Endocrinology: Hormones and Target Cells

Question 1

• the study of hormones, the endocrine system, and their physiological role in the body

Answer 1

Endocrinology

Question 2

Endocrine Gland
• secretes its products into the _____ and _____

Answer 2

interstitial fluid and the blood

Question 3

• a chemical messenger released from living cells that travels through the blood to target cells and induces a biological effect or response

Answer 3

Hormone

Question 4

• cells with receptors to specific hormones

Answer 4

Target Cells

Question 5

• only cells with specific_____ will react with a specific hormone

Answer 5

receptor

Question 6

Hormone Receptors
• In or on the surface of the cell membrane: _________
• In the cell cytoplasm:________
• In the cell nucleus:_______

Answer 6

peptide and catecholamine hormones

steroid hormones

thyroid hormones

Question 7

• may consist of a single cell or a group of cells that secrete substances into ducts (tubes), onto a surface, or into the blood in the absence of ducts

Answer 7

Glands

Question 8

Glands

two major types

Answer 8

• endocrine glands
• exocrine glands

Question 9

Exocrine Glands
• glands with_____

Answer 9

ducts

Question 10

• products pass out of the cell and away from the gland by means of ducts into a luminal area

Answer 10

Exocrine glands

Question 11

Exocrine Glands
example:
•______, as an exocrine gland, secretes amylase, lipase, and trypsinogen

Answer 11

pancreas

Question 12

Examples of exocrine glands

Answer 12

Sweat
Salivary
Pancreatic

Question 13

• products are released from the cell, passed directly into the circulation, and are carried by the blood to body tissues and eventually target cells

Answer 13

Endocrine Glands

Question 14

Manners of Secretion

Answer 14

• Autocrine
• Paracrine
• Juxtacrine
• Intracrine
• Ectocrine
• Endocrine

Question 15

• Example: insulin-like growth factor-| (IGF-I)

Answer 15

Autocrine

Question 16

• interaction between secreted chemical messenger with a receptor on the same type of cell that synthesized it

Answer 16

Autocrine

Question 17

• Example: somatostatin secretion inhibits insulin secretion

Answer 17

Paracrine

Question 18

• interaction of a secreted chemical messenger with receptors on adjacent cells on the same tissue

Answer 18

Paracrine

Question 19

• Example: cell adhesion proteins (laminin)

Answer 19

Juxtacrine

Question 20

• expressed on surface of effector cell and interacts with target cell via direct cell-cell contact

Answer 20

Juxtacrine

Question 21

• secretes own hormone that acts inside the same cell, regulating intracellular events

Answer 21

Intracrine

Question 22

• one organism releases a substance (pheromone) that causes a response in another organism

Answer 22

Ectocrine

Question 23

• a chemical messenger produced by a ductless gland or tissue and carried in the blood to a target organ where it effects a change in cellular activity

Answer 23

Endocrine

Question 24

Principal Functions of the Endocrine System (3)

Answer 24

• maintenance of the internal environment in the body (homeostasis)

• integration and regulation of growth and development

• control, maintenance, and instigation of sexual reproduction

Question 25

Types of Hormones

Answer 25

• Peptide • Steroids • Amines

Question 26

Peptide Hormones • May contain_______ amino acids (TRH: ___; GH: ___)

Answer 26

3 to 200 3; 200

Question 27

Peptide hormones • Secretion:_______

Answer 27

exocytosis

Question 28

• Water soluble; no need for transport proteins

Answer 28

Peptide hormone

Question 29

Peptide hormone • Synthesized in_____; stored in_____

Answer 29

ribosomes vesicles

Question 30

• fast acting, short half-life

Answer 30

Peptide hormone

Question 31

Steroid Hormones • Derived from_______ which are rapidly mobilized • found in____ • through_______

Answer 31

cholesterol Plasma De novo synthesis

Question 32

• Hydrophobic/lipophilic; require specific transport proteins as carriers

Answer 32

Steroid hormones

Question 33

Steroid hormones • Secretion:

Answer 33

diffusion across cell membrane

Question 34

• slow-acting; longer half-life

Answer 34

Steroid hormones

Question 35

• derivatives of ***single amino acid residues,*** either from tyrosine or tryptophan

Answer 35

Amine Hormones

Question 36

• can behave either like peptides or steroids

Answer 36

Amine hormone

Question 37

•________ (behave like peptides; cell surface receptors) • ________ (behave like steroids; nuclear receptors)

Answer 37

Catecholamines Thyroid hormones

Question 38

Amine Hormones • behave like protein hormones because they circulate unbound to protein, have a short half-life, and have a similar mechanism of action

Answer 38

catecholamines

Question 39

Amine Hormones • have a long half-life, circulate bound to a carrier protein, and have a mechanism of action similar to steroids

Answer 39

thyroid hormones

Question 40

Key Concepts to Remember • All hormones interact with ______by first binding to_____ located either on the plasma membrane or as a cytosolic protein • The receptor for hormones must be linked to a component that is able to respond to the binding of hormone with its receptor

Answer 40

target cells; specific receptors

Question 41

Control of Hormone Release

Answer 41

Substrate control Nervous control Tropic hormones

Question 42

Control of Hormone Release • Substrate control • Example:

Answer 42

glucose and insulin

Question 43

• Nervous control • Example:

Answer 43

adrenal medulla hormones

Question 44

• Tropic hormones • Example:

Answer 44

release of hormones by anterior pituitary to stimulate other glands (e.g., ACTH to adrenal cortex)

Question 45

: Direct response to substance levels in the blood (e.g., glucose controlling insulin). : Hormone release driven by signals from the nervous system (e.g., adrenaline release in response to stress). : Hormones that signal other glands to release their hormones (e.g., ACTH from the pituitary stimulating the adrenal cortex).

Answer 45

• Substrate Control • Nervous Control • Tropic Hormones

Question 46

Feedback Mechanisms • the final hormone produced regulates its own secretion by ***inhibiting the secretion*** of one or more of the precursor hormones

Answer 46

Negative Feedback (Homeostatic)

Question 47

Feedback Mechanisms • the final hormone produced actually ***enhances or induces the initial hormone*** and causes its own production to be ***increased***

Answer 47

Positive Feedback (Non-Homeostatic)

Question 48

Positive feedback • example:

Answer 48

estrogen and luteinizing hormone

Question 49

Disorders of the Endocrine System The levels of disorders

Answer 49

Primary disorder Secondary disorder Tertiary disorder

Question 50

• Explanation: In a ____ disorder, the gland responsible for producing the hormone is malfunctioning, either overproducing (hyper-) or underproducing (hypo-) the hormone.

Answer 50

Primary Disorder:

Question 51

• Example: when the thyroid gland fails to produce enough thyroid hormones (T3 and T4), leading to symptoms like fatigue, weight gain, and cold intolerance.

Answer 51

Primary Disorder:

Question 52

• Definition: The problem originates in the gland that produces the hormone itself.

Answer 52

Primary Disorder:

Question 53

• Explanation: In _____ disorders, the issue lies in the pituitary gland or any other gland that controls the primary gland. The primary gland doesn’t receive the correct signals to produce hormones.

Answer 53

Secondary Disorder:

Question 54

• Example: ______ when the pituitary gland fails to produce enough thyroid-stimulating hormone (TSH), which signals the thyroid to produce its hormones. The thyroid itself might be healthy, but it isn’t stimulated properly.

Answer 54

Secondary Disorder:

Question 55

• Definition: The problem is with the gland that stimulates the primary gland to release hormones.

Answer 55

Secondary Disorder:

Question 56

• Explanation: _____ disorders are at the top of the chain and affect the hypothalamus, which regulates the pituitary gland. This leads to downstream effects on the primary gland.

Answer 56

Tertiary Disorder:

Question 57

• Example: when the hypothalamus doesn’t release enough thyrotropin-releasing hormone (TRH), which signals the pituitary gland to produce TSH. This leads to low TSH and, in turn, low thyroid hormone production.

Answer 57

Tertiary Disorder:

Question 58

• Definition: The problem originates even higher up in the regulatory chain, usually in the hypothalamus.

Answer 58

Tertiary Disorder: