Chapter 11 Endocrine System

Endocrine System:

• The endocrine system is made up of the cells, tissues, and organs that secrete hormones into body fluids such as the blood stream.

• What is its function?

• 1. To enable the coordination of body parts communicating with each other.

• 2. To adjust to constantly changing conditions in the body (homeostasis)

• What is the difference between an endocrine gland and an exocrine gland?

• Endocrine secrets products into body fluids to affect target cells

• Exocrine secretes products into ducts

• What is the tissue called that hormones affect?

• Target cells

Hormone Action:

• _______hormones are lipid-soluble and can pass through cell membranes.

• Their receptors are located in the target cell's _______.

Steroid

Nucleus

Hormone Action:

• The hormone-receptor complex binds with the ____________ and activates specific _________________ that, in turn, direct the synthesis of specific _______________.

• ______________________ hormones combine with receptors in target cell _______________.

DNA

genes

proteins

Non-steroid

membranes

Hormone Action

• The receptors have a ___________________ site and a/an _____________________ site.

• BindingActivity

Hormone Action

• The hormone-receptor complex of non-steroidal hormones (as first messenger) triggers a cascade of biological activity. What happens after the complex forms?

• What is the name of the most common second messenger?

• The desired change within the cell occurs

• The most common second messenger is cAMP

• Prostaglandins: are locally-produced lipids that affect the organ in which they are produced with a variety of effects.

• What are some of these effects?

• Relax or contract smooth muscle, stimulate secretion, influence blood pressure

Control of Hormonal Secretions

• There are several ways in which hormone release is very closely regulated. All of these mechanisms use negative feedback.

Control of Hormonal Secretions

• The hypothalamus regulates the _____________ gland’s release of hormones

• The _________system influences certain endocrine glands directly with nerve impulses.

Anterior pituitary

Nervous

• Other glands respond directly to changes in the ____________ fluid composition.

• Explain in general how negative feedback works. How would this function in the above three situations?

Blood’s

Pituitary Gland:

• The pituitary gland is attached to the base of the brain and has a front lobe called the ________ and a rear lobe called the ________.

anterior

posterior

Pituitary Gland

• Releasing hormones from the ____________ control the secretions of the anterior pituitary and are carried in the bloodstream by __________________ .

hypothalamus

Hypophyseal portal veins

Pituitary Gland

• The posterior pituitary releases hormones into the bloodstream in response to nerve impulses from the _____________.

•

hypothalamus

Anterior Pituitary:

• The anterior pituitary consists mostly of ___________________ tissue arranged around blood vessels and enclosed in a capsule of collagenous _______________tissue.

epithelial

connective

Anterior Pituitary:

• How many hormones does it secrete?

• What function do most of them have in common?

• 6

• Several stimulate other endocrine glands

Anterior Pituitary:

• Growth hormone GH:• What is the function of

GH? • What hormones from

the hypothalamus control the levels of GH?

• What disorders may result from a lack of GH or too much GH?

• It stimulates cells to increase in size and divide more frequently

• GH-releasing hormone and GH-inhibiting hormone

• Dwarfism• Gigantism

Dwarfism

Not Mr. Reyes

Gigantism

Anterior Pituitary:

• Prolactin PRL:

• What is the function of PRL?

• What is its target tissue?

• What hypothalamic hormones affect it?

• PRL stimulates and sustains a woman’s milk production

• Mammary glands

• PR- Releasing Hormone

Anterior Pituitary:

• Thyroid stimulating hormone TSH:

• What is the function of TSH? (What is its target organ?)

• What hypothalamic hormones affect its release?

How are these hormones from the hypothalamus regulated?

Stimulates the thyroid gland

Thyrotropin-Releasing Hormone (TRH)

As the level of circulating thyroid hormones fall, the hypothalamus puts out TRH. When the levels of circulating thyroid hormones are at correct level, the hypothalamus stops putting out TRH.

Anterior Pituitary:

• Adrenocorticotropic hormone ACTH:

• What is the target organ for ACTH?

• What hormone does it affect the release of?

• What is the name of the hormone from the hypothalamus that controls ACTH’s release?

• Adrenal cortex

• Cortisol

• Corticotropin-releasing Hormone (CRH)

Anterior Pituitary: • Follicle stimulating

hormone FSH: • What are the target organs

for FSH?

• What effect does it have on the males?

• On females?

• What hormone from the hypothalamus affects its release?

• Gonads

• Testes start to produce sperm

• Ovaries begin to produce eggs and to produce and release estrogens

• Gonadotropin-Releasing Hormones

Anterior Pituitary:

• Luteinizing hormone LH:

• What does it do? • Causes ovulation and formation of corpus luteum in the ovary which then begins to release estrogen and progesterone

Anterior Pituitary:

• Luteinizing hormone LH:

• How is it different in males than in females?

• In males it stimulates the testes to release testosterone

• In females stimulates the follicle to release the egg (ovulation).

Anterior Pituitary:

• Luteinizing hormone LH:

• What is its controlling hormone from the hypothalamus called?

• Gonadotropin-releasing hormoneGnRH

Posterior Pituitary:

• The posterior lobe consists of ________________ fibers and supporting _________________ cells arising in the hypothalamus.

• What structure actually produces the hormones released by the posterior pituitary?

Nerve

Neuroglia

hypothalamus

Posterior Pituitary:

• Antidiuretic hormone ADH:

• What is the function of this hormone?

• What disorder may result if enough ADH is not secreted?

• ADH is a chemical that decreases urine production

• Diabetes insipidus

Posterior Pituitary:

• Oxytocin:

• What are the functions of this hormone ?

• causes contraction of the uterus walls during childbirth

• milk-letdown during breast feeding

Thyroid Gland:

• The thyroid gland is located below the _______________ and consists of two broad ____________ connected by an ________________.

larynx

lobes

isthmus

Thyroid Gland

• The thyroid consists of secretory parts called ___________________ filled with hormone-storing _________________.

follicles

colloid

Thyroid Gland• Thyroxine T4: • How many iodines does it contain?• Triiodothyronine T3: How many iodines?• What is the function of these two hormones?

• How does TSH affect their release?

• How do they affect the release of TSH?

• What is a goiter and what may cause one?

3

4

Regulate Metabolism

Stimulates the Thyroid Gland to release

Increased T3 and T4 levels cause the pituitary gland to stop releasing them

Low levels of Iodine or thyroid inability to produce T3 and/or T4

Thyroid Gland

• Calcitonin: • What is the function of

this hormone?• What part of the

thyroid secretes it?

• Inhibits osteoclasts (breakdown of bone) and increases kidneys excretion of calcium and phosphate ions resulting in lower calcium levels in blood

• Parafollicular cells

Parathyroid Glands:

•  • How many are there and

where are they found?• Parathyroid hormone

PTH: What is the function of this hormone?

• How does it achieve this function?

• Four: located on the back of the thyroid gland

• Increases blood calcium levels

• Stimulates osteoclasts to breakdown bone tissue and release calcium in the blood. Also makes kidney conserve calcium

Parathyroid

• How is it related to calcitonin from the thyroid?

• PTH and Calcitonin have opposite effects and work together to maintain the correct levels of calcium ions in the blood

Adrenal Gland: • The adrenal glands sit

atop the __________________ enclosed in a layer of __________.

• Adrenal medulla: The adrenal medulla is made up of modified ________________________ that are connected to the _____________

nervous system.

kidneys

Adipose tssue

Postganglionic neurons

Sympatheic division of the autonomic

Adrenal Gland:

• The hormones secreted are the same as neurotransmitters of this system but are called hormones because they are secreted into the __________________.body fluids and blood stream.

Adrenal Gland:

• Epinephrine & norepinephrine:

• What affect do these have on the body?

• What are they secreted in response to?

Similar effects to those of the sympathetic division of the autonomic nervous system

• Stress and “fight or flight” situations

Adrenal Gland:

• Adrenal cortex: The adrenal cortex makes up most of the adrenal glands and consists of ___________cells in three layers: an outer, middle, and an inner zone. Several groups of hormones are secreted by the cortex.

Epithelial_

Adrenal Gland:

• Mineralocorticoids - aldosterone:

• This hormone controls the levels of _______ ions by conserving them in the _______.

• This causes the conservation of water

sodiumkidneys

Adrenal Gland:

• Why is this important?

• Which zone secretes mineralocorticoids?

•Important in homeostasis of the body •Outer zone

• Glucocorticoids:

• These hormones influence the metabolism of glucose, protein, and fat in response to conditions that __________ the body and require a greater supply of _________________ in the bloodstream.

Stress

glucose

• How does negative feedback control the release of these hormones?

• What else can trigger their release?

• Name an important glucocorticoid.

• Which zone secretes these hormones?

Decrease in sodium

Decrease in blood pressure

Cortisol

Adrenal Cortex

• Sex hormones: Sex hormones, produced in the ____________zone, are mostly of the ___________ type but can be converted to ________________ hormones in the skin, liver, and adipose tissues.

• These hormones supplement those released by the gonads and may stimulate early development of reproductive organs.

inner

male

female

Pancreas:

• The pancreas secretes hormones as an __________________ gland, and digestive juices to the digestive tract as an ___________ gland.

• Where is the pancreas located?

endocrine

exocrine___

Behind and beneath the stomach

Pancreas:

• Its endocrine portions are the islets of __________ that include two cell types--________ cells that secrete glucagon, and ______________ cells that secrete insulin.

langerhans__

alpha

beta

Pancreas:

• Glucagon __________ the blood levels of glucose by stimulating the breakdown of _____________and the conversion of noncarbohydrates into _______________________.

increases

glucogen

glucose

Pancreas:

• What controls the levels of glucagons in the blood?

• Declining blood sugar levels

• Insulin _________ the blood levels of glucose by stimulating the liver to form ________increasing __________________ synthesis, and stimulating adipose cells to store ________________.

• What controls the blood levels of insulin?

decreases

glycogenprotein

fat

High blood sugars

Pineal Gland:

• The pineal gland, near the upper portion of the thalamus, secretes _________________-, which is involved in the regulation of ____________ rhythms of the body.

melatonin

circadian

Thymus Gland:

• The thymus gland, lying between the lungs under the __________________, secretes ___________________ that affect production and differentiation of T lymphocytes that are important in ______________.

sternum

thymosin

immunity

Reproductive Glands:

• The ovaries produce what two hormones?

• What does the placenta produce?

• The testes produce

• Estrogen and progesterone

• Estrogen, progesterone, and gonadotropin

• testosterone

Digestive Glands Other Hormone Producing Organs:

• The digestive glands secrete hormones associated with the processes of digestion.

• The ________________ secretes atrial natriuretic peptide affecting sodium and the kidneys secrete ______________ for blood cell production.

heart

erythropoietin

Stress:

• Factors that serve as stressors to the body produce stress and threaten __________________.

• Stress may be physical, psychological, or some combination of the two.

• What effects on the body does physical stress have?

homeostasis

Threatens the survival of tissues

Stress:

• What does psychological stress result from?

• Responses to stress are designed to maintain homeostasis.

• The _______________________ controls the general stress syndrome, which involves increased sympathetic activity and increased secretion of which hormones?

• Real or perceived dangers

hypothalamus

Cortisol, glucagon, growth hormone, and antidiuretic hormone