The brain and nervous system part 2 Flashcards
What is the middle cord of the spine made up of
Made up of neurones and other cells (grey matter)
What is the outside of the spinal cord made up of
Made up of the fibres (white matter) that carry info up and down the cord.
What sensory information goes into the spinal cord
1.proprioception, pain and temp
describe and locate the motor neurones
Motor neurones are located in the ventral spinal cord, and make direct contact onto the muscles. Stim of these neurones causes movement.
What is a motor pool
A motor pool is all the neurones that innervate a single muscle.
size of the innervation of muscles …
muscles capable of fine movements are innervated by more neurones
Describe the lateral descending system
The lateral descending system is made up of the corticospinal and rubrospinal tracts. The fibres in the lateral system connect to the motor neurones in the ventral horn, which influences lateral musculature.
What do corticospinal fibres influence
Influence movement of every part of the body, particularly important for finger use.
Describe the medial system
The vestibulospinal and reticulospinal tract make up the medial system. fibres connect motor neurones in the medial part of the ventral horn influencing the medial musculature
Functions of the medial system
Medial systems are involved in the control of balance and posture, and these functions happen with little conscious control.
Function of the dorsal column pathway
Carries sensory information from the joint and skin about fine touch, vibration and position from the skin and joints.
Function of the spinaothalamic pathway
It conveys pain and temperature
Where do cell bodies of incoming sensory neurons lie and how is it different to motor neurons
They lie outside the the spine in a series of ganglion called the dorsal root ganglion, unlike motor neurons of which the cell bodies lie in the ventral horn
Describe the spinal nerves
There are 31 pairs of spinal nerves, and the size of the nerves will be different depending on the size of the muscles.
what are dermatomes
An area of the skin supplied by nerves from a single spinal root
What are motor pools made up of
motor units
Where in the body are spinal enlargements
the arms and legs particularly the hands and feet.
What 3 things make up a spinal segment
1.dorsal horn
2.ventral horn
3.intermiediate zone
dorsal horn functions
Contains sensory neurones which receive sensory info and sends this to the brain
ventral horn function
Contains neurones that sends info directly to the muscles
Intermediate zone function
Contains interneurones that integrate information
What is rate coding in the motor system
Motor neurones use a rate coding system to signal the amount of force exerted by a muscle. The maximum contraction is called a tetanic contraction
what is the size principle in rate coding in the motor system
Size principle is with the increasing strength of input onto the neurones, smaller motor neurons are recruited before the larger ones.
What is the vestibular system
System that provides the sense of balance and spatial orientation coordinating movement with balance
What is the reticulospinal tract
It is a set of interconnected nuclei located in the brainstem, and play a role in maintaining tone balance and posture
Basal ganglia function
movement regulation, habbit formation, skill learning
Describe the primary motor cortex
Neurons have a simple relationship to movement e.g. force, direction and speed
Describe the pre motor cortex
Neurones have a more complex relationship with movement e.g. planning movement, spatial guidance of movement, sensory guidance of movement.
Describe the function of the primary sensory cortex
1.heat, pain, vibration
2.Proprioception
3.kinesthesia- the ability to reckognise joint movement
What is the corticospinal tract
The most important tract in the body for the precise control of limbs
function of spinal cord, medulla, cerebellum, basal ganglia, cortex
1.spinal cord-simple reflexes
2.medulla complex reflexes
3.cerebellum-coordinated movement
4.basal ganglia-programmed movement.
5.cortex-complex concious movements
