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