Formative 1 Flashcards
Where does the straight sinus receive venous blood from
Inferior Sagitta sinus and the great cerebral vein
Venous blood from the cerebral circulation exits the cranium via….
Jugular foramina
Venous blood from the cerebral circulation is returned to the heart via….
The Internal jugular veins
Which 2 layers are the brain sinuses formed between
Meningeal and periosteal Dural layers
Where does the cavernous sinus receive blood from
Superior ophthalmic vein of the The orbit
Which sinus is cerebrospinal fluid reabsorbed into
Superior Sagittal sinus via arachnoid granulations
Which 2 structures does the straight sinus separate
Falx cerebri and tentorium cerebelli
Where does the left anterior cerebral artery carry blood to
Motor cortex of the right leg
Which arteries carry blood to the basal ganglia
Lenticulo-striate arteries which are branches of the anterior cerebral artery and MCA
What is the arterial supply of the cerebellum
Superior cerebellar artery
Anterior inferior cerebellar artery
Posterior inferior cerebellar artery
Which artery is a direct continuation of the internal carotid artery
Middle cerebral artery
Where is a common site for berry aneurysms
Circle of Willis
Where is the a) wernickes and b) Broca’s area situated
a) temporal lobe
b) left frontal lobe
A stroke affecting the circulation of the occipital lobe may result in…..
Contralateral homonymous hemianopia
A stroke affecting the circulation to the temporal lobe may result in
Memory problems
Strokes affecting……?…….will result in a contra lateral neurological deficit
One side of the motor/sensory cortex
How are muscles of the lower and upper limb represented in the primary motor cortex
Lower - medially
Upper - laterally
The primary motor cortex occupies the…l.l
Pre central gurus
What supplies the primary motor cortex
Anterior and middle cerebral arteries
What is the primary motor cortex also known as
Brodmanns area 4
The corticospinal tract pass between which 2 structures to enter the central peduncle
Basal ganglia
Thalamus
In Parkinson’s disease, what produces an abnormal rhythmical output
Basal ganglia
What will differ in a same size stroke affecting the motor cortex vs internal capsule
Greater neurological deficit for the internal capsule
Where does the lateral corticospinal tract deccusate
Medullary pyramids
What type of motor neurons innervate muscles directly
Lower motor neurons
Where are axons of the UMN mainly located
In the lateral white matter of the spinal cord
Where are cell bodies of LMN located
Ventral horn of the spinal cord
What is a motor unit
Motor neuron and all the muscular motor units that it innervates
Do LMN leave the spinal cord anteriorly or posteriorly
Anteriorly - ventrally
Where do UMN originate
Motor region of the cerebral cortex or brain stem
What do LMN connect
The brainstem and spinal cord to muscle fibres bringing nerve impulse from UMN
What innervates A) extrafusal muscle and B) intramural muscle
A) alpha motor neurons ( muscle contraction)
B) gamma motor neurons ( body position, proprioception)
The lateral CST carries fibres controlling muscles involved in….
Fine muscle control
The vestibulospinal tract carries fibres controlling muscle involved in……
Balance and posture
The anterior CST mainly supplied which side of the body?
Side contralateral to the originating brain hemisphere
The anterior CST is located……. To the anterior horn of grey matter
Antero-medially
Which contains more fibres. Lateral CST or anterior CST
Lateral
Does the vestibulospinal tract consist of crossed or uncrossed fibres
Uncrossed
The vestibulospinal tract maintains……
Balance and head upright
How are fibres of the CST arranged
Somatotopically organised
Fibres concerned with lower extremity are located laterally
Upper extremity are located more medially
What is the rubrispinal tract
Crossed system which functions as a less skilled version of the lateral CST
The reticulospinal tract originates from cells found in the a)….. and b)…… and may act to faculae or inhibit the activity of various c)…… tracts
a) pons
b) medulla
c) descending
Where are muscle spindles found
Skeletal muscle
What are muscle spindles composed of
Intrafusal fibres
The middle 1/3 of the spindle is associated with what type of sensory nerves
Type 1a afferent sensory nerves
How does the middle 1/3 of the muscle spindle differ from the 2 ends In terms of contracting
Ends are contractile while central portion is non contractile
Muscle spindle activity contributes to……?……. Following a stroke
The change in muscle resistance to stretch
What detects changed in muscle tension
Golgi tendon organ
Where are Golgi tendon organs situated
Junction of skeletal muscle and tendon
What do afferent impulses form the go,GI tendon organ result in
Inhibition of the alpha motor neurons of the muscle fibres associated with the activated Golgi tendon organ to regulate muscle tension at a normal range and also to protect the muscle from the overload
How does the speed of afferent fibres differ in muscle spindles vs Golgi tendon organs
Faster in muscle spindles
Where are small receptive fields found
Areas like the fingers where we have the greatest tactile sensitivity
What are cutaneous receptors
Sensory receptors found in the skin
Part of somatosensory system
What’s the difference between phasic and tonic receptors
Phasic rapidly adapt
Tonic slowly adapt
How are fibres in the dorsal column-medial lemniscal system arranged
Topographically
The dorsal column carries info regarding…..
Touch and proprioception
Where does the dorsal column lie
In the dorsal/posterior white matter of the spinal cord
Where do fibres of the DCML system deccusate
As the tract ascends it deccusates in the medulla then the thalamus
How long does the refractory period last
5-10ms
Which comes first….relative or absolute refractory period
Absolute
In which type of synapse is a synaptic cleft found
Only chemical not electrical
Where are most neurotransmitters synthesised
Cell body
