Anatomy Chapter 10. Endocrine system

What are some examples of second messengers?

-Cyclic AMP -Calcium ions -Cyclic GMP

What are some chemical messengers the nervous and endocrine system share?

-Epinephrine (E) -Norepinephrine (NE)

What is the correct order of events for hormones activating Gs proteins?

1. Activation of G protein 2. Binding of GTP 3. Activation of adenylate cyclase 4. Conversion of ATP to cAMP

What stimulates the release of steroid hormones by the adrenal cortex?

ACTH

What does the pituitary gland Anterior lobe release?

ACTH, TSH, GH, PRL, FSH, LH, AND MSH

What does the hypothalamus produce?

ADH, oxytocin, regulatory hormones

What is the mechanism of action of lipid-soluble hormones?

Activation of genes, which increase protein synthesis in the cell

After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?

Acts as a transcription factor and binds to DNA, activating a gene

Increased sodium ion concentrations in the body can be caused by which adrenal hormone?

Aldosterone

What is a second messenger?

An intermediary molecule that forms due to a hormone-receptor intereaction

What does the gonads secrete

Androgens in males Estrogen, pro estrogen, inhibin in girls

What are amino acid derivatives?

Are small molecules structurally related to amino acids -Ex. Epinephrine, norepinephrine, thyroid hormone and melatonin

What adrenergic receptor increases cAMP levels?

B receptors

Why can a cell only respond to only a few of the hormones present?

Because the cell lacks the receptors needed to read the masses they contain

How do hormones alter cellular operations?

By changing the types, activities, locations or quantities of important enzymes and structural proteins

Parathyroid hormone stimulates the kidneys to form

Calcitrol

A single hormone can do what?

Can alter the metabolic activities of multiple tissues and organs at the same time because target cells can be anywhere in the Boyd

What can hormones that bind to plasma membrane receptors not do?

Cannot directly affect the activities inside the target cell

What are peptide hormones?

Chains of amino acids Ex. ADH, oxytocin, hypothalamic, pituitary, pancreatic hormones

What is hormonal stimuli?

Changes in circulating hormone levels, involve 2 or more hormones

What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor?

Chaperone proteins (chaperonins)

All hormones are what?

Chemical messengers

What are hormones?

Chemical messengers released in one tissue and transported by the bloodstream to target cells in other tissues

How is homeostasis maintained?

Chemical messengers- negative feedback

Steroid hormones are structurally similar to ____________

Cholesterol

What is the most important second messengers?

Cyclic AMP (cAMP)

What do enzymes do?

Direct the cells metabolism

What lipid derivative coordinated local cellular functions and affect enzymatic processes?

Eicosanoids

What does the endocrine system consist of?

Endocrine cells and tissues

What does the kidneys secrete

Erythropoietin (EPO), calcitriol

What are eicosanoids?

Fatty acid used, derived from arachidonic acid -Includes prostaglandins

What primarily targets the gonads (ovaries and testes)?

Follicle stimulating hormone

The pituitary hormone that stimulates the breakdown of stored fats and the release of fatty acids into the blood is what?

GH

structural proteins

Give a cell its general share and internal structure

What must the target cell have in order to respond to a hormone?

Has to have a receptor

Intercellular communication maintains ________

Homeostasis

Plasma membranes are required for what types of hormones?

Hormones that are not lipid soluble

In the simplest case, endocrine activity may be controlled by changes in the extracellular fluid composition called ________ stimuli.

Humoral

What provides the highest level of endocrine control?

Hypothalamus

Where are the hormones secreted by the posterior pituitary made?

Hypothalamus

What second messenger causes the release of calcium from the endoplasmic reticulum?

IP3

A hormone is released ________and is distributed throughout the body

Into the bloodstream

What receptors can change the structure or function of a cell?

Intracellular receptors

The endocrine system is slower or faster? and it does what?

It is slower -It releases hormones into bloodstream, with long lasting effects

The pituitary hormone that promotes testosterone release in males and ovulation in female is

LH

What intracellular substance degrade cAMP, thus inactivating the response to a hormone

Phosphodiesterase

Hormones cannot diffuse through the __________-

Plasma membrane

What does the pituitary gland posterior lobe release?

Release of ADH and oxytocin

Called neurotransmitters when released how?

Released across synapses

How are steroid hormones released?

Released by reproductive organs and cortex of the adrenal glands

Called hormone when released how?

Released from adrenal medulla

What does the heart release

atrial natriuretic peptide

An important second messenger in hormonal action is what?

cAMP

What is a G protein?

a protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein

What is humoral stimuli?

changes in composition of extracellular fluid

What hormone has intracellular receptors?

cortisol

What does the adrenal cortex secrete?

cortisol, corticosterone, aldosterone, androgens

What are the 2 lipid derivative's?

eicosanoids and steroid hormones

What does the adrenal medulla release?

epinephrine (E) and norepinephrine (NE)

Diabetes insipidus can be caused by

failure of kidneys to respond to ADH

Where are intracellular receptors found?

inside cytoplasm or nucleus

What does the pancreas secrete?

insulin and glucagon

What does the adipose tissue release

leptin

What does the pineal gland secrete?

melatonin

The posterior pituitary gland stores

oxytocin (OT)

What does parathyroid hormone secrete?

parathyroid hormone

What is the largest class of hormones?

peptide hormones

What does the hormone prolactin do?

stimulates milk production

What do hormones bind to?

target cells or tissues

Cellular communication is coordinated by what 2 systems?

the nervous and endocrine systems

What does the thymus release

thymosin

What are 4 similarities of the nervous and endocrine system?

1. Release chemicals that bind to specific receptors on target cells 2. Share chemical messengers 3. Primarily regulated by negative feedback processes 4. Maintain homeostasis by coordinating and regulating the activities of other cells, tissues, organs and systems

What are the 3 groups of hormones?

1. amino acid derivatives 2. peptide hormones 3. lipid derivatives

What is a neural stimuli?

Neural stimulation of a neuroglandular junction through neurotransmitter

hormone-receptor complex

Once inside a target cell, steroid and thyroid hormones combine (usually in the nucleus) with specific protein receptors

What does the hormone insulin do?

Lower blood glucose levels

What hormone is secreted by the human pituitary during fetal development in very young children and in pregnant women, but is not usually found in adults?

MSH

What can be affected by a single hormone?

Multiple tissues or organs

What are second messenger systems?

Small number of hormone molecules that can activate thousands of second messengers

Each hormone has target cells, what are they?

Specific cells that have the receptors that bind and read the hormonal message when it arrives

What hormone enters a cell by diffusion?

Steroid hormones

What lipid derivative is bound to transport proteins in the blood?

Steroid hormones

What are steroid hormones?

Structurally similar to cholesterol

What is the first messenger?

The hormone that binds to a receptor on the plasma membrane surface

What system is faster?

The nervous system is faster -More specific destinations and shorter lived effects -better coordination of responses to emergencies

The hypophyseal portal system is a network of blood vessels connecting _______

The pituitary gland to the hypothalamus

What determines a target cells sensitivity to a given hormone?

The presence or absence of a specific target cell receptor for that hormone

The endocrine system relies on

The release of chemicals that bind to target cells

What do circulating hormones do?

They keep the body water content and levels of electrolytes and organic nutrients within normal limits 24 hours a days throughout our lives

What hormone receptor is always bound to DNA even when the receptor is empty?

Thyroid hormones

Iodine is extremely important in the formation of what hormone?

Thyroxine (T4)

What does the thyroid gland release?

Thyroxine (T4), triiodothyronine (T3) and calcitonin (CT)

Growth factor such as insulin bind to what type of receptor?

Tyrosine kinase receptors

What is the role of the endocrine system?

Uses chemical messengers called hormones to relay information and instructions between cells

Communication between the hormone and the cell uses what?

Uses first and second messengers

What does the hormone ADH do?

Water reabsorption by the kidneys

What type of hormone binds to receptors located on the cell membrane?

Water-soluble hormones such as insulin and epinephrine

What is amplication?

When Small number of hormone molecules that can activate thousands of second messengers