Lecture 10

Question 1

What is stress?

Answer 1

Effects of factors that act on the body to increase energy consumption above basal level.

Question 2

What is an stressor?

Answer 2

A stressor is anything that throws the body out of homeostatic balance.

Question 3

What is the stress response?

Answer 3

A series of physiological and behavioral responses that serve to re-establish homeostasis.

Question 4

Homeostasis

Answer 4

It is the process by which the body maintains a relatively constant internal stability

Question 5

Allostasis

Answer 5

Achieving stability through physiological or behavior change (stress-specific)

Question 6

Describe the Allostatic load?

Answer 6

The cumulative cost incurred by the body during allostasis (chronic stress effects)

Question 7

Two endocrine responses to stress?

Answer 7

Two endocrine systems involved:
Epinephrine (adrenaline) from adrenal medulla
First respondent and it is FAST.
Glucorticoids from adrenal cortex.

Question 8

Effects of norepinephrine NE in response to stress

Answer 8

Release from locus coeruleus (to brain)
stimulates alertness
From the adrenal medulla to blood to activate vasoconstriction
From sympathetic spinal cord to target organ

Question 9

What is caused by Epinephrine EP in response to stress

Answer 9

Loss of senses (hearing, tunnel vision)
Inhibition of digestion. Increase of HR/Respiration. Vasoconstriction and dilation of large skeletal blood vessels. Dilation of pupils and bronchioles and production of glucose from glycogen. Does not cross Brain Blood Barrier (BBB)

Question 10

Glucocorticoids and stress

Answer 10

Good candidates for mediating the behavioral effects of stress. They are released in response to different stressors and can easily cross the BBB- epinephrine does not. GR (receptors) are found in the brain.

Question 11

Short term effects of the release of cortisol during stress

Answer 11

Stimulates gycogenolysis. Suppresses some immune functions and inflammatory responses. Enhances learning and NE release.

Question 12

what are other hormones involve in stress response and what are their response?

Answer 12

Vasopressin: Increases blood pressure and aggressive behavior
Β-endorphin: Inhibits pain sensation
Prolactin: Suppresses reproduction

Question 13

H-P-G Axis activation during normal response

Answer 13

Normally, low levels of prolactin stimulates testosterone production.

Question 14

H-P-G Axis activation during stress response

Answer 14

Under stress, high levels of prolactin make Lydig cells insensitive to LH AND potentiates negative feedback loops

Question 15

Adaptive effects of the stress response (fight or flight)

Answer 15

EP increases energy, glucocorticoids, O2 consumption and decreased blood flow to systems not required for escape. Opioids and canabinoids decrease pain perception. High glucose levels increase Sensory function and memory.

Question 16

General Adaptation Syndrome

Answer 16

The process of coping with stressors. Consists of three stages: Alarm reaction, Resistance and
Exhaustion

Question 17

What are the effects of Acute and Chronic stress in a individual

Answer 17

Acutely, stress is an adaptive response that allows the individual to survive
Prolonged stress shifts this useful, adaptive response to a pathological condition
Chronic Stress Inhibits wound healing.

Question 18

Effects of Prenatal Stress in Humans

Answer 18

Decreased birth weights, developmental delays. Attentional deficits, hyper-anxiety, impaired social behaviors and possible increased of schizophrenia.

Question 19

Prenatal glucocorticoid effects

Answer 19

Low birth weight, adult cardiovascular and metabolic disorders. Hypertension. Insulin resistance. Hyperlipidemia. Ischemic heart and brain disease. Behavioral problems in childhood.

Question 20

Exposure to exogenous glucocorticoids

Answer 20

Rats stressed or exposed to exogenous glucocorticoids in utero have decreased hippocampal GR, which may lead to impaired HPA negative feedback.

Question 21

Neonatal Maternal Separation (stressor)

Answer 21

Model of early-life stress. Neonates are removed from dams daily from postnatal day 1-21. 15 min separation has no effect
3 hour separation has reduced hippocampal neurogenesis. 24 hour separation: In Adults
elevated HPA axis response to stress
Increased anxiogenic-like behavior

Question 22

Psychosocial Dwarfism

Answer 22

Rare condition, observed in humans raised with little or no social contact. it is characterized by:
Lack of growth and development. Disruption of normal sleep cycles. Disruption of normal GH secretion. Lack of responsiveness to GH
Recover when placed in an environment where social and physical contact are available

Question 23

Stress and Reproductive Dysfunction

Answer 23

Reproductive behavior is suppressed in response to stress

Stress is a major contributing factor to sexual dysfunction and infertility in humans.

Question 24

Stress and Reproductive Dysfunction in Males

Answer 24

Stress inhibits testosterone synthesis

Reduces sexual motivation and performance.

Question 25

Stress and Reproductive Dysfunction in Females

Answer 25

In animals, litter size and birth weight are inversely proportional to corticosterone levels. In humans, functional hypothalamic amenorrhea (cessation of menstruation) have elevated cortisol levels

Question 26

Sex Differences in stress response

Answer 26

Female rats have higher basal levels of corticosterone than males.
In response to stress, females show higher levels of ACTH and corticosterone. This difference is activated by estrogens, Orvariectomy in adults eliminates sex difference, estradiol replacement restores it.

Question 27

Post-Traumatic Stress Disorder

Answer 27

Result of intensely stressful events
Severe behavioral (flashbacks, nightmares) and hormonal responses to stress and endocrine disregulation. Low basal levels of cortisol may predispose an individual to PTSD. Associated with reduced hippocampal volume

Question 28

Stress and sex in males

Answer 28

Stress impairs male sexual function by suppressing testosterone
Via actions at GnRH and LH

Question 29

Stress and sex in females

Answer 29

Stress effects female reproduction by inhibiting GnRH and LH and increasing testosterone.

Question 30

Effects of exposure to chronic stressor in rats

Answer 30

After 2 days: Adrenal ctx hypertrophy. Reduced immune response. Atrophy of thymus, spleen, lymph nodes.
2 weeks: No apparent symptoms
2 months: Death

Question 31

Cardiovascular Effects of stress

Answer 31

Parents who lost a child show an increase in myocardial infarction (heart attack) starting 6 years after death (especially SIDS)