Neurons
Nervous System
Endocrine System
The Brain
BIOLOGICAL PSYCHOLOGY
Biological Psychology
 A branch of psychology concerned with the
links between biology and behavior/mental
processes
 We are all biopsychological systems.
 Systems are composed of subsystems and then
even smaller systems.
 Separate but interconnected
NEURONS
Neuron
 Nerve cell
 Building block of the nervous system
 Found all over the body




Brain
Legs
Eyes
Anywhere there are nerves
Dendrites
 The bushy extensions of a neuron that receive
messages
Soma
 Cell body
 Contains nucleus – DNA, genetics, etc
Axon
 The extension of a neuron through which
electrical messages pass
A
X
O
N
Myelin Sheath
Multiple sclerosis – a disease in
which the myelin sheath
degenerates resulting in a
slowing of all communication to
muscles and the eventual loss
of muscle control
 Layer of fatty tissue on the axon that…
 Protects axon
 Speeds neural impulse (the message)
DENDRITES LISTEN…
… AXONS SPEAK
Axon Terminals
 Branches at the end of an axon that send
messages to the dendrites of another neuron.
 End in axon terminal buttons
Synapse
 The junction between neurons.
 Synaptic gap, synaptic cleft, etc
 Less than a millionth of an inch wide
Action Potential
 A neural impulse in the form of a brief electrical
charge that travels down the axon
 A neuron fires an impulse when it receives a signal
from sense receptors or by the neurotransmitters from
another neuron.
Direction of ACTION POTENTIAL
Threshold
 The level of stimulation required to trigger a
neural impulse.
 All-or-nothing
It either fires…
… or it doesn’t.
I need 5 volunteers…
 Stand next to each other facing the class.
 Hold hands.
 The person farthest to the RIGHT wants to
send a message to the person farthest to the
LEFT (without actually talking)– how will we
do this?
 When you feel the squeeze of your right
hand, squeeze the right hand of the person
beside you.
 Right hand and arm
 DENDRITES
 Chest
 SOMA
 Left arm
 AXON
 Left hand
 AXON TERMINALS
Neurotransmitters
 Chemical messengers that travel across the
synaptic gap between neurons
 How neurons talk to each other
1. Action potential reaches the axon’s terminal
buttons.
2. Buttons release neurotransmitters (chemicals)
3. Travel across the synapse
4. Bind/connect to receptor sites on the next
neuron’s dendrites
Neurotransmitters
 Lock-and-key relationship between the
neurotransmitter and the receptor site.
 When the neuron receives neurotransmitters, it
will fire/not fire
Dopamine
Serotonin
Neurotransmitters
 Many types of neurotransmitters that affect
us differently and are found in different parts
of the brain
Neurotransmitter
Acetylcholine
(ACh)
Dopamine
Serotonin
Norepinephrine
Function
Examples of Malfunction
Enables muscle
action, learning, and
memory.
Influences
movement, learning,
attention, and
emotion
(reward/pleasure)
Affects mood,
hunger, sleep, and
arousal
Helps control
alertness and arousal
Alzheimer’s disease – ACh producing neurons
deteriorate.
Excess dopamine receptor activity is linked to
schizophrenia.
Too little dopamine in the brain can lead to
Parkinson’s disease (tremors and decreased
mobility).
Too little serotonin is linked to depression.
(Anti-depression drugs raise serotonin levels)
Too little can depress mood
Endorphins
“Happy people don’t kill
their husbands!”
 Natural, opiate-like
neurotransmitters linked
to pain control and
pleasure
 Inhibit (block) pain
 Ex: Runner’s high
 One of the top suggested
remedies for depression is
exercise  naturally
produce chemicals that will
stimulate pleasure and
happiness
INTERACTIVE NEURON
IMPORTANT
 Communication WITHIN a neuron…
 ELECTRICAL – action potential
 Communication BETWEEN neurons…
 CHEMICAL - neurotransmitters
NERVOUS SYSTEM
Nervous System
 The body’s speedy electrochemical
communication network consisting of all
nerve cells
 Building blocks are neurons
 2 parts
Nervous
System
PNS
 Peripheral Nervous System (PNS)
 Central Nervous System (CNS)
CNS
Central Nervous System (CNS)
 The brain and the spinal cord
Peripheral Nervous System
(PNS)
 the sensory and motor neurons that connect
the CNS to the rest of the body.
 Everything but the brain and spinal cord
Nerves
 In the PNS
 Neural cables
 Connect the CNS to
muscles, glands, and
sense organs
 Ex: optic nerve connects
the eye to the brain
(sense organ – PNS to
the brain – CNS)
Nervous System Neurons
 Information travels through the nervous system in 3 type of
neurons.
1.
Sensory neurons – carry incoming information from the
senses to the CNS
2.
Interneurons – CNS neurons that internally communicate
between sensory inputs and motor outputs
3.
Motor Neurons – carry out going information from the
CNS to muscles and glands
Sensory feel… Inter interpret… Motor move
What happens if the Spinal Cord is
severed?
 Paralysis because
sensory messages
cannot reach brain and
motor messages cannot
leave brain
 Paraplegia - patient can
still move two limbs
 Quadriplegia - all four
limbs are paralyzed
 Most famous case in
recent times was the
actor Christopher Reeves
( d. 2004)
Somatic and Autonomic
Nervous Systems
 Somatic – controls the body’s skeletal muscles
 Running, dancing, etc
 Autonomic – controls the glands and the
muscles of internal organs
 Heartbeat, digestion, sweating
Somatic – Skeletal
PNS
Autonomic - Automatic
Autonomic
Somatic
Sympathetic and Parasympathetic
Nervous Systems
 Sympathetic – arouses the
body
 Parasympathetic – calms
the body
 Parasympathetic -
paralyzing
Autonomic
Sympathetic
Parasympathetic
Let’s Put It All Together!
Nervous System
Peripheral
Central
(PNS)
(CNS)
Autonomic
Sympathetic
Parasympathetic
Somatic
THE ENDOCRINE SYSTEM
Endocrine System
 The body’s “slow” chemical communication
system made of glands that secrete hormones
into the bloodstream
 Hormones – chemical messengers manufactured
by glands
 Travel slowly in the bloodstream
 When hormones act on the brain, they can trigger
interest in sex, food, aggression, “flight or fight”
 Gland - An organ in the body that secretes a
substance for use somewhere else in the body
Hormones vs
Neurotransmitters
Hormones
Neurotransmitters
 chemical messengers for
 Chemical messengers in
the endocrine system
 Travel in the blood stream
the brain
 Travel in the brain in the
synapse between neurons
The endocrine system tries to keep a balance in the body while we
respond to feelings of stress, anger, fear, and exertion.
Adrenal Gland
 Pair of glands above the
kidneys that release
adrenaline and
noradrenalin which helps to
arouse the body in times of
stress
 Increase heart rate, blood
pressure, and blood sugar for
energy
 Hormones can last in the
bloodstream after the
triggering event.
Daughter Lifts Car Off Dad
Pituitary Gland
 Small pea-shaped gland in
the limbic system of the
brain
 Most influential gland –
“master” gland
 Regulates growth (growth
hormone) and controls
other glands
 Controlled by the
hypothalamus
Gigantism – caused
by a tumor on the
pituitary gland
THE BRAIN
The Brain
 Brain size ≠ Intelligence
 Brain structure and complexity = Intelligence
Brainstem
 Begins where the
spinal cord enters the
brain, responsible for
basic survival
functions
 severe brainstem
injuries = death
Brainstem = area in the red box
Medulla
 At the base of the brain stem
 Controls heartbeat and breathing
Pons
 Above the medulla
 Helps coordinate movement by relaying
information to the cerebellum
Thalamus
 On top of the brainstem
 The brains sensory switchboard, directs sensory
input to the correct areas in the brain
Reticular Formation
 A nerve network in the brainstem
 Helps control arousal and sleep
 When stimulated, it arouses your focus.
 If severed, you could enter a coma.
 Narcolepsy = malfunction of reticular formation
Cerebellum
 Attached at the rear of the brainstem
 “little brain”
 Processes sensory input and coordinates
movement and balance
Limbic System
 In the core of the brain above the brainstem
 Associated with emotion and smell
Hippocampus
 In the temporal lobe
 Processes/stores memories
Amygdala
 Bean sized structures above the hippocampus
 Helps in the storage of emotional
events/memories
 Influences fear and aggression
Hypothalamus
 Below the thalamus
 Directs maintenance
activities (eating,
drinking, body temp.)
 Controls the pituitary
gland
 Interprets emotions
and tells the pituitary
gland which glands
need to secrete
hormones
Cerebral Cortex
 Interconnected cells that cover the
hemispheres of the brain
 Like bark on a tree
 Divided into 4 lobes - FPOT
Frontal Lobe
 Behind the forehead
 Speaking, muscle movements, making
plans/judgments, personality
 Contains the motor cortex that sends
outgoing movements.
Parietal Lobe
 At the top of the head.
 Contains the sensory cortex that receives
incoming sensory information
Occipital Lobe
 At the rear of the brain
 Contains the visual cortex that receives and
interprets information from the opposite
visual field.
Temporal Lobe
 On either side of the head between the ears.
 Contains the auditory cortex that receives
auditory input, each of which receive
information from the opposite ear.
Association Areas
 Wernicke’s area
 Areas in the cerebral
cortex that are not the
sensory, motor, visual,
or auditory cortexes.
 Broca’s area
 In the left hemisphere in
the frontal lobe
 Controls language
expression and speech
 In the left hemisphere in
the temporal lobe
 Controls language
reception and
comprehension
Split Brain
 When the two brain
hemispheres are not
attached by the corpus
callosum
 Corpus callosum
 Band of neural fibers
that connects the two
brain hemispheres
together and allows
them to communicate
 Possible to survive with
a split brain, but may
have difficultly
integrating vision,
speech, and motor skills.
Studying the Brain
 Lesion – damage to brain tissue
 Allows us to study the functions of the brain in
circumstances that would be unethical to replicate
 Ex: Phineas Gage
 Gabrielle Giffords’ brain after attempted assassination
 still has difficulty speaking and walking, and her right arm is
paralyzed. She continues to undergo speech and physical
therapy.
Electroencephalogram (EEG)
 An amplified recording of the waves of
electrical activity that sweep across the
brain’s surface; measured by electrodes
placed on the scalp
Positron emission tomography
(PET) Scan
 A visual display of brain activity that detects
where a radioactive form of glucose goes while
the brain performs a given task.
Magnetic Resonance Imaging
(MRI)
 A technique that uses
magnetic fields and
radio waves to
produce computergenerated images
that distinguish
among different types
of soft tissue, allowing
us to see structures
within the brain.
Functional MRI (fMRI)  A technique for revealing blood flow and
therefore, brain activity by comparing
successive MRI scans