AP Psychology

2.1 Nervous System / Endocrine System and Behavior

I. Neural CommunicationNeuron1. 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 Communication2. 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 CommunicationE. Schwann Cell – chain of cells around axon

F. Nodes of Ranvier – space between Schwann CellsG. Axon Terminals – contain synaptic vesciles that contain neurotransmitters

I. Neural CommunicationAction Potential1. Brief electrical impulse / info transmitted2. All neurons have charge3. Resting Potential – sodium and potassium channels closed -70mV4. Depolarization – sodium channels open and flood inside /

potassium channels closed5. 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 next7. Repolarization and hyperpolarization – decrease in potential

because potassium leaves cell, sodium channels close (goes from positive to negative potential)

I. Neural CommunicationPassage of a nerve to a reflex action1. Synapse – gap between nerve cells or nerve

cells and muscles2. Synaptic vesicle – small membrane that

releases neurotransmitters into the synapse

I. Neural Communication

Neurotransmitters1. Chemical messengers manufactured by neuron2. Hundreds3. 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 ?’sNeurotransmitter / 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 with1. *Parkinson’s (too little) /

*Schizophrenia (too much)2. Depression, Anxiety, OCD

3. High blood pressure, Anxiety

4. *Alzheimer’s, Muscular disorders

5. Anxiety6. 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 CommunicationDrug Effects on Nervous System1. Psychoactive drugs have inhibitory or excitatory effects2. Agonists are drugs that mimic neurotransmitters3. Antagonists are drugs that inhibit the effect of a

neurotransmitter4. Prozac is an antidepressant that works as an agonist of

serotonin5. Many psychoactive drugs have side effects because the drug

of choice may work on different neural pathways6. 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

actionsa. Injuries to result in paralysis of limbs / higher the

damage the more severe the injury3. “knee-jerk” reflex – used by doctors for

neurological exam4. Brain is required for voluntary movements

II. Nervous System

Peripheral NS (PNS)1. Connects the CNS with the rest of the body through

nerves2. 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 PNS1. Allows communication with the outside

world / consciously aware2. 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 PNS1. Carries info to the CNS and sends voluntary

signals to your muscles2. Regulates digestion, respiration, sleep and

other vital functions

II. Nervous System

Divisions of the ANS1. Sympathetic NS

a. responsible for arousing the body and mobilizing its energy during times of stress

b. Increase respiratory and heart rates, dilation of pupilsc. “Fight or flight” response allows you to attack or flee

2. Parasympathetic NSa. Allows a person to return to a calm and collected state

after arousal

III. Endocrine System1. System of hormones that carry messages through

different glands2. 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 ovaries8. Pineal Gland – small peanut-shaped gland near the

center of the brain

Gland Hormone Action1. Pituitary Oxytocin contraction of uterus; breast milk2. Pituitary Growth hormone stimulates growth3. Pituitary Prolactin stimulate milk production4. Pituitary Follicle Stimulating stimulates sperm5. Pituitary Luteinizing stimulates ovaries6. Pituitary Thyroid Stimulating stimulates thyroid7. Thyroid Triiodothyronine/thyroxine metabolism8. Thyroid Calcitonin stimulates bone construction9. Parathyroid Parathyroid raises blood calcium10. Pancreas Insulin lowers blood glucose11. Pancreas Glucagon raise blood glucose12. Adrenal Norepinephrine/epinephrine “fight-or-flight”, metabolism13. Testes Androgens sperm formation/secondary male14. Ovaries Estrogens stimulates uterine lining/secondary female15. Ovaries Progesterone maintains pregnancy16. Pineal Melatonin sleep-wake cycle/circadian rhythms

III. Endocrine System

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. BrainCT Scan (Computerized Tomography)3. X-rays / least expensive- Reveal effects of strokes, tumors and other

brain disorders

IV. Brain4. MRI (Magnetic Resonance Imaging)- Uses a high-frequency magnetic field to produce

detailed, high-resolution pictures - Map brain structures and identify abnormalities

IV. BrainHindbrain- 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. BrainMidbrain- 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. BrainForebrain- 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. BrainForebrain 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. BrainCorpus 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. BrainLobes 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. BrainLobes 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 sensoryreceptive area for the sense of touch - Temporal – temples / process sensory info fromears

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