Endocrine Systems and Receptors Flashcards
What are some membrane bound receptors?
Ligand gated ion channel = response occurs in milliseconds
G-protein coupled receptor = cellular response occurs in seconds
Receptor tyrosine kinase = response occurs in hours
How does autocrine regulation occur?
Chemicals released from the cells bind to receptors on or in the cell that is releasing them
How does paracrine regulation occur?
Chemicals released from the cells bind to receptors on adjacent cells
How does endocrine regulation occur?
Chemicals released from the secretory cells are usually transported via he circulatory system
What does maintaining homeostasis require?
Coordinated efforts of multiple organ systems
What are the two general regulatory mechanisms of homeostasis?
Intrinsic regulation = autocrine and paracrine signalling
Extrinsic regulation = nervous system and endocrine hierarchical control
What are the two methods of feedback control?
Positive feedback = initial stimulus produces a response that exaggerated the change
Negative feedback = resists physiological deflections away from the body’s set point
What is the primary mechanism of maintaining homeostasis?
Negative feedback control = provides long term control over internal conditions by opposing change
How does cortisol affect the hypothalamic pituitary adrenal axis?
Elevated cortisol levels exert negative feedback on both CRH and ACTH secretion
What are the actions of cortisol?
Stimulates gluconeogenesis, protein breakdown and liberation of free fatty acids, immune system suppression, facilitated stress response, maintains blood pressure
What are physiological functions maintained within?
A normal range (rather than a fixed value)
When May physiological set points vary?
According the changing environments or activity
What determines homeostatic set points?
Genetics, age, gender, health status and the environment
