Chapter 17 - Endocrine Glands Flashcards
What is the function of the endocrine system?
Responsible for maintaining homeostasis via prescise regulation.
What does the hypothalumus do in the endocrine system?
Regulates the pituitary glands activities through the production of neurohormones.
What is the function of the pituitary gland?
Regulates many body functions and other endocrine glands.
Where is the pituitary gland located?
Beneath the hypothalumus of the brain in the skull bone indentation called Stella Turcica which forms a nest to protect the gland.
What are the two areas of the pituitary gland?
Posterior Pituitary: Extention of the hypothalumus, produces neurohormones.
Anterior Pituitary: Produces endocrine hormones. Contains glandular tissue.
What are the two parts of the Posterior Pituitary?
Infundibulum
Pars Nervosa
What are the three parts of the Anterior Pituitary?
Pars Tuberalis
Pars Intermedia
Pars Distalis
What is the name of the structure that connects the Hypothalumus and the Posterior Pituitaty? How does it function?
Hypothalamo-Hypophysial Tract
Nerve cells are produced by the hypothalumus, they are sent through the posterior pituitary via the HHT and then they are released into the bloodstream.
What hormones are produced by the Posterior Pituitary?
Antidiuretic Hormone (ADH) - Prevents the output of large amounts of urine.
Oxytocin: Stimulates smooth muscle fibers in the uterus for childbirth and promotes ejection of milk during lactation.
What is the name of the structure that connects the hypothalumus to the anterior pituitary gland? How does it function?
Hypothalamo-hypophysial Portal System
Neurohormones are produced by Hypothalumus and decend through portal system. They enter anterior pituitary and leave the capillaries and enter the endocrine glands and tell them to produce certain hormones.
What are the 5 releasing neurohormones produced by the Hypothalumus and cause the anterior pituitary to release specific hormones?
GHRH- Growth hormone-releasing hormone
TRH - Thyrotropic-releasing hormone
CRH - Corticotropin-releasing hormone
GnRH - Gonadotropin-releasing hormone
PRH - Prolactin-releasing hormone
What are the 2 inhibiting neurohormones produced by the HT that inhibit the anterior pituitary gland from producing a specific hormone?
GHIH - Growth hormone-inhibiting hormone
PIH - Prolactin-inhibiting hormone
What is the function of the Growth Hormone?
Promotes bone and cartiledge growth.
Stimulates breakdown of fat to be used as energy.
What is the function of TSH - the thyroid hormone?
Causes the production of T3 an T4
What is the function of ACTH, the hormone released by CRH?
This hormone causes cortisol and aldosterone secretion from the adrenal cortex and also causes increase in production of melanin.
What is the function of MSH and endorphins?
MSH causes melanocytes to produce more melanin. Endorphins act as a pain killer during times of stress.
What are the functions of Gonadotropins, LH, FSH, and prolactin?
Gonadotropins promote the growth and function of the gonads.
LH and FSH: regulate the production of reproductive hormones.
Prolactin: Role in milk production
Describe the anatomy of the thyroid gland.
Consists of two lobes that are connected by the isthmus. It is highly vascular and the only gland that stores hormones.
What is the cell composition of the thyroid gland?
Composed of follicles filled with thyroglobulin. These are surrounded by a single layer of follicular cells.
How does the thyroid gland function to produce T3/T4?
First the follicular cells produce thyrogobulin and fills the follicle.
Then Iodine enters the cell from the outside.
Iodine then binds with the component of the thyrogobulin called tyrosine.
This binding causes T3/T4
What are the symptoms of hyperthyroidism or the overproduction of T3/T4?
Increase metabolic rate
Increase blood pressure/heart rate
Increase appetite/weight loss
What are the symptoms of hypothyroidism or the underproduction of T3/T4?
Decrease metabolic rate
Decrease blood pressure/heart rate
Decrease appetite/weight loss
What hormone does the parafollicular cells produce and what is its function?
Calcatonin
Triggered by high calcium in blood and it decreases blood calcium levels.
Describe the location of the parathyroid glands?
Embedded in the posterior of the thyroid gland.
They are tightly packed cells.
What hormone does the parathyroid secrete?
PTH- parathyroid hormone.
This inreases calcium levels in the blood by promoting calcium reabsorbtion.
Describe the composition of the adrenal gland
Foud on the superior poles of the kidneys.
Has two sections: Cortex - outer layer, Medulla - inner layer.
What does the adrenal medulla secrete?
Secretes the neurohormone epinephrine and norepinephrine.
What are the three layers of the adrenal cortex?
Zona Glomerulosa
Zona Fasciculata
Zona Reticularis
What is the makeup of the adrenal medulla and adrenal cortex?
Adrenal Medulla: made up of modified nerve cells.
Adrenal Cortex: made up of typical glandular cells.
What hormone is produced by the Zona glomerulosa layer of the adrenal cortex?
Mineralocorticoids: increase the rate of sodium reabsorption by the kidneys.
What hormone produced by the pituitary gland influences the adrenal cortex to produce its hormones?
ACTH: Adrenocorticotropic hormone
What hormone is produced by the Zona fasciculata layer of the adrenal cortex?
Glucocorticoids: increases fat and protein breakdown.
What hormone is produced by the Zona reticularis layer of the adrenal cortex?
Androgens: Stimulate pubic and axillary hair growth.
What are the two diseases associated with the adrenal cortex?
Addison’s Disease: Low levels of Adrenal Cortex hormones.
Cushing’s Syndrome: High levels of Adrenal Cortex hormones.
Describe the structure and function of the pancreas
Located along the small instestine and stomach.
Has a dual function as both an endocrine and exocrine gland.
How is the pancreas an exocrine gland?
It secretes digestive juices into the small intestine to break down food that did not fully digest in the stomach.
What are the three hormones secretes by the pancreas?
Alpha Cells: Secrete glucagon
Beta Cells: Secrete Insulin
Delta Cells: Secrete somatostatin
What kind of cells does the pancreas consist of?
Pancreatic Islets aka Island of Langerhans
What is the function of the insulin produced by the pancreas’ beta cells?
Increases the absorption of glucose and makes the cells use the sugar for energy. Keeps the blood sugar stabilized.
What is the function of the glucagon produced by the pancreas’ alpha cells?
Causes the breakdown of the secondary storages areas for sugar glycogen and fats. Uses it for energy.
What is the chain of breakdown for glucose to energy?
Glucose —> Glycogen storage —-> Fat
What is the function of delta cells of the pancreas?
Keeps the balance and regulation of Alpha and Beta Cells
Describe Type I diabetes
Insulin Depending Diabetes Melatose
Pancreas not producing enough insulin
Describe Type II diabetes
Non-Insulin Depending Diabetes Melatose
Receptors that are stimulated by insulin are not functioning properly
What is the male reproductive hormone?
Testosterone
What are the female reproductive hormones?
Estrogen and Progesterone
Where is the pineal gland and what is its function?
It is found in the epithalumus
Produces melatonin
What is the thymus gland and what is its function?
Development of immune system
Biggest during childhood and then it converts to adipose tissue.
