AP Psychology
2.1 Nervous System / Endocrine
System and Behavior
I. Neural Communication
Neuron
1. Building block of NS / uses chemical and
electrical signals
2. Components
A. Cell body / soma – contains nucleus; receives
message from dendrites
B. Dendrites – receive and communicate signals
from neuron to cell body
C. Axon – conduit that communicate signal down
the neuron away from cell body
I. Neural Communication
2. Components cont.
D. Myelin Sheath – insulation around Schwann cells
that stop leaking of signals (formed by glial cells),
increases velocity of transmission
** MS (multiple sclerosis) is caused by
deterioration of myelin sheath which results in loss
of controlling muscle movement
I. Neural Communication
E. Schwann Cell – chain of cells around axon
F. Nodes of Ranvier – space between Schwann
Cells
G. Axon Terminals – contain synaptic vesciles
that contain neurotransmitters
I. Neural Communication
Action Potential
1. Brief electrical impulse / info transmitted
2. All neurons have charge
3. Resting Potential – sodium and potassium channels closed
-70mV
4. Depolarization – sodium channels open and flood inside /
potassium channels closed
5. Action Potential – if depolarization reached threshold, an
action potential will be created and it will fire (all-or-none
law)
6. Saltatory conduction – chemical signal down the neuron
from one node to the next
7. Repolarization and hyperpolarization – decrease in
potential because potassium leaves cell, sodium channels
close (goes from positive to negative potential)
I. Neural Communication
Passage of a nerve to a reflex action
1. Synapse – gap between nerve cells or nerve
cells and muscles
2. Synaptic vesicle – small membrane that
releases neurotransmitters into the synapse
I. Neural Communication
Neurotransmitters
1. Chemical messengers manufactured by neuron
2. Hundreds
3. Endorphins – best-known / reduce pain or produce
feelings of pleasure (“runner’s high” – boosted mood)
4. Play a role in eating habits and body weight (when
levels of norepinephrine, dopamine, serotonin, leptin
and othes are low, hunger and or eating
results…when levels are high, satiety (fullness) results
5. Play a role in influencing or causing eating disorders
Neurotransmitters – AP MC ?’s
Neurotransmitter / function
1. *Dopamine – movement /
thought process
2. Serotonin – emotional
state / sleep
3. Norepinephrine – physical
arousal / learning, memory
4. *Acetylcholine – learning,
memory, muscle contact
5. GABA – inhibition of brain
activity
6. Endorphins – natural pain
killers
Disease associated with
1. *Parkinson’s (too little) /
*Schizophrenia (too much)
2. Depression, Anxiety, OCD
3. High blood pressure,
Anxiety
4. *Alzheimer’s, Muscular
disorders
5. Anxiety
6. Opiate addiction
(painkillers)
I. Neural Communication
Sensory (Afferent) - respond to touch, sound, light
and numerous other stimuli affecting cells of the
sensory organs that then send signals to the spinal
cord and brain
Motor (Efferent) - receive signals from the brain and
spinal cord, cause muscle contractions, and affect
glands
Interneuron - connect neurons to other neurons
within the same region of the brain or spinal cord.
I. Neural Communication
Drug Effects on Nervous System
1. Psychoactive drugs have inhibitory or excitatory effects
2. Agonists are drugs that mimic neurotransmitters
3. Antagonists are drugs that inhibit the effect of a
neurotransmitter
4. Prozac is an antidepressant that works as an agonist of
serotonin
5. Many psychoactive drugs have side effects because the
drug of choice may work on different neural pathways
6. Example – Prozac treats depression, but can alter sleep,
eating patterns and other thought processes
II. Nervous System
Central NS (CNS)
1. Brain and spinal cord (command center of body)
2. Spinal cord deals with reflex or involuntary
actions
a. Injuries to result in paralysis of limbs / higher the
damage the more severe the injury
3. “knee-jerk” reflex – used by doctors for
neurological exam
4. Brain is required for voluntary movements
II. Nervous System
Peripheral NS (PNS)
1. Connects the CNS with the rest of the body through
nerves
2. Carries incoming messages to your brain (afferent)
and outgoing signals to muscles and glands (efferent)
3. Ex…as you cross a traffic-filled street, your PNS will
notice the auditory sounds of cars and the visual
patterns of oncoming traffic. Your brain assesses the
situation and tells your body that danger may be
lingering, so you cross the street with caution
II. Nervous System
Somatic NS of the PNS
1. Allows communication with the outside
world / consciously aware
2. Carries info to CNS and sends voluntary
signals to your muscles / sensations we are
aware of (pain, sound, light)
3. Ex…you smell food, your muscles are induced
to eat the food
II. Nervous System
Autonomic NS of the PNS
1. Carries info to the CNS and sends voluntary
signals to your muscles
2. Regulates digestion, respiration, sleep and
other vital functions
II. Nervous System
Divisions of the ANS
1. Sympathetic NS
a. responsible for arousing the body and mobilizing its
energy during times of stress
b. Increase respiratory and heart rates, dilation of
pupils
c. “Fight or flight” response allows you to attack or flee
2. Parasympathetic NS
a. Allows a person to return to a calm and collected
state after arousal
III. Endocrine System
1. System of hormones that carry messages
through different glands
2. Major glands and tissues
1. Hypothalamus – links the nervous and endocrine
systems / located in lower half of brain / also allows
humans to sense thirst and hunger
2. Pituitary Gland – “master gland” (regulates activity
of other glands) / under control of the hypothalamus
3. Thyroid Gland – located near the trachea
(metabolism)
4. Parathyroid Gland – located on the surface of thyroid
III. Endocrine System
5. Pancreas – located near kidneys / contain special
cells called Islets of Langerhans that secrete
hormones
6. Adrenal Glands – located on top of kidneys / in
an emergency they release hormones that
cause increase in heart rate, blood pressure,
sugar levels while reducing blood flow to
digestive system
7. Gonads – testes and ovaries
8. Pineal Gland – small peanut-shaped gland near
the center of the brain
III. Endocrine System
Gland
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Hormone
Action
Pituitary
Oxytocin
contraction of uterus; breast milk
Pituitary
Growth hormone
stimulates growth
Pituitary
Prolactin
stimulate milk production
Pituitary
Follicle Stimulating
stimulates sperm
Pituitary
Luteinizing
stimulates ovaries
Pituitary
Thyroid Stimulating
stimulates thyroid
Thyroid Triiodothyronine/thyroxine metabolism
Thyroid
Calcitonin
stimulates bone construction
Parathyroid Parathyroid
raises blood calcium
Pancreas
Insulin
lowers blood glucose
Pancreas
Glucagon
raise blood glucose
Adrenal Norepinephrine/epinephrine “fight-or-flight”, metabolism
Testes
Androgens
sperm formation/secondary male
Ovaries
Estrogens
stimulates uterine lining/secondary female
Ovaries
Progesterone
maintains pregnancy
Pineal
Melatonin
sleep-wake cycle/circadian rhythms
IV. Brain
Tools for brain research:
1. EEG (electroencephalogram)
– Electrical activity throughout the brain sweep in
waves
– records these wave patterns
– reveals areas that are most active during a
particular task or change in mental state
– Can trace abnormal brain waves caused by brain
malfunctions (ie...epilepsy)
IV. Brain
Tools for brain research:
2. PET Scan (Positron Emission Topography)
- Harmless radioactive glucose injected into
bloodstream
- Color-coded images
- Originally designed for abnormalities, now
used to identify areas active during ordinary
activities
IV. Brain
CT Scan (Computerized Tomography)
3. X-rays / least expensive
- Reveal effects of strokes, tumors and other
brain disorders
IV. Brain
4. MRI (Magnetic Resonance Imaging)
- Uses a high-frequency magnetic field to produce
detailed, high-resolution pictures
- Map brain structures and identify abnormalities
IV. Brain
Hindbrain
- Oldest part of the brain to develop in
evolutionary terms / controls autonomic
behaviors (respiration and heartbeat)
- Medulla – controls vital life functions
(breathing, circulation, swallowing)
- Pons – Latin for bridge / responsible for
sleeping, walking, dreaming
- Cerebellum – coordinating fine muscle
movement, maintaining posture, equilibrium
IV. Brain
Midbrain
- Integrates auditory and visual sensory
information and muscle movements
- Reticular Formation – network of nerve fibers
that run through the center of the midbrain
- Regulates attention, arousal, and sleep
- Without this you would not be alert or even
conscious
IV. Brain
Forebrain
- Largest and most complex region / center for
complex behaviors and mental processes
- Thalamus – brain’s relay station (receives input
from all senses – except smell – and directs info
to appropriate area)
- Injury to can cause blindness / deafness
- Associated with Schizophrenia
- Hypothalamus – located under thalamus (hypo –
Latin for below) size of peanut
- Brain’s “master control center” – regulates hunger
and thirst (satiety)
- Damage to can increase eating or produce feelings of
fullness
IV. Brain
Forebrain cont.
- Hippocampus – forming new memories of events
and info
- Amygdala – production and regulation of
emotions (aggression, fear, disgust)
- Limbic System – made of hippocampus, amygdala
and hypothalamus / plays a key role in the
experience of emotions
- Cerebral Cortex – cortex means bark / thin outer
covering (1/4”) of the forebrain
- gray, wrinkled (convolutions) / 30 billion neurons /
270 billion glial cells
- Two hemispheres – control opposite side of body
IV. Brain
Left Hemisphere
• Verbal / Analytical
• Positive emotions
• Muscles for speech
• Movements
• Spontaneity
• Memory for words and
numbers
• Understanding speech and
writing
Right Hemisphere
• Nonverbal (visual
recognition and music)
• Negative emotions
• Response to commands
• Memory for shapes
• Memory for music
• Understanding spatial
relationships
• Understanding images
IV. Brain
Corpus Callosum – bundle of nerve fibers that
connect the left and right hemisphere
- In rare cases, neurosurgeons prevent the
spread of severe epileptic seizures by cutting
(disrupts communication between hemispheres)
IV. Brain
Lobes of the Cerebral Cortex
- Frontal – abstract thought and emotional control
- Example – weighing the consequences of an
important decision
- Damage – may lose the ability to make and carry out
plans / change personality (emotions) – Phineas Gage
(“no longer Gage” / polite and caring to selfish and
profane)
- Motor Cortex - planning, control, and execution of
voluntary movements
- Broca’s Area (left frontal) – speech production
- Injury would have difficulty making the muscle movements
needed for speech
IV. Brain
Lobes of the Cerebral Cortex cont.
- Parietal – receive and interpret bodily sensations
such as pressure, temperature, touch, pain,
location of body parts
Sensory Cortex (Somatosensory) – main sensory
receptive area for the sense of touch
- Temporal – temples / process sensory info from
ears
Wernicke’s Area – language development
damage – difficultly comprehending spoken
requests for directions
IV. Brain
Lobes of the Cerebral Cortex cont.
- Occipital – vision and visual perception
- Damage to – blindness, even if the eyes are
undamaged