Jackson- Endocrine System Lecture 1

Question 1

What are two ways in which the endocrine system communication differs from the nervous system?

Answer 1

Route of communication (blood)

Onset and duration of effects

Question 2

T/F- Hormones work because target cells express specific receptors to that hormone.

Answer 2

True

Question 3

What are the three classes of hormones?

Answer 3

Peptide/protein hormones
Steroid hormones
Amine hormones

Question 4

What is one way to increase variability in peptide hormones?

Answer 4

Glycosylation

Question 5

T/F some peptides function as both hormones and neurotransmitters?

Answer 5

True

Question 6

The preprohormones are synthesized where?

Answer 6

On the ribosomes

Question 7

How is the pro hormone formed?

Answer 7

By cleaving off extra amino acids in RER. Then it’s packaged into secretory vesicles in the Golgi

Question 8

T/F the final hormone can be made before packaging into the vesicle or after more cleavage occurs within the vesicle?

Answer 8

True

Question 9

Can hormones be stored?

Answer 9

Yes, they’re stored in vesicles so that they’re available for rapid release

Question 10

What are the glandular/major sources of steroid hormones?

Answer 10

Gonads, adrenal cortex and placenta

Question 11

All steroid hormones come from the precursor molecule _______.

Answer 11

Cholesterol

Question 12

What determines which steroid hormone is produced?

Answer 12

Enzymes

Question 13

T/F Some cholesterol is produced by de novo synthesis?

Answer 13

True

Question 14

T/F all cells have the capacity to synthesize cholesterol

Answer 14

True

Question 15

Most of the cholesterol used for synthesis of steroid hormones is derived from what?

Answer 15

Low density lipoproteins (LDLs)

Question 16

What releases cholesterol from its stores?

Answer 16

Cholesterol esterase

Question 17

After cholesterol is released from its stores, it needs to be transferred to the mitochondria so it can be made into a steroid hormone. What facilitates the transport?

Answer 17

Steroid acute regulator protein (StAR) helps cholesterol cross both the outer and inner membranes

Question 18

Cholesterol is converted to steroid by which enzymes and where does this happen?

Answer 18

Converted by P450 enzymes in the mitochondria

Question 19

Amine hormones are all derived from which amino acid?

Answer 19

Tyrosine

Question 20

T/F amine hormones have limited but important effects?

Answer 20

False. widespread and important effects

Question 21

Thyroid hormones (triiodothyronine and thyroxine) are produced by iodination of tyrosine at one or two carbons

Answer 21

Truth

Question 22

Where are catecholamines synthesized?

Answer 22

The adrenal medulla and hypothalamus

Question 23

What are the three catecholamines?

Answer 23

Norepinephrine
Epinephrine
Dopamine

Question 24

What three things can control patterns of hormone secretion?

Answer 24

1. Plasma concentrations of a nutrient
2. Neural control
3. Hormonal control

Question 25

What type of hormones readily dissolve in plasma?

Answer 25

Hydrophilic

Question 26

T/F- Lipophilic hormones require carrier or binding proteins to increase their solubility in the blood plasma

Answer 26

True

Question 27

If a hormone is circulating in the blood, how is it inactivated so that its response is cut off?

Answer 27

The liver and kidneys are important for metabolism and excretion of hormones. They contain enzymes that break down or inactive a hormone by hydrolysis or sulfation

Question 28

T/F binding hormones do not protect lipophilic hormones from circulating blood enzymes?

Answer 28

False. They most definitely do.

Question 29

For peptides and catecholamines, what is their mechanism of action when a hormone binds to a receptor?

Answer 29

Because both of these are hydrophilic, the receptors are on the cell surface or in the plasma membrane. Receptor activatio ntrigegers a signal transduction pathway that facilitates a response within the cell to an extracellular signal. Inotropic responses open ion channels Metabotropic response alter cell activity Rapid and delayed responses are possible

Question 30

For steroid and thyroid hormones, what is their mechanism of action?

Answer 30

The receptors are intracellular and/or nuclear. A receptor/ligand forms a DNA binding protein which regulates transcription. Responses like this are delayed ones because transcription and protein synthesis takes time. Some membrane receptors for steroid hormons control rapid, non-genomic processe as well.

Question 31

What are the two main components of central control for endocrine function?

Answer 31

Hypothalamus and pituitary gland

Question 32

The anterior pituitary gland develops from where?

Answer 32

an out pocketing of the oral ectoderm that pinches off from the roof of the mouth

Question 33

The posterior pituitary gland develops from where?

Answer 33

It buds off the floor of the hypothalamus

Question 34

Which two hormones are released from the posterior pituitary? Are they made there? Where are they made?

Answer 34

Oxytocin Vasopressin Not made in the posterior pituitary, but are made in the supraoptic and paraventricular nuclei

Question 35

What does oxytocin do?

Answer 35

Stimulates smooth muscle contraction

Question 36

What does vasopressin or ADH do?

Answer 36

Helps regulate blood pressure (ADH- anti diuretic-hormone helps you retain water)

Question 37

The anterior pituitary gland is regulated by what?

Answer 37

Hormones secreted by hypothalamic neurons

Question 38

Capillaries are at the base of the median eminence and that's where axon terminals for hypothalamic nuclei are found. The hypothalamic hormones go into the capillaries. The hypothalamic hormones travel down to the anterior pituitary via the blood stream. Then the anterior pituitary releases the indicated hormone back into the blood supply which is then sent out into the body.

Answer 38

mmhmm.

Question 39

The anterior pituitary secretes at least 8 hormones. What are the most important 6?

Answer 39

1. follicle stimulating hormone (FSH) 2. luteinizing hormone (LH) 3. growth hormone (GH) (somatotropin) 4. thyroid stimulating hormone (TSH or thyrotropin) 5. prolactin (PRL) 6. adrenocorticotropic hormone (ACTH or corticotropin)