faculty of medical laboratory physiology : mls-phyo-121 dr
TRANSCRIPT
National University
Faculty of medical laboratoryphysiology : MLS-PHYO-121
Dr: Tagwa Elsheikh Mohammed alhassanTel: 0121994567
CNS Physiology
Dept.Of Physiology
Central nervous
system
LECTURE NO (-)
The sensory system:
provide us with information about the
internal and the external environment:
The sensory receptors:
Special structure found at the peripheral
ends of afferent neurons
Properties of receptors:
1. Specificity:
Each types of receptor is most sensitive to specific from
of energy
Example:
For touch receptors, the stimulus is mechanical energy
For temperature receptors, the stimulus is thermal
energy
For pain receptors, the stimulus is not specific (i.e. any
form of energy can causes pain if it causes tissue
damage)
2. Adaptation:
Some receptors stop generation of action
potentials when a stimulus of constant
strength is applied for long time
Examples:
Touch receptors are rapidly adapting
Proprioceptors are slowly adapting
Pain receptors do not adapt at all
Sensory cortex:
Receives the ascending impulses through the
sensory tracts, and then gives perception about
type, site and strength of stimulation
Sensation from each side of the body is
represented on the opposite side at the brain
The motor system
The central nervous system consist of:
• The spinal cord
• The brain
Function of spinal cord
1. Contain ascending and descending tracts
2. Acts as integrating center for spinal cord
reflexes
The brain
The brain is divided into:
- Bain stem
- Diencephalon
- Cerebellum
- Cerebrum
The brain stem
Consist of:
1. Medulla
2. Pons
3. Midbrain
Contain vital centers (cardiac & respiratory
center)
Brain stem
the diencephalons
Contain:
Thalamus
hypothalamus
hypothalamus
1. Control release of hormones from
pituitary gland
2. Control water intake (thirst center)
3. Control body temperature (temperature
regulatory center)
Cerebellum
Lies posterior to the brain stem
Function:
Control balance of the
body
Cerebrum
Cerebrum
Consist right & left hemispheres
Each hemispheres is divided into:
Frontal lobe:
1. Has motor area
2. Area of smell
Temporal lobe:
1. Has area of hearing
2. Area of memory
Parietal lobe
1. Has sensory area
2. Area for speech
Occipital lobe:
Has area of vision
Basal ganglia
Collection of nucleus in the brain
Function:
Participate in control of voluntary
movement
تم بحمد الله