BIOLOGICAL PSYCHOLOGY

NeuronsNervous SystemEndocrine SystemThe Brain

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

Dendrite

s

Soma

Cell body Contains nucleus – DNA, genetics,

etc

Soma

Axon

The extension of a neuron through which electrical messages pass

AXON

Myelin Sheath

Layer of fatty tissue on the axon that… Protects axon Speeds neural impulse (the message)

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

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

Axon

Term

inal

s

Axon TerminalButtons

Synapse

The junction between neurons. Synaptic gap, synaptic cleft, etc Less than a millionth of an inch wide

Synapse

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 synapse4. 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

Neurotransmitters Many types of neurotransmitters that

affect us differently and are found in different parts of the brain

Neurotransmitter

Function Examples of Malfunction

Acetylcholine (ACh)

Enables muscle action, learning, and memory.

Alzheimer’s disease – ACh producing neurons deteriorate.

Dopamine Influences movement, learning, attention, and emotion (reward/pleasure)

Excess dopamine receptor activity is linked to schizophrenia.Too little dopamine in the brain can lead to Parkinson’s disease (tremors and decreased mobility).

Serotonin Affects mood, hunger, sleep, and arousal

Too little serotonin is linked to depression. (Anti-depression drugs raise serotonin levels)

Norepinephrine Helps control alertness and arousal

Too little can depress mood

DopamineSerotonin

Endorphins 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

“Happy people don’t kill their husbands!”

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 Peripheral Nervous System (PNS) Central Nervous System (CNS)

Nervous System

PNS 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

PNS

Autonomic Somatic

Somatic – Skeletal

Autonomic - Automatic

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(PNS)

SomaticAutonomic

ParasympatheticSympathetic

Central(CNS)

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 NeurotransmittersHormones Neurotransmitters

chemical messengers for the endocrine system

Travel in the blood stream

Chemical messengers in 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

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

Wernicke’s area 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 computer-generated 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