AP Psychology Module 10

The Nervous System

Neurons communicating with neurotransmitters all over the body make up the nervous system

Sensory Neurons (Afferent Neurons)

Input: From sensory organs to the brain and spinal cord

Motor Neurons (Efferent Neurons)

Output: From the brain and spinal cord, to the muscles and glands

Interneurons

Information processing between motor and sensory neurons (i.e. increased complexity)

Only found in the brain and spinal cord

Middleman between motor and sensory neurons

Central Nervous System

The body’s decision maker

Includes: Brain and Spinal Cord

Takes in sensory information, process the information, and send out motor signals to body parts

Peripheral Nervous System

Gathers the information for the CNS (sensory neurons)

Also sends out the processed information to the rest of the body (motor neurons)

Nerves

bundles of axons that connect the CNS to sensory organs, muscles, and glands

Somatic Nervous System

Enables voluntary control of our muscles and keeping balance

Autonomic Nervous System

Influences our glands and internal organ muscles

Influences functions like hormone release, heartbeat, and digestion

MOSTLY operates unconsciously/automatically

Sympathetic

The sympathetic nervous system is about alertness and arousal

“fight or flight” response

Remember: glands and internal organ muscles

Think of the heart, stomach, and bladder

Parasympathetic

The parasympathetic nervous system is about calming down

“rest and digest”

Works together with the sympathetic system to maintain bodily balance (i.e. homeostasis)

Neural Networks

Help us think, feel, and act

Neural networks get stronger with use and weaker with disuse

Spinal Cord

Two-way information highway between the PNS and the brain

Reflexes

Simple, automatic response to a sensory stimulus before it’s processed in the brain (i.e. NO processing in the brain)

They go through our spinal cord

Endocrine System

Hormonal information system

The endocrine system sends out hormones through the bloodstream

Hormones in the brain deal with interest in sex, food, sleep, and aggression

Hormones

Chemical messengers

Adrenaline

Flight-or-Flight (norepinephrine in hormone form)

Leptin

Inhibits hunger by reducing appetite

Ghrelin

Signals hunger to the brain

Melatonin

Produced in response to darkness promoting sleepiness

Oxytocin

“Love hormone” feelings of trust and emotional connection

Pituitary gland

Considered to be the master gland directing other endocrine glands to release their hormones

By itself, it releases growth hormones

Controlled by the hypothalamus (a brain region)

Note

The nervous system and the endocrine system work together

Brain

The brain enables the mind - thinking, feeling, sensing- and thus the self

So even with a new body, we would still be “ourselves”

But even then, our brains are part of an integrated whole - spinal cord of the nervous system, glands of the endocrine system, and the body itself

Lesions

Destruction of brain tissue

Electroencephalogram (EEG)

What: records electrical activity sweeping across the brain while a stimulus is given repeatedly

How: electrode shower caps attached to the scalp

MRI (magnetic resonance imaging)

What: detailed picture of the structure of the brain using magnetic fields

fMRI (functional MRI)

What: Shows brain’s functioning as well as its structure

How: compares successive MRI scans to see increases in blood flow, which indicate increase in activity