HDF 510 Brain Basics and Stress Response System

Neuron

The adult brain has about 80 of these specialized cells most of which existed from birth. They form the basis of brain development and the nervous system.

neurogenesis

The formation of new neurons

Synapses

The site of communication between two neurons; the junction between two neurons where information is transmitted from one to another by chemical or electrical signals.

Synaptic pruning

The normal developmental process through which synapses that are rarely activated are eliminated.

Myelin

A fatty substance that helps insulate neurons and speeds the transmission of nerve impulses.

White matter

Myelinated neural axons in the brain

Dendrites

A neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

Axon

A threadlike extension of a neuron that carries nerve impulses away from the cell body.

axon terminal

distal end of the neuron responsible for relaying chemical signals across a synapse to the dendrites of neighboring neuron.

synaptic plasticity

the ability of a synapse to change over time through use or disuse

prefrontal cortex

area in the frontal lobe (front of brain) responsible for higher-level cognitive functioning/executive functioning/problem solving

Toxic stress

stress that is long-last, severe in intensity, or frequent without effective resources to deal with it.

allostatic load

wear and tear on the body caused by prolonged or excessive stress responses

Amygdala

Almond shaped structure in the medial temporal lob, near the hippocampus (in the brain). Helps detect potential threats and triggers the body's fight or flight response

Sympatho-adrenomedullary (SAM) pathway

the neurons of the hypothalamospinal tract activate the sympathetic nervous system, which, in turn, stimulates the adrenal medulla to release epinephrine and norepinephrine.

hypothalamic-pituitary-adrenal (HPA) axis

Hypothalamus secretes corticotropin-releasing hormone (CRH) which stimulates the release of corticotrophin from the anterior lobe of the pituitary which stimulates and releases cortisol.

epinephrine

Neurotransmitter secreted by the adrenal medulla in response to stress. Also known as adrenaline. Induce biological changes like elevation of heart rate, blood pressure, and blood glucose levels preparing to fight or flight.

Cortisol

hormone slower than epinephrine but also gets the body ready for fight or flight by increasing glucose levels (energy for the muscles), dampening the immune system (no fevers while in a fight), and altering memory functioning (no reminiscing while on the run).

Freeze response

A response to a threat whereby we feel so helpless to deal with it that we become immobilized in its presence due to activation of the parasympathetic nervous system overriding the sympathetic nervous system. Prepares the body to be injured.

parasympathetic nervous system

the division of the autonomic nervous system that calms the body, conserving its energy or "rest and digest"

Oxytocin

hormone released by hypothalamus that promotes connection also known as the "love" hormone. Promotes the Affiliate or "tend and befriend" reaction to stress.

Hippocampus

located in the medial temporal lobe, vital role in forming and retrieving memories and emotional responses.

limbic system

neural system (including the hippocampus, amygdala, thalamus and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives and involved in the formation of long-term memory.

Principle of brain development: Asynchronous development

Different parts of the brain develop at different rates from back to front

Principle of Brain Development: Cumulative development

Early neural connections lead to more complex neural connections advancing development. Early experiences are the foundation for later development.

Principle of Brain Development: Integrated

Develop in one area of the brain impacts other areas of the brain.

Principle of Brain Development: Experience dependent

Neural pathways that are repeatedly get stronger while those that aren't used frequently get pruned away.

Principle of Brain Development: Dynamic

While early experiences shape our brain, plasticity exists allowing potential of re-wiring the brain. Synaptic plasticity remains across lifespan but we cellular plasticity decreases as we age.

"Easier to build strong children than repair broken men"--Fredrick Douglass