The Nervous System

sweet, sour, salty, bitter, umami, calcium

A given taste cell can respond through any of four to six chemical signaling routes that correspond to the basic tastes of ___, ___, ___, ___, and the possible fifth and sixth tastes of ___ and ___.

the central nervous system

A major division of the human nervous system that consists of the brain and spinal cord

the peripheral nervous system

A major division of the human nervous system that includes all the neural tissue outside the CNS plus the sensory organs

cones

A photoreceptor that functions best in bright light but are sensitive to color

rods

A photoreceptor that functions in dim light but are not sensitive to color

the autonomic nervous system

A subsystem which provides involuntary regulation of smooth muscle, cardiac muscle, and glands

the somatic nervous system

A subsystem which provides voluntary control over skeletal muscles

sensory receptors, stimuli

All human senses operate through cells called ___ ___ that respond to ___.

myelin

Can surround neuronal axons and which increases the speed of neural signals

efferent division

Carries action (motor) commands to the body's effectors- muscles and glands

sensory information, conscious mental activities

Differing portions of the cerebral cortex play a role in processing ___ ___ and in carrying out all of our ___ ___ ____

outer membrane, ions, nerve signal

In some sensory cells, the stretching of their ___ ___ prompts an influx of ___ that results in the initiation of a ___ ___.

eye, cornea, lens, retina, eye

Light first enter the __ through the ___ and then passes through the ___ on its way to the ___ at the back of the ___.

bent, refracted

Light is ___ or ___ by the cornea and the lens in such a way that it ends up as a tiny, sharply focused image on the retina.

photoreceptors

Light signals are converted to nervous system signals by cells in he retina called:

hearing

Our sense of ___ is based on the fact that vibrations result in 'waves' of air molecules that are, by turn more and less compressed than the ambient air around them.

taste, taste, taste, tastants, tastes

Our sense of ___ works through a group of ___ cells, located in ___ buds near the surface of the tongue, which have receptors that bind to ___, or molecules of food that elicit different ___.

smell, olfaction

Our sense of ___, or ___, works through a set of sensory receptors whose dendrites extend into the nasal cavity

rods and cones

Photoreceptors come in two varieties

stimuli

Reflexes are triggered by specific ___, that help us avoid danger or preserve a stable physical state

glial cells

Support neurons and modify their signaling

eyes and ears

The nervous system includes all the nervous tissue in the body plus the bodys sensory organs, such as the:

reflex arc, sensory, motor, muscle, gland

The neuron wiring of a single reflex, called a ___ ___, begins with a ___ receptor, runs through the spinal cord to a ___ neuron, and proceeds back out to an effector such as a ___ or ___.

rest and digest system

The parasympathetic division is often called:

fight or flight system

The sympathetic division of the autonomic nervous system is often called:

the central nervous system and the peripheral nervous system

The two major divisions of the human nervous system are:

cerebrum, cerebellum, thalamus, hypothalamus, midbrain, pons, and medulla oblongata

There are six major regions in the adult brain:

sensory neurons, motor neurons, and interneurons

There are three types of neurons

pressure, contact

Touch works through a variety of sensory receptors that distinguish among such qualities as light or heavy __ and new or ongoing ___.

neurons

Transmit nervous system messages

reflexes

What are automatic nervous system responses?

the spinal cord

What can receive input from sensory neurons and direct motor neurons in response, with no input from the brain? Also channel sensory impulses to the brain?

a nerve

What is a bundle of axons in the PNS that transmits information to or from CNS?

interneurons

What type of neurons are located entirely within the CNS and which interconnect other neurons?

motor neurons

What type of neurons carry instructions from the CNS to such structures as muscles or glands?

sensory neurons

What type of neurons sense conditions inside and outside the body and convey information about these conditions to neurons inside the CNS?

because it conserves energy and promotes digestive activities

Why is the parasympathetic division often called the rest and digest system?

because it generally prepares the body to deal with emergencies

Why is the sympathetic system often called the fight or flight system?

the somatic nervous system and the autonomic nervous system

Within the PNS's efferent division are two subsystems

dendrites, signals, axon, signals

Each neuron multiples ___ through which ___ travel to the neuron cells body and a single ___ that carries ___ away from the cell body.

myelin

Glial cells produce fat rich ___.

signal movement down a neuron's axon and signal movement from this axon to a second cell across a structure known as a synapse

Nervous system communication can be conceptualized as working through a two step process:

neurons and glial cells

Nervous tissue is composed of two kinds of cells:

thalamus, cerebral cortex

Signals from every sense except smell are routed through the brain's ___ and then to specific areas of the ___ ___.

afferent division

The PNS has an ___ ___, which brings sensory information to the CNS

sympathetic division and parasympathetic division

The autonomic system is further divided into the:

parasympathetic division

The autonomic system is further divided into this and generally facilitates routine maintenance activities

sympathetic division

The autonomic system is further divided into this and generally has stimulatory effects

cerebral cortex

The cerebrum has a thin outer layer of gray matter that surrounds a much larger volume of cerebral white matter