Chapter 11 - Endocrine Glands

Might want to look over, its just notes. didnt look at slides when making these

What are hormones?

Are regulatory molecules secreted into the blood by endocrine glands.

Hormones travel through the bloodstream to target tissues.

Interactions between hormones can be synergistic, permissive, or antagonistic

What affects how hormones travel?

Hormones are either polar/water-soluble or nonpolar/water-insoluble. This affects how they travel and interact with their target cells.

What are water-soluble hormones made of

Amino-acid based

What are lipid-soluble hormones derivatives of

cholesterol and are steroid-based

Synergistic hormones

When two hormones work together to produce a result.

Released at the same time.

Permissive hormones

When one hormone enhances the responsiveness of a target organ to a second hormone or when it increases the activity of the second hormone.

• Estradiol/progesterone

• Usually one hormone is present before the other

Antagonistic hormones

Two hormones having opposing functions

What can cause a greater response in a target cell by a hormone?

Priming and upregulation

Priming effect

Small amounts of a hormone can increase sensitivity of target cells

Upregulation of hormone receptors

Increased numbers of receptor proteins for hormone being primed

What can make a cell less sensitive to a hormone

Desensitization and downregulation

What conditions do we see desensitization?

Prolonged exposure to high concentrations of polypeptide hormones can desensitize the target cells

What is downregulation

Decrease in the number of receptor proteins caused by continuous exposure of target cells to high concentrations of the hormone

Where are the location of receptors for nonpolar (lipid based) hormones and what is the binding effect?

These pass through the plasma membrane and bind to receptor proteins inside their target cells - usually are nuclear receptors.

These help regulate gene expression of a target cell

Where are the location of receptors for polar (amino acid based) hormones and what is the bind effect?

These do not enter target cell and bind to receptors on plasma membrane.

Exerted by using second messenger systems.

How are nonpolar (lipid) hormones transported through the body?

They are carried by carrier proteins in the bloodstream

How are polar hormones transported through the body?

These generally float through the bloodstream

What hormones generally cause new protein synthesis?

Nonpolar (lipid) hormones when they bind to their receptors, after binding transcription can begin.

What do secondary messengers activate>

They activate enzymes that are already present within the cell

Which hormones bind to extracellular receptors and then use intracellular mediators to cause their effects?

Polar (amino acid based) hormones

How are a majority of hormones regulated?

by negative feedback

List the hormones made by anterior pituitary gland

GH

TSH

ACTH

FSH

LH

PRL

Target and effect of GH

Most tissue

Promotes protein synthesis and growth; lipolysis and increased blood glucose

Target and effect of TSH

Thyroid gland.

Stimulates secretion of thyroid hormone

Target and effect of ACTH

Adrenal Cortex.

Stimulates secretion of glucocorticoids

Target and effect of FSH

Gonads

Promotes gamete production and stimulates estrogen production in females

Target and effect of LH

Gonads

Stimulates sex hormone secretion; ovulation and corpus luteum formation in females; stimulates testosterone secretion in males

Target and effect of PRL

Mammary glands and other sex accessory organs

Promotes milk production in lactating females; additional actions in other organs.

Dwarfism is caused by

Inadequate GH during childhood

Gigantism is caused by

over secretion of GH during childhood

What does the posterior pituitary gland do?

It is made of neural tissue. Stores/releases two hormones produced by the hypothalamus

What are the two hormones stored in the posterior pituitary gland?

ADH

Oxytocin

Target and effect of ADH

Kidneys

Stimulation of water retention and less excretion of water in urine

Target and effect of Oxytocin

Uterus smooth muscle; mammary glands

Labor contractions; milk ejection

What glands are known as the stress glands?

Adrenal glands

What is the adrenal cortex composed of and what does it make?

The adrenal cortex is composed of epithelial tissue.

It creates steroid hormones from cholesterol

What is the adrenal medulla comosed of?

Neural tissue

What hormones increase energy consumption by cells?

The thyroid hormones T3 and T4

Where are the hormones T3 and T4 produced?

Thyroid follicles

Why is iodine important?

It is necessary for thyroid hormone production and too little of it can cause a large swelling of the neck which could result in a goiter

What produces calcitonin?

Parafollicular cells

What does calcitonin do?

lowers blood Ca2+ levels

What produces the parathyroid hormone?

The parathyroid gland

What does PTH (parathyroid hormone) do?

Increases blood Ca2+ by stimulating osteoclast activity and retention of ca2+ (instead of urinating it)

What does insulin do and where is it made?

Insulin lowers blood glucose and is produced by the beta cells of the pancreatic islets

What does glucagon do and where is it made?

Glucagon elevates blood glucose and is produced by the alpha cells of the pancreatic islets

What is used for signaling between cells

Paracrine and autocrine chemicals

Autocrine regulatiors are

Regulators that act on the same cells and cell type that produced them

Paracrine regulators are defined as

Regulators that neighboring cells within an organ