Endocrine System March 4 Flashcards
What is a hormone?
Chemical that is secreted into and transported via blood stream to activation site anywhere in the body
What is homeostasis?
The state of the body being in physiological balance
What does negative feedback do?
Keeps physiology in narrow parameters; if something moves too far outside of normal parameters, it is ‘shut off’ and an opposite reflex will move it in another direction
What happens when negative feedback fails?
It is decompensated; a failure of a very basic homeostatic mechanism
When is positive feedback present?
In only a few processes, such as childbirth, inflammation, and clotting
What is the primary control center for other endocrine organs?
Hypothalamus
What hormones does the hypothalamus release?
- Corticotropic Releasing Hormone (CRH) * Growth Hormone Releasing Hormone (GHRH) * Thyrotropin Releasing Hormone (TRH)
What does ACTH stimulate?
Adrenal glands to release stress hormones (glucocorticoids and mineralocorticoids)
What are the roles of glucocorticoids?
- Metabolism * Cardiovascular system * Immunity
What is the General Adaptation Syndrome (GAS)?
The body’s stress response mechanism, consisting of three phases: Alarm, Resistance, Exhaustion
What occurs during the Alarm phase of GAS?
SNS releases Epi and NE from adrenal glands; ‘Fight or Flight’ response
What role does the thyroid gland play?
Produces and stores hormones (T3 & T4) that increase basal metabolic rate and stimulate ATP production
What are the main hormones produced by the pancreas?
- Glucagon (from alpha cells) * Insulin (from beta cells)
What does erythropoietin (EPO) do?
Stimulates RBC production in response to low O2 levels in kidneys
What hormones do the ovaries produce?
- Estrogen * Progesterone * Inhibin * Relaxin
What is the role of testosterone?
Male sex characteristics and spermatogenesis
What is the function of Atrial Natriuretic Peptide (ANP)?
Decreases fluid reabsorption by kidneys
What are the two global body responses that dictate hormone responses?
Sympathetic and Parasympathetic
Fill in the blank: The hypothalamus is the primary _______ center in the body.
homeostatic
True or False: Positive feedback continues until a stimulus is completely removed.
True
What are the phases of the General Adaptation Syndrome?
- Alarm * Resistance * Exhaustion
What does cortisol do in the body?
Maintains a ‘fight or flight’ state and regulates metabolism
What is the primary function of the kidneys in relation to blood pressure?
Release renin in response to low blood volume or blood pressure
What is the role of calcitonin?
Decrease Ca+ blood levels and decrease bone breakdown
