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Biological Psychology
Key Point for this Unit:
Everything psychological is
simultaneously biological!!
NEURON
Dendrites
Dendrites – receive messages from other cells
and conduct impulses toward the cell body
NEURON
Dendrites
Cell Body
Cell Body – the cell’s life-support center
NEURON
Dendrites
Cell Body
Axon
Axon – the extension of a neuron through which messages
are sent to other neurons or to muscles or glands
NEURON
Dendrites
Cell Body
Axon
Myelin Sheath
Myelin Sheath – a layer of fatty cells covering
the axon, helps speed neural impulses
NEURON
Dendrites
Terminal branches of axon
Cell Body
Axon
Myelin Sheath
Terminal branches of axon – form junctions
with other cells
Biological Psychology
It is all about the body!!!!
Concerned with the links between biology and
behavior (also called Neuroscience)
The Nervous System
It starts with a NEURON: an
individual nerve cell; the basic
building block of the nervous
system
How does a Neuron fire?
• Resting Potential: slightly
negative charge.
• Reach the threshold when enough
neurotransmitters reach
dendrites.
• Threshold: level of stimulation
required to trigger a neural
impulse; excitatory signals minus
inhibitory signals must equal a
minimum intensity
• Go into Action Potential; a neural
impulse (brief electrical charge)
that travels down an axon.
• All-or-none response.
TYPES OF
NEUROTRANSMITTERS
Chemical messengers that that traverse the synaptic
gap between neurons
REVIEW… remember
agonists and antagonists???
Agonist – mimic neurotransmitters
**Example: Morphine mimics endorphins
Antagonist – block neurotransmitters
**Example: Poison blocks muscle
movement
Did you know? Botox is an antagonist that paralyzes facial muscles!
Acetylcholine (ACH)
• Involved with
voluntary muscle
movement, learning
and memory
• Lack of ACH has
been linked to
Alzheimer’s disease.
Dopamine
• Deals with motor
movement and
alertness.
• Lack of dopamine
has been linked to
Parkinson’s disease.
• Too much has been
linked to
schizophrenia.
Serotonin
• Involved in mood
control.
• Lack of serotonin
has been linked to
clinical depression.
Endorphins
Did you know? The word
“endorphin” literally means
“morphine within”!
• Involved in pain
control.
• Many of our most
addictive drugs deal
with endorphins.
“Runner’s High”
occurs when your
brain signals the
release of
endorphins to
reduce pain!
The Nervous System
The Nervous System - body’s speedy,
electrochemical communication network consisting
of nerve cells
Central Nervous System (CNS)
• The Brain
and spinal
cord
• Neural networks –
interconnected neural
cells; more
connections made as
experience gained
Peripheral Nervous System (PNS)
• All nerves that are
not encased in bone.
• Sensory and motor
neurons that connect
the CNS to the rest of
the body
• Is divided into two
categories….somatic
and autonomic.
Somatic Nervous System
• Controls voluntary
muscle movement.
• Uses motor neurons.
Autonomic Nervous System
• Controls the
automatic functions
of the body.
• Divided into two
categories…the
sympathetic and the
parasympathetic
Sympathetic Nervous System
• Arouses the body
• Fight or Flight
Response.
• Automatically
accelerates heart
rate and breathing,
dilates pupils
Parasympathetic Nervous System
• Calms the body
• Automatically slows
the body down after
a stressful event.
• Heart rate and
breathing slow down,
pupils constrict
Sympathetic and
Parasympathetic
Types of Neurons
• Sensory Neurons –
sends receptors to
CNS
• Interneurons – internal
communication neurons
• Motor Neurons – CNS
to muscle and glands
• Normally, sensory
neurons take info up
through spine to the
brain.
• With reflexes
though, some
reactions occur when
sensory neurons
reach just the spinal
cord.
• Automatic response
to sensory stimulus;
interneurons react to
sensory neurons w/o
going to brain
Reflexes