Function of a neuron
-The basic cell of the nervous system
~Highly specialized cells that transmit messages from one area of the body to another
sensory neuron
- convey impulses to the central nervous system from sensory receptors
motor neuron
- carry impulses from the CNS to effector organs
association neuron
-Connect sensory and motor neurons
different types of supporting cells
CNS
- Brain and Spinal cord
PNS
- Nerves outside brain and spinal cord
autonomic nervous system
-Involuntary
-Only motor nerves
-Divided into two divisions:
~Sympathetic division
~Parasympathetic division
Microglia
Spider-like phagocytes, dispose of debris
sympathetic division
-Sympathetic=”fight-or-flight”
-Response to unusual stimulus
-Takes over to increase activities
Ex: heart rate, breathing, etc…
-Remember as the ‘E’ division (Exercise, Excitement, Emergency, Embarrassment)
-Blood goes from digestive organs to skeletal muscles
-Glucose gets released from liver
-Dilates pupils
-Stimulates perspiration
Satellite Cells
Protect neuron cell bodies
Schwann Cells
Form myelin sheath in the peripheral nervous system
parasympathetic
supporting cells
are mitotic and can form tumors
what does myelin do for a nerve impulse
impulses travel faster
reflex arc pathway
Stimulus Afferent neuron Association neuron/Interneuron neuron Efferent Muscle/gland affected
minimum number of neurons in a reflex arc
2 ex: knee jerk
parts of the brain stem
medulla oblongata
-Lowest part of brain stem
-Merges with spinal cord
-Functions as an important control center:
~Heart rate, Breathing, Blood pressure regulation, Swallowing, Vomiting
cerebellum
-two hemispheres-convoluted
-Function:
~Involuntary coordination of body movements, times skeletal muscle, controls balance and equilibrium
hypothalamus
-under the thalamus
-Function:
~Autonomic nervous system center
corpus callosum
- Allows them to communicate with each other
cerebrum
Paired left and right hemispheres
More than ½ of brain mass
Surface made of ridges (gyri) and grooves (sulci)
broca’s area