Chapter 10 Nervous System

Neuron

An individual nerve cell.

Nerve

A macroscopic bundle of nerve cells that carry electrical messages all over the body.

Acetylcholine

An internal chemical that activates the cell membrane of nerve cells, resulting in electrical discharges.

Peripheral Nervous System (PNS)

Consists of cranial nerves, spinal nerves, plexuses, and peripheral nerves throughout the body.

Central Nervous System (CNS)

Consists of the brain and the spinal cord.

Cranial Nerves

Carry impulses between the brain and parts of the head and neck.

Plexus

A large network of nerves in the peripheral nervous system.

Motor Nerves

Also called efferent nerves; they travel from the spinal cord and brain to muscles in the body.

Cauda Equina

A bundle of spinal nerves below the end of the spinal cord.

Autonomic Nervous System

Nerve fibers that carry impulses to glands, heart, blood vessels, and involuntary muscles.

Sympathetic Nervous System

Responsible for the body's 'fight or flight' response.

Parasympathetic Nervous System

Promotes 'rest and digest' functions.

Neuron Structure

Consists of dendrites, cell body, and axon.

Myelin Sheath

Fatty tissue that insulates the axon and speeds up electrical impulse transmission.

Neurotransmitters

Chemical substances that enable the transmission of impulses across synapses.

Afferent Nerves

Sensory nerves that carry impulses to the brain and spinal cord from stimulus receptors.

Efferent Nerves

Motor nerves that carry impulses from the central nervous system to muscles or glands.

Parenchyma

The essential distinguishing tissue of an organ.

Stroma

The connective and supportive tissue of an organ.

Glial Cells

Supportive cells in the nervous system that do not transmit impulses.

Astrocytes

Star-like glial cells that transport water and salts between capillaries and neurons.

Oligodendrocytes

Glial cells that form the myelin sheath in the central nervous system.

Microglial Cells

Small cells that protect neurons by responding to inflammation.

Cerebrum

The largest part of the brain; the 'thinking' area.

Cerebrospinal Fluid (CSF)

Fluid that protects the brain and spinal cord from shock.

Thalamus

The part of the brain that processes and relays sensory information to the cerebral cortex.

Hypothalamus

Controls body temperature, sleep, appetite, emotions, and regulates hormone release from the pituitary gland.