Chapter 5 The Endocrine System Flashcards
What are the three classifications of hormones?
- Peptide hormones (can travel thru blood)
- Amino acid derivatives
- Steroids (cannot travel thru blood on own)
What is a direct hormone?
A direct hormone is a hormone that directly stimulates a physiological change and act directly on a target tissues. This is in contrast to tropic hormones.
What is a tropic hormone?
A tropic hormone is a hormone that acts as a second messenger which goes on to stimulate other hormones.
What are the 8 endocrine glands?
The hypothalamus, the pituitary, the pineal, thyroid, parathyroid, adrenal, pancreas, and the gonads.
What are the two divisions of the pituitary?
The anterior (front) and posterior pituitary (back)
The hypothalamus and pituitary are connected by what “system”?
The hypophyseal portal system, which is within the pituitary stalk.
What are the 4 hormones released by the hypothalamus intended for the anterior pituitary?
- Thyroid Releasing Hormone (TRH)
- Gonadotropin-releasing hormone (GnRH)
- Growth hormone-releasing hormone (GHRH)
- Corticotropin
When stimulated by the hypothalamus, the posterior pituitary releases what two hormones?
- Oxytocin
2. Antidiruetic Hormone (ADH)
What is the goal of ADH (Antidiuretic Hormone)
The goal of this is to reserve water and decrease release via the kidneys. This increases blood osmolarity (more water in blood).
What are the 7 hormones released by the anterior pituitary? (FLATPEG)
Follicle stimulating hormone (FSH)
Lutenizing Hormone
Adrenocorticotropic Hormone (ACTH)
Thyroid stimulating hormone (TSH)
Prolactin Endorphins Growth Hormone (GH)
What does Prolactin do?
Prolactin stimulates milk production in the mammary glands. This is a unique hormone in that dopamine release decreases prolactin secretion.
What are endorphins?
Endorphins mask the perception of pain
What hormone contributes to gigantism and dwarfism?
Growth Hormone is the cause of both of these conditions. Too much GH pre-puberty will result in gigantism and too little will cause dwarfism.
What are the Thyroid’s 2 main functions?
- Setting Basal Metabolic Rate
2. Maintaining Calcium Homeostasis
What hormones are release by the thyroid and what do they do?
- T3 and T4 - Increased amounts = increase cell. respiration
- Calcitonin - increased amounts = less blood calcium
What does T3 and T4 do?
T3 and T4 speeds up BOTH degradation and synthesis of fatty acids and proteins
T3 and T4 work by negative feedback. If there are high amounts of T3 and T4, what hormone(s) would you expect to be inhibited?
- TRH (from hypothalamus)
2. TSH (from pituitary)
Calcitonin released by the thyroid gland does what 3 things to control calcium levels?
- Induces calcium secretion in kidneys
- Inhibits calcium uptake in gut
- Increase calcium storage in bone
The parathyroid gland’s goal is to what?
The goal is to INCREASE blood calcium levels by doing quite the opposite of what the thyroid gland does.
What hormone is released by the parathyroid gland to maintain increased blood calcium levels?
Parathyroid Hormone (PTH)
What 3 classes of hormones are released by the adrenal Cortex?
- Glucocorticoids
- Mineralocorticoids
- Cortical sex hormones
What are the main glucocorticoids and what do they do?
The main ones are cortisol and cortisone. These both increase blood glucose levels AND regulate protein synthesis. They do this via increasing gluconeogenesis and decreasing protein synthesis.
What upstream hormones control the adrenal cortex’s release of glucocorticoids?
The hypothalamus releases Corticotropin relasing factor (CRF) which stimulates the pituitary to release ACTH (AdrenoCorticotropic Hormone) which stimulates adrenal cortex production of the glucs.
What is the main mineralcorticoid hormone released by the adrenal cortex, and what does it do?
Aldosterone; this hormone controls blood volume & pressure - note that this hormone only increases volume and does not change blood osmolarity, that is, it does not change the molarity of sodium/other ions in the blood.
