AP Psychology Unit III: Biopsychology

Dendrite

Dendrite

Bushy tale of neuron that receives messages from another neuron’s axon.

Axon

Skinny body of a neuron that sends messages to another neuron’s dendrites.

Myelin sheath

Fatty layer that insulates axons and speeds up transmissions, laid down until age 25. Break down of this leads to MS.

Action potential

Impulse, brief electrical charge that travels down the axon

Neuron firing

1. Positive ions from outside the axon’s membrane and negative ions from within the axon switch/depolarize

2. If the threshold is crossed, neurons fire

3. Another axon channel opens (action potential)

All or nothing

If exhibitory signals exceed inhibitory signals by a threshold, action potential is triggered. Strong stimulus can trigger more neurons to fire, but they fire at the same speed and intensity.

Synapse

The meeting point between the axon of the sending neuron and the dendrite of the receiving neuron.

Acetycholine

Neurotransmitter that influences learning and memory, controls muscles and motor neurons. Deteriorates under Alzheimer’s.

Dopamine

Neurotransmitter that influences movement, learning, attention, emotion. Reward. Too much = schizophrenia, not enough = decreased mobility/Parkinson’s.

Norepinephrine

Neurotransmitter that influences alertness and arousal, calms down epinephrine (adrenaline). Undersupply = sad mood.

GABA

Major inhibitory neurotransmitter. Not enough = insomnia, tremors, seizures.

Glutamate

Major excitatory neurotransmitter. Memory. Overstimulation = migraines and seizures.

Endorphins

Natural, opiate-like neurotransmitters connected to control and pleasure.

Agonists

Molecules that bind to the receptor site of a neuron and stimulate a response (like opiates).

Antagonists

Molecules that bind to a neuron’s receptor site and block response (like poison).

Somatic nervous system

Enables voluntary control of our skeletal muscles

Automatic nervous system

Usually operates on its own, controls muscles of our internal organs, influences glandular activity, heartbeat, and digestion.

Neural networks

Neuron work groups that create short, fast, connections.

Adrenal gland

A pair of glands located right above the kidney that secret epinephrine (adrenaline) and norepinephrine, help arouse the body in times of stress.

Pituitary glands

Most influential gland in the endocrine system, Regulates growth and controls other endocrine glands, located in the head.

EEG

Amplified recording of brain waves. Measured with electrodes placed on head. No direct access to the brain.

CT

Examines the brain by taking x-rays that can reveal brain damage. Combines images with a computer to represent a slice of the brain structure.

PET

Visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a task.

MRI

Uses magnetic fields and radio waves to produce images of soft tissue. Shows brain anatomy.

fMRI

Revels blood flow in the brain as well as brain activity by comparing successive MRI scans.

Thallamus

Sensory control center. Directs messages to cortex and replies to cerebellum.

Medulla

Base of brain steam, controls heartbeat and breathing.

Cerebellum

Enables nonverbal learning and memory. Helps us judge time, regulate emotions, and discriminate sounds and textures. Also: sensory input processing, coordinating movement output, and balance.

Reticular formation

Inside the brainstem, between ears. Filters spinal chord’s sensory input and relays important brain info to other areas. Plays an important role in controlling arousal.

Limbic system

Neural system associated with emotions and drives. Pituitary gland, hippocampus, hypothalamus, amygdala.

Hypothalamus

Directs eating, drinking, body temperature, sexual behavior. Helps maintain a steady internal state.

Nucleus accumbens

System reward center in front of hypothalamus.

Frontal lobe

Involved in speaking, muscle movements, planning, and judgement.

Parietal lobe

Receives sensory input for touch and body position.

Somatosensory cortex

Area at the front of the parietal lobes that registers and processes body touch and movement sensations.

Left hemisphere

Makes quick, literal translations of language. Part of speaking and calculating.

Right hemisphere

Perceptual tasks, making inferences, modulating speech to make meaning clear, helps orchestrate our sense of self.