Nervous System

the basic units of the nervous system

when neurons transmit information in the form of electrochemical charges to other neurons or cells

the major biosynthetic center of a neuron that contains a spherical nucleus and the normal organelles

branching extensions of a neuron that receive electrochemical measurements

neuron process that carries impulses away from the nerve cell body

plasma membrane of an axon

cone-shaped area of a cell body that attaches to the axon

knob-like distal endings of the terminal branches

type of supporting cell in the PNS that forms myelin sheaths around the axons

fatty insulating sheath that surrounds the axon

surrounds the myelin sheath

narrow gaps in the myelin sheath between schwann cells

very well-developed rough ER

monitor external environment factors such as light and sound and the body's internal environment such as temperature and oxygen

use peripheral neurons to carry impulses from the CNS to effectors

collect sensory information and make decisions that motor neurons carry out

help support the nervous system, they make up half the mass of the brain

support neurons and phagocytize bacterial cells and cellular debris in the CNS

occur in rows along the nerve fibers and they provide insulating layers of myelin around axons within the brain and spinal cord

from a membrane that covers specialized brain parts and forms the inner linings that enclose spaces within the CNS

found between neurons and blood vessels in the CNS; support and join neurons to blood

found in the PNS; surround neuron cell bodies for protection

Arrival of the depolarization wave (nerve impulse) results in the opening of calcium gates and influx of calcium ions into the axon terminal

Calcium ions promote fusion of synaptic vessels with the presynaptic membrane and exocytosis of the nuerotransmitter

The neurotransmitter diffuses across synaptic cleft and attaches to receptors on the postsynaptic membrane

Binding of neurotransmitter causes ion channels to open, which results in voltage changes in the postsynaptic membrane...because sodium ions are entering the next neuron

Events are short-lived because the neurotransmitter is quickly destroyed by enzymes or taken back up into the presynaptic terminal, which closes ion channels

chemicals found inside vesicles that cause a muscle to contract

controls skeletal muscle actions

creates a good feeling

concerned with regulation of body temperature, sleep, consciousness and emotions

brain's natural morphine

low levels in Parkinson's Disease (creates sense of well-being)

orientation of body in space, understanding and interpreting musical patterns, nonverbal visual experiences, emotional and intuitive thinking, language related activities

speech, writing, reading, analytical and and computation skills

controls concentrating, planning, complex problem solving, judging consequences of behavior, motor functions, coordinates the complex muscular actions of the mouth, tongue and larynx to allow speech

help in understanding speech and choosing words to express thoughts and feelings

interpret complex sensory experiences, also provide memory of visual scenes, music and other complex sensory patterns

important in analyzing patterns and combining visual images with other sensory experiences

contains centers for certain visual and auditory refexes

relays impulses to and from the medulla and the cerebrum; also transmits impulses from the cerbellum to centers within the cerebellum

helps alter the heart rate, contains a vasomotor center that sends impulses to smooth muscles in the walls of certain blood vessels causing them to contract or dilate and it also contains a respiratory center that regulates the rate, rhythm and depth of breathing

contains a reflex center for integrating sensory information concerning the position of body parts and for coordinating complex skeletal muscle movements, helps maintain posture

central relay station for sensory impulses from the various parts of the body and sends and sends them to the cerebral cortex. allows awareness of pain, touch, temperature

helps maintain homeostasis by regulating heart rate, blood press., blood temp., water and electrolyte balance, control of hunger weight, also controls glandular secretions in the stomach and intestines

myelinated axons appear white; pass messages through areas of gray matter

unmyelinated axons and cell bodies; route sensory or motor stimuli to CNS; sensory perceptions, emotions, speech and hearing

• Brain and spinal cord
• Integrative and control centers

• Cranial nerves and spinal nerves
• Communication lines between CNS and rest of the body

• Somatic and visceral sensory nerve fibers
• Conducts impulses from receptors to CNS

• Motor nerve fibers
• Conducts impulses from CNS to effectors

• Involuntary
• Conducts impulses from CNS to cardiac muscles, smooth muscles, and glands

• voluntary
• conducts impulses from CNS to skeletal muscles

Mobilizes body systems during emergency situations

• Conserves energy
• Promotes nonemergency functions