AP Psychology Unit 2

Glial Cells (Aka neuroglia)

Help support neurons (structure, nutrition, etc.) ex. Schwann Cells

Neurons

The basic building block of the nervous system

Dendrites - receive incoming messages

Cell Body (Soma) - Contains the Nucleus

Nucleus - Makes the decision to fire or not fire

Myelin Sheath - Fatty tissue that insulates axon, speeding up transmission of the passage

Node of Ranvier - Space between the sheath

Schwann Cells - Non-neural cells in the CNS that form myelin sheath

Axon - Longest part of the neuron which the electrical message travels the length of

Axon Terminal Buds - The end point of a neuron that releases neurotransmitters into the synapse, hence sending the message on to the next neuron

Resting Potential

When a neuron is NOT firing and has a negative charge with mostly potassium ions inside and mostly sodium ions outside. A neuron in homeostasis

Polarization

At resting potential, when sodium is on the outside, potassium on the inside of a neuron

Action Potential

“nerve impulse” - causes the neuron to fire - the electrical pulse or message that travels the length of an axon.

All-or-nothing principle

When the nucleus decides to fire, it fires down the axon completely (all the way) or not at all. - At the same intensity

• Intensity - Strength/power of message

Depolarization

When message begins, Sodium (+Na) ions come in & depolarize (neutralize) section of axon

• When “opposites” are no longer away from each other

• Axon Terminal

• Dendrites

Neurotransmitters - chemical substance that crosses the synapse to carry on the message to the next neuron

Synapse - open space between two neurons at which neurotransmitters cross

Receptor sites - specific points on dendrites of neurons that receive specific types of neurotransmitters

Reuptake - Reabsorption of neurotransmitters by firing neurons

Neurotransmitter - Acetylcholine

Learning. Enables muscle action (spinal cord & skeletal muscles), learning attention, & Memory. Deterioration leads to Alzheimer.

Neurotransmitter - Glutamine

Memory. Major excitatory (helps neurons fire) involved in memory. Oversupply can overstimulate the brain leading to migraines and seizures.

Neutransmitter - Dopamine

Reward / pleasure. Influences movement, learning, attention, and emotion (similar to cocaine). Oversupply = schizophrenia. Undersupply = tremors and Parkinson's. Completing a tasks gets Dopamine.

Neurotransmitter - Serotonin

Mood. Affects hunger, mood arousal, and sleep (similar to LSD & Ecstasy). Undersupply = depression. Antidepressant drugs increase levels.

Neurotransmitter - Norepinephrine

Concentration. Also associated with sympathetic nervous system. Increases alertness, blood pressure, and heart rate. Release glucose to support fight or flight.

Neurotransmitter - GABA (gamma-aminobutyric acid)

Calming. Major inhibitory (slows neurons firing) “Get A Break Adjustment.” Undersupply linked to seizures, tremors, insomnia, & anxiety.

Neurotransmitter - Endorphins

Pain or pleasure. Linked to europhia, pain control, and pleasure. Associated with OCD & “Runners High.” Opioids can suppress natural supply.

Neurotransmitter - Substance P

Pain Pain & immunity. Found in the brain and spinal cord and is associated with inflammatory processes and pain. Oversupply can lead to chronic pain.

Agonist

MIMIC neurotransmitter activity.

• Fitting in the receptor site like a master key

• It works just like the original key but it is not exactly the same

Example:

• Morphine (opiate derivative) mimics endorphins

  
  

Antagonist

BLOCK neurotransmitter activity

• Fitting in the receptor site like a fake key, preventing the neurotransmitters from getting to its receptor site and doing its job

Example

• Botox (form of botulism) blocks Acetylcholine.

• Prevents muscles in the face from moving by blocking the neurotransmitter, which ultimately stops wrinkles

Reuptake Inhibitor

A type of agonist that blocks the reuptake process to increase a neurotransmitter

Example

• Selective serotonin reuptake inhibitors (SSRI) like fluoxetine (Prozac), setraline (Zoloft) and citalopram (Celexa), which are widely used to treat depression and other conditions by increasing seretonin levels in the brain

Two parts fo the nervous system

• Peripheral: Sensory and motor neurons that connect the CNS to the rest of the body

  • Includes Autonomic and Somatic

• Central (CNS): Contains the spine and brain. In the center of the body

Autonomic vs Somatic

• Autonomic: Controls involuntary functions or items that happen automatically within our body - berathing, heartbeat, digestion, etc.

  • *includes sympathetic and parasympathetic

• Somatic: Control voluntary (soma = body) movements and communications to and from the sense organs

  • You control these items, they don’t “just happen”

Brain vs Spinal Cord

• Brain: The neural center of the body; the body’s control center

• Spinal Cord: Super Highway of nerves - the body’s means of transmitting messages to and from the brain

Reflex Arcs

The neural pathway for a rapid, automatic response to a stimulus bypassing the brain and acting through the spinal cord

Ex. Withdrawal reflex: When you touch a hot stove

Interneurons vs Sensory Neurons vs Motor Neurons

• Interneurons: The only neurons in the CNS, acting as messengers between sensory and motor neurons

• Sensory (afferent) neurons: Carries incoming mesages/information from the sense receptors to the CNS

• Motor (efferent) neurons: Carries outgoing information from the CNS to the peripheral nervous system and muscles.

Endocrine system

Communicates with the brain using chemical messages called hormones

• Hormones are released into and circulate through the bloodstream - recieved only at a specific site

• Under “normal” circumstances works in parallel with the parasympathetic NS to sustain our basic processes. (HOMEOSTASIS)

• In a crisis, the sympathetic nervous system actitvates, and the endocrine system (adrenal gland) releases adrenaline/epinephrine

The Pituitary Gland

• The “Master Gland

  • Directed by the hypothalamus

  • It releases several important hormones and controls the function of many other endocrine system glands.

Adrenaline

Secreted by the adrenal glands; responsible for arousal and the "fight or flight" response. Plays a role in emotional memory formation. Same chemical as Epinephrine.

Leptin

Involved in turning off hunger (keeps you LEAN). Produced by fat cells it sends signals to your hypothalamus.

Ghrelin

Involved in turning on hunger (tummy goes grrrr) comes from the stomach and activates the pituitary gland

Melatonin

Secreted by the pineal gland; signals the relaxation and lower body temperature that help with a restful sleep.

Oxytocin

Produced by the hypothalamus and secreted by the pituitary gland. When it affects the brain, it acts as a neurotransmitter. Plays a role in mother-child attachment; believed to play a role in social bonding and is the “Us vs them” hormone (social trust / bonding).

Hormones vs Neurotransmitters

	Hormones	Neurotransmitters
Speed	Minutes or longer	Milliseconds
Length	Hours, days, or weeks	Short-term
Method	Travel through the blood	Neuron-to-neuron signaling

Cerebral Cortex

• Outer portion of brain, higher order thought processes, perception, and voluntary movement (& 4 lobes)

• 💀 If damaged: Varied effects including memory, personality, decision making, motor control.

Corpus Callosum

• Bundle of nerve fibers that connect hemispheres, enabling communication

• 💀 If damaged: “Split-Brain

Hippocampus

• Processes conscious memories (explicit memories)

• Converts short-term to long-term memory

• Involced in processing and retrieving declarative (facts and events) memory

• Spacial Relationship memories

• 💀 If damaged: Inability to remember, getting lost, difficulty following directions.

Thalamus

• Brain’s relay center for all but smell

• Directs messages to sensory receptors

• Transmits replies to cerebellum & medulla

• 💀 If damaged: sensory issues (blind, aphasia), numbness, coma.

Hypothalamus

• Directions maintenance activities (eating, drinking, body temp)

• Helps govern endocrine system

• Fight or Flight

• Linked to emotion & reward/pleasure.

• Homeostasis

• 💀 If damaged: Weight change, fatigue, insomnia, thirst, dehydration, high or low blood pressure, frequent urination, infertility

Amygdala

• Plays a role in emotion, (fear, anger, aggression, anxiety)

• 💀 If damaged: high emotional responses, no emotional responses

Cerebellum

• Processes sensory input, coordinates movement output and balance

• Enables nonverbal learning and implicit memory. (long-term memory that involves unconscious recall of skills, tasks, and knowledge without conscious effort)

• Known as the “little brain”

Pons

• Connects upper and lower brain

• Sleeping

• waking

• dreaming

• Bladder Control

• 💀 If damaged: Coma, sleep issues

Medulla

• Controls autonomic functions heartbeat and breathing, blood pressure, reflexes.

• 💀 If damaged: respiratory failure, paralysis, or loss of sensation.

Reticular formation

• Controls arousal, alertness, attention, regulating sleep cycle

• 💀 If damaged: Coma, difficulty staying awake or paying attention.

Ventricles

Fluid filled with cavities in the brain which serve as reservoirs of cerebrospinal fluid

Left to right

1. Corpus Callosum

2. Thalamus

3. Hypothalamus

4. Pituitary Gland

5. Spinal Cord

6. Cerebral Cortex

7. Cerebellum

8. Pons

9. Medulla

10. Reticular Activating System (RAS) *Back of brain stem (activiating system)