host many automatic functions, including cardiac, vasoconstrictor, gastrointestinal motility, respiratory and swallowing
What does medulla do in terms of reflexes?
Mediate reflexes: coughing, vomiting and gagging
Where is pons located at?
Located between medulla and mid-brain
What does pons relay?
Relays neural tracts between the cerebral cortex, cerebellum, medulla and spinal cord
WHat does pons host?
Hosts the nuclei of cranial nerves V, VI, VII, and VIII
What does pons regulate?
Regulates respiration, swallowing, hearing eye movements, and facial expression and sensation
Where does midbrain locate at?
Located between pons and diencephalon
What does midbrain link?
Links the pons with the cerebral hemispheres
What does midbrain produce?
- Produces the neurotransmitter dopamine (related to addiction and movement)
- Produces melatonin (in pineal gland) to regulate sleep
What does midbrain receive and control?
Receives auditory and visual information and controls eye movement
What are cranial nerves?
All information we collect from sensors in our body will go through htalamus and project to different places in the cortex
What is CN I?
Olfactory Nerve
What is the feature of the olfactory nerve?
- does not go through brainstem and thalamus (a central information relay centre)
- directly penetrates through the skull and directly arrives at the temporal cortex
What is the first part that receives and captures information from the olfactory nerve?
Olfactory bulb
What is the destination of the olfactory bulb
Olfactory cortex (temporal lobe, orbitofrontal lobe, amygdala, hippocampus)
What filters things in olfactory nerve?
Cribriform plate (cranial nerves pass through cribriform plate)
What is olfactory nerve responsible for?
Smell information (e.g. when and where you have that smell)
What is CN II?
The Optic Nerve
What are the three layers in the eye that light penetrates?
- Photoreceptors: first layer that light enters and neuron takes information from light
- Bipolar neuron: second layer that light penetrates
- Ganglion cell: third layer that light penetrates and directly sends information to the brain
How does light enter eyes through optic nerve?
Light will first enter the innermost layer of retina to receive light and it will be reflected from the internal wall, then light can go through the first two transparent layres
Tow types of photoreceptors
Cones and Rods
How does optic nerve has a complicated visual pathway?
It separates information sent to the left visual area to be processed in the right hemisphere, and the right visual area to be processed in the left hemisphere
What is lateral geniculate nucleus?
A turning point to receive information from only one side of your eyeballs
How is the visual information sent to the hemisphere?
Right (left) hemisphere receives left (right) visual field, the pathway is then connected to the right (left hemisphere through lateral geniculate nucleus
What happens if the visual pathway is cut?
- When a visual pathway is cut in the temporal, the cut visual path way. is not working while the other eye can see clearly
- When the visual pathway is being cut at the point where the two optic nerves cross, each of the eye can only see half of the visual field from both eyes (i.e. left eye can only see the right side while right eye can only see the left side)
- When a visual pathway in the brain is damaged at lateral geniculate nucleus, you cannot see from a certain side as the visual field is damaged but can see another side using both eyes
What does superior colliculus integrate?
- Integrates visual, auditory and vestibular signals to control eye and body movements
- Controls ocular muscles and pupils
What types of control is sent to control your body and eyeball in superior colliculus?
Top-down control to downstream information processing to control your body and eyeball
What does superior colliculus do in terms of body posture based on visual information obtained?
adjusts position and posture to maintain body balance based on visual information obtained
What connection does pulvinar nucleus?
Possesses reciprocal connection with most visual cortices areas of the occipital, parietal and temporal lobes
What important role does pulvinar nucleus play?
Plays important role in visual attention
What information does pulvinar nucleus provide?
Tell the cortex which part is important so that the cortex can do top-down feedback based on importance
What are the three cranial nerves related to eye movements?
The Oculomotor Nerve (CN III), The Trochlear Nerve (CN IV), The Abducens Nerve (CN VI)
What do The Oculomotor Nerve (CN III), The Trochlear Nerve (CN IV), The Abducens Nerve (CN VI) do in terms of eye movement?
They control the eye movements which are very complex and important
What does the oculomotor nerve control?
Controls the inferior oblique, inferior rectus, superior rectus, and left medial rectus
What does trochlear nerve do?
It changes the direction of force by pulling the eyeball forward against all tensions pulling the eyeball backward using the superior oblique to maintain the balance of eyeball
What does abducens nerve do?
Controls the right medial rectus
What does trigeminal nerve do?
Controls and receives signal from the muscles in the facial areas, tongue and mouth
What is trigeminal nerve responsible for?
Essential for sound production, chewing and facial expressions
What is the function of facial nerve?
Facial muscle (facial muscle control), facial sensation, taste, parasympathetic function (increases the flow of saliva)
What disorder may be caused by facial nerve?
Bell’s palsy
What s the function of vestibulocohclear nerve?
Processing auditory information and maintaining body balance
What does glosspharyngeal nerve receive?
Receives sensory information from tongue, pharynx, tonsils, middle ear, phraryngotympanic tube, carotid body
What does glosspharyngeal nerve control?
Controls muscles in pharynx (mediate gag reflex)
What does glosspharyngeal nerve affect?
Parotid gland
What is the longest and most complex of the cranial nerves?
The Vagus Nerves
What does the vagus nerve innervate?
Innervate (part of ) ear, pharynx, larynx, soft palate, tongue, esophagus, lungs, trachea, heart, digestive tract
What are the functions of the vagus nerve?
- Receives sensory information (from the innervate structures
- Heavily engaged in parasympathetic functions
- Movement in digestive tracts
- Speech, gag reflex, swallow
What does vagus nerve have?
recurrent laryngeal nerve that controls the larynx which is important to speech production
What is the Spinal Accessory Nerve
- partly mingled with CN X
- control neck muscles
What does hypoglossal nerve control?
Tongue movements
What connection does cerebellum have?
A bidirectional connection that one is towards thalamus while the other is towards downwards (to the body)
What coordination does cerebellum have?
Visual motor coordination
What are the key functions of cerebellum?
- Visual motor coordination
- Motor control: fine motor control and gross motor control
- Motor skill learning
What is motor skill learning?
Collect, calculate and correct error that is the most essential process underlying learning
What is proprioception?
Every channel of information about yourself and body state that needs to be understood by ourselves
What is parallel computation?
Information from different body parts are processed simultaneously in a parallel way that is cognitively demanding -> cerebellum executes parallel compilation for calculating information from every part of body
Cerebellum has _________ neurons than the cerebrum.
More neurons
What relationship does cerebellum have with the body?
Receives input form, and controls output to, the ipsilateral side of the body
Does cerebellum initiate movement?
No, cerebellum does not initiate movement
Cerebellum _________ movements.
Cerebellum coordinates movement
- calculating error between actual movement and predicted movement
- send error signal back to cerebrum
- helps your body to adjust movement when it detects your body is not doing the motion in a correct way
What is the process of coordination of movement in cerebellum?
- Motor plan and execute the movement
- cerebellum receives proprioception from two streams of information, and then calculate error
- Parallel computations when calculating errors fro different body parts using different nuerons and cells
- Cerebellum sends information back to thalamus’s and it will go back to motor cortex to tell the motor correction
