Bio1152
Chapter
49
Nervous Systems
All animals except
sponges
have some type of
system.
In
vertebrates,
the
brain
and spinal cord make up the
nervous system (CNS), while nerves and ganglia make up the
nervous system (PNS).
The nervous system also contains several types of
cells
which provide various support functions.
The spinal cord can mediate
independently of the
brain.
The
peripheral
nervous system transmits information to and from the
and regulates movement and the internal environment.
The brain is organized into several
regions:
,
,
, and
.
The
is divided into right and left
hemispheres
as well as four
lobes.
The nervous system exhibits
neural
: some synapses can be modified after birth, often in response to its own activity.
Bio1152
Chapter
50
Sensory and Motor Mechanisms
Energy from a stimulus is detected at a sensory
, and after
and
in a sensory
pathway,
produces
of the stimulus in the CNS.
There are several kinds of sensory receptors.
sense
stimuli
such as pressure, touch, and
sound.
detect
solutes in a solution or specific molecules such as
.
receptors detect
electromagnetic
radiation
including
light and
.
In the human ear, vibrating objects create sound waves in the air that are detected by
in the
ear,
which are perceived as sound of different
pitches.
The
canals in the inner ear function in maintaining
equilibrium.
Chemoreceptor cells for
(taste) are modified epithelial cells organized into
taste
in the tongue.
Chemoreceptor cells for
(smell) line the upper, mucus portion of the nasal
cavity.
Vertebrates
eyes
focus light by changing the
shape
of the
.
Signals from rods and cones travel
from
cells to
cells, whose axons form the optic
and transmit the signal to the
brain.
Review:
Vertebrate eye
Humans have an
endoskeleton
consisting of bones which are connected at
by
, and to muscles
at
.
Skeletal
muscles
are attached to the skeleton in
pairs.