Ppt chapter 34

Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
Introduction to the Endocrine
System
Chapter 34

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 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 System

Where Hormones are Produced
• Pituitary Gland
• Ovaries
• Testes
• Adrenal
• Thyroid
• Parathyroid
• Pancreas

Hormone 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 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
• Growth Hormone–Releasing Hormone (GHRH)
• Thyrotropin-Releasing Hormone (TRH)
• Gonadotropin-Releasing Hormone (GnRH)
• Corticotropin-Releasing Hormone (CRH)
• Prolactin-Releasing Hormone (PRH)

Question
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

Answer
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
• Growth Hormone Release–Inhibiting Factor
(Somatostatin)
• Prolactin-Inhibiting Factor (PIF)

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
• 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 Gland
• Anterior Lobe
– Produces six major anterior pituitary hormones
• Posterior Lobe
– Stores two hormones
• Intermediate Lobe
– Produces endorphins and encephalins

Major 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
• 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

Question
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

Answer
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 System

Negative 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
• Insulin, Glucagon, and Somatostatin
• Parathormone
• Erythropoietin and Renin
• GI Hormones
• Calcitonin
• Prostaglandins
• ACTH and the Adrenocorticoid Hormones
• Aldosterone

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.

Question
The release of which hormone prepares the body for “fight
or flight?”
A. ADHD
B. ACTH
C. Aldosterone
D. ADH

Answer
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.

Ppt chapter 34

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Ppt chapter 34