Intro to endocrine

Question 1

What is the endocrine system?

Answer 1

Produces chemical messengers (hormones) that influence growth, development, and metabolic activities. Two major categories of glands– exocrine and endocrine

Question 2

What are hormones?

Answer 2

Chemical messengers that are released in one tissue and transported by bloodstream to reach target cells in their tissues

Question 3

What are exocrine glands?

Answer 3

Produce secretions which are released to the outside; the sweat, salivary, mammary, and digestive gland systems

Question 4

What are endocrine glands?

Answer 4

Hormones are secreted directly into the blood and are carried throughout the body where they influence the appropriate receptor sites

Question 5

What are mixed glands?

Answer 5

Some glands have non-endocrine regions that have functions other than hormone secretion. For example, the pancreas has a major exocrine portion that secretes digestive enzymes and an endocrine portion that secretes hormones

Question 6

Describe the hypothalamus

Answer 6

Regulates activities of nervous and endocrine systems in three ways: releases hormones ADH and OXYTOCIN, secretes REGULATORY HORMONES, and control endocrine cells in the adrenal medulla

Question 7

Describe the pituitary gland

Answer 7

aka hypophysis. Small oval gland seated in the sella turcica of the sphenoid bone. Consists of two lobes: Anterior – ADENOHYPOPHYSIS (made up of glandular cells). Posterior – NEUROHYPOPHYSIS (cells are non-secretory, resemble neuroglial tissue

Question 8

What are the hormones of adenohypophysis?

Answer 8

TSH, ACTH, FSH, LH, PRL, Growth hormone, MSH

Question 9

Describe the pineal gland

Answer 9

Lies in the roof of the thalamus (third ventricle), under the posterior end of the corpus callosum. It contains neurons, glial cells and secretory cells that synthesize the hormone MELATONIN

Question 10

Describe the thyroid gland

Answer 10

Lies anterior to the trachea and just below the thyroid cartilage, which forms most of the anterior surface of the larynx. Produces the hormones triiodothyronine (T3), thyroxine(T4), and calcitonin

Question 11

Describe the parathryoid glands

Answer 11

two pairs embedded in the posterior surface of the thyroid gland. CHIEF CELLS produces parathyroid hormone (PARATHORMONE ). Fxn of oxyphil cells is unknown

Question 12

What is the fxn of the parathormone?

Answer 12

stimulates osteoclasts, inhibits osteoblasts, increases intestinal absorption, and reduces urinary excretion of calcium ions

Question 13

Describe the thymus

Answer 13

Embedded in the mediastinum, usually posterior to the sternum. The CORTEX secretes the thymic hormones (thymosins= T Cells). The MEDULLA has the thymic corpuscles (Hassall´s corpuscles) surrounded by lymphocytes

Question 14

Describe the adrenal glands

Answer 14

Lie along the superior borders of the kidneys. Pyramid-shaped glands. ADRENAL CORTEX
produces adrenocortical steroids or CORTICOSTEROIDS. ADRENAL MEDULLA produces EPINEPHRINE and NOREPINEPHRINE

Question 15

What are the zones of the adrenal cortex?

Answer 15

Zona glomerulasa – outermost layer. Secretes aldosterone. Zona fasciculata – middle layer, produces glucocorticoids (cortisol, corticosterone and cortisone). zona reticularis – inner layer, produces androgens

Question 16

Describe the pancreas

Answer 16

Endocrine cells are found within the pancreatic islets (ISLETS OF LANGERHANS): alpha cells secrete glucagon and beta cells secrete insulin

Question 17

Describe the gonads

Answer 17

testes: the INTERSTITIAL CELLS secrete ANDROGENS, notably TESTOSTERONE. ovaries: follicles produce estrogens and corpus luteum that produces progesterone.

Question 18

What factors affect the response of a target cell to a hormone?

Answer 18

number of receptors present (up-regulation/down regulation) or the affinity of these receptors for hormones

Question 19

What are the two groups of hormones derived from tyrosine?

Answer 19

thyroid hormones and catecholamines (epi and norepi)

Question 20

What are the adipokines?

Answer 20

adiponectin, resistin, leptin, TNFa, IL6 (produced by adipose tissue as endocrine organ)

Question 21

What are the five cell types of the anterior pituitary gland?

Answer 21

Thyrotrophs: produce thyrotropin, also called TSH. Corticotrophs: produce corticotrophin, also called ACTH. Gonadotrophs: produce the gonadotropins—LH and FSH. Somatotrophs: produce GH. Lactotrophs: produce prolactin

Question 22

What is the function of leptin?

Answer 22

suppresses appetite, increases energy expenditure