Intro to Endocrinology Flashcards
What is endocrinology?
Study of the endocrine glands and tissues that secrete hormones which impact homeostasis and reproduction
What does endocrine physiology emphasize?
Homeostasis
What does the endocrine system regulate?
Its a key controller of homeostasis, regulating basal metabolic rate (BMR), growth, etc. but also electrolytes, volume and fuel sources (glucose, fats, etc.)
What is the central role of the hypothalamus?
Maintaining homeostasis, particularly in the endocrine system
What hormones originate in the hypothalamus?
Releasing hormones: GnRH, CRH, TRH, CHRH. Inhibitory hormones: Somatostatin, Dopamine
What hormones originate in the Thyroid gland?
T3, T4, Calcitonin
What hormones originate in the Adrenal Gland?
Cortisol, Aldosterone, Androgens, Estrogens, Epinephrine
What hormones originate in the ovaries?
Estradiol, Progestrone
What hormones originate in the pituitary gland?
Anterior pituitary: ACTH, TSH, FSH, LH, Growth Hormone, Prolactin. Posterior pituitary: Vasopressin, Oxytocin
What hormones originate in the Parathyroid Gland?
Parathyroid hormone
What hormones originate in the Pancreas?
Insulin, Glucagon, Somatostatin
What hormones originate in the testes?
Testosterone
What secretes hormones?
Secreted by endocrine glands and tissues, typically acting at distal site
What are three types of hormones?
Protein, steroid, amine
At what concentrations are the effects of hormones excepted?
VERY SMALL concentrations (nano- to pico- molar levels)
What do hormones bind?
Bind carrier proteins in serum
What types of effects to hormones have?
Endocrine, paracrine and autocrine effects
Where do hormones act?
On receptors on target cells
What do hormones activate?
Secondary messenger systems and/or transcription in target cells
What body systems and functions are hormones critical for?
Growth and development, Respiration, excretion, metabolism, Reproduction, Electrolyte balance.
What does the hierarchy of the endocrine system involve?
Hypothalamus, Pituitary gland and maybe a third endocrine gland and a bunch of hormones.
What does the hypothalamus integrate?
Many homeostatic and reproductive signals.
What does the secretion of hypothalamic hormones regulate?
Anterior pituitary hormone production and secretion.
What do some hypothalamic neurons do?
Extend into the posterior pituitary from which hormones can be released.
In what bone does the pituitary gland sit?
Sphenoid bone
What is the Anterior pituitary?
A true endocrine gland of epithelial origin.
What is the Posterior pituitary?
An extension of the neural tissue.
What is the Infundibulum?
The stalk that connects the pituitary to the brain/hypothalamus.
How does the Hypothalamus interact with the Posterior Pituitary?
Hypothalamic neurons which produce the hormones oxytocin and vasopressin project into the posterior pituitary. With appropriate signals, hormones are released from these hypothalamic neurons in the posterior pituitary and immediately enter the general circulation. Target cells see these hormones rapidly after release.
What is the process by which the hypothalamus causes release of hormones from posterior pituitary?
- Hormone is made and packaged in cell body of neuron. 2. Vesicles are transported down the cell. 3. Vesicles containing hormone are stored in posterior pituitary. 4. Hormones are released into blood.
What is Levothyroxine?
Third most prescribed drug, for hypothyroidism, supplementary thyroid hormone
What are all hormones inhibited by?
Negative Feedback!
What is the stimulus for ADH?
High osmolarity
