Unit 1: Biological Basis of Behavior

Heredity

The passing on of physical or mental characteristics genetically from one generation to another

Environment

All external conditions and influences affecting the life and development of an organism

Nature

Pre-wiring and influenced by genetic inheritance and other biological factors

Nurture

The influence of external factors after conception, e.g., the product of exposure, life experiences, and learning on an induvidual

Genetic predisposition

An increased chance or likelihood of developing a particular disease based on the presence of one or more genetic variants and/or a family history suggestive of an increased risk of the disease

Evolutionary Psych

The branch of psychology that studies the mental adaptations of humans to a changing environment

Natural selection

Certain behaviors and genes best for survival (survival of the fittest)

Identical twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms

Fraternal twins

Twins who develop from separate fertilized eggs, They are genetically no closer than brothers and sisters, but they share a fetal environment

Eugenics

The study of how to arrange reproduction within a human population to increase the occurrence of heritable characteristics regarded as desirable

Twin studies

Studies conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders

Adoption studies

Studies conducted to compare pairs of persons, e.g., adopted child and adoptive mother or adopted child and biological mother, to assess genetic and environmental influences on behavior

Family studies

Studies conducted to provide a way for professionals to further examine the relationship between genetics and mental disorders

Nervous System

The body’s electrochemical communications network

Central Nervous System

The brain and spinal cord, which distribute and process messages

Peripheral Nervous System

A branch of the human Nervous System that includes all components except the brain and spinal cord

Somatic Nervous System

A part of the Peripheral Nervous System that controls voluntary movements

Autonomic Nervous System

A part of the Peripheral Nervous System that regulates bodily processes such as breathing, heart rate, and digestion

Sympathetic Nervous System

A branch of the Autonomic Nervous System that excites the body by preparing it for action (increased heartbeat, pupils dilate, lungs increase oxygen, relax bladder, etc)

Fight or Flight

Parasympathetic Nervous System

A branch of the Autonomic Nervous System that restores the body’s energy sources once they have been depleted (pupils contract, heart beat slows, constrict airways, stomach contract, etc)

Rest and Digest

Nerves

Bundles of fibers that transmit impulses between different areas within our bodies

Spinal Reflex Arc

A neural pathway that controls reflex actions, allowing for rapid, automatic responses to sensory stimuli without conscious thought (primitive reflexes)

Neurons

Individual nerve cells that make up our entire nervous system

Glial cells

Cells that provide nutrition and protection for neurons

Sensory neurons

Neurons that take information from the senses to the brain

Motor neurons

Neurons that take information from the brain to the rest of the body

Interneurons

In the brain or spinal cord, neurons that take messages and send them elsewhere in the brain or spinal cord

Spinal reflex

An immediate response to external stimuli directed at the level of the spinal cord

Mirror neurons

Neurons that play a role in action understanding, imitation learning, and language processing. Enables use to recreate and embody the intentions of others

Dendrites

What is #1?

Soma

What is #2?

Nucleus

What is #3?

Axon

What is #4?

Myelin sheath

What is #5?

Schwann cell

What is #6?

Node of ranvier

What is #7?

Axon terminal

What is #8?

Action potential

An impulse or brief electric charge that travels down the axon

Threshold

The level of stimulation needed to trigger a neural impulse

All or None response

A neuron either sends an impulse or it does not

Resting potential

When a neuron does not have an action potential

Polarized

The state of a resting neuron; the outside of the membrane is positively charged while the inside of the membrane is negatively charged

Depolarization

Describes an axon that is firing. Positive ions enter the axon and cause other positive ions to move into the axon in the form of a neural impulse down the axon

Refractory period

A resting pause where neurons pump positively charged sodium ions back outside of the cell

Reuptake

The reabsorption of neurotransmitters by the sending neuron

Excitatory nerotransmitters

Neurotransmitters that send signals to calm the brain down and create balance

Inhibitory neyrotransmitters

Neurotransmitters that send signals to calm the brain down and create balance

Multiple Sclerosis

The loss of muscle control resulting from a deterioration of myelin sheath

Myasthenia gravis

A relatively rare, acquired autoimmune disorder caused by an antibody-mediated blockade of neuromuscular transmission resulting in skeletal muscle weakness and rapid muscle fatigue (caused by a blockade of acetylcholine)

Neurotransmitters

Chemical messengers that cross the synaptic gaps between neurons that generate the next neural impulse, growth and development, tissue function, reproduction, sleep, mood, etc.

Hormone

A chemical messenger produces in the body that controls and regulates the activity of certain cells or organs (released in the bloodstream)

Adrenaline

A hormone that activates the Sympathetic Nervous System. This triggers our “fight o flight” response, which increases heart rate, dilates the pupils, increases blood flow to skeletal muscle, and reduces digestive and reproductive activity

Melatonin

A hormone known to regulate sleep and wake cycles

Ghrelin

Increases hunger, secreted by an empty stomach

Acetylcholine

Enables muscle action, learning, and memory

Ex. A depletion of this neurotransmitter is connected to Alzheimer’s disease

Dopamine

Influences movement, learning, attention, and emotion

Ex. An oversupply is linked to schizophrenia. An undersupply is linked to tremors and decreased mobility in Parkinson’s disease

Serotonin

Affects mood, hunger, sleep, and arousal

Ex. An undersupply is linked to depression. Some drugs that raise levels of this neurotransmitter are used to treat depression

Norepinephrine

Helps control alertness and arousal

Ex. An undersupply can depress mood

GABA

A major inhibitory neurotransmitter

Ex. A undersupply is linked to seizures, tremors, and insomnia

Glutamate

A major excitatory neurotransmitter; involved in memory

Ex. Oversupply can overstimulate the brain, producing migraines or seizures

Endorphins

Neurotransmitters that influence the perception of pain or pleasure

Ex. Oversupply with opioid drugs can suppress the body’s natural supply

Substance P

Involved in pain perception and immune response

Ex. Oversupply can lead to chronic pain

Leptin

Decreases hunger, protein hormone secreted by fat cells

Oxytocin

A hormone produced by the hypothalamus and released by the pituitary gland that plays a significant role in social bonding, sexual reproduction, childbirth, and postpartum

Psychoactive drugs

Chemical substances that alter perceptions, mood, or behavior

Addiction

Craving for a chemical substance despite its adverse effects

Tolerance

After long-term use, the brain then produces less of that specific neurotransmitter - this creates a need for increasing amounts of the drug to experience the same effect

Withdrawal

Set of symptoms associated with discontinuing a drug - reverses neuroadaptation

Depressants

Lower neural activity and slow body functioning

Ex. Barbiturates

Alcohol

A type of depressant that slows neural processing, thinking, and impairs physical activity

Opiates

A type of depressant that reduces neurotransmission and temporarily lessens pain and anxiety

Stimulants

Drugs that speed up the body’s functions

Ex. Caffeine, Nicotine, Cocaine, Meth, Amphetamines

Hallucinogens (psychedelics)

Drugs that distort perceptions of reality

Ex. LSD, Marijuana

Opioids

Psychoactive drugs that act on ______ receptors in the brain and body, producing pain relief, euphoria, and sedation

Ex. Heroin typically acts as pain relievers

Agonists

Chemicals that activate the receptors for certain neurotransmitters and make the effects of neurotransmitter stronger

Ex.

• Caffeine for Acetylcholine (ACH)

• Selective Serotonin Reuptake Inhibitors (SSRIs) for Serotonin

• Adderall, Methamphetamine, Cocaine, and Speed for Norepinephrine

  • Cause euphoria and extreme alertness

• Benzodiazepines and alcohol for GABA

• Opiates (morphine, oxycodone, heroin, etc.) for endorphins

Antagonists

Chemicals that inhibit the actions of neurotransmitters

Ex.

• LSD for serotonin

• Drugs for dopamine that treat psychosis, schizophrenia, and bipolar disorder

Reuptake inhibitors

Drugs that prevent the axon terminals from engaging in the reuptake of neurotransmitters

Ex.

• Cocaine is one of these for dopamine

Brainstem

The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull

This part is responsible for automatic survival functions

Medulla

Controls heartbeat, blood circulation, breathing, muscle maintenance, regulation of reflexes like sneezing/coughing

Reticular activating system

Regulate behavioral arousal, consciousness, and motivation (generally control some voluntary movement, eye movement, and some types of learning, cognition, and emotion)

Cerebellum

The “little brain” at the rear of the brain stem

Functions include processing sensory input, coordinating movement output and balance, and enabling nonverbal learning and memory

Thalamus

The brain’s sensory control center, located on top of the brainstem

It directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla

Limbic system

Neural system (includes hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres

Associated with emotions and drives

Hippocampus

Vital to our memory system

Amygdala

The center of emotion

Responsible for fear and aggressive responses

Hypothalamus

Regulates the Autonomic Nervous System (fight or flight), temperature, hunger, and reproduction