anatomy descending pathway

Question 1

function of descending pathways

Answer 1

modify all activity of ascending pathways

controlling conscious and reflex responses to stimuli

Question 2

FUNCTIONAL ORGANIZATION OF THE CNS: mode of control

• external control
• internal control

Answer 2

-sensory guided…..parietal cortex, premotor cortex and cerebellum

-non-sensory guided….prefrontal cortex, supplementary motor area, basal
ganglia

Question 3

motor projection fibres

Answer 3

Neurons in the motor cortex give rise to axons that travel through the corona radiata and the internal capsule

Question 4

upper motor nuerons
where does cell body originate
aka
impulses

Answer 4

• cerebral cortex or brainstem
• first order neurons
• doesnt transmit impulse directly to muscles

Glutamatergic

Question 5

lower motor nuerons
cell body originates from
aka
impulses

Answer 5

• anterior horn of the spinal cord, the brainstem or cranial nerve nuclei
• second order nuerons
• transmits impulses directly to muscles

Question 6

Pyramidal tracts :
pass through
types
function

Answer 6

pyramids to synapse on cranial nerves or nuerons on the ant horn of spinal cord

lateral and anterior corticospinal tracts

voluntary movements

Question 7

extrapyramidal tracts
pass thru
types
function

Answer 7

• doesn’t pass through pyramids
• rubrospinal , reticulospinal, olivospinal ,vestibulospinal
• coordinates movement, posture and muscle tone

Question 8

Pyramidal tracts are either

Answer 8

corticospinal tracts or corticobulbar tracts

Question 9

PYRAMIDAL TRACT - CORTICOSPINAL
input from
travel thru

Answer 9

motor and pre-motor cortex. areas:

internal capsule to the cerebral peduncles and then come to lie on ventral surface of the medulla (ie pyramids)

Question 10

Anterior Corticospinal Tracts:
controls
decussates

Answer 10

central axial and proximal muscles involved in postural control
spinal cord

Question 11

Lateral Corticospinal Tracts:
controls
decussates

Answer 11

appendicular muscles for fine movement of ipsilateral limbs

pyramids

Question 12

corticobulbar
follows
Synapse with and where
Responsible for

Answer 12

• same pathway as the corticospinal tracts INITIALLY
• motor nuclei of the cranial nerves beginning at the level of the upper pons
• voluntary movement of the muscles of the face head and neck in phonation, swallowing and facial expression.

Question 13

EXTRAPYRAMIDAL TRACTS: 1)where do they arise from and 2)function
vestibulospinal
reticulospinal

Answer 13

-1)vestibular nuclei 2) transports balance info to spinal cord

• 1)recticular formation of pons 2) medial fibres=excites voluntary
  movements. lateral fibres=inhibits voluntary movements

Question 14

EXTRAPYRAMIDAL TRACTS: 1)where do they arise from and 2)function

• Rubrospinal
• tectospinal

Answer 14

• 1) red nucleus 2)control of hand

- 1)sup colliculi 2) recieves input from optic nerves and cordinates head movements in relation to visual stimuli