Question

. Explain how descending motor pathways

1. Activate the muscles

2. Control muscle force and tension

Answer 1

The descending motor tracts carry motor signals from the cerebrum to different body parts.
Descending tracts are responsible for muscle contraction, muscle tone, balance, posture and locomotion.
The descending tracts are divided into :

1. pyramidal : originate in cerebral cortex fibres end in brainstem and spinal cord.
- corticospinal tract begins from cerebrum descend down to internal capsule, midbrain, pons and medulla. The fibres then divide into anterior and lateral  corticospinal tract. The fibres then run down the spinal cord and supply the musculature of body activating the muscles to contract.

Fibres of corticobulbar tract emerge from primary motor cortex and descend down to spinal cord. They then supply the face and neck.
2. Extrapyramidal : originate in brainstem and travel to spinal cord. Rubrospinal, tectospinal, vestibulospinal and reticulospinal tract are responsible for muscle tone, balance and posture
Vestibulospinal tract are responsible for balanace.
Reticulospinal regulate muscle tone

tectospinal are involved in coordinated moveme