2. The Neurons and the Neurotransmitters
Neurons
the specialized cells that conduct impulses through the nervous
system and contain three major parts - a cell body, dendrites, and
an axon
3. anatomy of a neuron
cell body (soma) contains the nucleus and carries out the metabolic, or life-sustaining,
functions of a neuron.
dendrites (comes from the Greek word for "tree") and are the primary receivers of signals
from the neurons, they look life the leafless branches of a tree
axon is the slender, tail-like extension of the neuron that transmits signals to the
dendrites or cell body of other neurons and to muscles, glands, and other parts of the
body
4. works of neurons
afferent (sensory) neurons relay messages from the sense
organs and receptors - eyes, ears, nose, mouth, and skin -- to
the brain or spinal cord;
efferent (motor) neurons convey signals from the central
nervous to the glands and the muscles, enabling the body to
move
interneurons (thousand of times more numerous than
motor or sensory neurons) carry information between
neurons in the brain and between neurons in the spinal cord
5. Glial Cells are specialized cells in
the brain and spinal cord that
hold the neurons together,
remove waste products, such as
dead neurons, from the brain by
engulfing and digesting them, and
they handle other manufacturing,
nourishing and cleanup tasks
smaller than neurons and make up
more than one-half the volume of
the human brain
The Synapse is the junction
where the axon terminal of a
sending neuron communicates
with a receiving neuron across the
synaptic cleft.
The Myelin Sheath is a white,
fatty coating, wrapped around
some axons that acts as insulation
6. Neurotransmitters
Neurotransmitter is
a chemical substance
that is released into
the synaptic cleft
from the axon
terminal of a sending
neuron, crosses a
synapse, and binds
to appropriate
receptors sites on
the dendrites or cell
body of a receiving
neuron, influencing
the cell either to fire
or not to fire
7. why synaptic vesicles can continue to
pour out
the cell body of the neuron is always
working to manufacture more of the
neurotransmitters
unused neurotransmitters in the
synaptic cleft may be broken down into
components and reclaimed by the axon
terminal to be recycled and used again
the process of REUPTAKE - the
neurotransmitter is taken from the
synaptic cleft back into the axon
terminal, intact and ready for immediate
use thus terminating the
neurotransmitter's excitatory or
inhibitory effect on the receiving neuron
8. the variety of
neurotransmitters
acetylcholine (Ach), a neurotransmitter
that exerts excitatory effects on the
skeletal muscle fibers, causing them to
contract so that the body can move and
has an inhibitory effect on the muscle
fibers in the heart, which keeps the
heart from beating too rapidly
Dopamine (DA), one of four
neurotransmitters called monoamines,
produces both excitatory and inhibitor
effects and is involved in several
functions, including learning, attention,
movement, and reinforcement
Norepinephrine (NE) has an effect on
eating habits (it stimulates the intake of
carbohydrates) and plays a major role in
alertness and wakefulness.
Epinephrine complements
norepinephrine by affecting the
metabolism of glucose and causing the
nutrient energy stored in muscles to be
released during strenuous exercise
9. Serotonin plays an
important role in regulating
mood, sleep, impulsivity,
aggression, and appetite
Glutamate is the primary
excitatory neurotransmitter
in the brain
GABA (gamma-
aminobutyric acid) is the
main inhibitory
neurotransmitter in the
brain
Endorphins provide relief
from pain or the stress of
vigorous exercise and
produce feelings of pleasure
and well-being
13. 2 divisions of the human nervous system
Central Nervous System (CNS) - composed of brain and the spinal cord
Peripheral Nervous System - connects the central nervous system to all
other parts of the body
14. why is an intact spinal cord
important to normal functioning?
the spinal cord is an
extension of the brain that
reaches from the base of the
brain, through the neck, and
down the hollow center of
the spinal column; it
transmits messages between
the brain and the peripheral
nervous system
15. the brainstem
brainstem is part of the hindbrain that begins at the site
where the spinal cord enlarges as it enters the skull, and it
handles functions that are so critical to physical survival that
damage to it is life-threatening
medulla is the part of the brainstem that controls heartbeat,
breathing, blood pressure, coughing, and swallowing
reticular formation (reticular activating system RAS), plays a
crucial role in arousal and attention
16. the
Cerebellum
important to the body's ability to execute smooth, skilled movements
regulates muscle tone and posture
coordinates the series of movements necessary to perform many simple activities without
conscious effort
help to heighten ability to focus attention on incoming sensory stimuli and to shift
attention
may increase our efficiency in acquiring sensory information and discriminating between
sensory stimuli
17. the Midbrain
lies between the hindbrain &
the forebrain
act as relay stations through
which the basic physiological
functions of the hindbrain
are linked to the cognitive
functions of the forebrain
substantia nigra is located in
the midbrain and is
comprised of darkly covered
nuclei of nerve cells that
control our unconscious
motor actions.
18. the thalamus & hypothalamus
thalamus has two egg-
shaped parts, serves as
relay station for virtually
all the information that
flows into and out of the
forebrain, including
sensory information from
all the senses except smell
hypothalamus regulates
hunger, thirst, sexual
behavior, and a wide
variety of emotional
behaviors, and internal
body temperature
19. the Limbic System
group of structures in the brain,
including the amygdala and the
hippocampus, that are
collectively involved in emotional
expression, memory, and
motivation.
amygdala plays an important role
in emotion, particularly in
response to unpleasant or
punishing stimuli
hippocampus is located in the
interior temporal lobes and plays
a central role in the storing of
new memories, the response to
new and unexpected stimuli, and
navigational ability
plays a role in the brain's
internal representation
of space in the form of
neural maps
20. the cerebrum
most essential part of the brain is the cerebrum & its cortex
cerebrum is the largest structure in human brain. it is composed of
two cerebral hemisphere, the left & right which control movement &
feeling on the opposing side of the body
corpus callosum connects the two hemisphere and makes possible the
transfer of information and the coordination of activity between them
cerebral cortex is the thin gray outer covering about 1/8 inch thick. it
is primarily responsible for the higher mental processes of language,
memory & thinking
21. Cerebral cortex
gray outer covering about 1/8
inch thick and is primarily
responsible for the higher
mental processes
contain sensory input areas
where vision, hearing, touchy
pressure, and temperature
register
motor areas, which control
voluntary movement
association areas house
memories and are involved in
thought, perception, and
language
22. 4 lobes of the cerebral hemisphere
motor cortex - a strip of tissue at the rear of the
frontal lobes that controls voluntary body
movement
plasticity - the brain's capacity to adopt to
changes such as brain damage - of the motor
cortex is maintained throughout life
broca's area - involved in directing the pattern of
muscle movement required to produce speech
sounds in the left hemisphere of the brain
frontal association areas -involves thinking,
motivation, planning for the future, impulse
control, and emotional responses
frontal lobes - begin at the front of the brain and extend to the top center of the
skull. they contain the motor cortex, Broca's area, and the frontal association
areas
23. the Parietal Lobes - lie
directly behind the frontal
lobes, in the top middle
portion of the brain and
are involved in the
reception and processing
of touch stimuli
somatosensory cortex,,
the site where touch,
pressure, temperature,
and pain register in the
cerebral cortex
24. the Occipital Lobes at
the rear of the brain are
involved in the reception
and interpretation of
visual information
at the very back of
the occipital lobes
is the primary
visual cortex, the
site where vision
registers in the
cortex
25. the Temporal Lobes, located slightly
above ears, are involved in the
reception and interpretation of
auditory stimuli. the site in the
cortex where the hearing registers is
known as the primary auditory cortex
wernicke's area - is located
adjacent to the primary
auditory cortex in the left
temporal lobe. this is the
language area involved in
comprehending the spoken
word and in formulating
coherent written and spoken
language
26. wernicke's asphasia is a type asphasia resulting from
damage to wernicke's area
wernicke's patient when asked how he was
feeling, replied " i that there's an awful lot of
mung, but i think i've a lot of net and tunged in a
little wheat duhvayden" (Buckingham & Kertesz,
1974)
auditory asphasia (word deafness) - the person may hear
normally but may not be able to understand spoken
language
27. the cerebral hemisphere
Left hemisphere - handles most of the language functions, including
speaking, writing, reading, speech comprehension, and
comprehension of the written information
Right Hemisphere - (controlling the left side of the body) more
adept at visual spatial relations
auditory cortex in the right hemisphere appears to be far
better able to process music that the left
augments left hemisphere's language-processing activities'/
(figures out what its meant and who says it)
(e.g the balancing act)
28. the right hemisphere's role
in emotion
responds to the emotional message conveyed by
another's tone of voice
reading and interpreting nonverbal behavior
involve in the expression of emotion through tone of
voice and facial expression
brain mechanisms responsible for negative emotions
are located in the right hemisphere
31. 2 subdivisions of the PNS
somatic nervous system -
(1) compose of all the sensory nerves which transmits
information from the sense receptors - the eyes, ears,
nose, tongue, and skin -- to the central nervous
system,
(2) all the motor nerves, which relay messages from
the central nervous system make it possible for you
to sense your environment and to move, and they are
primarily under conscious control
32. autonomic nervous system -
operates without any conscious control or
awareness
transmits messages between the CNS and the
glands, the cardiac (heart) muscle, and the
smooth muscles (such as those in the large
arteries and the gastrointestinal system)
ANS is further divided into 2 parts - the
sympathetic & the parasympathetic
nervous system
35. the Endocrine System
Endocrine system is
a series of ductless
glands located in
various parts of the
body, that
manufactured and
secrete the chemical
substances known
as hormones, and
secrete them into
the bloodstream,
thus affecting cells
in other parts of the
body