Endocrine Hormones

Question 1

Cell types of the pituitary gland:

Somatotropes release __________

Answer 1

Growth hormone

Question 2

Cell types of the pituitary gland:

Corticotropes release ________

Answer 2

adrenocorticotropic hormone

Question 3

Cell types of the pituitary gland:

Thyrotropes

Answer 3

Thyroid stimulating hormone

Question 4

Cell types of the pituitary gland:

Gonadotropes release _______

Answer 4

Leuteninzing hormone, follicle stimulating hormone

Question 5

Cell types of the pituitary gland:

Lactotropes release ______

Answer 5

prolactin

Question 6

Hormones that come from the anterior pituitary gland

Answer 6

1. Thyrotropin
2. Growth hormone
3. Corticotropin
4. follicle stimulating
5. luteinizing
6. prolactin

Question 7

What stimulates release of hormones from the posterior pituitary gland?

Answer 7

posterior: nerve signals that originate in the hypothalamus

Question 8

What controls release of hormones from the anterior pituitary gland?

Answer 8

• hormones secreted within the hypothalamus called hypothalamic releasing and hypothalamic inhibitory hormones
• brought to the anterior pituitary through small blood vessels called the hypothalamic-hypophysial portal vessels
• the hormones act on the glandular cells to control their secretions

Question 9

osmoreceptor

Answer 9

found in hypothalamus. Shrinks and expands depending on osmolarity of blood going by

Shrink = increased signals, increased ADH

Question 10

Growth hormone physiologic effects

Answer 10

1. promotes growth of many body tissues (increased size and number of cells)
2. promotes protein synthesis
3. increased use of fatty acid for energy
4. decreased use of glucose

* GH enhances body protein, uses up fat stores, and conserves carbohydrates

Question 11

What does Growth hormone need in order to have effect?

Answer 11

insulin

carbohydrates

*to provide the energy needed for the metabolism of growth and enhance transport of some amino acids into cells

Question 12

How much does the amount of growth hormone change throughout the lifespan?

Answer 12

you will have 25% of what you had as an adolescent when you are elderly

Question 13

What stimulates release of growth hormone?

Answer 13

• starvation (especially severe protein deficiency)
• hypoglycemia or low concentration of fatty acids in the blood
• exercise
• exciement
• trauma
• ghrelin (tells you you are hungry)
• increased during first 2 hours of deep sleep

Question 14

GH regulation

Answer 14

• Controlled mostly by GHRH more than GHIH
  
  • GHRH attaches to GCPR on the GH cells, activates adenylate cyclase, etc…increases Ca into cell and causes vesicle release
• also controlled by Gherlin and IGF-1

Question 15

GH summary

Answer 15

Question 16

What are the two major thyroid hormones and the percent which you find them in?

Answer 16

Thyroxine (T4)- 93%

Triiodothyronine (T3)- 7%

Question 17

Which thyroid hormone is more potent?

Answer 17

Triiodothyronine is 4x as potent

it is present in smaller quantities and has a shorter DOA

Question 18

What is thyroglobulin?

Answer 18

A vesicle containing thyroid hormones

Question 19

Formation of a thyroid hormone

Answer 19

1. Iodide enters cuboidal cell surrounding colloid.
2. conversion of iodide to an oxidized form of iodine which can then combine directly with the amino acid tyrosine.
   
   1. Enzyme peroxidase makes oxidation happen faster
3. over time the iodotyrosines become coupled with each other.
4. This thyroxine remains in the thyroglobulin molecule

Question 20

How is Thyroid hormone transported?

Answer 20

• upon enteing blood, more than 99% of T4 and T3 are bound to proteins
  
  • thyroxine-binding globulin (mostly)
  • thyroxine-binding prealbumin
  • albumin
• this affinity for proteins acts as a reservoir for the thyroid hormones, releasing them slowly into the tissues

Question 21

Thyroid hormone receptors:

Answer 21

• Attached to DNA or very close to them
• the thyroid hormone receptor forms a heterodimer with retinoid X receptor (RXR) at specific thyroid hormone response elements on the DNA
• This activates receptor and starts the transcription process
• Make a bunch of mRNA then RNA
• actions of thyroid hormones result from the functions of these new proteins

Question 22

generally, what do thyroid hormones do?

Answer 22

increase the metabolic activities of almost all the tissues of the body

** number and size of mitochondria increase

Question 23

How is thyroid hormone stimulated?

Answer 23

• hypothalamus secretes thyrotropin releasing hormone (TRH)
• this activates the anterior pituitary to secrete thyroid stimulating hormone (TSH)
• TSH increases all the known secretory activities of the thyroid glandular cells
• T4 and T3 (more T4) go to target organs

Question 24

How is thyroid hormone negatively controlled?

Answer 24

Increased thyroid hormone in the body fluids decreases the secretion of TSH from the anterior pituitary

Question 25

what does the medulla of the adrenal gland produce?

Answer 25

catecholamines

Question 26

what does the cortex of the adrenal gland produce?

Answer 26

* 2 major types of hormones * mineralcorticoids * corticosteroids * 1 minor type of hormone * androgenic hormones

Question 27

What are the three layers of the adrenal cortex? And what do they each secrete?

Answer 27

1. zona glomerulosa- thin cells just under capsule 1. secrete aldosterone in response to extracellular ang II and K. 2. zona fasciculata- middle and widest zone (75%) 1. secretes glucocorticoids (cortisol and corticosterone 2. secretes andrenal androgens 3. secretion controlled by ACTH 3. zona reticularis- inner zone 1. secretes androgens

Question 28

Actions of Aldosterone

Answer 28

1. retains Na and excretes K into tubule in exchange 2. causes secretion of H ions in exchange for Na in the intercalated cells of collecting ducts 1. decreases the H concentration and causes metabolic alkalosis

Question 29

what role do intercalated cells play? alpha vs beta?

Answer 29

* they are involved with acid/base homeostasis * alpha- secreces acid (H), reabsorbs HCO3 * beta- secretes HCO3, reabsorbs (H)

Question 30

What do principle cells do?

Answer 30

* mediate Na/K balance in the collecting duct with Na/k channels in the cells membrane

Question 31

Aldosterone pathway

Answer 31

* triggered by RAAS system when low circulating volume is sensed * released directly when high K is sensed * increases number of Na/K exchangers and Na/Cl symporters * water follows Na * fluid balance increases

Question 32

What do thiazide diuretics antagonize?

Answer 32

anything that aldosterone does. thiazide diuretics: decrease Na/K channels decrease Na/Cl symporter water follows and is secreted

Question 33

What does cortisol do?

Answer 33

* increases gluconeogenesis * antagonizes insulin's effects to inhibit gluconeogenesis * increases protein mobilization * increases fat mobilization * removes the GLUT4 from cell membranes, causing insulin resistance * suppresses immune system

Question 34

What percentage of cortisol binds to plasma proteins? How long is the half life?

Answer 34

90-95% has a long half life 60-90 minutes

Question 35

How much circulating aldosterone is bound to proteins? What is the half life?

Answer 35

60% shorter half life of 20minutes

Question 36

what is the normal plasma and ISF concentration of ionized Ca? What is the ionized Ca used for?

Answer 36

1.2 mmol/L 50% Used for most important functions

Question 37

What is the concentration of bound Ca in plasma and ISF? How is this Ca used?

Answer 37

1 mmol/L the Ca bound to proteins is used as a reservoir/backup supply

Question 38

What do you need/needs to function to be able to absorb Ca?

Answer 38

Vitamin D liver function, kidney function

Question 39

What stimulates the secretion of parathyroid hormone? Where is it released from?

Answer 39

decreased blood calcium