Transcript Human Nervous System

Human Nervous System
Bombick
7th Grade Science
November 2010
Outline of Presentation
A. Nerve Cell Biology
1. Anatomy
2. Physiology
B. Parts of Nervous System
1. Brain
2. Spinal Cord
3. Peripheral Nerves
C. Nervous System Physiology
1. Brain Physiology
2. Autonomic System
D. Human Psychology
E. Pharmaceuticals and Psychotropic
agents
Nerve Cell Biology
Nerve Cell Physiology
•Nerve impulse (think of it as a wave)
travels down the axon because ions (sodium
and potassium) temporarily travel across
the plasma membrane
•Nerve impulse at a synapse releases a
neurotransmitter from synaptic vesicles
•Neurotransmitter crosses the synapse and
binds to specific receptors to start
another nerve impulse on the other nerve
cell
•Neurotransmitter that travelled across
the synapse is destroyed or reabsorbed by
the nerve cell
•Large number of drugs and biochemicals
interact with this physiological mechanism
Nervous System Anatomy
• Nervous system can be divided
into two major components—
central and peripheral nervous
system
• Central nervous system is
comprised of the brain and spinal
cord
• Peripheral nervous system is
comprised of nerves that come off
the brain (cranial) or spinal cord
(cervical, thoracic, lumbar, and
sacrolumbar)
Brain Anatomy
• Brain contains many folds and
convolutions to increase surface
area
• Brain can be separated into three
principle regions—forebrain,
cerebellum, and brain stem
Brain Functions-Brain Stem
• Brain stem is comprised of
medulla, pons, and midbrain
• The medulla is the center for
respiration, cardiovascular, and
digestive functions
• The pons has inhibitory control
centers for respiration and
interacts with the cerebellum
• The midbrain is involved with the
regulation of walking and posture;
and of reflexes for head and eye
movements
Brain Functions-Cerebellum
• Cerebellum is located behind
the brain stem
• Cerebellum is involved in
movement coordination
• Involved in the vestibular
apparatus
Brain Functions-Forebrain
• Forebrain is comprised of two principle
organized regions—a lower diencephalon
and a higher telencephalon
• The diencephalon is comprised of the
hypothalamus and the thalamus
• The hypothalamus is a homeostatic
center controlling body temperature,
blood sugar, hunger and satiation, and
sexual behavior
• The thalamus is a complex relay station
that integrates sensory signals and
relays them to the cerebral cortex; also
involved in motor control
Brain Functions-Forebrain (cont.)
• The telencephalon of the forebrain
contains two nearly symmetrical
cerebral hemispheres
• The cerebral hemispheres contain the
cerebral cortex, the basal ganglia, and
the limbic system
• Each hemisphere is divided into four
distinct areas—frontal, parietal,
occipital, and temporal
Brain Functions-Forebrain (cont.)
• Frontal lobe is involved in learning,
planning, speech, other psychological
functions, and some motor functions
• Parietal lobe is involved in some sensory
functions (e.g., skin senses); important in
certain cognitive and intellectual
processes
• Occipital lobe is involved in visual
functions
• Temporal lobe is involved in hearing
functions and associated speech
centers; important involvement in
memory
Brain Functions-Forebrain (cont.)
• Basal ganglia helps plan and coordinate gross
voluntary movements
• In lower animals the basal ganglia are the
highest motor structures
• Limbic system is comprised of the
hippocampus, amygdala, cingulate gyrus, and
the septum
• Limbic system works with the hypothalamus
to control the expression of instinctive
behavior, emotions, and drives
• Hippocampus and amygdala also have major
cognitive functions, mainly in processing of
memory
• Limbic system of mammals are similar
indicating similar instinctive behaviors
common to all mammals
Simple Anatomy of the Human Brain
Important Note about Brain Function
Even though many functions can be
localized to specific regions of the
brain, there are many connections via
fiber pathways throughout the brain
resulting in the brain working as a
whole. This is true for the “global
functions” of the brain such as
learning, memory, and consciousness.
Autonomic Nervous System
The autonomic nervous system and
the endocrine (hormone) system
control the body’s internal organs.
It innervates smooth muscle,
cardiac muscle, and glands,
controlling the circulation of blood,
the activity of the gastrointestinal
tract, body temperature, and a
number of other body functions.
Most of this control is not
conscious.
Autonomic Nervous System (cont.)
The autonomic nervous system is divided
into two parts, the sympathetic and
parasympathetic nervous systems,
whose actions are mostly antagonistic.
Many organs are supplied by nerves
from each division, but some are not.
The sympathetic nervous system is
activated in times of crisis (fight or
flight) while the parasympathetic
nervous system operates in ordinary
times.
Autonomic Nervous System (cont.)
• Autonomic nervous system also
stimulates the secretions of the
adrenal gland
• The principle secretion of the
adrenal gland is epinephrine
(adrenalin)
• Epinephrine further effects other
parts of organ systems in the
autonomic nervous system
response (fight or flight)
Sympathetic
Parasympathetic
Psychopharmacotherapy
• Antipsychotics (Neuropleptics)Gradually reduce psychotic symptoms
such as hallucinations, delusions,
paranoia, disordered thinking, and
incoherence. Examples include Haldol,
Mellaril, Thorazine, and Clozapine
• Antidepressants (Thymoleptics)Designed to relieve symptoms of
depression. Examples include Tofranil,
Elavil, Prozac, Anafranil, and Nardil
Psychopharmacotherapy (cont.)
• Antianxiety Drugs (Anxiolytics)Commonly called tranquilizers, these
mood-altering substances are calming,
reduce anxiety and stress, and lower
excitability. They are the mose widely
prescribed of all legal drugs. Examples
include Librium, Valium, Xanax, BuSpar,
Equanil, Miltown, and Tranxene.
• Antimania Drugs (Lithium)-If taken
regulary, lithium carbonate can be
effective in preventing both the
depression and mania associated with
bipolar disorder. Examples include
Lithium carbonate and Eskalith.