Homeostasis N Stress

Week 1

What is homeostasis regulated by

Feedback loops

What are the three components of a control system (feedback loop)

Sensor, integrator (control centre) n effector

What is a negative feedback loop

Regulates homeostasis by reversing stimulus

What is a positive feedback loop

Does not regulate homeostasis, increase/promote stimulus

What can stress contribute to | 2

• Production/exacerbation of a disease

• Development of behaviours that may increase the risk of disease

What are stressors

Events or agents responsible for initiating a stress response

What are stress responses influenced by | 2

Nervous and endocrine systems

What is a stress hormone hangover

After a stress response the hormones involved begin to disappear n residual affects

What may a pt feeling after a stress hormone hangover | 4

Headaches, nausea, insomnia n emotional disturbances

What are five stress hormones

• Corticotropin-releasing factor (CRF)

• Adrenocorticotropic hormone (ACTH)

• Cortisol

• Angiotensin II

• Antidiuretic hormone (ADH)

What’s important to note about the immune response w/stress

The stress response supresses the immune response

What is important to note about the corticotropin-releasing factor (CRF) | 2

• Secreted by hypothalamus

• Induces secretion of adrenocorticotropic hormone from the anterior pituitary gland

What is adrenocorticotropic hormone (ACTH) | 2

• Secreted by the anterior pituitary gland

• Stimulates the secretion of cortisol (glucocorticoid hormone) from the adrenal glands

What is cortisol | 3

• Secreted by adrenal glands

• Functions within stress response

• Maintains BGL, enhances effects of CV catecholamines, inhibits less essential activities

What is angiotensin II | 2

• Stimulates the release of norepinephrine, enhances CRF formation n release n causes vasoconstriction

• Part in renin-angiontensin-aldosterone system (RAAS)

What is antidiuretic hormone (ADH) | 3

• Aka vasopressin

• Secreted by posterior pituitary gland

• Increased water retention by kidneys, vasoconstriction