Neurology Flashcards
Which lobe of the cerebral cortex is responsible for generating motor commands? A) temporal B) parietal C) occipital D) frontal
D) frontal
You have read with interest Terje Lomos original observations on long-term potentiation (LTP) in the rabbit hippocampus. You are convinced that subsequent research provides strong evidence for a role of LTP in memory formation.This role depends upon which neuronal property? A. Faster signal conduction B. Increased pre-synaptic excitability C. Increased axonal branching D. Reduced numbers of synapses E. Increased synaptic strength
E. Increased synaptic strength
- indirect
- mostly subconcious
- doesn’t pass down to spine, but to brain stem nuclei (ANS)
Which motor neuron pathway does this describe?
Extra-pyramidal
If the dorsal coloumn pathway is damaged, where does damage show i.e. contra or ipsilateral side
Ipsilateral side as the axon doesn’t decasate
In a ‘generic’ sensory pathway, where would a 2nd order neuron most likely be located?
•Cell body in dorsal horn or Brain stem
If someone injures their head and loses vision in the left field, what brain region is damaged? A) Left Parietal Lobe B) Right Parietal lobe C) Left occipital lobe D) Right occipital lobe E) Left optic nerve
D) Right occipital lobe
Describe proprioceptive deafferentation
interuption/disruption of the afferent nerve cells
Without the usual proprioceptive input from the dorsal horn, the sensory pathway is virtually unable to make meaningful movements
Name the 6 main sensory receptors responsible for limb proprioception
- pacinian corpuscle
- raffini ending
- free nerve endings
- Golgi tendon organ
- Kinaesthetic receptors
- muscle spindle
what are the two motor pathway categories in the spinal cord?
Pyramidal and Extrapyramidal
What are chemically gated ion channels opened by
Neurotransmitters
Describe what triggers an action potential
All or nothing event An increase in membrane potential above the threshold potential (usually around -70mV)
what is a sensory neuron
neurons responsible for converting external stimuli from the environment into corresponding internal stimuli. They are activated by sensory input, and send projections to other elements of the nervous system, ultimately conveying sensory information to the brain or spinal cord.
Which neurotransmitter is used in the post-ganglionic sympathetic innervation of sweat glands in the skin? A) Noradrenaline B) Acetylcholine C) Dopamine D) Glutamaye E) Serotonin
B) Acetylcholine
Describe the role of proprioception in the control of normal movement
The sense though which we perceive the position and movement of our body, including our sense of equilibrium and balance (senses that depend on the notion of force)
How does botox work
cleaves SNARE proteins to stop Ach vesicles fusing to the terminal bouton. This prevents exocytosis, and ‘freezes’ the muscle
Where is the vestibular system?
The inner ear
what are oligodendrocytes
cell type in the CNS concerned with the production of myelin in the central nervous system.
What are the 3 basic functional classes of a neuron
sensory interneuron motor
What does ischaemic damage do to nerves
Cellular respiration stops Cells depolarise Massive calcium influx Excitotoxicity (glutamate)
Describe the withdrawal reflex
- Pain signal travels along the Ad fibre, to the dorsal root ganglion
- travels across an interneuron to the anterior horn cell
- travels along a motor neuron to move e..g the hand
In a ‘generic’ sensory pathway, where would a 1st order neuron most likely be located?
•Sensory cell body in DRG
Which pathway (spinothalemic, spinocerebellar or dorsal coloumn) does the muscle spindle fibres use
Spinocerebellar- unconcious
Muscle/Tendon
What are the 2 types of glial cell seen in the PNS
- Satellite cells - Schwann cells
Botulinum toxin interferes with neuronal signalling by blocking exocytosis. What type of biological molecule is normally released in this situation? A. Neurotransmitter B. Peptide hormone C. Phospholipid D. Prostaglandin E. Steroid hormone
A. Neurotransmitter
what are ependymal cells
epithelial cells in the CNS which mainly produce CSF
Which layer of the meninges surrounds and supports the sinuses that form the route through which blood drains from the CNS? A) dura mater B) arachnoid mater C) subarachnoid D) pia mater
A) dura mater
describe what happens at the synaptic cleft
- action potential reaches the pre-synaptic knob 2. vesicles are transported to the membrane by the SNARE complex 3. vesicle contents (ACh) released via exocytosis into the synaptic cleft 4. ACh binds to the receptors on the post-synaptic knob 5. Na released causing depolarisation 6. Action potential propagated
Fill in the blanks: The brain is folded inwards, producing —— (rounded ridges). The grooves in between these are ——. Deeper versions of these are called ——. A) Sulci, Grooves, Fissures B) Fissures, Gyri, Sulci C) Gyri, Fissures, Sulci D) Gyri, Sulci, Fissures
D) Gyri, Sulci, Fissures
Why do we have 3 semicircular canals at different angles?
To detect movement in the 3 planes
what are astrocytes
the most numerous cell type within the central nervous system (CNS) and perform a variety of tasks, from axon guidance and synaptic support, to the control of the blood brain barrier and blood flow.
How are neurotransmitters removed from the synaptic cleft
-diffuse away in the cleft -broken down by enzymes -reuptaken and transported to neighbouring cells
What are the 4 types of glial cell seen in the CNS
Astrocytes Microglial cells Ependymal cells Oligodendrocytes
What is the SNARE complex
a group of proteins which mediate vesicle fusion, that is, the fusion of vesicles with their target membrane bound compartments
What do muscle spindles detect
proprioception
What do free nerve endings detect
pain, temperature, light touch
What do kinaesthetic receptors detect
proprioception
Where does the indirect spinothalamic pathway go?
NOT to the somatosensory cortex, but to other areas of the brain such as:
- reticular formation
- hypothalamus
- limbic system
- periaqueducted grey- descending pain modulation
What do raffian endings detect
Stretching of skin/muscle and heavy touch pressure
What is the function of the scarpes ganglion
(a vestibular ganglion)
Projects nerves to the vestibular nuclei via the vestibular nerve
function of the utricle
posture and equilibrium during linear accleration in the horizontal plane
what is a motor neuron
eurons located in the central nervous system, and they project their axons outside of the CNS to directly or indirectly control muscles. They interface between a motor neuron and the neuromuscular junction.
Describe the projection of the spinocerebellar pathway
- 1st order neuron in DGR synapses in dorsal horn
- 2nd order neuron projects ipsilaterally to the cerebellum
What are voltage-gated ion channels opened by
Changes in membrane potential
“At the resting membrane potential, the membrane is most permeable to which ion? A. Calcium B. Chloride C. Magnesium D. Potassium E. Sodium
D. Potassium
What is the difference between graded and action potentials.
An action potential is a binary all-or-nothing event, while a graded potential is an analog signal based on the amplitude of the signal
Parkinsons disease is a neurological condition, characterised by hypokinesia (diminished motor function), tremor and muscular rigidity. L-DOPA is used to treat this disease because? A. Dopamine does not cross the blood-brain barrier B. L-DOPA evokes dopamine release C. L-DOPA selectively antagonises enzymes which inactivate dopamine D. The chemical synthesis of dopamine is uneconomic E. The effects of L-DOPA are longer lasting than those of dopamine
A. Dopamine does not cross the blood-brain barrier
what are the two areas of the spinothalamic pathway (in the spinal cord)?
ventral spinothalamic (crude touch)
lateral spinothalamic (pain/heat)
“What is the innermost protective layer of the brain? A. Arachnoid membrane B. Arachnoid trabecula C. Cerebrospinal layer D. Dura mater E. Pia mater
E. Pia mater
Function of the semicircular canals
posture and equilibrium during rotational/angular acceleration
where does the corticobulbar pathway go?
face, head and neck
In a ‘generic’ sensory pathway, where would a 2nd order neuron most likely be located?
•Cell body in thalamus
What is the cell body
each neurone has a cell body (or soma) that contains a nucleus, smooth and rough endoplasmic reticulum, Golgi apparatus, mitochondria, and other cellular components.
The frontal lobe controls: A) higher cognition B) memory C) Olfaction D) spatial awareness
A) higher cognition
The movement of which ion initially depolarises the membrane to activate Ca2+ channels? A) Calcium B) Chloride C) Magnesium D) Potassium E) Sodium
E) Sodium
Which pathway (spinothalemic, spinocerebellar or dorsal coloumn) does the kinaesthetic receptor use
Dorsal column- fine touch/vibrations
Skin and Joints
If the spinothalamic pathway is damaged- where does damage present i.e. contra or ipsilateral side?
contralateral side as the pathway descasates
What are the 4 main stages of an action potential
- resting state 2. depolarisation 3. repolarisation 4. hyperpolarisation
Which part of the peripheral nervous system is responsible for control of skeletal muscle contraction? A) Sympathetic B) Parasympathetic C) Enteric D) Somatic
D) Somatic
What are the 3 ‘-neurium’ layers of a nerve
endoneurium (innermost) perineurium epineurium (outermost)
Function of the ampullae
a structure in the vestibular system, providing the sense of spatial orientation.
Give us vectoral information regarding acceleration and location
what is saltatory conduction
where the AP ‘jumps’ between nodes of ranvier increasing the conduction speed
Which of these is not a type of glial cell? A) Oligodendrocytes B) Schwann cells C) Astrocytes D) Motor neuron
D) Motor neuron
What are microglia
cells derived from mesoderm that function as macrophages (scavengers) in the central nervous system
What is conduction velocity dependent on
the axon diameter myelination
What are the 3 nerve injury classifications of Seddon’s classification scheme
- Neurapraxia 2. Axonotmesis 3. Neurotmesis
State the 3 inputs which work together to coordinate meaningful muscle movements
- Visual input
- Vestibular input
- Proprioceptive input
What are the general roles of the glial cells
Surround and support neurons Electrical insulation Supply nutrients Maintain chemical environment Destroy / remove dead cells and pathogens
what is an electrical synapse
direct electrical connections formed by connexons which all the cell to act as a functional syncytium with other cells
Which system is depicted here
The vestibular system
where does the corticospinal pathway go?
to the spine
What type of glial cell is responsible for filtering blood to produce CSF at the choroid plexus? A) ependymal cell B) astrocyte C) oligodendrocyte D) Schwann cell
A) ependymal cell
How is the SNARE complex affected by botox
the SNARE proteins are cleaved by botox, resulting in the prevention of the release of the neurotransmitter acetylcholine from axon endings at the neuromuscular junction and thus causes flaccid paralysis.
- direct
- concious
- down spine to spinal level target
- axons project down through pyramids of medulla
Which type of motor neuron is this a description of?
Pyramidal
What are otolith organs
The otolith organs sense gravity and linear acceleration such as from due to initiation of movement in a straight line.
A set of hair cells are coupled to a mass of stones.
The parietal lobe controls: A) Speech B) Proprioception C) Personality D) Voluntary motor action
B) Proprioception
Name two of the extrapyramidal pathways
–Rubrospinal
–Tectospinal
–Vestibulospinal
–Reticulospinal
Outline a very basic concept for how we control movement
what does the spinocerebellar pathway control
unconcious movements, balance, fine tuning of motor control
What is an axon
a structure that carries an electrical impulse from the cell body (or from another cell’s dendrites) to the structures at opposite end of the neuron—axon terminals,
Describe what happens in the ageing process to the CNS
Neuronal atrophy Loss of myelination Noisy processing Dopamine loss
What is the refractory period
short phase in time following an action potential where another action potential cannot be generated. Means that the AP must travel forwards, and not back down the axon.
State 3 target areas in the brain for proprioceptive information
Somatosensory cortex and associative areas: early cognition
Primary motor cortex: e.g. initiation of motor control
Pre-motor cortex: e.g. develops patterns of movement
Cerebellum: e.g. refinement of motor control
Brain stem nuclei: e.g. refinement of motor control
Spinal cord: e.g. spinal reflex loops
What is the resting membrane potential maintained by
leak channels and Na/K ATPase
Describe what happens in the ageing process to the PNS
Declined axonal transport Axonal atrophy Myelin loss Impaired regeneration
what does the dorsal column pathway control?
fine touch and concious proprioception
What are dendrites
branch-like structures extending away from the cell body, and their job is to receive messages from other neurons and allow those messages to travel to the cell body.
What do pacinian corpuscles detect
Changes in pressure
What do golgi tendon organs detect
proprioception
what is an interneuron
neither sensory nor motor; rather, they act as the “middle men” that form connections between the other two types. Located in the CNS, they operate locally, meaning their axons connect only with nearby sensory or motor neurons.
How do otolith organs work
- When the stones accelerate, with respect to the hairs, they exert a shearing force on the hairs.
- This force is detected by the hair cells and sent to the brain via branches of the vestibular nerve.
- The utricle sends input to the brain via the superior division of the nerve, and the saccule, via the inferior division.
Describe the projection of the generic motor neuron
- UMN, axon from the somatic motor cortex projects down through spine and decasates
- May be an interneuron
- LMN axon projects through the ventral root of the dorsal horn
Where is the sensory homunculus found?
somatosensory cortex, post-central gyrus, parietal lobe
Which pathway (spinothalemic, spinocerebellar or dorsal coloumn) does the raffian corpuscle use
Dorsal column- fine touch/vibrations
Skin and Joints
what is the purpose of the extrapyramidal motor pathway
•Modifies movements: Modulatory actions on LMN
Which pathway (spinothalemic, spinocerebellar or dorsal coloumn) does the pacinian corpuscle use
Dorsal column- fine touch/vibrations
Skin and Joints
Which pathway (spinothalemic, spinocerebellar or dorsal coloumn) does the free nerve ending use
Spinothalemic- concious
Detects changes in skin
Which of these are not roles of the basal ganglia? A) involuntary movement B) some cognitive function C) sleep
C) sleep
What does the spinothalamic pathway send information regarding?
pain, heat, vague sense of touch
What type of pathway is the spinothalamic pathway?
sensory pathway
What is the resting membrane potential
the electrical potential difference across the plasma membrane when that cell is in a rested state
Which pathway (spinothalemic, spinocerebellar or dorsal coloumn) does the golgi tendon organ use
Spinocerebellar- unconsious
Muscles/Tendon
function of the saccule
measures posture and equilibrium during linear accleration in vertical accleration
