Trevino Diana, Nervous P.6
Major Functions of the Nervous System
Information processing- stores some aspects & makes decisions regarding appropriate behaviors
Motor output-May respond to stimuli by initiating muscular contraction or glandular secretions
Sensory input- detects change within and outside the body
Major divisions and subdivisions of the nervous system (PNS&CNS)
Medulla
Pons-
spinal Cord
cerebral hemisphere
CNS
cerebellum
mid brain-
PNS
Somatic-Thoughts of as conscious or voluntary
Autonomic-supplies motor impulse to the cardiac muscle to smooth muscle and glandular epithelium
Tissues
Schwann cell- produces the myelin sheath
Axon- Transfers signals to other cell and organs
Axon terminal- forms junction with other cells
Node of Ranvier- allows diffusion of ions
Neuron
Diencephalon
Myelin sheath-Increase the speed of the signal
Nucleus- controls the entire neuron
Neuroglia
Function- supports and protects cells
Axon hillock- generates impulse in the neuron
Function - sends impulses to other parts of the body
cell membrane- protects the cells
dendrites-receive signals from other cells
axons-conducts electrical impulse away from the cell body
cell body- contains nucleus and other organelles
Structure-Cell body, axons,dendrites
Structure -supportive Gila cells from a cortex in the nerve cord
Classification of neurons and covering
Inter-neurons- they connect spinal motor and sensory which also they transfer signals
Motor-process information to muscle and glands
Sensory-carries impulses from sensory receptors to the CNS
Major parts & functions of the spinal cord
Thoracic(chest)-helps hold the rib-cage,and protect the heart & lungs
lumbar(lower back)-help hold all your weight of your body
Cervical(neck)-protects the brain stem and spinal cord also supports the skull which allows their to be movement for the head
Action Potential
If strong enough depolarization occurs,threshold is reached & impulse is sent down to the axon
The phases are stimulus,depolarization,re-polarization,resting state
Nerve impulse is transmitted during action potential
Cranial Nerves& Spinal Nerves
6-Abducens-lateral rectus of facial expression;sensory taste
7-Facial-facial expression;sensory-taste
5-Trigeminal- 3 branches- motor-chewing;sensory-skin of face
8-Vestibulococholear-sensory-hearing and balance
4-Trochelar-superior oblique muscle of eye
3-Oculomotor- mostly motor
9-Glossopharyngeal-secretion of saliva;sensory-taste
2-Optic-arises from retina of the eye & function in vision
10-Vagus-motor- smooth muscle contraction & relaxation,secretion
1-Olfactory- sense of smell
11-Accessory-swallowing & movement of head;sensory proprioception
12-Hypolossal -movement of tongue during speech & swallowing,sensory-proprioception
Spinal Nerve
Anterior/Ventral-roots contain motor axons & conduct impulses from brain & cord to periphery
Posterior/dorsal- roots contain sensory fibers,whose cell bodies are located in the dorsal root ganglion
Anatomy of the Spinal cord
31 pairs of spinal nerves
Cervical enlargements- C4-T1-nerves to & from upper limbs
connection between the brain & brain steam to the body
Lumbar enlargements- T9-T12- nerve to & from lower limbs
the conus medularis,spinal cord divides into nerves that then leave at lower levels
Neurotransmitters
synaptic end bulbs may contain 2-3 different neurotransmitters
some re-uptake into cells
30-50 different neurotransmitters identified
some degrade by enzymes
Reflex Arc
Integration sensory- involves one or two synapses, in the gray matter of the spinal cord
Motor neuron- transmits a nerve impulse from the spinal cord to a peripheral region
Sensory neuron- transmits impulse from a receptor such as the eye or ear to a central location like spinal cord& brain
Effector- Is a skeletal muscle
Sensory receptors- nerves cells that activate muscle cells which then leads to the reflex action
Compare and Contrast the Autonomic System
Autonomic-two motor neurons from CNS to effector
- tissue can function mostly without nerve supply
-effect-or-smooth& cardiac muscle,glands
Somatic-one motor neuron from CNS to effect-or
-mainly voluntary
-effect-or-skeletal muscle
Similar- receives input from sensory neurons - relays messages