Neuro Flashcards
Name three neuromodulators
Dopamine, adrenaline and serotonin
What happens during local anaesthetics?
Sodium channels are blocked in that area
Where is the motor cortex?
In the pre-central gyrus in the frontal lobe
Where is the sensory cortex?
In the post-central gyrus in the parietal lobe
Where does the spinal cord terminate?
L2
What are the two types of fast twitch muscle fibres?
2A glycotic (anaerobic) and oxidative (aerobic) and 2B glycotic (anaerobic)
What are the three bones of the ear?
Malleus, incus and stapes
What nerve innervates the tensor tympani?
The Vii nerve
Are most of the hair cells in the cochlear afferent or efferent?
95% are of the outer hairs are afferent and the inner hairs are efferent
What is the function of the round window in the cochlea?
It releases fluid and pressure
Calcium moving into what side of the cochlea hairs causes depolarisation?
Moving towards the tectoral side
What cranial nerves are parasympathetic?
2,3,7,9,10
What areas of the CNS do parasympathetic nerves come from?
They are some cranial nerve and sacrum nerves
What is the sympathetic neurotransmitter?
Adrenaline
What is the parasympathetic neurotransmitter?
ACh
Do somatic nerves have ganglia?
No, because they do not synapse after the CNS
What is the somatic neurotransmitter?
ACh
Are somatic neurones myelinated?
Yes
What type of muscle do autonomic neurones go to?
Smooth muscle
Are autonomic neurones myelinated?
Pre-ganglion yes but post-ganglion no
What are the autonomic neurotransmitters?
ACh and adrenaline
What do alpha 1&2 receptors do?
Constrict muscle
What are three fast neurotransmitters?
ACh, Glutamate, and GABA
What are the branches of the trigeminal nerve?
- Ophthalmic nerve 2. Maxillary nerve 3. Mandibular nerve
What is a nerve impulse?
The signal used by neurones to transmit information between different spatial locations
What are dystrophies?
They are genetically determined, destructive and mainly progressive disorders of muscle
What does the media of the eye contain?
The vitreous, hyaluronic acid (GAG)
What makes up the parasympathetic component of the autonomic nervous system?
The cranial and sacral outflow
What makes up the sympathetic components of the autonomic nervous system
The sympathetic chain (T1-L2) and the adrenal gland
What is axonal transmission?
Transmission of information from location A to location B
What is synaptic transmission?
Integration / processing of information
Can a neurone use more than one neurotransmitter?
Yes
Where is ACh used?
At neuromuscular junctions, in the brain and in the spinal cord
Where is noradrenaline?
It the heart and the central nervous system
Where is dopamine used?
In the basal ganglia
Where is serotonin used?
In the brain
Is GABA excitatory or inhibitory?
It is the main inhibitory transmitter
What does the dorsal stream from the primary visual cortex detect?
The distance and where the object is
What does the ventral pathway from the primary visual cortex detect?
What the object is
What does the medial rectus do?
Adducts the eye
What does the lateral rectus do?
It abducts the eye
What does the superior rectus do?
It elevates, intorts and adducts the eye
What does the inferior rectus do?
It depresses, extorts and adducts the eye
What does the superior oblique do?
It intorts, depresses and abducts the eye
What does the inferior oblique do?
It extorts, elevates and abducts the eye
What does vestibular eye movement do?
It holds images of the seen world steady on the retina during brief head rotations or translations
What does visual fixation do?
It holds the image of a stationary r object on the fovea by minimising ocular drifts
What does optokinetic eye movement do?
It holds the images of the seen world steady on the retina during sustain d head rotation
What does smooth pursuit eye movement do?
It holds the image of a small moving target on the fovea. It holds the image of a small near target on the retina during linear self-motion
What do nystagmus quick phases do?
Reset the eyes during prolonged rotation and direct gaze towards the oncoming visual scene
What do saccades do?
Bring images of objects of interest into the fovea
What does vergence eye movement do?
It moves the eyes in opposite directions so that images of a single object are placed or held simultaneously on the fovea of each eye
What is the function of the basal ganglia in the sensorimotor system?
The basal ganglia determines what to do and the cerebellum determines how to do it
What is a motor neuron pool?
A collection of motor neurone innervating a single skeletal muscle. They are organised somatotropically
What is the pneumonic for the motor or sensory function of the cranial nerves?
Some say money matters but my brother says big breasts matter most
What are the parasympathetic cranial nerves?
3, 7, 9, 10
What does the olfactory nerve do?
It senses smells
Where does the olfactory nerve start?
The cribiform plate
Where does the olfactory nerve project to?
The entorhinal cortex in the anteriomedial part of the temporal lobe.
How does the olfactory nerve work?
Air gets sucked in and hits the hair fibres on the olfactory to synapse with second generation neurones that send impulses to the brain
How do the hypothalamus and the olfactory nerve work together?
The hypothalamus remembers the emotions that come with the smell from the olfactory nerve
What is CN 1 ?
The olfactory nerve
What is CN 2?
The optic nerve
What does the optic nerve detect?
Vision
What nerves control eye movement?
CN 3,4,6
What does CN 6 do?
Abducts the eye
What muscle does CN 4 innervate ?
The superior oblique muscle of the eye
What muscle does CN 6 innervate?
The lateral rectus muscle
What is CN 3?
The oculomotor nerve
What is CN 4?
The trochlear nerve
What is CN 6?
The abducens nerve
What muscles does CN 3 innervate?
The superior rectus, the medial rectus, the inferior rectus and the inferior oblique muscles. Also the locator and pupillary constrictors
What is the path of the oculomotor nerve?
It originates from the midbrain, near the posterior cerebral arteries, through the cavernous sinus, through the superior orbital fissure and it branches.
What is the path of the trochlear nerve?
It originates in the midbrain, decusses centrally, exits dorsally near the posterior cerebral arteries, through the cavernous sinus and through the superior orbital fissure
What is the path of the abducens nerve?
It originates in the pons, along the petrous temporal bone, through the cavernous sinus and through the superior orbital fissure
What is CN 5?
The trigeminal nerve
What does the trigeminal nerve do?
It gets sensation from the face and mouth and control the muscles of mastication
What happens in Meckel’s cave?
The trigeminal afferents meet
What muscles does the mandible division of the trigeminal innervate?
The temporalis, the masseter and pterygoids
What is CN 7?
The facial nerve
What does the facial nerve do?
Somatic motor innervation of the muscles of facial expression. Visceral motor innervation of the lacrimal gland, submandibular and sublingual salivary glands. It senses the taste buds of the anterior two thirds of the tongue
What are the five branches of the facial nerve?
The temporal, zygomatic, buccal, mandibular and cervical
What is the nucleus of the somatic motor component of the facial nerve?
The facial motor nucleus. It acts on the muscles of facial expression.
What is the nucleus of the visceral motor component of the facial nerve?
The superior salivatory nucleus. It goes to the pterygopalatine (lacrimal glands) and submandibular ganglia (submandibular and sublingual salivary glands) and stimulates secretion
What is the nucleus of the special sense (taste) component of the facial nerve?
The solitary tracts which goes to the geniculate ganglia, which detect taste from the taste buds
What do the corticobulbar fibres innervate?
The contralateral side of the lower face. The bilateral side of the upper face.
What is CN 8?
The vestibocochlear nerve
What does the vestibulocochlear nerve do?
It conducts auditory and vestibular-related impulses from the organ of Corti, the semicircular canals, the utricle and the saccule
Where does the vestibulocochlear nerve originate?
In the pons, it goes through the internal acoustic meatus to get to the vestibular ganglia and the spiral ganglion in the cochlea
What does the vestibular branch of CN 8 do?
It goes to the vestibular ganglia, which receives fibres from the semicircular canals, the utricle and the saccule. It can accelerate the position of these things
What does the cochlea branch of CN 8 do?
It goes to the cochlear ganglia, which receives input from the organ of Corti about hearing
What is CN 9 ?
The glossopharyngeal nerve
What is the path of the glossopharyngeal nerve?
It emerges from the lateral sulcus of the medulla and exits the skull via the jugular foremen, accompanied by the vagus and accessory nerves
Where are the presumptive neural crest cells?
They run dorsolaterally along the neural groove
What do the neural crest cells form?
The sensory ganglia of the spinal cord; schwann cells; adrenal medulla and the meninges and the dermis
What is the function of CSF?
Protection
At what point do eyes form in an embryo?
week 3
When does CNS myelination take place in an embryo?
5 months
How much does the speed of impulse increase between a neonate and a two year old?
The speed of impulse depends on myelination. At neonate it is 20-25m/s and at two years it is 40-60m/s and as far as I am aware it doesn’t get any quicker
What is a lemnisci?
A narrow strip of fibres
What is the difference between a funiculi or a fasiculi?
A funiculi is a ‘rope’ or ‘cord’ of fibres. A fasiculi is a ‘bundle’ of fibres
What is a capsule?
A sheet of white matter fibres bordering a nucleus of grey matter
What is a cortex?
A laminated grey matter on the outside of the brain
What is a nucleus?
A nucleus is a collections of nerve cell bodies within the CNS
What is a ganglia?
A collection of nerve cell bodies outside the CNS or inside the CNS that have a capsule (basal ganglia)
What does the frontal lobe do?
It controls voluntary movement on the opposite side of the body. The frontal love dominant hemisphere controls speech and writing. It controls intellectual functioning, thought processing, reasoning and memory
What is the basal ganglia made up of?
The caudate nucleus, the putamen and the globus pallidus
What does the basal ganglia control?
Motor control, cognition and non-motor behaviour
What separates the cerebellum and the brainstem?
The 4th ventricle, the cerebellum forms part of its roof
What are transverse folia?
The folds of cerebellum
What is the function of the cerebellum?
It is involved in the coordination of voluntay motor movement, balance and equilibrium and muscle tone (posture)
What makes up the tegmentum of the midbrain?
It is the ventral (front) part. It consists of the red nucleus, reticular formation and the substantia nigra
What makes up the tectum of the midbrain?
It is the dorsal side (back) made of the inferior and superior colliculi
What is the function of the hippocampus?
It is critical for episodic, short term and spatial memory. It is essential for constructin mental images
What is anterograde tracing?
It traces from the neuronal cell bodies to the axon terminals
What is retrograde tracing?
It traces from the axon terminals to the neuronal cells bodies. It can be double labelled, which detects two separate branches going to the same cell body
What are bidirectional tracers and what is wrong with them?
They can be anterograde or retrograde so it can move down both branches of the neurone but not the neurone cell body
What are class A experiments?
Some behavioural, physiological or pharmagological variable is manipulated and the consequent effects on brain structure/activity are determined
What does an EEG measure?
It is an indication of regoinal brain activity
What is a class B experiment?
Some brain aspect of brain structure or activity is manipulated and the consequent effects on behaviour/physiology/endocrinology is determined
How can the brain be manipulated in a class B experiment?
Suppression of neural activity (mechanical, electrolytic, chemospecific). Activation of neural activity (electrical stimulation and ECT)
What do excitatory neurotransmitters do?
They depolarise the cell membrane, which icnreases the probability of an action potential being elicited, causing an excitatory post-synaptic potential (EPSP)
What do inhibitory neurotransmitters do?
They hyperpolarise the cell membrane, which decreases the probability of an action potential bein elicited, causing an inhibitory post-synaptic potential (IPSP)
What is a neurone?
It is a highly specific interconnection that collect information, process it and provide memory capacity, they also generate signals to produce a response
What is a neurotransmitter?
It a molecule that interacts with receptors to cause a change a cell cell function
Name an excitatory neurotransmitter
Glutamate
Name an inhibitory neurotransmitter
GABA
What are neuroglia?
Supporting cells that have a protective role and provide structural and functional roles
What are astrocytes?
They are multipolar cells that help control the neuronal environment, influencing local neurotransmitter and electrolyte concentrations. They regulate the blood-brain barrier by foot processes close to the capillaries
What do radial glia do?
They are crucial in guiding developing neurons
What do oligodendrocytes do?
They are most numerous cell in the CNS, they produce myelin sheath that insulate CNS axons. They are in both grey and white matter
What cells provide a barrier between the CSF and the brain?
Ependymal cells
What cells are the resident macrophages of the CNS
Microglia. They are in the meninges, brain parenchyma and vasculature. They contribute to CNS homeostasis
What does the innervation pathway of the skeletal muscle consist of?
The anterior horn cells, the corticospinal tract, the basal ganglia, the cerebellar systems and the primary motor cortex
What type of innervation do myofibrils have?
They have both afferent and efferent innervation. The afferent innervation is from the muscle spindles and from the golgi tendon organs
Why are skeletal muscle fibers not fixed when histologically tested?
They are frozen so when you warm them up the enzymes still work and are easily detectable
What is the sclera of the eye?
The sclera is a tough outer collagen layer that protects the eye. The extraocular muscles attach to the sclera
What is the function of the cornea?
It transmits light and refracts it. It has 2/3rds of the focusing power of the eye. It must be transparent and it has a smooth spherical surface.
What is the function of cornea endothelium?
It is the innermost layer of the cornea. It keeps the corneal clarity by pumping water out of it
Why must the cornea remain dehydrated?
Because the water molecules alter the regular spacing between collagen fibres, causing opacity. It is never regenerated.
What is the limus?
Where the cornea joins the white of the eye