Biological Psychology

Key Point for this Unit:

Everything psychological is

simultaneously biological!!

Dendrites – receive messages from other cells

and conduct impulses toward the cell body

DendritesNEURON

Cell Body – the cell’s life-support center

Dendrites

Cell Body

NEURON

Axon – the extension of a neuron through which messages

are sent to other neurons or to muscles or glands

Dendrites

Cell Body

Axon

NEURON

Myelin Sheath – a layer of fatty cells covering

the axon, helps speed neural impulses

Dendrites

Cell Body

Axon

Myelin Sheath

NEURON

Terminal branches of axon – form junctions

with other cells

Dendrites

Cell Body

Axon

Myelin Sheath

Terminal branches of axonNEURON

Biological Psychology

It is all about the body!!!!Concerned with the links between biology and

behavior (also called Neuroscience)

The Nervous System

It starts with a NEURON: an individual nerve cell; the basic building block of the nervous system

How does a Neuron fire?• Resting Potential: slightly

negative charge.

• Reach the threshold when enough neurotransmitters reach dendrites.

• Threshold: level of stimulation required to trigger a neural impulse; excitatory signals minus inhibitory signals must equal a minimum intensity

• Go into Action Potential; a neural impulse (brief electrical charge) that travels down an axon.

• All-or-none response.

TYPES OF NEUROTRANSMITTERS

Chemical messengers that that traverse the synaptic

gap between neurons

REVIEW… remember

agonists and antagonists???

Agonist – mimic neurotransmitters

**Example: Morphine mimics endorphins

Antagonist – block neurotransmitters

**Example: Poison blocks muscle

movement

Did you know? Botox is an antagonist that paralyzes facial muscles!

Acetylcholine (ACH)

• Involved with voluntary muscle movement, learning and memory

• Lack of ACH has been linked to Alzheimer’s disease.

Dopamine

• Deals with motor movement and alertness.

• Lack of dopamine has been linked to Parkinson’s disease.

• Too much has been linked to schizophrenia.

Serotonin

• Involved in mood control.

• Lack of serotonin has been linked to clinical depression.

Endorphins

• Involved in pain control.

• Many of our most addictive drugs deal with endorphins.

“Runner’s High”

occurs when your

brain signals the

release of

endorphins to

reduce pain!

Did you know? The word

“endorphin” literally means

“morphine within”!

The Nervous System

The Nervous System - body’s speedy,

electrochemical communication network consisting

of nerve cells

Central Nervous System (CNS)

•The Brain and spinal cord

• Neural networks –

interconnected neural

cells; more

connections made as

experience gained

Peripheral Nervous System (PNS)

• All nerves that are not encased in bone.

• Sensory and motor

neurons that connect

the CNS to the rest of

the body

• Is divided into two categories….somaticand autonomic.

Somatic Nervous System

• Controls voluntary muscle movement.

• Uses motor neurons.

Autonomic Nervous System• Controls the

automatic functions of the body.

• Divided into two categories…the sympathetic and the parasympathetic

Sympathetic Nervous System

• Arouses the body

• Fight or Flight Response.

• Automatically accelerates heart rate and breathing, dilates pupils

Parasympathetic Nervous System

• Calms the body

• Automatically slows the body down after a stressful event.

• Heart rate and breathing slow down, pupils constrict

Sympathetic and

Parasympathetic

Types of Neurons

• Sensory Neurons –sends receptors to CNS

• Interneurons – internal communication neurons

• Motor Neurons – CNS to muscle and glands

Reflexes• Normally, sensory

neurons take info up through spine to the brain.

• With reflexes though, some reactions occur when sensory neurons reach just the spinal cord.

• Automatic response to sensory stimulus; interneurons react to sensory neurons w/o going to brain