Podcast
Questions and Answers
What happens to the negative feedback system in chronic stress?
What happens to the negative feedback system in chronic stress?
Which receptor primarily binds norepinephrine to increase total peripheral resistance (TPR)?
Which receptor primarily binds norepinephrine to increase total peripheral resistance (TPR)?
What is a consequence of prolonged activation of the stress response system?
What is a consequence of prolonged activation of the stress response system?
Which syndrome is characterized by excessive cortisol levels due to overactivation of the HPA axis?
Which syndrome is characterized by excessive cortisol levels due to overactivation of the HPA axis?
Signup and view all the answers
What is a potential effect of chronic stress on cardiovascular health?
What is a potential effect of chronic stress on cardiovascular health?
Signup and view all the answers
What primary physiological response is activated by stressors in the body?
What primary physiological response is activated by stressors in the body?
Signup and view all the answers
Which hormone is primarily associated with anti-inflammatory responses during stress?
Which hormone is primarily associated with anti-inflammatory responses during stress?
Signup and view all the answers
How does cortisol influence T-helper cell balance in the immune system?
How does cortisol influence T-helper cell balance in the immune system?
Signup and view all the answers
In Addison's Disease, what is the primary hormonal deficiency?
In Addison's Disease, what is the primary hormonal deficiency?
Signup and view all the answers
What is a common symptom of Cushing Syndrome?
What is a common symptom of Cushing Syndrome?
Signup and view all the answers
Which function is NOT a result of excess cortisol's action on metabolism?
Which function is NOT a result of excess cortisol's action on metabolism?
Signup and view all the answers
What condition is commonly associated with excessive DHEA production?
What condition is commonly associated with excessive DHEA production?
Signup and view all the answers
What is the primary effect of cortisol during the acute stage of stress?
What is the primary effect of cortisol during the acute stage of stress?
Signup and view all the answers
What term best describes the shift in immune response caused by cortisol?
What term best describes the shift in immune response caused by cortisol?
Signup and view all the answers
Which of the following is a consequence of prolonged excess cortisol exposure?
Which of the following is a consequence of prolonged excess cortisol exposure?
Signup and view all the answers
What is the main effect of cortisol on protein synthesis and catabolism during stress?
What is the main effect of cortisol on protein synthesis and catabolism during stress?
Signup and view all the answers
Which hormone is primarily associated with the T-helper 2 shift and immune response alteration?
Which hormone is primarily associated with the T-helper 2 shift and immune response alteration?
Signup and view all the answers
What is NOT a sign of Cushing Syndrome?
What is NOT a sign of Cushing Syndrome?
Signup and view all the answers
In Addison's Disease, what is a consequence of insufficient cortisol secretion?
In Addison's Disease, what is a consequence of insufficient cortisol secretion?
Signup and view all the answers
Which physiological process is a consistent outcome of HPA axis activation during stress?
Which physiological process is a consistent outcome of HPA axis activation during stress?
Signup and view all the answers
What adverse effect can result from excess levels of DHEA?
What adverse effect can result from excess levels of DHEA?
Signup and view all the answers
Which symptoms are associated with Cushing Syndrome as a result of excess cortisol?
Which symptoms are associated with Cushing Syndrome as a result of excess cortisol?
Signup and view all the answers
What occurs to fat distribution in the body under long-term exposure to cortisol?
What occurs to fat distribution in the body under long-term exposure to cortisol?
Signup and view all the answers
What primary hormonal imbalance is noted in Addison's Disease?
What primary hormonal imbalance is noted in Addison's Disease?
Signup and view all the answers
Which of the following can be an outcome of the increased anti-inflammatory effects of cortisol?
Which of the following can be an outcome of the increased anti-inflammatory effects of cortisol?
Signup and view all the answers
Study Notes
Cortisol
- Cortisol is secreted by the adrenal cortex and is a significant component of the stress response
- Influences protein synthesis and catabolism
- Increases protein synthesis in the liver
- Promotes catabolism in the muscles
- Works synergistically with glucagon and epinephrine
- Promotes lipolysis (breakdown of fatty acids) in the extremities
- Acute stage - Promotes the breakdown of fatty acids for energy
- Long-term - Redistributes fat, promotes lipogenesis in the face, and trunk
- Cushingoid signs - Fat pad at the back of the neck (buffalo hump), moon face, or increased abdominal fat
- May be linked to increased autoimmune responses
- Linked to decreased levels of IL-1, 2, 6, and TNF-a which helps limit damage
- Causes a T-helper 2 (Th2) shift, increasing immunity
- Th1 - Promotes cell-mediated immunity (immune system directly attacks infected cells)
- Th2 - Increases humoral immunity (antibody production and defense against pathogens)
- A balance of Th1 & Th2 is required to prevent immune dysfunction
- Cortisol suppresses Th1, decreasing cellular immunity
- Cortisol promotes Th2, increasing humoral immunity and anti-inflammatory response
- This is called the T-helper 2 shift
Addison Disease
- Characterized by low cortisol and mineralocorticoid secretion
- Reduced cortisol levels limit required hormonal effects
Cushing Syndrome/Disease
- Characterized by excessive cortisol secretion
- May be caused by excessive corticosteroid medication
- Symptoms include: hyperglycemia (steroid diabetes), hypertension edema, poor wound healing (risk for infection), and Cushingoid signs
Zona Reticularis
- Innermost layer of the adrenal cortex
- Produces gonadocorticoids, primarily DHEA (dehydroepiandrosterone)
- DHEA is a weak androgen that regulates male/female traits
- DHEA and its sulphated form (DHEA-Sulphate) are converted to testosterone (males) or estrogen (females)
- Excess DHEA can lead to increased virilisation (male traits in females) or hirsutism (facial hair in women)
- Common in PCOS (Polycystic Ovarian Syndrome)
Hypothalamic-Pituitary-Adrenal Axis (HPA)
- The HPA is the physiological response to stress
- No matter the stimuli or stressor, the response is always the same
- Exogenous stressors: e.g. Heart disease - A person may not have the cardiac reserve to cope with catecholamine surge during stress
- The stress response involves:
- Hypothalamus - Stimulates the locus ceruleus, activating the sympathetic nervous system (SNS)
- Adrenal Medulla - Releases catecholamines
- β-1 receptor - Increases heart rate (HR) and contractility, and dilates bronchioles (mainly binds epinephrine)
- α-1 receptor - Increases total peripheral resistance (TPR) (mainly binds norepinephrine)
- Adrenal Cortex - Releases cortisol and aldosterone
Chronic Stress Feedback
- Function
- Negative feedback systems become blunted and desensitized, losing responsiveness to increased cortisol levels
- Increased cortisol causes the hypothalamus to secrete more CRF (corticotropin-releasing factor)
- Increased cortisol causes the anterior pituitary to secrete more ACTH (adrenocorticotropic hormone)
- Corticoid effects are greater than catecholamine effects
- Consequences
- Neural and hormonal pathways become dysfunctional with prolonged activation, leading to overactivation of the HPA axis
- Loss of muscle mass due to gluconeogenesis and protein catabolism
- Nitrogen depletion due to muscle catabolism
- Increased nitrogen excretion in urine
- Immune suppression through decreased T-cells and thymic atrophy
- Hyperglycemia
- Cardiovascular wear and tear due to constant catecholamine release
- Impact:
- Symptoms: Hypertension, renal and vascular disease, sustained hyperglycemia
- Example: Controlled diabetes are harder to manage in hospital settings due to the stress response
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
