Endocrine system and hormones

Question 1

The Endocrine System

Answer 1

coordinates and integrates cellular activity throughout the body to maintain homeostasis

Question 2

Functions of the Endocrine System

Answer 2

homeostasis
control of the storage and utilization of energy
regulation of growth, development, reproduction
regulates the body’s response to environmental stimuli

Question 3

Endocrine Glands

Answer 3

Ductless glands that secrete hormones into blood stream (directly release into blood stream)

Question 4

Target organs

Answer 4

The organ that contains cells with receptors that have hormone specific receptors

Question 5

Hormones

Answer 5

Messengers transported through the blood
“chemical messengers released by one cell and exert a biological action on a target cell)

chemical substances produced by the body and exerts a regulatory effect on the activity of cell/tissue/organ

Question 6

Hormone Signaling

Answer 6

endocrine, paracrine, autocrine and intracrine

Question 7

Endocrine Signaling

Answer 7

• target tissue is distant

- hormone travels through blood stream to reach target tissue

Question 8

Paracrine Signaling

Answer 8

Target tissue is more local
Examples of Paracrine Signaling
nitric oxide, bradykinin, neurotransmitters, cytokines (small proteins, interleukins, TNF, IF, growth factors, TGF), prostaglandins

Question 9

Nitric Oxide

Answer 9

paracrine signaling

in blood vessel walls and released into immediate area, promotes vasodilation

Question 10

Bradykinin

Answer 10

paracrine signaling

Promote BV vasodilation, often with injury

Question 11

Neurotransmitters

Answer 11

paracrine signaling

Epi and NE

Question 12

Cktokines

Answer 12

paracrine signaling

small proteins, immunoregulating and growth function (interleukins, TNF, IF, growth factors, TGF

Question 13

Prostaglandins

Answer 13

paracrine signaling

fatty acid messengers, multiple functions

Question 14

Autocrine

Answer 14

target cell is same cell

hormone released by a cell and then acts on the same cell that released it

Question 15

Intracrine

Answer 15

hormone produced in cell, acts within its self

Question 16

Regulation of hormone secretions

Answer 16

Negative Feedback–> most common, hormone actions directly or indirectly inhibit further release of that hormone

Positive feedback–> less common, hormone actions stimulate further release of that hormone
ex: lutinizing hormone

Question 17

2 classifications of hormones

Answer 17

derivative content classification, solubility classification

Question 18

Derivative Content Classifications

Answer 18

-Amino acids derivatives: catecholamines, thyroid hormones

Peptide/protein derivatives: Glycoproteins…many of the “releasing hormones”are formed of peptides

Steroid derivatives: estrogens, testosterone, etc…

Fatty acid derivatives- eicosanoids, Prostaglandins

Question 19

Solubility Classification: Lipid Soluble

Answer 19

Steroid Hormones and thyroid hormones (cholesterol is precursor for all steroid hormones)

circulate in plasma via binding to plasma proteins (longer half life)

Hormone/protein carrier will disassociate at target tissues

Question 20

Solubility Classification: Water Soluble

Answer 20

most hormones are water soluble
GH, TSH, PTH
circulates freely in plasma, easily borken down
short half life

Question 21

Hormone receptors

Answer 21

located on or in cell membrne. Not a fixed quanity, continuous receptor turn over

Question 22

Up Regulation

Answer 22

low concentration of hormone=increase # of receptors on target tissue
=increased sensitivity to hormone

Question 23

Down Regulation

Answer 23

high concnetration of hormone=decreased # of receptor in target tissue
=decreased sensitivity to hormone

Question 24

Signal trasnduction

Answer 24

extracellular signlas (hormones) are communicated into a cell

primary messenger, secondary messenger

Question 25

Primary Messenger

Answer 25

hormone enters cell and mediates cell fxn

fat soluble (lipophilic) hormones, easily diffuse across cell membrane to communicate to receptors within

Question 26

Secondary Messenger

Answer 26

link between primary messenger (hormone) and inside cell, communicates to interior structures of cell to produce desired physiological action

Water soluble–> require secondary mechanism, cant diffuse across the membrane. Primary messenger communicates w/secondary messenger mechanism to reach internal structures of cell (using cAMP)