Chapter 3

What is another name for Neuron?

Nerve impulse in the form of electrochemical impulse runs through our entire body and communicate with each other (glands, muscles)

Regulates our internal functions

Learn new behavior or information - N.S.

Registers experience and changes to accommodate its storage

nerve cells

Why do you think the transparency show the anatomy of two neurons instead of one?

Because the function of the neurons is to communicate with one another.

TRANSMITS IN ONE DIRECTION

Chapter 3

EACH NEURON HAS: (pg. 54)

CELL BODY – produces energy that fuels cell activity

AXON – Carries messages away from the cell body

Axon has MYELIN - white fatty substance insulates and protects axon

MYELIN SHEATH - protects the axon and helps speed up the transmission of the message

DENDRITES - receives information from other neurons and pass information through the cell body

Leafy fibers branching out – contain neurotransmitters

AXON TERMINALS - pass messages from one neuron to the dendrites of the next neuron.

Neurotransmitters are chemicals stored in sacs in the axon terminals. When released chemicals cross the synapse to reach the

next neuron.

SYNAPTIC GAP - space between axon terminal and membrane of the postsynaptic cell (dendrite)

SYNAPSE - the space between 2 cells

that separates the axon terminals of sending neuron from the dendrites of its receiving neuron.New synapse can develop between neurons not previously connected when learn something new

Chapter 3NEURON IMPULSE TRAVELS ONLY IN ONE DIRECTION and takes a fraction of a second.

Pain is transmitted through SENSORY NEURONS which carry information received by senses to CNS

MOTOR NEURONS - carry information from CNS to muscles / glands

INTER NEURONS - specialized nerve cells within the brain and spinal cord that communicate internally and intervene between sensory inputs and motor inputs

Chapter 3NEUROTRANSMITTERS

Neuron releases only ONE type of neuron transmitter.

Each type of neurotransmitter has a specific structure and fits into a receptor site on the next neuron like a key fits a lock.

1. ACETYLCHOLINE

involves in the control of MUSCLES as well as AROUSAL, MEMORY, MOTIVATION (motor neurons - spinal cord stimulates muscles)

Patients who have low levels of acetylcholine may help Alzheimer disease if use a chemical stimulate enhances memory

Patients who have high levels lead to spasms and tremors

2. DOPAMINE

involved in MOTOR BEHAVIOR, LEARNING, REINFORCEMENT, maintain FOCUS and ATTENTION

deficiency - plays role in Parkinson’s (tremor, uncoordination)

excess - contribute to PD - schizophrenia

Chapter 3NEUROTRANSMITTERS

3. NORADRENALINE

involved in preparing the BODY FOR ACTION, CONTROL, ALERTNESS

4.**EPINEPHRINE (ADRENALINE)

prepare body fight/flight

**Hormone and/or neurotransmitter

5. NOREPINEPHRINE

brings body back to slow level, calm tranquilizes body after stress

6. ENDORPHINS

morphine; dulls pain; addictive pain suppressors brain response to pain

7. SUBSTANCE P - pain

8. SEROTONIN

involved in EMOTIONAL AROUSAL & SLEEP, EATING DISORDERS, MOOD

low levels - Depression, OCD

(Prozac raise serotonin level to brain)

Chapter 3CENTRAL NERVOUS SYSTEM

Made up of spinal cord and brain

FUNCTIONS OF THE SPINAL CORD

Spinal cord transmits messages between the brain and the muscle and glands of the body and is involved in reflex action.

WHAT IS THE SPINAL REFLEX ACTION? - simple automatic response to something.

ex. touching a hot stove; removal of hand is a spinal reflex by motor neuron

pain does not cause the reflex - a person may register pain in head but pain not felt until after the hand has been removed.

Ex. Blinking your eyes when lights are turned on in dark room because pupil automatically contracts when exposed to bright light;

Ex. knee jerk - lower leg swings.

Spinal reflex action DOES NOT receive its triggering message from the brain.

Message goes from the sensory nerve to the spinal cord where special cells send a message to appropriate motor neurons which stimulate the muscles to take action.

Chapter 3PERIPHERAL NERVOUS SYSTEM

Lies outside the central nervous system and is responsible for transmitting messages between central nervous system and all parts of the body.3 MAIN DIVISION OF peripheral nervous system:1.SOMATIC Nervous System • Transmits sensory messages to the central nervous system• Activated by touch, pain , changes in temperature, changes in

body position• Enables us to experience sensations of hot/cold and feel

pain/pressure• Also sends message to muscles and glands and helps maintain

posture and balance.

2. AUTONOMIC Nervous System• occurring involuntarily or automatic• regulates the body’s vital functions: Heartbeat, Breathing,

Digestion, and Blood Pressure, tear production

Psychologists are interested in this Nervous System because OBSERVING RESPONSE when a person experiences something STRESSFUL in the environment.

Chapter 3PERIPHERAL NERVOUS SYSTEM

2 DIVISIONS of AUTONOMIC NERVOUS SYSTEM:

1. SYMPATHETIC Nervous System Activated when a person is going into an action,

perhaps because of some stressful event. Prepares body either to confront the situation OR

run away = FIGHT or FLIGHT response

Ex. Attack by a dog Prepares body by suppressing digestion, increasing

heart & respiration rates, elevates blood pressure

Ex. POP QUIZ Sympathetic Nervous System is overly active in people

who are anxious, including people with anxiety disorders. Over activity in SNS leads to high blood pressure, stroke, or heart problems

Chapter 3PERIPHERAL NERVOUS SYSTEM

AUTONOMIC NERVOUS SYSTEM

2. PARASYMPATHETIC Nervous System Restores the body’s reserves of energy after an action

has occurred. Heart rate and blood pressure are normalized Breathing slowed, digestion returns to normal

REMEMBER: Sympathetic starts with S = STRESS

Parasympathetic starts with P = PEACE

PERIPHERAL NERVOUS SYSTEM

3RD DIVISION

3. ENTERIC Nervous System Meshwork of nerve fibers that innervate the viscera

(gastrointestinal tract, pancreas, and gallbladder)

Chapter 3Brain functions effectively because intricate system of support and protection receives from other parts of body.

Brain supported by nutrients and oxygen carried by blood vessels

PROTECTED:

By bones of the skull

3 layers of membranes (meninges) (meningeez)

Fluids surrounds brain acts as a SHOCK ABSORBER

LOCALIZATION OF FUNCTION - different parts of brain carry out different functions

LATERALIZATION - some functions are carried out exclusively on one side of the brain, even for functions that take place on both sides of brain. Right/Left sides usually take care of different aspects of same functions.

Chapter 3VITAL FUNCTIONS

HINDBRAIN

heart rate

blood pressure

respiration

balance/coordination

MIDBRAIN

Vision and hearing

FOREBRAIN

Complex function: thought & emotion

Chapter 3MAIN STRUCTURE

HINDBRAIN - Basic body activities. Connects spinal cord with rest of body.

Medulla - directly connects the spinal cord with brain and helps regulate HEART RATE, BLOOD PRESSURE and BREATHING

Cerebellum - next to the medulla behind the brain stem (“little brain”); controlling balance & coordination, posture and maintaining equilibrium; allows us to walk and run

without tripping

Pons - just above the medulla; Regulates BODY MOVEMENT (facial expression), ATTENTION, SLEEP, ALERTNESS, EATING

(Produces chemicals help maintain sleep wake cycle)

Chapter 3Reticular Activating System (RAS) -

network of neurons extending from the medulla to forebrain

(acts as a filter)

Allows sensory information to enter brain

i.e. sleep & arousal

ex. AIR TRAFFIC CONTROL OF BRAIN

regulates the flow of traffic

ex. Teacher calls your name your RAS stimulates the higher brain centers that allows you to become alert.

When asleep RAS restricts most environmental stimuli from entering your brain.

Chapter 3MIDBRAIN - important for hearing and sight; one place in brain where pain is registered

Connects HINDBRAIN and FOREBRAIN

Midbrain appears to function mainly as a relay station for messages coming into the brain.

It also contains structures that play a role in seeing, hearing, and movement.

Reticular Activating System - network of neurons extending from the medulla to forebrain; allows relevant sensory information such as AROUSAL or SLEEP to enter the brain. (air traffic control of the brain - regulates the flow of traffic); controls overall level of activity of central nervous system including WAKEFULNESS and SLEEPEx. teacher calls your name - RAS stimulates higher brain centers that allow you to become alert. OR while sleeping your reticular formation restricts most environmental stimuli from entering your brain.

Chapter 3FOREBRAIN

Biggest and most complex part

It not only influences many of the basic life-support functions controlled by the midbrain and hindbrain but is also responsible for such higher level behaviors as thinking and speaking.

Major structures of the forebrain:

Thalamus • major sensory relay center to cerebral cortex • influences mood and movement. • Includes visual, auditory, touch stimuli. • Messages from these sense organs are channeled into

the thalamus and from there are carried into specific parts of the forebrain for interpretation and action.

Chapter 3Hypothalamus (Size of pea) maintains stable internal

environmental state involved in the motivation of such behaviors as:

eating drinking, sexual drive, sleeping, and regulating body temperature, storage of nutrients.

It also influences the pituitary gland which regulates biochemical reactions in the body and the part of the peripheral nervous system that regulates the internal body organs. pg.60

Chapter 3Limbic System - autonomic response to SMELL, EMOTION, MOOD & other functions like sex, aggression, fear , pressure, pain.

4 important parts:

hypothalamus, thalamus, hippocampus, amygdala The hypothalamus regulates motivation and

emotion. The thalamus primarily relays sensory information to

the cerebrum, the part of the brain that allows humans to think and store information.

The hippocampus is involved in memory processing and learning. (Alzheimer’s disease patients often have low levels of acetylcholine in the hippocampus.) People with severe damage to this area can still remember, names, faces, events, before incident; can’t remember anything new.

The amygdala is involved in anger and aggression.

Automatic response to smell, emotion, mood, and other such functions: sex, aggression, fear, pressure and pain.

Chapter 3 Basal Ganglia (base of forebrain) lie to the side of the thalamus and are important in

voluntary motor responses (movement). The neuromuscular disorder Parkinson’s disease is

associated with a breakdown of the neurotransmitter dopamine in the basal ganglia.

If part of the limbic system is damaged people can recall old memories but don’t create new memories. May make you more passive/aggressive.

Chapter 3

Cerebrum is the largest part of the forebrain; consists of two distinct structures called HEMISPHERES;

Hemispheres are connected by the corpus callosum= bundle of neurons that keeps each hemisphere informed about what is happening in the other.

Left Hemisphere controls the right side of the body and

Right hemisphere controls the left side.

Left Hemisphere - logical, analytical and verbal - reading, language, and understanding speech

Right Hemisphere - process nonverbal info and concerned with emotion, imagination, and artistic information.

Most people are left dominant

Chapter 3

Paul Broca - BROCA’s AREA

located in Frontal lobe

essential ability to talk (produces speech sounds)

important for talking

If Broca’s area damaged:

APHASIA = (speechlessness) tends to expressive; language difficulty lies predominantly in sequencing and producing language (talking)

Results from patients who suffered left hemisphere strokes and result brain damage. Produce language problems = APHASIA

Chapter 3

Karl Wernicke later modified - Wernicke’s AREA

toward back of temporal lobe

processing and understanding what others saying

important to listening

If Wernicke’s area damaged:

APHASIA = tends to be RECEPTIVE; difficulty understanding language

Chapter 3WHAT IS THE RELATIONSHIP BETWEEN THE CEREBRAL CORTEX AND THE CEREBRUM?

Cerebral Cortex - is outer layer of the cerebrum (wrinkle ridges) ; controls overall level of activity of CNS

Part of the brain used for THINKING - where messages from our SENSE ORGANS are interpreted and stored and where decisions about behavior are made.

Has distinct sections/lobes that control different activities.

(thought, voluntary movement, language, reasoning, perception)

BRAIN STEM –

area between thalamus and spinal cord

structure within brain stem includes medulla, pons, RAS

Functions: breathing, heart rate, blood pressure

Chapter 3LOBES – Frontal, Occipital, Temporal, Parietal

Vision - Occipital - allow you to interpret what you see in the environment

Hearing - Temporal - when you hear your teacher talking

Somatosensory- Parietal - temperature, touch, pain

Movement/memory - Frontal - when you remember past events or giving an answer to a question

Left frontal more active than right frontal - tend to be more cheerful, sociable, self-confident

Right frontal more active than left frontal - more stressed, frightened, upset by unpleasant things more suspicious and depressed

Chapter 3

METHODS OF STUDYING THE BRAIN

EEG - Electroencephalography - records general wave patterns of electrical activity

CAT - Computerized Axial Tomography - x-rays reveal brain abnormalities; creates cross sectional pictures of brain only shows density of tissue of how much radiation absorbed [contrast]

PET - Positron Emission Tomography - injects with radioactive glucose; examines brain activity

MRI - Magnetic Resonance Imaging -use radio waves and magnetic fields to study chemical activity of brain cells.

Chapter 3ENDOCRINE SYSTEM

Consists of glands that secrete substances called HORMONES into the BLOODSTREAM

Hormones stimulate growth and many kinds of reactions - activity levels and moods

Hormones affect behavior & emotional reactions

Hormones have specific receptor sites.

Hormones produced by several different glands.

Glands include: PITUITARY GLAND = MASTER GLAND (lies under the hypothalamus)

Stimulated by Hypothalamus - responsible for secretion of various hormones affect various behaviors

a. Growth hormone - regulates growth of muscle, bone, glands

b. Females to pregnancy and Production of milk

THYROID

ADRENAL

TESTES & OVARIES

Chapter 3THYROID GLAND

Produces THYROXIN

affects body’s metabolism and converts food to energy

ADRENAL GLAND

Located above kidneys

Outerlayer or cortex - secrete CORTICAL STEROIDS - increase resistance to stress and promote muscle development.

Also produces ADRENALINE & NORADRENALINE

These hormones arouse body enabling person to cope with stress

Adrenaline - can intensify emotions such as fear & anxiety, raise blood pressure

This hormone acts as a neurotransmitter as well

Chapter 3HEREDITY

Transmission of characteristics from Parents to offspring

plays key role in development of traits

shown to be one factor involved in psych disorders (PD): anxiety, depression, schizophrenia, bipolar disorder, alcoholism

KINSHIP STUDIES

Common way to sort out roles that heredity and environment play determining a trait

Kinship refers to degree how people related.

Identical twins share 100% of genes

Psych use info to determine how much a trait is influenced by genetics and how much by environment

2 Types of KINSHIP STUDIES

1. Twin

2. Adoptees