AP Psych Unit 3: Biology

Neurons

Specialized cell in the nervous system that receives and sends messages with electrochemical signals

Glial cells

Cells that provide physical support for the neurons to grow on and around (glue)

90% of the brain is composed of this

Soma “Life Support”

The cell body of the neuron responsible for maintaining the life of the cell, contains nucleus

Dendrites “Antenna”

Part of neuron, branch-like extensions that receives electrical messages from other cells.

Axon “talker”

Fiber that extends from the cell body to the terminal endings, its job is to carry messages out to other cells.

Myelin Sheath

Layer of fatty substance produced by certain glial cells, wraps around the axon to protect the nerve fiber from damage, insulating sheath, speeds up the neural message.

Axon Terminals

Tips at the end of the axon, send signals to other neurons.

Terminal Buttons/synaptic knobs

Synapse “contact point”

Meeting point between neurons

Synaptic Gap

Less than a millionth of an inch wide

Receptor Sites

Receive signals

Sensory Neurons “Afferent Neurons”

Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.

Motor Neurons “Efferent Neurons”

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

Efferent means outward, Motor means movement

Interneurons

Neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.

Neural Transmission

Process by which information travels through a neuron.

- Neurons transmit messages when stimulated by signals from our senses.

- Process happens at the synapse.

Resting Potential

The state of the inactive neuron when not firing a neural impulse.

• Positively charged ions are OUTSIDE of the neuron

• Negatively charged ions are INSIDE the neuron.

No electrical charge, called polarized

Action Potential “Firing”

When a neuron is stimulated (to threshold) enough, an electrical charge is generated, and the neuron has reached action potential (neuron fires/talks).

• Positively charged ions cross into the neurons, mixing with negatively charged ions, causing an electrical charge.

• Called depolarized

All-or-None Principle

When a neuron fires it is at full strength or not at all, strength of action potential is constant.

• The speed of a neural impulse can range from 2 to 200 miles per hour.

Refractory Period

Period of time during which a cell is incapable of repeating an action potential (recovery time).

• Occurs after an action potential and generally lasts one millisecond.

Depolarizes

That section of the axon, causing the axon’s next channel to open, and then the next, like dominoes falling.

• Related to action potential

• Positive ions mix with negative ions, ions are no longer polarized.

Synapse

Information from one neuron flows to another neuron across a small gap, meeting point between neurons.

• At the synapse, electrical signals are translated into chemical signals in order to cross the gap. Once on the other side, the signal becomes electrical again.

Neurotransmitters

Chemicals in the brain that carry messages from one neuron to another.

Excitatory Neurotransmitters

They excite connecting neurons and cause them to fire, more action potentials are triggered.

Inhibitory Neurotransmitters

Inhibit (prevent) the next neurons from firing

Inhibitory and excitatory balance each other out in the brain and body.

Acetylcholine (ACh)

Active in both the PNS and CNS, connected to motor movement (muscle action), attention and arousal, memory and hearing.

• Excitatory

• First neurotransmitter discovered

Serotonin

Connected to mood regulation, emotion, hunger regulation, sleep/wakefulness (arousal), sexual desire

• A major part of many popular drug treatments for depression and anxiety

Dopamine

“Pleasure chemical of the Brain” released into the pleasure centers of the brain, related to rewards and motivation (learning), also connected to movement, attention, and emotion.

Norepinephrine

Associated with response to danger, increase alertness and arousal, mood elevation Adrenaline

• Levels of this neurotransmitter are typically lowest during sleep and highest during times of stress.

Reuptake 

Neurotransmitters are released back into the synapse and the originating neuron reabsorbs the excess neurotransmitters.

• In other cases, an enzyme destroys the neurotransmitter, breaking it down to be used elsewhere in the brain.

GABA

Inhibitory transmitter that slows things down, calming the central nervous system “natural tranquilizer” regulates daily sleep-wake cycles.

• increases sleepiness and decreases anxiety, alertness, memory, and muscle tension.

Glutamate

Major excitatory neurotransmitter, involved with most normal operations of the brain including thinking, long-term memory, and learning.

The G in MSG

Endorphins

Relieve pain and stress, “Brain’s natural pain killer”, feelings of pleasure/euphoria.

• Triggered by activities such as aerobic exercise. For example, experiences a “runner’s high”

Nervous System

Body’s communication network that consists of the brain and all our nerve cells.

Central Nervous System (CNS)

Coordinates the actions/interactions of the brain and spinal cord, body’s main control center.

Peripheral Nervous System (PNS)

Includes the sensory nerves outside the brain and spinal cord that connect the CNS to the rest of the body.

Motor pathway:

Signals from brain to muscles/glands

Efferent - outward

Sensory pathway:

Signals from sensory receptors to the brain Afferent - inward

Somatic Nervous System

Includes the nerves that transmit signals from your brain to the skeletal muscles to allow voluntary movement

Autonomic Nervous System

Regulates involuntary and unconscious actions.

Sympathetic Nervous System

Emergency response system, if something alarms, enrages, or challenges.

“Fight, flight, or freeze”

Parasympathetic Nervous System

“Rest and digest”

Functions to calm the person

Digest, getting ready to sleep, reduced body arousal, energy, decreases blood sugar, decreases heart rate.

Endocrine System

Our second communication network.

Passes hormones through the bloodstream. These hormones are secreted (produced/passed on) from a number of different glands/organs of the brain/body.

Glands

Organs in the body that secrete chemicals.

Hormones

Chemical messengers that travel through the bloodstream and move throughout the body.

Cortisol

The body's main stress hormone, works with certain parts of your brain to control your mood, motivation, and fear.

Oxytocin

The love chemical

Powerful hormone that acts as a neurotransmitter in the brain, regulates social interaction, and sexual reproduction.

Pituitary Gland

Pea-sized structure located in the core of the brain, where it is controlled by an adjacent brain area, the hypothalamus

Thyroid Gland

Located inside the lower neck, secretes a hormone called thyroxin that regulates metabolism, growth, and appetite.

Pineal Gland

Located in the brain, near the back, secretes a hormone called melatonin which regulates sleep and body rhythms.

Adrenal Glands

Adrenaline

Two glands on top of each kidney are involved in stress response.

Increase heart rate, blood pressure, blood sugar, surge of energy.

Gonads

Sex glands, including the ovaries (female) and testis (male), regulate sexual hormones, behavior, and sex characteristics.

Estrogen in women and testosterone in men.

Hemispheres

The brain has two hemispheres, the left controls the right side of the body, the right hemisphere controls the left side of the body

The two sides of the brain are always working together

Lateralization

There is evidence that each brain hemisphere has its own distinct functions.

Left Hemisphere

Specializes in language, speech, handwriting, calculation, sense of time and rhythm, and basically any kind of thought requiring analysis.

(Math, analytical, solving puzzles)

Right Hemisphere

Appears to specialize in more widespread processing involving perception, visualization, spatial perception, recognition of patterns, faces, emotions, melodies, and expression of emotion, creativity.

(Emotional, visual, spacial, artistic)

Cerebral Cortex

The outer layer of the brain, the tissue is folded in on itself, the folding and wrinkling allows for more surface area of cortex to fit into the skull.

Lobes

Areas of the cerebral cortex, location and primary function, each with a specialty.

Frontal Lobes

Areas of the cortex located in the front and top of the brain, responsible for higher mental functions, interpret and control emotional behaviors, make decisions, carry out plans, judgement, creativity

Parietal Lobes

Processing sensory signals

Located at the top and back of each cerebral hemisphere.

Touch, pressure, temperature, pain.

Occipital Lobes

Visual centers of the brain.

Located at the rear and bottom of each cerebral hemisphere.

Information from the left half of visual field of both eyes processed in right occipital lobe, right processed in left occipital lobe.

Temporal Lobes

Sense of hearing and meaningful speech

Located just behind the temples.

Also helps you make sense when you talk.

Corpus Callosum

Bundle of nerve fibers that connects the two hemispheres messages more from one side of the brain to the other.

Brainstem

Most primitive (old) part of the brain.

The base of the brain is connected to the spinal cord.

Makes Life Possible.

Medulla

Located at the top of the spinal cord (transition zone), controls life sustaining functions.

Regulates heart rhythm, blood flow, breathing rate, digestion, vomiting.

Pons

The larger swelling above the medulla that connects the top of the brain to the bottom.

• Helps manage pain and other sensory signals to the rest of your brain. Also helps with arousal.

Reticular Formation

Network of nerves that carry messages between parts of the brain stem.

Helps people focus on useful sensory input while filtering out unnecessary stimuli.

Looks like twizzler

Cerebellum

Coordinates motor function and muscle memory helps maintain balance.

Also helps coordinate movement/balance with your ear (fluid that helps us maintain balance)

Mid Brain/Limbic System/Lizard Brain

Makes life Easier

(Regulatory systems like hunger, sleep, thirst, fear, memory)

Thalamus

All sensory information passes through this.

It is considered the sensory “relay station” of the brain, passing information on to the cortex.

Receives information from all senses EXCEPT SMELL, which then travels to the somatosensory cortex (parietal lobe).

Hypothalamus

Regulates body temperature, thirst, hunger, sleeping, walking, sexual activity, and emotions, controls the pituitary and connects the brain w/ endocrine.

Hippocampus

Rounded part of the limbic system near the center of the brain, important role in forming new long-term memories about past experiences