Endocrine system

Question 1

Identify the location of the pituitary gland

Answer 1

Sella turcica of sphenoid bone

Question 2

Describe the overall function of the endocrine system

Answer 2

Reproduction, growth and development, internal homeostasis, helps to cope with environmental changes

Question 3

Contrast endocrine and exocrine glands

Answer 3

Endocrine make hormones & are released into the bloodstream; exocrine make a substance released directly onto skin surface or into a duct, e.g. salivary duct.

Question 4

Define Hormone

Answer 4

Hormone is made by an endocrine gland & is a chemical messenger traveling in the bloodstream.

Question 5

What are target cells

Answer 5

The target cell responds to the hormone because it has matching receptors for the hormone

Question 6

Explain how a hormone affects the activity of target cells

Answer 6

It can go to the nucleus and act upon the genes, or it can stimulate and intermediate compound such as cAMP, which acts as a second messenger and stimulates or inhibits a process or metabolic pathway in the cell.

Question 7

Dexcribe the structure and transport mechanisms of hormones

Answer 7

Most are amino acids, some are cholesterol based. All are organic compounds and are transported in the bloodstream; usually they are attached to some carrier protein making them physically larger so that they are not urinated out.

Question 8

Describe the 2 lobes of the pituitary gland

Answer 8

Question 9

What are the hormones of the anterior pituitary gland?

Answer 9

FSH

LH/ICSH

TSH

ACTH

GH

Prolactin

MSH

endorphins (not endocrine)

Question 10

Posterior pituitary

Answer 10

releases: ADH causes water reabsorption (from urine to blood) in kidney; Oxytocin causes uterine contractions during childbirth and milk secretion.

Question 11

What is an endorphine

Answer 11

Morphine like compound made by anterior pituitary gland, but is really a neuromodulator, not a hormone.

Question 12

Describe the controls of the pituitary gland

Answer 12

Hypothalamus makes stimulatory hormones called releasing hormones and inhibitory hormones; Negative feedback

Question 13

Expaine why the posterior pituitary is not a true endocrine gland.

Answer 13

It doesn’t make ADH and Oxytocin. They are made by hypothalamus but stored and released by posterior pituitary.

Question 14

Describe the location and histology of the tyroid gland

Answer 14

Inferior to larynx, and histology shows follicles filled with thyroid hormone (colloid), and the surrounding follicle cells make the hormone. The interstitial cells are called parafollicular cells and make calcitonin.

Question 15

Name and describe the formation and function of thyroid hormones

Answer 15

Made from an amino acid called tyrosine. Three iodine molecules in T3 and four in T4.

Question 16

How are thyroid hormones transported in the blood stream

Answer 16

Attached to TBG

Most thyroid hormones are carried in plasma bound to tyroid binding globilin

Question 17

Describe the controls over thyroid hormone synthesis and release

Answer 17

Negative feedback, TSH from ant. pituitary and Thyroid releasing hormone from hypothalamus.

Question 18

Name the gland and cells that make calcitonin

Answer 18

Parafollicular cells of thyroid gland = C cells

Question 19

Describe the function and control of calcitronin

Answer 19

Decreases blood calcium levels

Question 20

Describe the location of the parathyroid gland and the function of its hormone and the controls of its release

Answer 20

Embedded in the thyroid gland. It makes Parathyroid hormone which increases blood calcium levels. Obviously, blood calcium levels determine whether PTH or Calcitonin should be released.

Question 21

Describe the location and the 2 portions of the adrenal gland

Answer 21

Above the kidneys. Outer region is adrenal cortex, inner region is adrenal medulla.

Question 22

Name the 2 hormones made by the adrenal medulla and describe their functions and the controls of their release

Answer 22

Epinephrine & Norepinephrine are released under fight of flight situations. They exaggerate the fight or flight response. Mostly, epinephrine is released.

Question 23

Name the 3 layers of the adrenal cortex.

Answer 23

Zona Glomulrtosa-Outermost layer

Zona Fasciculata-Middle layer

Zona reticularis-Innermost Layer

Question 24

Adrenal medulla

Answer 24

Chromafin cells

Produces: 80% Epinephrine, 20% Norepinephrine

Action: Glucose, HT, bl. vessels, bl. pressure, airways

Release: Pregang, neurons, excitement, injury

Question 25

Zona glomerulosa

Answer 25

Outermost layer of adrenal cortex

• production 90% aldosterone*
• involved with Na rebsorbtion, K excretion-in Kidneys*

Renin/Angiotensinogen

Renin is an enzyme made by the kidneys in response to low blood pressure. It causes inactive angiotensinogen to activate into Angiotensin, which stimulates Aldosterone release.

Question 26

Renin/angiotensinogen

Answer 26

Question 27

Zona fasciculata

Answer 27

Thick middle layer

Glucocorticoids

Conserves and supplements energy

Anti-inflammatory

Release-ACTH, CRH, stress

Question 28

Zona reticularis

Answer 28

Innermost layer

Sex hormone

Question 29

Name the 3 layers of the adrenal cortex. Name and describe the effects of the hormones made by each layer. Describe the controls of their release.

Answer 29

Outer is the zona glomerulosa where aldosterone is made which causes sodium reabsorption in the kidneys (sodium goes from urine back to blood, and water passively follows); Zona fasciculata is middle layer making glucocorticoids that help one deal with long term stress by conserving energy for later. It is also anti-inflammatory. Inner zone is zona reticularis making sex hormones to be discussed under reproduction.

Of course ACTH from the ant. pituitary stimulates the release of these hormones. Also, low blood sodium would stimulate release of aldosterone. If your blood pressure is low, the kidneys release renin. Renin is an enzyme that converts angiotensinogen to angiotensin. These will be discussed under cardiovascular system. However, angiotensin can cause the adrenal cortex to release aldosterone. Since aldosterone causes more salt to be in the bloodstream, and water passively follows, it will help to restore the low blood pressure to a more normal value.

Question 30

Name the 2 hormones made by the adrenal medulla and describe their functions and the controls of their release

Answer 30

.Epinephrine & Norepinephrine are released under fight of flight situations. They exaggerate the fight or flight response. Mostly, epinephrine is released.

Question 31

Define the islets of langerhans, pancreatic islets, and chromaffin cells.

Answer 31

Islets of Langerhans = pancreatic islets and are the endocrine cells of the pancreas. The chromaffin cells are the endocrine cells of the adrenal medulla.

Question 32

Name the organ that has both exocrine and endocrine functions

Answer 32

Pancreas

Question 33

Describe the location and structure of the pancreas

Answer 33

Inferior to stomach. The pancreas is mostly exocrine - only the islets are the endocrine portion

Question 34

Name the cells that make inulin, glucogon, and somatostatin. Describe their effects.

Answer 34

The islets, specifically beta cells make insulin which lowers blood glucose by allowing it to go into cells. Alpha cells make glucagon which raises blood glucose by bringing it out of storage, and delta cells make somatostatin which opposes GH release.

Question 35

Describe the controls of insulin and glucagon release

Answer 35

High blood glucose leads to insulin release; Low blood glucose leads to glucagon release.

Question 36

Name the male and female gonads and briefly describe their endorine roles

Answer 36

Male - testes; Female - Ovaries

Question 37

Describe the location and function of the pineal gland

Answer 37

Roof of third ventricle. Makes melatonin which depresses reproductive activity

Question 38

Name the gland that is replaced by connective tissue and fat in adults. Briefly describe its location and function

Answer 38

Thymus. It has a lymphatic role, in that T lymphocytes are made and “trained” here. The endocrine role is that it releases thymic hormone to stimulate these T cells.

Question 39

Describe the structure and function of prostaglandins

Answer 39

Fatty acids that have a variety of functions. They are unique in that they tend to act locally. For example, a prostaglandin released by the uterus into the bloodstream has target cells in the uterus and acts upon the uterus.