Health Sciences 1001A/B Lecture Notes - Sympathetic Nervous System, Hans Selye, Autonomic Nervous System

41 views5 pages
Published on 19 Apr 2013
School
Western University
Department
Health Sciences
Course
Health Sciences 1001A/B
Professor
Stress: The Constant Challenge
What is Stress?:
Stress refers to:
1. Situations that trigger physical and emotional reactions = Stressor
2. The reactions themselves = stress response
Stress: the general physical and emotional state that accompanies the stress response
Responses to Stressors:
- The primary determinant of the health consequences of stress is how the individual
responds to the stress
Responses to stress include:
- Physical changes
- Emotional and behavioural responses
Physical Responses to Stressors:
Two control systems are responsible for the physical responses to stessors:
1. Nervous system
2. Endocrine system
Nervous System:
- Autonomic nervous system
- Sympathetic nervous system
- Activated during arousal and emergency situation (pain, anger, fear)
- Releases norepinephrine which commands body to mobilize energy resources to respond
to crisis and causes arousal (increases attention and alertness) when released in the brain
Endocrine System:
- The system of glands, tissues, and cells that help control body functions by releasing
hormones and other chemical messengers into the bloodstream
- Help prepare the body to respond to a stressor
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in
Brain detects threats:
- Neurochemical message sent to hypothalamus which releases chemical to pituitary gland
which releases adrenocorticotropic hormone (ACTH) into the bloodstream
- ACTH reaches adrenal glands which release cortisol and other key hormones into the
bloodstream
Simultaneously:
- Sympathetic nerves instruct adrenal glands to release the hormone norepinephrine
(adrenaline) which triggers several bodily changes
- Examples include acute hearing and vision, increase in heart rate, increase in perspiration
rate
Fight or flight reaction (Sir Walter Cannon)
**Physical changes vary in intensity but the same physical reactions occur in response to both
positive and negative stressors
Homeostasis
- A state in which blood pressure, heart rate, hormone levels, and other vital functions are
maintained within a narrow range of normal
- Once a stressful situation ends, the parasympathetic division of the ANS initiates
adjustments necessary to restore homeostasis
Fight or flight in Modern Life
- A survival mechanism that is part of our biological heritage
- Not often necessary many stressors we encounter do not require a physical reaction
- Fight or flight reaction prepares the body for physical action regardless of whether it is an
appropriate response
Emotional and Behavioural Responses to Stressors:
Tend and Befriend
- In addition to fight or flight, humans may respond to stress with social and nurturant
behaviours
- Especially characteristic of females; female response to stress evolved to protect self and
offspring
- May depend on underlying biological mechanisms (e.g the hormone oxytocin)
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Document Summary

Stress refers to: situations that trigger physical and emotional reactions = stressor, the reactions themselves = stress response. Stress: the general physical and emotional state that accompanies the stress response. The primary determinant of the health consequences of stress is how the individual responds to the stress. Two control systems are responsible for the physical responses to stessors: nervous system, endocrine system. Activated during arousal and emergency situation (pain, anger, fear) Releases norepinephrine which commands body to mobilize energy resources to respond to crisis and causes arousal (increases attention and alertness) when released in the brain. The system of glands, tissues, and cells that help control body functions by releasing hormones and other chemical messengers into the bloodstream. Help prepare the body to respond to a stressor. Neurochemical message sent to hypothalamus which releases chemical to pituitary gland which releases adrenocorticotropic hormone (acth) into the bloodstream. Acth reaches adrenal glands which release cortisol and other key hormones into the bloodstream.

Get OneClass Grade+

Unlimited access to all notes and study guides.

YearlyMost Popular
75% OFF
$9.98/m
Monthly
$39.98/m
Single doc
$39.98

or

You will be charged $119.76 upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.