THE NERVOUS SYSTEMThe Communication System

THE NERVOUS SYSTEM FUNCTIONFunction: to communicate

conditions within the body and the surrounding environment◦Stimulus – something that

causes a change or response in an organism

◦Response – any reaction or change in an organism that is caused by a stimulus.

THE NERVOUS SYSTEM FUNCTION

NEURON – NERVE CELLhttp://argosymedical.com/Nervous/samples/animations/Firing%20of%20Neurons/index.html

Dendrites – receive signals from other cellsCell Body – contains the nucleus and organelles of the neuronAxon – long, slender part of neuron that carries impulse from cell body to terminalsSchwann cells – produce the myelin sheathmyelin sheath – fatty substance – increase speed signal travels down axonAxon Terminals – end of neuron that releases neurotransmitters to signal other neurons

TYPES OF NEURONS

Sensory Neurons – run from sensory receptors (sight, smell, touch, taste, sound) to the CNSInterneurons – found exclusively in the spinal cord and brain (CNS) – communicate with other neuronsMotor Neurons – carry information from the CNS to muscles or glands that carry out a response

THE NERVOUS SYSTEM COMPOSITIONCentral Nervous System

◦Brain◦Spinal Cord

Peripheral Nervous System◦Connects the central nervous

system to the rest of the body through nerves

THE BRAIN Cerebrum:

◦ Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving

◦ Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli

◦ Occipital Lobe- associated with visual processing ◦ Temporal Lobe- associated with perception and

recognition of auditory stimuli, memory, and speech Cerebellum is associated with regulation and

coordination of movement, posture, and balance. Brain stem is responsible for basic vital life functions

such as breathing, heartbeat, and blood pressure.

THE BRAIN (DOMINANCE)

THE SPINAL CORDA bundle of nerves that passes

through the bones of the vertebraedown the back.

It sends sensations to the brain from the body, and returns motor commands to the various parts of the body.

Responsible for most reflexes

PERIPHERAL NERVOUS SYSTEMConnects the central nervous system to the rest of the body through nerves.

HOMEOSTASIS

The human body uses stimuli it receives from internal and external sources to make adjustments so that the body can maintain homeostasis (a constant internal environment).

NERVOUS SYSTEM SUMMARY