Chapter 46 (trans): Organization of the nervous system, Basic
functions of synapses
Physiology ( Davao Medical School Foundation )
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CHAPTER 46: ORGANIZATION OF THE NERVOUS SYSTEM, BASIC FUNCTIONS OF SYNAPSES AND
NEUROTRANSMITTERS - Dr. Bisnar
body surface and from
GENERAL DESIGN some deep structures
CENTRAL NERVOUS SYSTEM
NEURON: THE BASIC o This information enters
the CNS through
FUNCTIONAL UNIT peripheral nerves and
Incoming signals enter the is conducted
neuron through SYNAPSES immediately to multiple
(location: neuronal dendrites sensory areas.
and cell body)
MOTOR PART OF THE NS: THE
For different types of EFFECTORS
neurons, there may be about Control various bodily
200,000 synaptic activities achieved by:
connections from input fibers 1.) Contraction of appropriate
skeletal muscles
The output signal travels 2.) Contraction of smooth
via a single axon leaving the muscles in the internal organ
neuron. Then, this axon may 3.) Exocrine and endocrine
have many separate gland secretions
branches to other parts of the
Motor functions: refer to the
nervous system or peripheral activity of the NS
body
Effectors: refer to the muscles
Special feature of most and glands
synapses: the signal
normally passes only in the THE SKELETAL MOTOR
forward direction NERVE AXIS OF THE NERVOUS
SYSTEM
SENSORY PART OF THE NS – o Controls skeletal muscle
contraction
SENSORY RECEPTORS
Most activities of the nervous o The skeletal muscles can
system are initiated by sensory be controlled from many
experiences that excite sensory levels of the CNS and
receptors each of those areas has
its own specific role.
receptors can be visual,
aural, tactile, body surface, etc. o LOWER PART: primarily
concerned with
These sensory experiences automatic
can either cause: instantaneous muscle
o Immediate response responses to sensory
o In form of stored stimuli
memories
o HIGHER PART:
SOMATIC PORTION of the concerned with
sensory system deliberate complex
o transmits sensory muscle movements
information from the controlled by the
receptors of the entire thought processes of the
brain
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CHAPTER 46: ORGANIZATION OF THE NERVOUS SYSTEM, BASIC FUNCTIONS OF SYNAPSES AND
NEUROTRANSMITTERS - Dr. Bisnar
INTEGRATIVE FUNCTION OF b. Cerebellum,
THE NS (Functions): Reticular substance
1. To process incoming of Medulla, Pons,
information to produce Mesencephalon:
appropriate mental and control equilibrium
motor response
c. Medulla, Pons,
2. It discards 99% of Mesencephalon,
information considered as Amygdala,
irrelevant Hypothalamus:
control feeding,
3. It allows channeling and salivation, lip licking
processing of information
into the brain to produce
d. Emotional
a correct or desired
patterns: Anger,
response
excitement, sexual
response, reaction
MAJOR LEVELS OF CNS: to pain, reaction to
pleasure
1. SPINAL CORD
If cut in higher neck region:
its function can still occur 3. HIGHER BRAIN OR
(e.g. walking movement, CORTEX
withdrawal reflex from pain, Performs a COMPLEX
reflex that stiffen the legs to function
support the body against
gravity, reflexes controlling Has a large memory
local blood vessel, GI storehouse, and opens the
movement, urinary excretion world of stored information
for use of the mind
The upper NS sends direct
signal to the control NEVER FUNCTIONS ALONE;
commanding spinal cord always in association with
center to perform its LOWER BRAIN
function, then sends signal to
the periphery of the body Transforms imprecise signals
from lower brain centers to
2. LOWER BRAIN OR determinative and precise
SUBCORTEX operation
controls the SUBCONSCIOUS
activities of the body: Essential for most of our
thought processes but need
a. Medulla, Pons: the subcortex
control BP,
respiration
.
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