Lab 5: Physiology of Stress

Question 1

What is eustress?

Answer 1

Prepares us to meet certain challenges and is therefore beneficial

Question 2

What is distress?

Answer 2

Harmful stress

Question 3

What is a stressor?

Answer 3

Any stimulus that produces a stress response in the body

Question 4

Define the stress response or general adaptation syndrome.

Answer 4

A variety of stressful conditions will elicit a similar sequence of changes in the body.

Question 5

What are the 3 stages of the stress response?

Answer 5

1. Fight-or-flight
2. Resistance reaction
3. Exhaustion

Question 6

What is the fight-or-flight (alarm phase)?

Answer 6

Occurs shortly after the stressful event and gives people a burst of energy (blood glucose incr. and heart rate incr. to deliver more nurtients to the body’s tissues)

Question 7

What happens in the resistance phase?

Answer 7

Longer-lasting response intiated by the endocrine system to help the body continue fighting a stressor long after the fight-or-flight response dissipates.

Question 8

What happens in the exhaustion phase?

Answer 8

If the stress continues, the body will enter the exhaustion phase in which the body has depleted its energy resources by continually trying to respond to the stressor.

Question 9

What is the stress response regulated by?

Answer 9

Activation of the stress response is controlled by the hypothalamus, which recieves a variety of stress signals from the amygdala.

Question 10

What are the 2 stress pathways the hypothalamus can activate?

Answer 10

1. Autonomic response: a fast, neurally-mediated pathway
2. Endocrine response: slower, but long lasting

Question 11

How is the fight-or-flight response intitated?

Answer 11

• action potentials from the hypothalamus activate the sympathetic division of the ANS
• the hypothalamus activates preganglionic neurons that project to autonomic ganglion outside the CNS
• postganglionic neurons that project to the effector tissues

Question 12

What neurotransmitters are involved in activating the fight-or-flight response?

Answer 12

• pre. ganglionic neurons from the hypothalamus release aCH onto nicotinic cholinergic receptors on the post. ganglionic neuron
• post. ganglionic neuron release Norep which binds to receptors on the target tissue

Question 13

What is the difference in blood flow when activating a-receptors or b-receptors?

Answer 13

• Activation of a-receptors results in vasoconstriction
• Activation of b-receptors resuls in vasodilation

Question 14

Where would we find B2-receptors?

Answer 14

• blood vessels to heart, skeletal muscle, and liver

Question 15

How does activation of the HPA axis sustain energy during the resistance phase?

Answer 15

1. HPA is activated by hypothalamus in response to stress and secretes CRH
2. Directs the anterior pituitary to release ACTH
3. ACTH directs the adrenal cortex to secrete cortisol to help mobilize energy

Question 16

What effects does cortisol have to mobilize energy?

Answer 16

• promotes gluconeogenesis in the liver
• lipolysis in adipose tissue
• protein catabolism in skeletal muscle

Question 17

What is the cold-pressor test?

Answer 17

A clincial test to evaluate cardiovascular autonomic function by immersing the hand and arm into an ice water bath and measuring changes in blood pressure, heart rate, and/or cortisol

Question 18

Where would we find glucocorticoid receptors?

Answer 18

• adipose tissue
• liver
• skeletal muscle

Question 19

Where would we find alpha receptors?

Answer 19

• blood vessels to GI tract
• pancreas

Question 20

Where would we find beta receptors?

Answer 20

• adipose tissue
• liver
• skeletal muscle

Question 21

Where would we find B1 receptors?

Answer 21

Heart