AP Pysch module 9-10

Neuron

A nerve cell; the basic building block of the nervous system

Cell Body

The part of a neruon that contains the nucleus; the cell's life-support center

Dendrite

A neuron's often bushy branching extensions that reduce and integrate messages

Axon

The neuron extension that passes messages through its branches to other neurons or to muscles or glands

Myelin Sheath

A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next

Glial Cells

Cells in the nervous system that support

Action Potential

A neural impulse; a brief electrical charge that travels down an axon

Threshold

The level of stimulation required to trigger a neural impulse

Refractory Period

(1) in neural processing

All-or-None Response

A neuron's reaction of either firing or not firing

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron

Reuptake

A neurotransmitter's reabsorption by the sending neuron

Endorphins

"Morphine within"— natural

Agonist

A molecule that increases a neurotransmitter's action

Antagonists

A molecule that inhibits or blocks a neurotransmitter's action

Nervous System

The body's speedy electrochemical communication network

Central Nervous System (CNS)

The brain and spinal cord

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body

Nerves

Bundled axons that form neural cables connecting the central nervous system with muscles

Sensory Neurons

Neurons that carry incoming information from the body's tissues and sensory receptors to the brain and spinal cord

Motor Neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Interneurons

Neurons within the brain and spinal cord; they communicate internally and process information between the sensory inputs and motor outputs

Somatic Nervous System

The division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system

Autonomic Nervous System (ANS)

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). It's sympathetic division arouses; it's parasympathetic division calms

Sympathetic Nervous System

The division of the autonomic nervous system that arouses the body

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body

Reflexes

simple it occurs only in spinal cord George reaching brain

Endocrine System

The body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

Hormones

Chemical messengers that are manufactured by the endocrine glands

Adrenal Glands

A pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress

Pituitary Gland

The endocrine system's most influential gland. Under the influence of hypothalamus