Nervous System

SCIENCE - 3RD GR

Nervous system

controls and interprets all the activities that happen within the body; It enables us to think, move, and feel something

Central Nervous System (CNS)

the main processing center for the entire nervous system

Brain

funtions as organizer and distributor of information for the body

Cerebrum

large, upper part of the brain that controls activity and thought

Cerebellum

the part under the cerebrum that controls posture, balance, and coordination

Brain stem

the part that connects tha brain to the spinal cord and controls automatic functions such as breathing, digestion, heart rate, and blood pressure.

Spinal Cord

this serves as a channel for signals between the brain and the rest of the body, and controls simple muskoskeletal reflexes without input from the brain

Peripheral Nervous System (PNS)

connects the central nervous system to the organs, limbs, and skin; carries sensory and motor information to and from the central nervous system; regulated involuntary body funtions like heartbeat and breathing.

Somatic Nervous System

associated with the voluntary control of body movements

Spanial Nerves

the nerves that carry motor and sensory signals between the spinal cord and the body

Cranial Nerves

the nerve fibers that carry information into and out of the brain stem

Autonomic Nervous System

associated with the involuntary control of body movements and has 2 subdivisions

Sympathetic

it is activated when the body is in a dynamic role of stress (e.g. increased heart rate and breathing, dilation of pupil, sweating, etc.)

Parasympathetic

it maintains body functions and restores the body to normal or relaxed mode

Neurons

are nerve cells, the basic cellular unit of the nervous system; described as receivers and transmitters of information that allow an organism to respond appropriately

Dendrite + cell body

carry impulses towards the cell body

Axon

carry impulses away from the cell body

Sensory Neurons (Afferent)

receive information and send impulses to the spinal cord or the brain

Motor Neurons (Efferent)

conduct impulses from the bran or the spinal cord to the rest of the body

Interneurons (Association)

relay impulses or information from the sensory neurons to the motor neurons