Download Intro Chap 2n.ppt

Human Nervous System
A network of interconnected parts that
controls behavior & connects us to the world
•Central Nervous System – consists of the
brain and spinal cord
•Peripheral Nervous System – consists of the
autonomic and somatic systems
•Autonomic System – consists of the
sympathetic and parasympathetic systems
•What are all these parts made of?
100 Billion Neurons + connections
Each Neuron consists of 3 structural parts
1. Soma or cell body
2. Axon
3. Dendrites
Some axons are coated with myelin (for speed),
and some may also be coated with
neurilemma (allows for healing).
90% of nervous system cells are Glial Cells
These provide structural support, nutrition, fuel,
insulation and assistance with growth and
development.
How do these puppies interact?
• It all starts with a resting potential (-70 mv)
• When a signal is picked up by receptors (holes)
on the dendrites we shift into an action potential
(+ charge)
• This new + charge travels along the axon to a
knob where there is a gap – a.k.a. synapse
• Off goes some neurotransmitter substance and
the signal (excitatory or inhibitory) goes on
• Travel speeds range from 2 to 270 mph.
• Afterwards… recycling (reuptake) or clean up
• A drug may act as an antagonist, or an agonist
for a given neurotransmitter substance.
Okay, let’s talk Spinal Cord
• A long bundle of neurons (mostly axons)
for data flow between the body and the
brain? Sure… but wait, there’s more!
• Speedy reflex reactions are possible too
• Afferent neurons detect a (pain?) signal
• Interneurons pass the info along to
• Efferent neurons that issue instructions for
actions before even getting the brain
involved.
The Peripheral Nervous System?
• All nerves NOT in the brain/ spinal cord.
• Connections allow 2 way communication
between the spine and the rest o’ the
body.
1. Somatic system provides sensory and
motor pathways for VOLUNTARY
muscles.
2. Autonomic system manages involuntary
muscles, organs and glands.
The Autonomic System has 2 parts
• The Sympathetic System helps us deal
with emergencies. Fight or flight.
• The Parasympathetic System helps us get
back to normal afterwards.
• And then we’ve got a whole other system
to consider… the Endocrine System.
• These are glands that secrete hormones
into the blood stream.
The Pituitary is the Master Gland. It releases
HGH & can stimulate the other glands
• Pineal Gland – biorhythms and the
sleep/wake cycle
• Thyroid Gland – growth & metabolism
• Pancreas – regulates blood sugar using
insulin
• Gonads – influence sexual behavior
• Adrenal Glands – manage our stress
reactions via cortisol
What about BRAINS!?!
• How are we gonna study them? Damage?
• Can we change ‘em without breaking them?
Transcranial Mag Stim or EBS?
• Can we look in on them non-invasively?
• EEG allows us to monitor surface activity
• CAT scan using computer enhanced Xrays
• MRI gives us even more structural detail
• fMRI lets us watch the action as it unfolds
• PET scan can see brain activity by tracking
radioactive sugars.
How about some brain parts? Lets start
with the hind brain.
• Medulla – controls things like breathing
and swallowing
• Pons – influences sleep, dreaming,
arousal and coordination of movement
• Reticular Formation (RAS) – controls our
general levels of arousal and attention
• Cerebellum – coordinates fine, rapid motor
movement, learned reflexes, posture and
muscle tone
How about the Mid Brain (the limbic system)
• Thalamus – sends sensory information to the
proper areas of the cortex
• Hypothalamus – controls hunger, thirst, sleep
body temp, sex, emotions & pituitary gland
• Hippocampus – helps with storing memories
and remembering the location of objects
• The Amygdala – manages emotions, our fear
response, and memories of fearful stimuli
• Cingulate Cortex – helps us with emotional
and cognitve processing
And finally, the Forebrain!
• Is divided into two halves or hemispheres
• At the back, Occipital lobes – for vision
• Then the Parietal Lobes – includes the
somatosensory cortex – for body processes
• Temporal Lobes – primarily auditory info,
language and some taste data
• Frontal Lobes – planning, memory storage,
emotional control, decision making + the
Motor Cortex for control of body movements
• Hemispheres connected by corpus callosum
Anything else we should know?
• Some areas that really handle very limited or
specialized jobs
• Broca’s Area – devoted to speech production
• Wernicke’s Area – devoted to understanding
the meaning of words
• Some areas with an assortment of jobs… the
Association Cortex filters incoming sensory
data
What about those hemispheres?
• The left hemisphere handles things like
spoken/written language, math calculations,
logical thought processes, analysis of detail
and controls the right side of the body.
• The right hemisphere handles things like
non-verbal communication, visual and
spatial perception, music and art
processing, emotions, pattern and facial
recognition and controls the left side of the
body.