MGEM2012 Flashcards
What is meant by central & peripheral nervous systems?
Where are neuronal cell bodies in CNS & PNS?
CNS: Brain & spinal cord
Cell bodies of neurons in NUCLEI
PNS: Nerves linking CNS to rest of body
(e.g. spinal/cranial nerves)
Cell bodies of neurons in GANGLIA
Anatomy & Functions of left & right cerebral hemisphere?
Left & right hemisphere connected by corpus callosum
Left: speech, language, comprehension;
calculation; analysis;
recognition of words/numbers;
sensory input from & motor control of right side of body
Right: creativity;
spatial ability;
context/perception;
recognition of places, faces & objects;
sensory input from & motor control of left side of body
Functions of Premotor cortex?
-coordinate voluntary movement
planning
-spatial orientation
-learning (imitation of others)
Functions of Primary motor cortex?
initiate voluntary, refined movement
contain motor homunculus
Functions of Primary somatosensory cortex?
sensory info processing
proprioception
Functions of Frontal lobe?
conscious thought
mood/personality
motor functions
Functions of Parietal lobe?
-integrate sensory info from various senses
-manipulation of objects
-partly involved in visuospatial processing
Functions of Temporal lobe?
smell & sound
processing of complex stimuli like faces & surroundings
Functions of Occipital lobe?
-visual info processing
-visuospatial processing
-distance & depth perception
-colour determination
-object & face recognition
-transmit visual info to other brain areas to help memory formation
Anatomy & Functions of Basal ganglia?
=motor control: prevent unwanted movements by reducing the excitatory input to cerebral cortex
=motor learning
=behaviors & cognition
=emotions
=provide feedback mechanism to motor cortex, modulate & refine cortical activation
(provide motor cortex with planning of movements)
=select appropriate movements (habitual & goal-directed)
basal ganglia connect the rest of the cortex with motor/premotor cortex
Located deep within the cerebral hemispheres
Subcortical nuclei included in basal ganglia: caudate nucleus, putamen, globus pallidus in the cerebrum, the substantia nigra in the midbrain, the subthalamic nucleus in the diencephalon
caudate nucleus & putamen collectively known as striatum
Anatomy & Functions of thalamus (an example of subcortical nuclei)?
situated at the core of the diencephalon, which is a part of the forebrain also containing hypothalamus
mostly made of grey matter but surrounded by 2 layers of white matter
Functions:
=perception
=Relay motor & sensory info
=memory
=Alertness & attention
=Consciousness & awareness
=cognition
Anatomy & Functions of Midbrain?
-anterior & posterior regions called?
-where & what are cerebral peduncles?
-where & what are corpora quadrigemina?
-Internal structures & their functions? (nuclei of which cranial nerves?)
Aqueduct divides midbrain into 2 regions:
Anterior= tegmentum
Posterior= tectum
External structures:
Tegmentum contain Cerebral peduncles (aka crus cerebri)= 2 large bundles of mostly descending motor fibres from cerebral cortex
Tectum contain Superior & inferior colliculi (collectively known as corpora quadrigemina)
Superior colliculi= group of cell bodies linked to visual pathways
Inferior colliculi= group of cell bodies linked to auditory pathways
Internal structures:
=Periaqueductal grey
(Pain propagation & modulation, behaviour)
=Substantia nigra
(Part of basal ganglia, Movement control)
=Red nuclei
(Motor coordination)
=nuclei of Cranial Nerves III (oculomotor) & CN IV (trochlear)
CN III (motor neurons only) have 2 nuclei: oculomotor nuclei (most skeletal muscles for eye movement) & Edinger-Westphal nuclei (Parasympathetic, innervate involuntary muscles for constricting pupil & lens shape change, eg important in light reflex)
CN IV (Only somatic Motor neuron): innervate superior oblique muscle - move eyes medially & down
Anatomy & Functions of Pons?
external features?
Contain nuclei of which cranial nerves?
internal nuclei & tracts?
- Superior cerebellar peduncles: fibres from cerebellum to red nuclei in midbrain
- Middle cerebellar peduncles: formed by fibers from pontine nuclei decussate, then to cerebellum
- Inferior cerebellar peduncles: fibres from spinal cord & medulla oblongata to cerebellum
Cranial nerves V (trigeminal), VI (abducens), VII (facial) & VIII (vestibulocochlear)
internal nerve tracts:
Descending corticospinal tracts –voluntary motor control of body.
Descending corticobulbar tracts – voluntary motor control of face, head & neck.
Ascending medial lemniscus tracts to thalamus –for fine touch, vibration & proprioception.
Ascending spinothalamic tracts – for pain and temperature sensation
ventral pons has pontine nuclei, which are responsible for coordinating movement
Trigeminal (has 3 divisions): both sensory & motor
Abducens: motor ONLY
Facial: both
Vestibulocochlear: sensory ONLY - hearing & balance
Anatomy & Functions of Medulla oblongata?
external features of anterior & posterior medulla?
internal nuclei?
contain nuclei of which cranial nerves?
Anterior external:
* olives: contain inferior olivary complex/nuclei
* pyramids: contain descending corticospinal tract, most fibres cross to opposite side at the ‘decussation of the pyramids’
Posterior external:
fasciculus cuneatus & gracilis form the ascending dorsal column-medial lemniscus tract (to thalamus & somatosensory cortex) – for sensory info about proprioception (joint position sense/perception of body position within a space) & touch
=contain nucleus gracilis & nucleus cuneatus
cranial nerves IX (glossopharyngeal), X (vagus) & XII (hypoglossal)
Glossopharyngeal: both sensory & motor
Vagus: both
Hypoglossal: motor ONLY
Anatomy & Functions of Cerebellum?
inferior to what lobes? separated from the lobes by what?
at the same level & posterior to what anatomical structure?
receive input from? output to?
coordination, precision & timing of movements; attention & planning of motor learning (automaticity)
(provide motor cortex with planning of movements)
modify the firing patterns of upper motor neurones =feedback to motor cortex
Detects errors, compares intended movements to actual movements
Anatomy:
inferior to occipital & temporal lobes, separated from these lobes by tentorium cerebelli, a tough layer of dura mater.
at the same level of & posterior to the pons, separated from pons by fourth ventricle.
Relies on sensory feedback to modulate ongoing (or planned) motor activity – Proprioception, visual, vestibular(hearing) inputs
Receive Input from cerebral cortex via pons & input from spinal cord
Outputs from cerebellar cortex via the deep cerebellar nuclei to thalamus to cerebral cortex (eg primary motor/premotor cortex)
