Fear & Stress

Question 1

What nervous system does stress activate?

Answer 1

Stress activates the sympathetic division of
the autonomic nervous system

• Fight or flight response

Question 2

What is the HPA axis?

Answer 2

Stress activates the HPA axis

Hypothalamic-pituitary-adrenal (HPA) axis

Question 3

What brain area controls the stress response?

Answer 3

The medulla is a key control center for activating the response of the sympathetic nervous system

The medulla can be activated by other neurons in the brainstem: locus coeruleus, dorsal raphe

Question 4

What neurotransmitters are released by the adrenal gland as a result of sympathetic nervous system activation?

Answer 4

adrenaline and norepinephrine.

Question 5

How does stress affect the immune system?

Answer 5

Stress can affect immune system function through the sympathetic nervous system (noradrenaline and adrenaline) and through the HPA axis (glucocorticoid hormones)

Stress impairs some aspects of immune system function but enhances others

Question 6

What is the innate immune system?

Answer 6

When stress enhances the response of the immune system

Question 7

What is the adaptive immune system?

Answer 7

When stress impairs the nervous system

Question 8

What is stress resilience?

Answer 8

Resilience = ability to return to a balanced
state quickly

Question 9

What is the effect of more vs. less receptors?

Answer 9

more Glucocorticoid receptors = more negative feedback, shorter stress response

less Glucocorticoid receptors = less negative feedback, longer stress response

Question 10

What does maternal attention do in pups?

Answer 10

increases glucocorticoid expression in HPC

• Pups are less reactive to stress

Childhood abuse -> less HPC glucocorticoid
receptors -> vulnerability to stress

Question 11

What is extinction?

Answer 11

Extinction: the cue becomes disassociated with the fear memory

• The fear memory is NOT erased
• Suppression of fearful behavior in response to CS

Question 12

What is the mPFC (medial prefrontal cortex)?

Answer 12

It mediates fear extinction recall

mPFC is necessary for extinction recall

Question 13

What is the hypothalamus?

Answer 13

plays a crucial role in regulating various bodily functions, including hunger, thirst, body temperature, and circadian rhythms.

It also plays a key role in controlling the release of hormones from the pituitary gland, which in turn regulates the activity of other endocrine glands throughout the body.

Question 14

What is the pituitary?

Answer 14

produces and secretes a number of important hormones, including growth hormone, prolactin, luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, and oxytocin.

Question 15

What are adrenal glands?

Answer 15

The adrenal glands are two small glands located on top of each kidney.

They are responsible for producing hormones such as adrenaline, which helps the body respond to stress, and cortisol, which plays a role in regulating metabolism and immune function.

Question 16

What are the two forms of stress response?

Answer 16

1) sympathetic nervous system response

2) HPA

Question 17

What is the SNS response?

Answer 17

The SNS response is a rapid, short-term response that prepares the body for action in response to a stressor.

It involves the release of adrenaline and noradrenaline from the adrenal glands, which increases heart rate, blood pressure, and breathing rate, and causes the body to divert blood flow to the muscles.

Question 18

What is the HPA axis response?

Answer 18

The HPA axis response is a slower, longer-lasting response that involves the release of cortisol from the adrenal glands.

It begins with the release of corticotropin-releasing hormone (CRH) from the hypothalamus, which stimulates the release of adrenocorticotropic hormone (ACTH) from the pituitary gland.

ACTH then stimulates the adrenal glands to release cortisol.

Cortisol increases blood sugar levels, suppresses the immune system, and helps the body to mobilize energy stores.

Question 19

What is the negative feedback loop?

Answer 19

neurons in the hippocampus detecting elevated cortisol levels and telling the hypothalamus to quiet down

In the context of the stress response, the negative feedback loop involves the detection of elevated cortisol levels by neurons in the hippocampus.

These neurons then send a signal to the hypothalamus to reduce the release of corticotropin-releasing hormone (CRH), which in turn reduces the production of adrenocorticotropic hormone (ACTH) by the pituitary gland.

ACTH stimulates the adrenal glands to produce cortisol, which is the primary stress hormone.

Therefore, by reducing the release of CRH, the negative feedback loop acts to bring cortisol levels back to normal and prevent excessive activation of the stress response.