Ppt chapter 34-1

Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins

Introduction to the Endocrine System

Introduction to the Endocrine System

Chapter 34


Complementary Actions of the Nervous and Endocrine Systems

Complementary Actions of the Nervous and Endocrine Systems

• The systems work together to maintain internal homeostasis.

• The systems integrate the body’s response to the external environment.


Characteristics of All HormonesCharacteristics of All Hormones

• Produced in very small amounts

• Secreted directly into the bloodstream

• Travel through the blood to specific receptor sites

• Act to increase or decrease the normal metabolic processes of cells when they react with receptor sites

• Are immediately broken down


Endocrine SystemEndocrine System


Where Hormones are ProducedWhere Hormones are Produced

• Pituitary Gland

• Ovaries

• Testes

• Adrenal

• Thyroid

• Parathyroid

• Pancreas


Hormone Actions in the BodyHormone Actions in the Body

• Hormones can work two different ways in the body:

– React with a specific receptor site on a cell membrane and cause the activation of camp leading to a change in cell activity. Analyzing input from the periphery and the CNS. This type of hormone causes a fast reaction, such as insulin reacting with an insulin receptor site.

– Enter the cell, react with messenger RNA, and enter the nucleus, causing a change in cell function. This takes time to cause effects. Estrogen and testosterone work this way, explaining the years to cause all of the changes associated with puberty.


Hypothalamus GlandHypothalamus Gland

• Definition

– “Master gland” of the neuroendocrine system

• Action

– Constantly monitors the body’s homeostasis by:

• Analyzing input from the periphery and the CNS

• Coordinating responses through the autonomic, endocrine, and nervous systems


Releasing Hormones Produced and Secreted by the Hypothalamus

Releasing Hormones Produced and Secreted by the Hypothalamus

• Growth Hormone–Releasing Hormone (GHRH)

• Thyrotropin-Releasing Hormone (TRH)

• Gonadotropin-Releasing Hormone (GnRH)

• Corticotropin-Releasing Hormone (CRH)

• Prolactin-Releasing Hormone (PRH)


QuestionQuestion

Hormones function within the body in two ways. One way is for it to enter the cell and react with what?

A. Estrogen

B. ACTH

C. Cellular DNA

D. Messenger RNA


AnswerAnswer

D. Messenger RNA

Rationale: Hormones can work two different ways in the body: One way is to enter the cell, react with messenger RNA, and enter the nucleus, causing a change in cell function. This takes time to cause effects. Estrogen and testosterone work this way, explaining the years to cause all of the changes associated with puberty.


Inhibiting Factors Produced by the Hypothalamus

Inhibiting Factors Produced by the Hypothalamus

• Growth Hormone Release–Inhibiting Factor (Somatostatin)

• Prolactin-Inhibiting Factor (PIF)


Two Other Hormones Produced by the Hypothalamus

Two Other Hormones Produced by the Hypothalamus

• Antidiuretic Hormone (ADH)

• Oxytocin

– Stored in the posterior pituitary to be released when stimulated by the hypothalamus


Networks Connecting the Hypothalamus to the Pituitary Gland

Networks Connecting the Hypothalamus to the Pituitary Gland

• A vascular network carries the hypothalamic releasing factors directly into the anterior pituitary.

• A neurological network delivers ADH and oxytocin to the posterior pituitary to be stored.


Lobes of the Pituitary GlandLobes of the Pituitary Gland

• Anterior Lobe

– Produces six major anterior pituitary hormones

• Posterior Lobe

– Stores two hormones

• Intermediate Lobe

– Produces endorphins and encephalins


Major Anterior Pituitary HormonesMajor Anterior Pituitary Hormones

• Growth Hormone (GH)

• Adrenocorticotropic Hormone (ACTH)

• Follicle-Stimulating Hormone (FSH)

• Luteinizing Hormone (LH)

• Prolactin (PRL)

• Thyroid-Stimulating Hormone (TSH, also called Thyrotropin)


Anterior Pituitary Hormones That Do Not Have a Target Organ

Anterior Pituitary Hormones That Do Not Have a Target Organ

• Growth Hormone and Prolactin

– Cannot be regulated by the same type of feedback mechanism

– Release are directly inhibited by the hypothalamic inhibiting factors somatostatin and PIF


QuestionQuestion

The nurse is caring for a patient whose physician has just ordered cyclomen PO 800 mg daily in 2 divided doses. For what disease process would the physician be ordering the cyclomen?

A. Fibrocystic breast disease

B. Cholestatic hepatitis

C. Endometriosis

D. Delayed male puberty


AnswerAnswer

C. Endometriosis

Rationale: In women, danazol (Cyclomen) may be used to prevent or treat endometriosis or fibrocystic breast disease. Anabolic steroids are more often abused for body-building purposes than used for therapeutic effects.


Negative Feedback SystemNegative Feedback System


Negative Feedback SystemNegative Feedback System

• Hypothalamus senses a need for a particular hormone.

• It secretes the releasing factor directly into the anterior pituitary.

• In response, the anterior pituitary secretes the hormone.

• In turn, it stimulates the gland.

• The hypothalamus will sense increases for a particular hormone and send messages to the anterior pituitary to stop producing the hormone.


Other Hormones Released in Response to Stimuli

Other Hormones Released in Response to Stimuli

• Insulin, Glucagon, and Somatostatin

• Parathormone

• Erythropoietin and Renin

• GI Hormones

• Calcitonin

• Prostaglandins

• ACTH and the Adrenocorticoid Hormones

• Aldosterone


Hypothalamic–Pituitary Axis (HPA)Hypothalamic–Pituitary Axis (HPA)

• The hypothalamus secretes releasing factors to cause the anterior pituitary to release stimulating hormones.

• These hormones act with specific endocrine glands to cause the release of hormones or stimulate cells directly.

• This stimulation shuts down the production of releasing factors.

• This leads to decreased stimulating factors and decreased hormone release.


QuestionQuestion

The release of which hormone prepares the body for “fight or flight?”

A. ADHD

B. ACTH

C. Aldosterone

D. ADH


AnswerAnswer

B. ACTH

Rationale: Activation of the sympathetic nervous system directly causes release of ACTH and the adrenocorticoid hormones to prepare the body for fight or flight. Aldosterone, an adrenocorticoid hormone, is released in response to ACTH, but also is released directly in response to high potassium levels.

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Ppt chapter 34-1