Endocrine System

Question 1

Why this matters…

Answer 1

Understanding the endocrine system enables you to monitor and advise patients with diseases such as diabetes mellitus

Question 2

Endocrine system

Answer 2

• Ask with the nervous system to coordinate and integrate activity of body cells
• Influences my metabolic activities via hormones transported in blood
• Responses slower but longer lasting than the nervous system responses

Question 3

Endocrinology

Answer 3

Study of hormones and endocrine organs

Question 4

Endocrine system controls and integrates:

Answer 4

• Reproduction
• growth and development
• maintenance of electrolyte water and nutrient balance of blood
• regulation of cellular metabolism and energy balance
• mobilization of body defense

Question 5

Exocrine glands

Answer 5

• Produce non-hormonal substances examples sweat

- have saliva have ducts to carry secretion to membrane surface

Question 6

Endocrine glands

Answer 6

• Produce hormones

- lack ducts

Question 7

Endocrine glands include…

Answer 7

Pituitary, thyroid, parathyroid, adrenal, and pineal gland’s

Question 8

Hypothalamus

Answer 8

Is a Neuroendocrine organ

Question 9

Sam have exocrine and endocrine functions

Answer 9

Pancreas, gonads, and placenta

Question 10

Other tissues and organs that produce hormones…

Answer 10

Adipose cells, thymus, and cells in the walls of the small intestine, stomach, kidneys, and heart

Question 11

Chemical messengers of the endocrine system

Answer 11

Hormones, Autocrines, and Paracrines

Question 12

Hormones

Answer 12

Long-distance chemical signals; travel in blood or lymph

Question 13

Autocrines

Answer 13

Chemicals that exert effects on same cells that secrete them

Question 14

Paracrines

Answer 14

Locally acting chemicals that affect cells other than those that secrete them

Question 15

Autocrines and Paracrines

Answer 15

Are local chemical messengers; not considered part of the endocrine system

Question 16

Two main classes of hormones

Answer 16

1. Amino acid-based hormones
2. steroids
3. and a possible third class eicosanoids

Question 17

Amino acid-based hormones

Answer 17

Amino acid derivatives, peptides, and proteins

Question 18

Steroids

Answer 18

• Synthesized from cholesterol

- gonadal and adrenocortical hormones

Question 19

Eicosanoids

Answer 19

It’s considered a hormone by some scientists but most classify it as a paracrine

Question 20

The hormones circulate systemically

Answer 20

Only cells with the receptors for that home or are affected

Question 21

Target cells

Answer 21

Tissues with the receptors for a specific hormone

Hormones alter a target cell activity

Question 22

Hormone action on target cells may be too

Answer 22

• Alter plasma membrane permeability and or membrane potential by opening or closing ion channels
• stimulate synthesis of enzymes or other proteins
• activate or deactivate enzymes
• induce secretory activity
• stimulate mitosis

Question 23

Hormones act in one of two ways depending on their chemical nature and receptor location

Answer 23

1. Water soluble hormones

2. lipid soluble hormones

Question 24

Water-soluble hormones

Answer 24

All the amino acid-based hormones exact thyroid hormone

• acts on plasma membrane receptors
• act via G proteins second messengers
• cannot enter cell

Question 25

Lipid soluble hormones (steroid and thyroid hormones)

Answer 25

- Act on intracellular receptors that directly activate genes - can enter a cell

Question 26

Amino acid-based hormones

Answer 26

Except thyroid hormones exert effects through the second messenger system

Question 27

Two main second messenger systems

Answer 27

1. Cyclic AMP | 2. PIP2-calcium

Question 28

Cyclic AMP (cAMP) signaling mechanism #1

Answer 28

1. Hormone (first messenger) binds to a receptor 2. Receptor activates a G protein 3. G proteins activate or inhibits effector enzyme adenylate cyclase 4. Adenylate cyclase Then converts ATP to see a cAMP (second messenger) 5. cAMP activates protein Kinases that phosphorylate (add a phosphate) other proteins

Question 29

Cyclic AMP (cAMP) signaling mechanism #2

Answer 29

- Phosphorylated proteins are then either activated or an activated - cAMP is rapidly degraded by enzyme phosphodiesterase, stopping Cascade - Cascades have huge amplification effect

Question 30

PIP2-calcium signaling mechanism #1

Answer 30

Hormone activated G Protein activates a different effector enzyme: phospholipase C Activated phospholipase C splits membrane protein PIP2 into two second messengers

Question 31

Diacylglycerol (DAG)

Answer 31

Activates protein kinases

Question 32

Inositol triphosphate (IP3)

Answer 32

Causes. CA2+ release from intracellular storage sites

Question 33

PIP2-calcium signaling mechanism #2

Answer 33

Calcium ions actors another second messenger - CA 2 plus alters enzyme activity and channels or binds to regulatory proteins calmodulin - Calcium bonded calmodulin activates enzymes that amplifies cellular response

Question 34

Other signaling mechanisms

Answer 34

cGMP (cyclic guanosine monophosphate) is a second messenger for selected hormones Other hormones work without second messenger system

Question 35

Example

Answer 35

insulin receptor is a tyrosine kinase enzyme that autophosphorylates upon insulin binding - Activated tyrosine kinases provide docking sites for relay proteins that trigger cell responses