Endocrine System

What is the endocrine systems signaling mechanism?

chemical

What is the endocrine systems first chemical signal?

hormones via blood

What is the endocrine systems distance traveled?

can be long or short

What is the endocrine systems response time?

can be fast or slow

What is the endocrine systems targeted environment?

internal

What is the nervous systems signaling mechanisms?

chemical/electrical

What is the nervous systems primary chemical signal?

neurotransmitters via action potentials

What is the nervous systems distance traveled?

always short

What is the nervous systems response time?

always fast

What is the nervous systems targeted environment?

internal and external

What is the endocrine system used for?

used to regulate “big picture” functions in the body

What functions does the endocrine system regulate?

-growth & development

-metabolism & energy balance

-water, electrolyte, & nutrient balance in the blood

-immune system activation

-reproduction

What does the endocrine system use to regulate body functions?

hormones

How does the endocrine system use hormones to regulate body functions?

hormones (chemical messengers) are secreted into the bloodstream and travel through the body until they attach only to their specific receptors that are on/in their target cells

Endo-

inside

-crine

secretion

How many types of hormones are there?

2

What are the 2 types of hormones?

Lipid-soluble and water-soluble

Lipid-soluble Hormones

bind to intracellular effectors (receptors), lipid based (like steroid hormones), exocrine

Exocrine

outside secretion, product is released across an epithelial barrier to the exterior

Exocrine examples

sweat glands, salivary glands, digestive enzymes

Water-soluble Hormones

bind to extracellular effectors (receptors), amino acid constructs (protein based)

Water-soluble Hormone Examples

Amine hormone, Peptide hormone, Protein hormone, and Steroid hormone

Amine Hormone

amino acid with modified groups

Peptide Hormone

short chains of linked amino acids

Protein Hormone

long chains of linked amino acids

Steroid Hormones

derived form the lipid cholesterol

Which hormones can diffuse across the plasma membrane of their target cells and use transport proteins to move through the bloodstream?

Lipid-soluble hormones

How do lipid-soluble hormones work?

Once diffused across plasma membrane they attach to intracellular receptors and then receptor-hormone complex enters the nucleus and changes gene expression.

Lipid Soluble Hormone Steps:

1.Lipid-soluble hormone diffuses through plasma membrane

2.Hormone binds with receptor in cytoplasm, forming a receptor-hormone complex

3.Receptor-hormone complex enters the nucleus and triggers gene transcription

4.Transcribed mRNA is translated into proteins that alter cell activity

What type of hormones are Thyroid hormones?

Lipid soluble hormones

Thyroid Hormones

the only amino acid-derived hormones that are lipid-soluble

Types of thyroid hormones

thyroxine (t₄) and triiodothyronine (T₃)

What type of hormones are steroid hormones?

lipid soluble hormones

Steroid Hormones

lipid-soluble and derived from cholesterol

Types of steroid hormones

aldosterone (mineralocorticoid), cortisol (glucocorticoid), androgens & estrogen, progesterone & estradiol, and testosterone

Which steroid hormones are made by the outer cortex of the adrenal gland?

aldosterone, cortisol, and androgens & estrogen

Aldosterone

mineralocorticoid, made with corticosterone

What is corticosterone used to make?

aldosterone

Cortisol

glucocorticoid

Androgens and Estrogen

sex hormones

Progesterone and Estradiol

made mainly by the ovaries

Testosterone

made mainly by the testes, makes dihydrotestosterone

What is dihydrotestosterone made with?

testosterone

Which hormones circulate freely through the bloodstream and attach to the outer surface of their target cells?

water soluble hormones

How do water soluble hormones work?

After attaching to the outer surface of their target cells, the hormone binding activates the receptor. This then activates an internal messenger which then activates another internal protein and so on… cascade effect occurs, amplifying signal as it goes.

Most water-soluble hormones are amino acid derived EXCEPT:

Thyroxines (T₃ & T₄)

Water-soluble Hormone Steps:

1.Water-soluble hormones are membrane insoluble. They bind to membrane receptors.

2.The binding activates G protein.

3.The activated G protein activates adenylyl cyclase.

4.Adenylyl cyclase catalyzes the conversion of ATP to cAMP, the secondary messenger in this pathway

5.Protein kinases phosphorylate proteins in the cytoplasm. This activates these proteins, allowing them to alter cell activity.