• The Nervous System

- Divisions of the nervous system

- Cells of the nervous system

- Neuron structure and function

• Intro to Psychological Health and Social

Connections (Ch 2, 3)

The Nervous System • CNS – brain & spinal cord

• PNS – connects CNS to other parts of the body

CNS: The Brain • Protected by the skull and three meninges

The brain is divided into forebrain,

midbrain, and hindbrain • Forebrain: “Central processor”, thinking, language,

motor function, thirst, hunger, temp. control

• Midbrain: Vision, hearing, motor control

• Hindbrain: Balance, coordination,

breathing, heart rate, digestion

CNS: The Spinal Cord

• Conducts signals between PNS and brain

• Control center for simple reflexes

• Protected by spine

spinal cord

vertebra

Components of PNS

• Somatic: Carries

signals to and from

skeletal muscles in

response to external

stimuli

• Autonomic: Regulates

internal environment by

controlling smooth and

cardiac muscle

Divisions of Autonomic System • Sympathetic: “Fight or Flight”

• Parasympathetic: “Rest and Digest”

Cells of the Nervous System

• Neurons: Transmit

messages

• Glia: Support and

protect neurons,

maintain ion balance

3 Basic Types of Neurons

• Sensory neurons –

collect and relay info

• Interneurons –

receive and process

info

• Motor neurons – relay

signals to muscles

and glands

Parts of a Neuron

dendrites input zone

cell body

trigger zone

conducting zone

axon axon endings

output zone

• Outer membrane of neuron regulates the

passage of ions into and out of the cell

Na+ K+

K+ Na+

outside

plasma membrane

inside

Resting Potential

• Neuron not transmitting signal (“at rest”)

• Cytoplasm inside neuron has slight negative charge as compared to fluid outside the cell

fluid outside cell

cytoplasm -

+

Action Potential • Signal received, spreads to trigger zone

• Sodium gates open, Na+ rushes in

• Cytoplasm becomes positive as compared to fluid outside (charges reverse)

gated sodium channel Na+

Na+ Na+

voltage reversed

• Action potential then travels down plasma

membrane away from trigger zone

K+ K+

K+

Na+

Na+ Na+

Sodium / Potassium Pump • Uses energy to restore the resting potential

• 3 Na+ pumped out for every 2 K+ pumped in

• Cytoplasm becomes negative again

Na+/K+ pump

Na+

Na+

Na+

K+

propagating action potential

Na+ Na+

How does an action potential move

from one neuron to another?

• Neurotransmitters

(chemical signals)

diffuse across a

synapse (gap)

Psychological Health & Social Connections

(Chapters 2 & 3)

The Maslow Pyramid

Fig 3.1, pg 42

Positive Psychology

• Idea that everyone, regardless of genes or fate, can achieve a happy, gratifying, meaningful life

What

determines

happiness?

How to gain and maintain happiness?