Stress

Question 1

What are stressors?

Answer 1

Stressors are stimuli that challenge the body’s homeostasis and triggers a response.

Stress and stressors are not the same

Question 2

What is the stress response?

Answer 2

It is the body’s response to the challenge of a stressor. Involves physiological and behavioural changes that attempt to cope with or escape the stressor

Question 3

What does the stress response accomplish?

Answer 3

1. Temporarily put brain into overdrive in order to deal with stressor
2. Suspends bodily repair, construction, and growth ti deal with stressor

Question 4

Who was the first scientist to characterize stress?

Answer 4

Hans Selye

Question 5

What are Selye’s 3 stages in the general adaptation syndrome model called and what do they do?

Answer 5

1. Alarm: Initial reaction to stressor, fight or flight
2. Resistance: Psychological adaptations take place to cope with prolonged stressors ( Involves cortisol and HPA axis)
3. Exhaustion: Physiological resources depleted as body cannot cope with prolonged stressors (diseases appear here)

Question 6

What are the 2 pathways involved in the stress response?

Answer 6

• The sympatho-adrenomedullary axis (SAM)
• Thehypothalamic-pituitary adrenal axis (HPA)

Question 7

What does the SAM axis do?

Answer 7

The SAM is known as the fast pathway. It mediates the initial “alarm” phase of the stress response

Question 8

What does the HPA axis do?

Answer 8

It is known as the slow pathway. It mediates the physiological adaptations involved in dealing with prolonged stress.

Question 9

What is the adrenal gland?

Answer 9

The adrenal gland sits atop the kidneys. It is also critical for the stress response. It has 2 glands in 1

-The adrenal medulla
-the adrenal cortex

Question 10

What does the adrenal medulla do?

Answer 10

It secretes epinephrine (adrenaline) and norepinephrine (noradrenaline)

Question 11

What does the adrenal cortex do?

Answer 11

It secretes cortisol

Question 12

What are the 2 steps in the activation of the SAM axis?

Answer 12

1. Neural circuits in hypothalamus project to spinal cords, they synapse with neurons of the sympathetic nervous system (SNS)
2. SNS neurons project adrenal medulla, adrenal medulla releases the cathecholamines epinephrine and norepinephrine into circulation

Question 13

what are the effects of epinephrine and norepinephrine?

Answer 13

-increased heart rate
-bronchodilation
-decreased digestion
-increased BP

Question 14

What are the 3 steps in HPA axis activation?

Answer 14

1. Hypothalamus releases corticotropin releasing hormone (CRH) into anterior pituitary (AP)
   2 . CRH stimulates AP to release adrenocorticotropic hormone (ACTH) into general circulation.
2. ACTH stimulates release of cortisol from adrenal cortex

Question 15

What are the properties of cortisol?

Answer 15

-it is a steroid hormone
-released by adrenal cortex, member of the glucocorticoids
-a ligand for 2 main types of receptors which are mineralocorticoid receptors and glucocorticoid receptor, both are widespread throughout the whole body which allows cortisol to have widespread effect on almost all body systems

Question 16

What type of receptors Mineralocorticoid and Glucocorticoid receptors?

Answer 16

They are transcription factor type receptors. When they bind with their ligands , they act to increase expression of certain stress-response genes

Question 17

What are cortisols metabolic effects?

Answer 17

-reduced bone and connective tissue formation
-increased breakdown of lean body mass
-increased blood sugar level by stimulatory hepatic gluconeogenesis and glycogenolysis
-altered sensitivity if tissues to other hormones

all these together are useful in short term demands of a stressor

Question 18

How does stress impair cognition?

Answer 18

Stress tends to surpress higher level reasoning, flexible thinking, and memory. Also increases anxious, fearful thinking. Stress can improves performances in simples, well rehearsed tasks

Question 19

How is the prefrontal cortex affected by stress?

Answer 19

PFC is involved in concentration, planning, decision making, insight, judgement, error detection, and memory retrieval. Stress weakens the influence of the PFC and allows more primitive parts of brain take over which is not good

Question 20

What happens when the PFC is affected by stress

Answer 20

We give into our impulses and compulsive behaviour.