Download 1134434Neurons JS09

PSYCHOLOGY
Neural and Hormonal
Systems
True or False?
1. A small amount of brain tissue from a person
cannot be distinguished from that of a monkey.
2. The human brain produces its own natural
opiates.
3. Some one can write but be unable to read.
4. Electrically stimulating a cat’s brain at a certain
point can cause the animal to cower in terror
in the presence of a small mouse.
5. Some people have had their brain cut in half
with no apparent ill effect.
What does your skull tell
us about you?
Demostration: take your hands and feel
your skull/head
What do you notice?
Phrenology
Franz Gall - phrenologist
Bumps on skull reveal mental abilities &
character traits
Not very scientific
However it did highlight the presumed
function of specific brain regions
Neural
Communication
 Biological Psychology
 branch of psychology concerned with the links
between biology and behavior
 some biological psychologists call themselves
behavioral neuroscientists, neuropsychologists,
behavior geneticists, physiological
psychologists, or biopsychologists
Neuron
 Neuron
 a nerve cell
 the basic building block of the nervous
system
Neural
Communication
 Dendrite (listen)
 the bushy, branching extensions of a neuron
that receive messages and conduct impulses
toward the cell body
 Axon (speak)
 the extension of a neuron, ending in branching
terminal fibers, through which messages are
sent to other neurons or to muscles or glands
The insulator
 Myelin [MY-uh-lin] Sheath
 a layer of fatty cells encasing the fibers of
many neurons
 enables vastly greater transmission speed of
neutral impulses
Neuron
Axon terminals - where message leaves
axon
Synaptic gap - space the message jumps
across from the axon terminal to the next
dentrite
Neural
Communication
 Synapse [SIN-aps] (Sherrington)
 junction between the axon tip of the sending neuron and
the dendrite or cell body of the receiving neuron
 tiny gap at this junction is called the synaptic gap or cleft
 Neurotransmitters
 chemical messengers that traverse the synaptic gaps
between neurons
 when released by the sending neuron, neurotransmitters
travel across the synapse and bind to receptor sites on
the receiving neuron, thereby influencing whether it will
generate a neural impulse
Neural
Communication
Neural communication
How does a neuron fire a message?
Neural
Communication
Action Potential
 a neural impulse; a brief electrical
charge that travels down an axon
Threshold
 the minimum level of stimulation
required to trigger a neural impulse
How does a neuron fire a
message?
For Action potential a Threshold has to be reach:
The + sodium ions (partiers) around the axon
have to be excited
There has to be more partiers (excitatory) then
party poopers (inhibitory) for the message to be
sent down the axon
Neural impulse - Action
potential
1. Resting potential (polarized neuron;
- potassium inside, + sodium outside)
1. Excitatory (+ sodium, partiers - gas pedal) vs
Inhibitory (- potassium, party poopers -brake)
2. All or nothing response
•
Reach threshold for action potential
3. Depolarization (+sodium come into the axon)
•
Selectively permeable - gate opens
4. Refractory period (recharging, +sodium move
back out)
Neural
Communication
Cell body end
of axon
Direction of neural impulse: toward axon terminals
Neural communication
Where does a neural impulse begin?
Know the order of transmission
How does one neuron communicate to
another?
Be able to explain the process
Neural comm.
Know names of neurotransmitters and
their functions & malfunctions - see chart
in book
Should also know whether they inhibit or
excite
Neural
Communication
Neural
Communication
 Acetylcholine [ah-seat-el-KO-leen]
 a neurotransmitter that, among its
functions, triggers muscle contraction
 Endorphins [en-DOR-fins]
 “morphine within”
 natural, opiate-like neurotransmitters
 linked to pain control and to pleasure
Agonist vs Antagonist
Agonists - excite / mimic
Antagonists - inhibit / block
Neural
Communication
Neurotransmitter
molecule
Receptor site on
receiving neuron
Receiving cell
membrane
Agonist mimics
neurotransmitter
Antagonist
blocks
neurotransmitter
Reuptake
Reuptake - neurotransmitters that don’t
get absorbed by the receiving neuron go
back to the sending neuron
Neural
Communication
Neural
Communication
Serotonin Pathways
Dopamine Pathways
3 kinds of neurons
1. Sensory Neurons
 neurons that carry incoming information from the
sense receptors to the central nervous system
2. Interneurons
 CNS neurons that internally communicate and
intervene between the sensory inputs and motor
outputs
3. Motor Neurons
 carry outgoing information from the CNS to muscles
and glands
The Nervous System
Nervous System
 the body’s speedy, electrochemical
communication system
The Nervous System
Nerves
 neural “cables” containing many axons
 part of the peripheral nervous system
 connect the central nervous system with
muscles, glands, and sense organs
The Nervous System
Nervous
system
Central
(brain and
spinal cord)
Peripheral
Autonomic (controls
self-regulated action of
internal organs and glands)
Skeletal (controls
voluntary movements of
skeletal muscles)
Sympathetic
(arousing)
Parasympathetic
(calming)
2 parts of nervous system
Central Nervous System (CNS)
 the brain and spinal cord
Peripheral Nervous System (PNS)
 the sensory and motor neurons that connect
the central nervous system (CNS) to the rest
of the body
PNS
Skeletal or Somatic Nervous System
 the division of the peripheral nervous system
that controls the body’s skeletal muscles
PNS
Autonomic Nervous System (think automatic)
the part of the peripheral nervous system that controls
the glands and the muscles of the internal organs
(such as the heart)
a. Sympathetic Nervous System
 division that arouses the body, mobilizing its energy in
stressful situations
b. Parasympathetic Nervous System
 division that calms the body, conserving its energy
The Nervous System
The Nervous System
The Nervous System
 Reflex
 a simple, automatic, inborn response to a sensory stimulus
Brain
Sensory neuron
(incoming information)
Muscle
Skin
receptors
Motor neuron
(outgoing
information)
Interneuron
Spinal cord
Networks
Neurons in the brain
connect with one
another to form networks
Inputs
The brain learns by modifying
certain connections in
response to feedback
Neural Networks
 interconnected neural
cells
 with experience,
networks can learn, as
feedback strengthens
or inhibits connections
Outputs
that produce certain
results
 computer simulations
of neural networks
show analogous
learning
The Endocrine
System
 Endocrine System
 the body’s “slow”
chemical
communication
system
 a set of glands
that secrete
hormones into the
bloodstream
Endrocrine system
Hormones
 Slow & long lasting chemical messengers that
travel through the blood
Endocrine System
Pituitary Gland (the master gland)
 under the influence of the hypothalamus, the
pituitary regulates growth and controls other
endocrine glands
Endrocrine system
Adrenal [ah-DREEN-el] Glands
 a pair of endocrine glands just above the
kidneys
 secrete the hormones epinephrine
(adrenaline) and norepinephrine
(noradrenaline), which help to arouse the
body in times of stress