Lecture 2 1/28/14

Question 1

Endocrine System Overall Function

Answer 1

The Overall Function of the Endocrine System: Responsible for homeostatic regulation of the body

Question 2

Homeostasis

Answer 2

body’s ability to maintain a steady constant environment internally, blood pressure, volume, and hormones

Question 3

Negative Feedback Loop

Answer 3

Much more common in the body. Mechanism that opposes variations that extend outside the normal limits.

Question 4

Negative Feedback Examples

Answer 4

Hormones are a good example of negative feedback, if they go too far, negative feedback brings it back down. Wanna stay in a narrow range.

Thermostat - normal temperature in our bodies. In the picture below our body temperature fluctuates.

Question 5

Two Systems that Maintain Homeostasis

Answer 5

Nervous System

Endocrine System

Question 6

Nervous System

Answer 6

Responds rapidly, and the effects are short lived

Examples:
Bear attacking you from far away, the nervous system recognizes that and responds, disrupting homeostasis

Putting your hand on a hot stove and take your hand quickly away

Burn victims - infection and loss of body fluids

Question 7

Endocrine System

Answer 7

Responds much more slowly but it’s effects are much longer lasting

Question 8

Two Glands within the body

Answer 8

Exocrine Glands

Endocrine Glands

Question 9

Exocrine Glands

Answer 9

Produce their secretions to specific locations on or in the body, secretions get to the specific locations via ducts. Pancreas, majority of the pancreas is tissue, exocrine tissue. Produces digestive enzymes that is then released in the duodenum the first part of the small intestine for digestion to occur. Sweat glands, release secretions of the body via ducts

Question 10

Endocrine Glands

Answer 10

Release their secretions to the inter-cellular space. Inter means between. Interstitial tissue space, the space in between the cells same as inter-cellular space. Diffuse into the bloodstream and travel throughout the body.

Ductless Glands

Pancreas is a endocrine gland

Islet of Langerhans

Question 11

Examples of Endocrine Glands

Answer 11

Pineal Glands

Adrenal Glands

Thyroid Glands

Thymus Glands

Pituitary Glands - Master Gland

Pancreas

Parathyroid

Gonads (Testes and Ovaries)

Kidneys

Hypothalamus

Posterior Pituitary Gland

Question 12

Hormones

Answer 12

secretions of endocrine glands made up of proteins and steroids. Proteins binds to receptors on cell membrane surface. Steroids bind to intra-cellular receptors. Proteins are large

Question 13

Hormone Affects

Answer 13

Generalized. Affects to most cells throughout the body, growth hormones is an example.

Question 14

Thyroid Hormone

Answer 14

Increase, ramp up cellular machinary

Question 15

EPO

Answer 15

Binds to specific stem cells in the bone marrow to increase the production of red blood cells

Question 16

Target Cell

Answer 16

Cell that has the receptor for that specific hormone that we are referring to.

Could be in the cytoplasm of the cell or receptor of the cell

Question 17

Hormones binding to Cells

Answer 17

Different ways or different intra-cellular pathways that can be activated when these hormones bind to the cell or bind intra-cellular receptors

Question 18

Intra Cellular Receptors Do 3 Things:

Answer 18

1. Open ionopores - channel that allows ions to travel through it. Exciting the cell or inhibiting the cell. Some ions go in and go out, exciting the cell or inhibiting that cell.
2. Activate Intracellular Pathways - Dozens of pathways that can be activated
3. Can activate transcription and translation, more specific version of the activated intracellular pathway. Transcription and translation is involved in RNA & DNA (Cell replication). But most of the time they’re making proteins, is the main function of the activating intracellular pathway.

Question 19

cAMP

Answer 19

Cyclic AMP first intracellular pathway that was discovered

Question 20

General Pathway

Answer 20

Typical way to activate cAMP is when the hormone binds to the cell membrane receptor, and when it does, it activates Adenyl Cyclase Enzyme. Then it converts ATP into cyclic amp.

Cyclic AMP is commonly called the Secondary Messenger, so that it means, that the hormone is going to be the primary messenger.

Cyclic AMP might activate another pathway, or it may be involved in opening an ionopore, or channel.

Question 21

G Protein Pathway

Answer 21

Hormone binds causing a conformational change or morphological change in the G Protein receptor. Thus causing a Alpha Subunit to dissociate and gets activated after the hormone binds and changes conformation.

Question 22

Cyclic AMP and Adenyl Cyclase

Answer 22

Is always common to Adenyl Cyclase and will always convert ATP into cAMP

Question 23

Steroid Pathway

Answer 23

Cell Membrane, has a phospholipid bilayer

To make a steroid from a Cholesterol you have to cut off side chain, called sidechain cleavage.

Cholesterol wedges itself in between the phospholipids heads so there’s a little space in between.

Does 2 Things:

1. Provides a little bit more fluidity to the cell membrane
2. Cholesterol separates the phospholipids apart a little bit and allows the steroid molecule to move through. Steroid molecules do not bind to cell membrane receptors, they bind to intracellular receptors.

Question 24

ICR

Answer 24

Intra Cellular Receptor

Question 25

Receptor Protein Hormone Complex

Answer 25

When the Steroid and Intra-Cellular Receptor both come together. And then go off to the nucleus and binds to a segment of a DNA.

Question 26

Hormone Response Element

Answer 26

The receptor protein hormone complex binds to the HRE which is a segment of the DNA. Initiates translation and transcription to make a protein. This is the way a testosterone would activate protein synthesis within a cell.