intro to endocrine system

Question 1

What is the primary function of the endocrine system?

Answer 1

To maintain internal homestasis in response to external and internal stimuli.

Question 2

Do hormones work rapidly or at a slower pace?

Answer 2

They work slowly but last much longer as a result

Question 3

For a target cell to respond to a hormone, what must it have?

Answer 3

The target cell must have the appropriate receptors.

Question 4

Name the 6 major endocrine glands in the body

Answer 4

the hypothalamus, pituitary gland, thyroid gland, parathyroid gland, thymus and adrenal glands.
NOTE: these are just the endocrine glands, not organs.

Question 5

What is humoral hormone release?

Answer 5

When factors in the blood, or changed conditions are detected by the endocrine gland and hormone release is triggered.

Question 6

What is neural hormone release?

Answer 6

when either pre or postganglionic nerve fibres stimulate an endocrine gland to secrete a hormone.

Question 7

What is traditional hormone based hormone release?

Answer 7

When an tropic hormone binds to and stimulates the endocrine gland to secrete more hormones.

Question 8

What are tropic hormones? (Tropic not trophic hormones)

Answer 8

Hormones designed to target other endocrine glands.

Question 9

what are sex hormones

Answer 9

Special hormones of the reproductive system that target reproductive organs and tissue.

Question 10

What are anabolic hormones?

Answer 10

A hormone that promotes anabolism on its target cells. Anabolism causes increased cellular growth and build-up, consuming energy.

Question 11

What is the difference between peptide and steroid hormones?

Answer 11

Composition- peptide hormones are protein based, like insulin. Steroid hormones are lipid based and derived from cholesterol.

Question 12

With what mechanism do hormones bind to receptors?

Answer 12

They use the lock-and-key mechanism.

Question 13

What is the relationship between steroid hormones and diffusion through cell membranes?

Answer 13

Steroid hormones are hydrophobic, just like the lipid membranes. Thus they diffuse across into the cell easily.

Question 14

what is the aim of steroid hormones once in a cell?

Answer 14

Steroid hormones help regulate production of proteins inside the cell. It does this by controlling protein gene expression in the nucleus.

Question 15

Do steroid hormones elicit this response quickly?

Answer 15

No. It is a slow process that can take days.

Question 16

What are non-steroid hormones?

Answer 16

Basically, protein hormones (g-protein family) and gonadotrophins.

Question 17

Which mechanism do non-steroid hormones use to stimulate target tissue?

Answer 17

They use the second messenger mechanism. They are hydrophilic and cannot diffuse into the cell directly.
So they bind to the fixed g-protein receptors on the cell membrane. The g-proteins then send the signal to the second messenger chemical.

Question 18

Name 2 important second messengers in the cell.

Answer 18

cyclic AMP and calmodulin (calcium based)

Question 19

Hormonal synthesis and secretion is regulated by which feedback mechanism?

Answer 19

Negative feedback

Question 20

Where is the pituitary gland located?

Answer 20

On the ventral surface (underneath) the brain

Question 21

What are the 3 parts of the pituitary gland?

Answer 21

The infundibulum is the stalk that connects the hypothalamus above to the pituitary below. The pituitary comprises of the anterior (adenohypophysis) and posterior (neuropophysis) halves.

Question 22

What are the 5 types of secretory cells in the anterior pituitary gland?

Answer 22

Somatotrophs-secrete growth hormone
Corticotrophs-secrete ACTH
thyrotrophs-secrete thyroid stimulating hormone
lactotrophs- secrete prolactin
gonadotrophs-secrete LH and FSH

Question 23

What other structure controls the activities of the anterior pituitary gland?

Answer 23

The hypothalamus

Question 24

Name the 4 key tropic hormones (hormones that stimulate other endocrine glands).

Answer 24

Thyroid stimulating hormone, follicle stimulating hormone, lutenising hormone and adrenocorticotropic hormone.

Question 25

Name the 2 main hormones secreted from the posterior pituitary gland.

Answer 25

Antidiuretic hormone and oxytocin

Question 26

Where is the the pineal gland located?

Answer 26

On the dorsal aspect of the brain

Question 27

What does the pineal gland secrete?

Answer 27

Melatonin. This fuels the body clock

Question 28

Where is the thyroid gland located?

Answer 28

Sits below the larynx but above the trachea in the neck.

Question 29

Name the 3 thyroid gland hormones

Answer 29

T3(precursor to T4), T4 (thyroxine) and calcitonin (decreases blood Ca levels).

Question 30

What hormones are secreted by the parathyroid glands?

Answer 30

Parathyroid hormone. It is the antagonist to calcitonin because it increases blood calcium levels.

Question 31

Where are the parathyroid glands located?

Answer 31

They are embedded within the posterior surface of the thyroid gland, in little clumps.

Question 32

Explain how calcitonin and parathyroid hormone work together to maintain calcium homeostasis?

Answer 32

Increased blood calcium levels causes increased calcitonin secretion from the thyroid gland. Increased calcitonin causes decreased bone breakdown by the osteoclasts. This results in decreased blood calcium levels Decreased blood calcium levels cause increased PTH from the parathryoid hormone. Inceased PTH causes increased bone breakdown by osteoclasts. This results in increased blood calcium levels.

Question 33

Where are the adrenal glands located and what 2 regions is it comprised of?

Answer 33

The adrenal glands sit on top of either kidney. They have an internal medulla and an external cortex. The cortex is normal endocrine tissue whilst the medulla is neurosecretory tissue.

Question 34

Which 3 types of hormones are secreted from which of the 3 layers of the adrenal cortex?

Answer 34

Mineralcorticoids from the zona glomerulosa (superficial) Glucocorticoids from the zona fasciculata (middle) Precursor androgens (DHEA and adrostenedione) from the zona reticularis (deep)

Question 35

What is the main mineralcorticoid produced by the zona glomerulosa of the adrenal cortex?

Answer 35

Aldosterone. It increases blood pressure by increasing ECF volume. It does this by increasing Na+ and water retention. Part of the Renin-Angiotensin-Aldoserone system.

Question 36

What is the function of glucocorticoids like cortisol in the body?

Answer 36

Glucocorticoids like cortisol are released in times of stress. They put the body into a catabolic state, where breakdown of body tissue increases the amount of available nutrients.

Question 37

What hormones are secreted from the neurosecretory part of the adrenal gland, the medulla?

Answer 37

The androgens, noradrenaline and adrenaline are produced here. The environment is hydrophobic, and is needed for the production of hydrophobic steroid hormones.

Question 38

What 2 hormones are secreted by the pancreas and from where?

Answer 38

Insulin is secreted from the beta (islet) cells whilst glucagon is secreted from the alpha cells.

Question 39

What hormone does the testes produce?

Answer 39

Testosterone, under instruction from LH and FSH.

Question 40

What hormones does the ovaries produce?

Answer 40

Oestrogen (developing follicles) and progesterone (corpus luteum).

Question 41

What 3 hormones does the placenta produce during pregnancy?

Answer 41

hCG (Human chorionic gonadotrophin), oestrogen and progesterone.

Question 42

Where is the thymus located?

Answer 42

In the mediastinum. It is larger in children and atrophies into adulthood.

Question 43

What 2 hormones does the thymus secrete?

Answer 43

Thymosin and thymopoietin for t-cell development.

Question 44

What are paracrines (tissue hormones)?

Answer 44

Localised hormones that only act on nearby tissue and cells.

Question 45

Which prostaglandin type is responsible for uterine contractions?

Answer 45

Type F.

Question 46

What effect does aging have on the endocrine system?

Answer 46

It causes atrophy of endocrine glands and thus decreased hormone production and levels.