Chapter 7 Endocrine System

The study of hormones is called

The study of hormones is called

Endocrinology

List the three basic ways hormones act on their target cells.

1) alter the rate of enzymatic reactions

2) control transport of molecules into and out of cells

3) change gene expression and protein synthesis

For a chemical to be defined as a hormone, it must be secreted

into the … for transport to a(n) … and take effect at …

concentrations.

Blood, distant target, very low

What is meant by the term half-life in connection with the activity of hormone molecules?

The time required for half a dose of hormone to disappear from the blood

Candidate hormones often have the word … as part of their name.

Factor

three chemical classes of hormones

Peptide, steroid, amino acid derived

Are lipophobic and must use a signal transduction system

Peptide

Have a short half-life, measured in minutes

Peptide

Often have a lag time of 90 minutes before effects are noticeable.

Steroid

Are water soluble and thus easily dissolve in the extracellular fluid for transport

Peptide

Most hormones belong to this class

Peptide

Are all derived from cholesterol

Steroid

Consist of 3 or more amino acids linked together

Peptide

Are released into blood to travel to a distant target organ

All classes

Are transported in the blood bound to protein carrier molecules

Steroid

Are all lipophilic, so diffuse easily across membranes

Steroid

Why do steroid hormones usually take so much longer to act than peptide hormones

Steroid hormones usually initiate new protein synthesis, which takes time. Peptides modify existing proteins.

When steroid hormones act on a cell nucleus, the hormone-receptor complex acts as a _ factor, binds to dna, and activates one or more _ , which create mRNA to direct the synthesis of new _.

Transcription factor, genes, proteins

Researchers have discovered that some cells have additional steroid hormone receptors on their _, enabling a faster response.

Cell membrane

Melatonin is made from the amino acid _, and the cat-echolamines and thyroid hormones are made from the amino acid.

Tryptophan, tyrosine

When two hormones work together to create a result that is greater than additive that interaction is called

Synergism

When hormone A must be both present to achieve full expression of hormone B that interaction is called

Permissiveness

When hormone activities oppose each other, that effect is called

Antagonistic

Endoplasmic reticulim

is a network of interconnected membrane-bound sacs and tubules within a cell's cytoplasm, primarily responsible for protein synthesis and processing (on the rough ER) and lipid synthesis (on the smooth ER), acting as a transportation system within the cell

Exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

Golgi complex

it packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination.

Hormone receptor

is a receptor molecule that binds to a specific hormone

Preprohormone

is the precursor protein to one or more prohormones

Prohormone

is a committed precursor of a hormone consisting of peptide hormones synthesized together that has a minimal hormonal effect by itself because of its expression-suppressing structure

Target cell response

is the reaction of a cell to a signal molecule, such as a hormone, that binds to a specific receptor on the cell's surface.

What hormone would have a abundance of Rough ER

Peptide

What hormone has an abundance of Secretory vesicles

Peptide

What hormone has an abundance of smooth ER

Steroid

Where do endocrine glands secrete steroid hormones?

The Gonads and adrenal glands (cortex)

__ Hormones are transported in the blood bound to plasma protein?

Steroid and thyroid

Thyroid hormone

Shares same traits as steroid hormone

If a particular cell in the body does not express a receptor for a specific hormone, ___

This hormone will have no effect on this cell

T/F , all peptide hormones are hydrophobic

False