Endocrine Flashcards
A number of glands can signal each other in sequence called…
Axis
What is the master gland
Pituitary gland/ hypophysis
The pituitary gland is subdivided into ANT and POST, what is the cell origin of each?
ANT- Epithelial
POST- Nervous
What are the names of the ANT and POST divisions of the hypophysis gland?
Adenohypophysis
Neurohypophysis
What types of cells are found in the adenohypophysis?
Chromophils (acidophil and basophil)
Chromophobes
What hormone does Acidophils (from ANT lobe of pituitary) secret? And what do they do?
Growth Hormone (GH) Growth plates
Prolactin (LTH) mammary gland acini
What hormone does Basophil (from ANT lobe of pituitary) secret? And what do they do?
Thyrotropic hormone (TSH)
Follicle-Stimulating Hormone (FSH) and luteinizing hormone (LH)
Adrenocorticotropic hormone (ACTH) and lipotropic hormone (LPH)
What are Chromophobe cells?
Non-secreting, dormant cells that proliferate into chromophils
What are Chromophobe cells?
Non-secreting, dormant cells that proliferate into chromophils of the anterior pituitary gland
What is the axis of Growth hormone releasing hormone (GH-RH)
Simulates acidophils to produce GH
What is the axis of Dopamine?
Inhibits acidophils producing prolactin.
What is the axis of Thyrotropin-releasing hormone (TRH)
Stimulates basophils to secret TSH
What is the axis of Gonadotropin-releasing hormone (GnRH)
Stimulates basophils to secret FSH and LH
What is the axis of Corticotropin-releasing hormone (CRH)
Stimulates basophils to secret ACTH and LPH
What do pituicytes do?
Regulate secretion from nerve cells of neurohypophysis
Unmyelinated nerve fibers of the Neurohypophysis are derived from neuro secretory cells of the Supraoptic and Paraventricular hypothalamic nuclei. What do they secret?
Paraventricular nucleus- oxytocin
Supraoptic nucleus- antidiuretic hormone (ADH)
Accumulating hormone bound granules are stored near axon terminals in what?
Herring bodies
What is the fluid inside follicles of the thyroid gland called?
Colloid
Follicles of the thyroid gland have a single cuboidal epithelial layers that are the only cell able to absorb what molecule?
Iodine
What is found in the follicles of the thyroid gland?
Thyroglobulin, enzymes, T3 and T4, Iodine
Follicular cells are also known as…
principal cells
Explain the regulation of thyroid hormone production.
T3 and T4 concentration in blood is monitored. If levels are low, hypothalamus releases TRH, triggering TSH released from pituitary. This will trigger release of T3 and T4 by thyroid follicle cells. This will increase metabolic rate of body cells and raise body temperature.
Via negative feedback, elevated T3 and T4 levels inhibit release of TRH and TSH from hypothalamus and anterior pituitary.
Name the cells of the thyroid gland
Follicular cells
Para follicular cells
What do parafollicular cells secret and what does it do?
Calcitonin- suppresses bone reabsorption (Ca+ regulation)
by increasing osteoblast activity and decreasing osteoclast activity
What does the parathyroid gland secrete? And what does it do?
Parathyroid hormone (PTH) Regulates Ca+ and Phosphate levels in the blood. (counter acts parafollicular cells of thyroid)
What types of cells are found in the parathyroid gland?
Chief/principal cells (active)
Oxyphil cells (inactive)
Adipose cells
Name the layers (Sup-Deep) of the Adrenal cortex
Zona Glomerulosa
Zona Fasiculata
Zona Reticularis
What does the zona glomerulosa secret?
Aldosterone
What does zona fasciculata secret?
Glucocorticoids (like cortisone/corticosterone)
What does the zona reticularis secrete?
Sex hormones (androgen and estrogen)
What is another word for zona fasciculata?
Spongiocytes due to their foamy appearance
What are the cells of the adrenal medulla and what do they secret?
Chromaffin cells
Epinephrine and norepinephrine
What does the pineal gland secret?
Melatonin
What are the cells of the pineal gland?
Pinealocytes
Glial cells
What types of cells are found in the Islets of Langerhans?
Alpha cells
Beta cells
Delta cells
Epsilon cells
Pancreatic polypeptide (PP)
What do Alpha cells secret? And what does it do?
Glucagon - responds to low glucose levels in the blood
What do Beta cells secret? And what does it do?
Insulin - Responds when glucose levels in the blood are too high
What do Delta cells secret? And what does it do?
Somatostatin - inhibits secretion of insulin and glucagon
What do Epsilon cells secret? And what does it do?
Ghrelin - stimulates hunger
What do PP cells secret? And what does it do?
Pancreatic polypeptide - satiety
