Endocrine System Overview Exam1

Question 1

Types of Cellular Communication

Answer 1

• Synaptic Connection
  
  • neurotransmitters (type of chemical messenger)
• Endocrine communication
  
  • classical hormones
  • neurohormones
  • cytokines
• Paracrine communication
• Direct communication
  - gap junction (electrical)
  - juxtacrine communication
• Pheromone communication (animals)

Question 2

Pheromone Communication

Answer 2

A pheromone is released by one animal that travels through the air and binds a receptor on a target cell in another animal.

Question 3

Characteristics of Classical Hormone action

Answer 3

1. Glands secrete hormones into the blood stream
2. Hormones travel through blood to target cell in target tissue
3. They bind a receptor in or on the target cell.
4. Receptor binding activates a cell signaling pathway that changes what is happening inside the target cell

Question 4

Methods by which a endocrine cell can be stimulated to secrete hormones

Answer 4

3 Major methods

1. Ions or nutrients- changes in concentrations of ions or organic nutrients in blood and interstitial fluid (humoral regulation)
2. Neurotransmitters-Neurotransmitters released on endocrine cell (nervous regulation)
3. Another Hormone or Neurohormone (endocrine regulation)

Question 5

Tropic Hormone

Answer 5

A hormone that stimulates the release of another hormone.

Question 6

Juxtacrine Communication

Type of Direct Cellular Communication

Answer 6

The binding of molecules on adjacent cells (literally cells touching each other)

Question 7

Are Water Soluble and Lipid Soluble Hormones transported in the blood stream? Where are they found in the blood?

Answer 7

Yes

Water Soluble Hormones are found in the solution (directly in blood)

Lipid Soluble Hormones are bound to carrier proteins to facilitate their transport

Question 8

Are water soluble hormones also bound to carrier proteins in some instances?

Answer 8

Yes, there are carrier proteins for many water soluble hormones

Question 9

Carrier Proteins

Answer 9

They help to raise the concentration of the hormone in the bloodstream.

Question 10

Location of receptors for water soluble hormones

Answer 10

In Cell Membrane

Question 11

Location of receptors for lipid soluble hormones

Answer 11

• In Cell Nucleus
• Cytoplasm

! The main receptors are in the nucleus or cytoplasm and affect transcription of genes (i.e. turn on protein synthesis) !

*rarely on cell membrane

Question 12

Will water soluble hormone receptors be found on the cell membrane

Answer 12

The receptors for water soluble hormones such as peptides/proteins and most amines will on the cell membrane just like receptors for neurotransmitters.

Question 13

Signaling Pathway

Answer 13

Physical interactions that take place when a hormone binds with a receptor

Question 14

Signaling Pathway for a Water soluble hormone

Answer 14

• Enzymatic reactions
• protein binding
• Second Messenger systems

Question 15

What does a signaling pathway do?

Answer 15

A cell signaling pathway is turned on when a hormone or neurotransmitter binds its receptor.
These pathways “translate” the signal of receptor binding into the activity that needs to occur in the target cell.

Question 16

Signaling Pathway for a Lipid Soluble Hormone

Answer 16

Alter transcription of specific proteins

Question 17

What do some of the most common types of signaling pathways include?

Answer 17

A protein known as the G-Protein

Question 18

Why are G-proteins called G-proteins? Also, what do they do?

Answer 18

These proteins are called G-proteins because they bind and break down a GTP molecule as they perform their action, much like myosin binds and breaks down ATP as it helps create muscle contractions.

Question 19

Receptors that have G-Protein involved in their signaling pathway are called what?

Answer 19

G-Protein Coupled Receptors or GPCRs

Question 20

Do G-proteins utilize a second messenger during their signaling pathway?

Answer 20

Most G-proteins utilize a second messenger, a chemical whose concentration rises within the cell cytosol so that it will bind and activate another protein such as an enzyme or calmodulin.

Question 21

Calmodulin

Answer 21

An intracellular protein that binds calcium ions and mediates many of the second messenger effects of calcium.

Question 22

Second messenger pathways

Answer 22

• cAMP (cyclic adenosine monophosphate)
• Calcium
• Inosital trisphosphate (IP3)
• Diacylglycerol
• cGMP (cyclic guanosine monophosphate)

Question 23

Description of hydrophobic hormone signaling pathway.

Answer 23

• The hydrophobic (lipid soluble) hormone is carried in the blood with the aid of one or more specific transport proteins.
• The free hormone (hormone not bound to a transport protein) in the blood is able to diffuse into the target cell and bind an intracellular receptor.
• Binding of hormones and receptors lets the H-R complex move into the nucleus and bind specific sequences of DNA that help control transcription.
• The DNA sequence that is specifically bound by a particular hormone-receptor complex is known a RESPONSE ELEMENT.

Question 24

Where are response elements usually found?

Answer 24

Response elements of typically in upstream regulatory regions of a gene.

Question 25

What is the time to activity in the target cell? How long does it take to effect things?

Answer 25

* Cell membrane receptors = seconds to minutes * Intracellular receptors= hours to days ! Water soluble hormones will only use cell membrane receptors ! ! Lipid Soluble (hydrophobic) hormones generally have intracellular receptors with some cell membrane receptors !

Question 26

What are some affects of interaction between hormones and receptors? (increasing or decreasing interaction)

Answer 26

*Up-regulation= and increase in the # of a hormones receptors. Usually occurring because of an absence or a decreased level of the hormone that binds to that receptor. *Down-regulation= a decrease in the # of a hormones receptors. Generally occurring because of a constant binding of the hormone to the receptor (high levels of hormone)

Question 27

Can regulations of receptor quantities be affected by more than one type of hormone?

Answer 27

An example of up-regulation of progesterone receptors by estrogen. That's why most formulations of the pill include both a synthetic form of progestin and a synthetic estrogen, even though it's the progestin (progesterone activity) that prevents the ovulation.

Question 28

What are some steroidal categories and forms of each with specific examples of hormones?

Answer 28

* Sex Steroids - Androgens - e.g. testosterone - Estrogens - e.g. estradiol - Progestins or Progestagens - e.g. progesterone * Steroids produced in the Adrenal Cortex - Glucocorticoids - e.g. cortisol - Mineralocorticoids - e.g. aidosterone - Androgens - DHEA

Question 29

What are some characteristics of Steroids?

Answer 29

* Steroids comprise many of the important hormones that regulate stress, cardiovascular and kidney function. * They are all lipid soluble (hydrophobic) hormones that have intracellular receptors. * Steroids have group names which indicate the general activity of the hormone. this activity correlates with a particular receptor. There may be more than one specific hormone that binds to a specific receptor.

Question 30

What are some divisions of the ANS (Autonomic Nervous System)? Also< what are the hormones and receptors responsible for carrying out some of the ANSs functions?

Answer 30

* Sympathetic Division (Fight/Flight/Fright) - Epinephrine (hormone from adrenal modulla) - Norepinephrine- sympathetic fibers -Adrenergic receptors on target cells *Alpha receptors - contract smooth muscle usually inhibit hormone secretion *Beta receptors-relax smooth muscle usually stimulates hormone secretion

Question 31

Is the sympathetic division of the ANS needed for emergency situations?

Answer 31

The sympathetic division, of the ANS, generates the reactions known as fight, fright, flight in an extreme activation of the system.

Question 32

What other division of the ANS does the sympathetic division work with to achieve homeostasis?

Answer 32

The sympathetic division of the ANS works every minute of every day in balance with the parasympathetic division to regulate homeostasis and cycles of activity and rest in your body.

Question 33

What happens when an extreme sympathetic activation occurs?

Answer 33

-increased blood pressure -increased heart rate -halted urine production -halted digestion -conservation of fluids and energy -blood directed away form kidney and intestines (vasoconstriction) -blood directed toward skeletal muscles (vasodilation) -dilated pupils and relaxed ciliary muscles for flattened lenses. (enemy detection)

Question 34

What are the hormones and receptors involved? | What are some characteristics of a parasympathetic activation?

Answer 34

Relax and take care of living * Parasympathetic Division - Acetycholine for parasympathetic fibers - Muscarinic cholinergic receptors - Cleaning blood - making urine - digesting food ! during sex the body is relaxed and excited parasympathetic and sympathetic divisions !