Week 2: Stress Psychophysiology

PSY805 Week 2

Biomedical Model

* a traditional model of health
* health is primarily a product of **biological factors**
* health and illness are **dichotomous** (either-or)
* Either healthy or ill

Biopsychosocial Model

* a more recent model of health
* health is a product of __biological, psychological, and social influences__
* health and illness are on a *continuum*
* a more accurate and comprehensive description of illness

Has a **linear model of illness**; cause of illness is **physical**

Biomedical Model

an **interactive model** of illness; the causes of illness are **physical, social, psychological**

Biopsychosocial Model

The Biopsychosocial model includes:

* behavioral pathogens
* behavioral immunogens
* psychosocial stress
* poor coping behaviors

Behavioral pathogens

risk-increasing behaviors (smoking, drinking excessive amounts of alcohol)

behavioral immunogens

health-enhancing behaviors (such as not smoking, eating healthy, exercising)

* considers the relationship between mind and body as **separate entities** (treatment is focused on the body)
* treatment approaches are **physical**: medications, surgery because the illness is __purely physical__

Biomedical Model

* considers the relationship between mind and body as **integrated entities and interact** with each other in a holistic manner (treatment focused on both)
* treatment approaches may be physical, behavioral, and/or psychological

Biopsychosocial Model

* individuals are __passive victims of illness;__ have no responsibility
* a linear model of health illness
* illness causes psychological consequences, and not the reverse

Biomedical Model

* individuals are **not** **passive victims**; have a responsibility and contribute to the illness
* behavior and lifestyle play a role
* an interactive model of illness (continuum)
* psychological factors can **both** *affect* illness and also be *consequences* of illness

Biopsychosocial Model

The value of psychology in health: biopsychosocial model of health

biological, social, and psychological factors interact in an interdependent way in maintaining health (or causing illness)

Psychological Factors play a **key role** in health and illness as well (T/F)

True

Our lifestyles are **indirectly** related to health and illness (T/F)

False; directly

When under (dis)stress, we tend to engage in behavioral -----, which affect our ----, and hence our health

pathogens; lifestyles

Health Psychology

__a specialty area of psychology__ which uses the __knowledge based on the discipline__ of psychology **to promote maintain health and treat illness**

Stressors can produce ---, ----, ----, ---- changes which may be detrimental to health 

cognitive, emotional, physiological, behavioral

Negative stressors (and distress) have an impact on ----

life expectancy

Explain why Stress is a **2-way street?**

* it is a cycle of stress **contributing** to poor health and poor health **contributing** to stress
* interdependence between health and stress

What is the most effective way to manage stress is to ----

* **live a healthy lifestyle**
* examples: drinking in moderation, not smoking, eating healthy

Goal of stress management is to stay in an **------** of functioning & life satisfaction through the use of health-promoting strategies 

**optimal zone**

What is the **Yerkes-Dodson Curve/Law?**

* identifies a relationship between **physiological** **arousal** and **performance**
* identifies optimal performance

What is Optimal Performance

* occurs when we are **midlevel** of physiological arousal
* neither overstimulated or understimulated for a period of time

What law is accepted as the basis for the __physiological explanation__ for anxiety

Yerkes-Dodson Curve/Law

High levels of anxiety will impair performance, while low levels of anxiety (co-exists with low levels of motivation) **doesn’t** impair performance (True or False)

False; both high and low levels of impair performance

Are optimal levels stable or not stable? Why or Why not?

* **It’s not stable** because it __changes and adapts__ based on *prolonged changes in the* __*external environment*__
* Sometimes we adapt → habituation

How does **Habituation** occur?

When a new stimulus __elicits increase in physiological arousa__l (fight-or-flight response) → *repeated exposure* results in __no observable response__ due to having adjusted to it

The CNS **monitors** *bodily functions* by picking up *signals* that indicate when any part of the body deviates from ----

**Homeostatic Stability**

What does the brain do to counteract this deviation to return to homeostasis?

* The brain initiates a response.
* This response can be in terms of an **autonomic/endocrine mechanisms**
* or **behavioral responses**

\

What can autonomic/endocrine mechanisms do

* alter physiological processes within the body (such as sweating to cool down and return to homeostasis)

\

**Behavioral response** to counteract deviation from homeostasis

alters the external environment (i.e., open a window to cool doen and return to homeostasis)

What axes are activated during the fight-or-flight response?

SAM and HPA axes

What part of the PNS innervates the voluntary or skeletal muscles (i.e., striated muscles such as biceps), skin and sense organs

Somatic

What part of the PNS innervates the organ systems of the body (viscera)

Autonomic

Sympathetic Branch is associated with

the **fight-or-flight** reaction (i.e., **physiological response** to a potential threat)

Parasympathetic Branch is associated with

the **relaxation and restoration** responses (i.e., activated to shut down fight-or-flight response and decrease arousal once we realize there is no threat)

•Sympathetic & parasympathetic branches __________ one another

•As one becomes more __________, the other is ___________

opposite; activated; suppressed

What is the outermost layer of the brain

Cerebral Cortex/ Gray Matter

What are the folds and grooves of the brain called?

Fold: Gyrus/Gyri

Groove: Sulcus/Sulci

Proof that folds on the brain are not random

* Every healthy human brain has similar folds and grooves on the cortex
* Locations and functions are stable across the typical brain
* Degree to how much each part of the cortex is folded is important → psychological disorders

The Brain analyzes

**sensory information** *&* **higher-order brain functions** (i.e., reasoning, problem-solving, language, etc.)

How many hemispheres are in the brain?

2: Right and Left

What are the terms for the front, back, right, left of the brain?

Front: Anterior

Back: Posterior

Right: Lateral

Left: Medial

White Matter

* consists of fibers that connect different regions of gray matter together, allowing them to communicate with one another
* inside of the brain
* connection: axons

Corpus Callosum

Large bundles of fibers connecting the 2 cerebral hemispheres (part of white matter)

Anterior Cingulate Gyrus/Cortex (ACC)

* __part of the limbic system__
* processing **emotional information**
* extinguishing **conditioned fear**
* regulating **emotional responses**

Lateralization

* cognitive functions that **rely more on one hemisphere** than the other
* The brain produces a **crossing over** for movement
* Right H controls Left part of body
* Left H controls Right part of body 

What are the 4 lobes of the Cerebral Cortex?

1. Frontal lobe
2. Parietal Lobe
3. Occiptal Lobe
4. Temporal Lobe

What are Subcortical Areas?

* areas that are located deep inside the brain
* i.e., amygdala, hypothalamus, etc.

Brainstem

* responsible for the **basic bodily functions** of the body that help keep us alive (i.e., heartbeat, respiration, etc.)

The Brainstem consists of 3 parts:

1. midbrain
2. pons
3. medulla

Medulla

* controls (and regulates) **autonomic processes** (i.e., heartbeat, blood pressure, respiration)
* responsible for physiological responses (i.e., heartbeat) during fight-or-flight

Pons

* Latin for ‘bridge’
* **connects** the *cerebral cortex* to the *cerebellum*

Midbrain

* controls and coordinates **sensory and motor activities**
* plays an important role in __voluntary motor movement__
* controls the tracking of **visual stimuli and reflexes** that are *triggered by sound* (i.e., causes us to jump when hearing a loud sound)

The Thalamus is a subcortical structure that’s part of the mesencephalon (T/F)

False, it’s part of the diencephalon

The Thalamus contains:

1. The Sensory Relay Station
2. The Sensory Projection System

Sensory Relay Station

* **all sensory information** *pass through* the **thalamus** first for the *initial process*, then are sent to the **cortex** for *further processing*
* each sensory system has a specific endpoint in the cortex

\

Sensory Projection System

* circuit from a sense organ, moving through the thalamus to its **specific region in the cortex**

The Thalamus has a --- nucleus for each sense organ

distinct

The Hypothalamus is part of the Diencephalon (T/F)

True

The Hypothalamus is responsible for r**egulating internal bodily states** by

* overseeing hormone release through connections with **pituitary gland**
* being involved in **normal homeostatic regulation** of the __autonomic nervous system__

The hypothalamus has both direct and indirect control over the **fight-or-flight** **activities** *during stress*. What does it directly control?

**directly controls** the hypothalamus through influencing the brain stem to __activate__ the **sympathetic responses** of the viscera, like stimulating the endocrine system

The hypothalamus has both direct and indirect control over the **fight-or-flight** **activities** *during stress*. What does it indirectly control?

**indirectly controls** the hypothalamus through connection to the **pituitary gland** to stimulate the *endocrine system*

What part of the diencephalon/subcortical structure of the brain plays an important role in **motivation behavior** and **controls homeostatic regulation of our body’s temperature**

The Hypothalamus

Amygdala

* subcortical area
* Greek for ‘almond’
* Part of the __limbic system__
* Involved in **mediating emotional responses** (especially fear & anxiety)
* Involved in **emotional memory formation** & assessing threat stimuli  
* Plays a key role in **fear conditioning**

Fear Conditioning

predicting when something fearful is about to occur

Hippocampus

* subcortical area
* Greek for ‘seahorse’
* Part of the limbic system
* Involved in **encoding long-term memories** of **declarative memories**
* Also plays a role in fear-conditioning

declarative memories

conscious memories of events

* Hippocampus encodes the ________
* Amygdala adds in the ________

* Hippocampus encodes the context
* Amygdala adds in the emotion

Limbic System

* __**“Emotional center”**__ of the brain
* Includes:


1. __**hippocampus,**__
2. __**thalamus,**__
3. __**hypothalamus,**__
4. __**amygdala,**__  
5. **cingulate gyrus (ACC)**,
6. __parts of the cerebral cortex (i.e., prefrontal cortex)__
7. __and other structures__ 

* Plays an important role in **fear response to potentially dangerous stimuli**

\

PNS: somatic nervous system

* fuels the voluntary and skeletal system
* consists of the efferent and afferent neural pathways

Efferent and Afferent pathways are examples of

bidirectional neural networks

Efferent

* neural pathways that send (motor) signals from the brain to the periphery
* brain → periphery

Afferent

* neural pathways that send signals from the periphery to the brain 
* periphery → brain

During the fight-or-flight response: Brain sends messages through the --- pathway

efferent, to tense muscles and prepare for fight or flight

Why are there health problems when the fight-or-flight response is constantly stimulated?

chronic stimulation of the somatic nervous system may lead to:

* Muscle tension
* Headaches
* Teeth grinding 

(physiological effects)

PNS: Autonomic nervous system

* Innervates the body’s __**viscera (internal organ systems of the body)**__
* consists of the **sympathetic and parasympathetic** branches

Sympathetic branch

* responsible for activating the **fight-or-flight response**
* Increases heartbeats or blood pressure
* Increases dilation of lungs for more oxygen in blood stream

Parasympathetic branch

* associated with the **state of relaxation**; activation serves to decrease the fight-or-flight response 
* Restoration


* Calm down the fight or flight response
* Decrease arousal when we realize that the stressor in the environment is not dangerous

Endocrine System

A system of organs & glands that __secrete hormones__ into our bloodstream which *act as biochemical messengers* to their __target cells & organs__ 

The **primary command centre** of the endocrine’s stress response is in the

hypothalamus (paraventricular nucleus)

one of the primary target organs in the endocrine’s stress response is in

adrenal gland

Adrenals

* glands sitting atop the kidneys
* contains adrenal cortex and adrenal medulla

Adrenal Cortex

**outer covering** of the adrenal glands, responsible for **secreting glucocorticoids**

Adrenal Medulla

**inner cor**e of the adrenal glands, responsible for **secreting the catecholamines epinephrine & norepinephrine** 

Sympathetic-Adrenal-Medulla Axis (SAM Axis)

* Forms one of the primary systems of the fight-or-flight response

Describe the process of the Sympathetic Adrenal Medulla (SAM) Axis

1. signals from **brainstem → to paraventricular**
2. **pv** → **sympathetic nervous system**
3. **sympathetic nervous system** → **adrenal medulla**
4. **adrenal medulla** secretes __catecholamine and epinephrine__

Norepinephrine and Epinephrine

keep the body __vigilant & able__ to deal with stress by prompting **alertness & increasing blood flow** to the *skeletal muscles*, to ensure they are ready to act  

Epinephrine (Adrenaline)

* Affects the cardiovascular system → **increase in heart rate & constriction & dilation of blood vessels** to shunt blood away from the  outer periphery & digestive systems, and into the brain & large skeletal muscles  
* Dilates lungs
* stimulates the release of glucose into the bloodstream
* increases metabolic rate 
* Generally, has the __same effect__ as the s**ympathetic nervous system** on its target organs 

Norepinephrine

* has much of the same effects as epinephrine
* Physical stressors
* Anger

Hypothalamic Pituitary Adrenal (HPA)

* A primary system of the fight-or-flight response
* slower involving the release of many hormones → immune suppression

in the HPA axis the __**The paraventricular nucleus**__ of the __**hypothalamus**__ recognizes the

homeostatic imbalance

in the HPA axis the __**Hypothalamus**__ influences the **----** by secreting **CRH** into the **----**

**pituitary gland** ; **anterior pituarity**

pituitary gland

gland at the **base of the brain** consisting of an __anterior and posterior region__

**CRH** stimulate the anterior pituitary to secrete __**----**__ into the bloodstream

__**ACTH & beta-endorphins**__

beta-endorphine

* **a natural opiate** that has a **strong pain-relieving effect** 
* Adapt to not feel anything to fight off danger

__**ACTH**__ stimulates the __**adrenal cortex**__ to __**release ----**__

 glucocorticoids: play an important role in the fight-or-flight response

Cortisol

* **raises glucose levels in the bloodstream**, prepares stress responses by increasing catecholamine synthesis  → aimed to restore homeostasis
* Short term → homeostasis is restored

Psychological & physical stressors __increase cortisol__ levels (T/F)

True

Cortisol is the *body’s primary glucocorticoid* secreted by the __**pituarity gland**__ during the fight-or-flight response (T/F) 

False; Adrenal cortex