Medical assisting Administrative and clinical procedures (5e) Chapter 34 The endocrine system

After completing chapter 34, you will be able to: Describe the general functions of hormones and the endocrine system; identify the hormones released by the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, and other hormoneproducing organs, and give the functions of each; explain the effect of stressors on the body; describe the causes, signs and symptoms, and treatments of various endocrine disorders.

The Endocrine

System

Learning Outcomes (cont.)

34.1 Describe the general functions of hormones

and the endocrine system

34.2 Identify the hormones released by the

pituitary gland, thyroid gland, parathyroid

glands, adrenal glands, pancreas, and other

hormone-producing organs, and give the

functions of each

Learning Outcomes (cont.)

34.3 Explain the effect of stressors on the

body

34.4 Describe the causes, signs and

disorders

– Regulate chemical reactions in cells

– Control functions of the organs, tissues, and other

– Ductless

– Release hormones

• Directly into target tissues

• Into bloodstream to be carried to target tissues

that affect the functions of other cells

Types of Hormones

– Cross cell membrane

– Bind to receptor in cell nucleus

– Hormone-receptor complexes

• Turn a gene on or off

• Enable cell to carry out functions

Types of Hormones (cont.)

– Cannot cross the membrane

– Bind to receptors on the membrane

– Hormone-receptor complexes

• Activate G-proteins which turn on enzymes

• Cell takes on new functions

Types of Hormones (cont.)

– Derived from lipid molecules

– Target cells are located close by

– Produced by organs such as

Negative and Positive Feedback Loops

• Negative feedback loop – hormone

release stops in response to decrease in

Milk is released and the baby continues to feed

Negative and Positive Feedback Loops

• Positive feedback loop – as long as

stimulus is present, action of hormone

continues

Apply Your Knowledge

Match the following:

_ Chemicals that effect cell function A Nonsteroidal hormone

_ Easily cross cell membranes B Steroidal hormone

_ Made of amino acids C G-protein

_ Target nearby cells D Prostaglandins

_ Activated by hormone-receptor E Hormones

complex

_ Cannot cross cell membranes easily

_ Estrogen and cortisol

Hormone Production

• Hypothalamus

– Hormones

• Oxytocin

• Antidiuretic hormone (ADH)

– Hormones transported to the

posterior pituitary for storage – Directs posterior pituitary to release hormones

The Pituitary Gland

The Pituitary Gland (cont.)

• Disbursement of melanin to skin cells

Adrenocorticotropi

c hormone (ACTH)

Adrenocorticotropi

c hormone (ACTH) Stimulates the

adrenal cortex to release its

hormones

Thyroid-stimulating

hormone (TSH) Thyroid-stimulating

hormone (TSH) Stimulates the thyroid gland to release its hormones

The Pituitary Gland (cont.)

•Ovulation

•Production of estrogen

Males – production

of testosterone

Prolactin (PRL)

Females – milk production

Males – enhances LH

The Pituitary Gland (cont.)

Posterior lobe

Antidiuretic hormone (ADH)

Stimulates kidneys to

conserve water

•Decreases urine output

•Maintains blood pressure

Oxytocin (OT)

Females

•Uterine contractions

•Ejection of milk Males – contraction of the prostate and vas deferens

• Calcitonin – lowers blood calcium levels by activating osteoblasts

– Posterior surface of thyroid gland

– Secrete parathyroid hormone (PTH) –

• An agonist to calcitonin

• Raises blood calcium levels by activating osteoclasts

The Adrenal Glands

• Adrenal medulla

– Central portion

– Hormones produce same effects as the

sympathetic nervous system

• Epinephrine

• Norepinephrine

The Adrenal Glands (cont.)

– Decreases inflammation

The Pancreas

• Has both exocrine and endocrine

functions

enzymes into a duct leading to the small

intestine

• Endocrine gland – secrete

hormones into blood stream

The Pancreas (cont.)

• Islets of Langerhans

– Cells with endocrine function

• Alpha cells secrete glucagon

• Beta cells secrete insulin

Blood glucose concentrations Protein synthesis Protein synthesis

Blood glucose concentrations

Other Hormone-Producing Organs

– Regulates circadian rhythms

– May play a role in onset of

puberty

Other Hormone-Producing Organs (cont.)

Other Hormone-Producing Organs (cont.)

Apply Your Knowledge

1 Match the following:

Increases cellular energy production

Lowers blood calcium levels

Released during stress

Apply Your Knowledge

2 What are the effects of insulin and glucagon?

ANSWER: Insulin decreases blood glucose

concentration and increases protein synthesis.

Glucagon does just the opposite It increases blood

glucose and decreases protein synthesis.

The Stress Response

The Stress Response (cont.)

• General stress syndrome

– Physiologic response to stress

– Caused by hormone release

– Effects

• Increased heart rate, respiratory rate, and BP

• Increase in glucose and fatty acids in blood

• Increase in cortisol

Apply Your Knowledge

Match the following:

_ Extreme heat A Physical stress

_ Death of friend B Psychological stress

_ Fractured leg C Positive stimulus

Disease/Disorder Description

thickened skinCauses: Too much growth hormone produced in adults;

tumor of pituitary

Addison’s

Cause is unknown – possibly an autoimmune dysfunction; cancer

Endocrine System

Endocrine System (cont.)

Disease/Disorder Description

Cushing’s

disease Moon face, buffalo hump, thin arms and legs; large abdomen

HypercortisolismCauses: excessive production of ACTH; tumor of the adrenal gland

or pituitary gland; long term use of steroids

Diabetes

insipidus Kidneys fail to reabsorb water, resulting in excessive urination

Cause: hyposecretion of ADH

Endocrine System (cont.)

Noninsulin-dependent diabetes mellitus; primarily in adults but increased incidence in teens Occurs during pregnancy; usually temporary

Endocrine System (cont.)

Disease/Disorder Description

features, cleft lip or palate, delayed puberty

Causes: Too little growth hormone produced during childhood;

trauma to or tumor of the pituitary gland

Endocrine System (cont.)

Disease/Disorder Description

thick facial bonesCauses: Too much growth hormone produced during childhood; pituitary gland tumor

causing swelling in neckCause: deficiency of iodine in diet

Endocrine System (cont.)

Disease/Disorder Description

Graves’ disease Hyperthyroidism

Exophthalmos; goiter Causes: antibodies attack the thyroid gland, causing it to produce too much thyroid hormone; autoimmune disorder

Common Diseases and Disorders (cont.)

Disease/Disorder Description

prior to or soon after birthCauses: absence or malformation

of thyroid gland; abnormal formation of thyroid hormones;

pituitary failure

Causes: removal of thyroid gland;

radiation treatments to neck;

obesity; may be congenital

Apply Your Knowledge

True or False:

_ Acromegaly develops as a result of too much growth hormone in a

child.

_ In diabetes insipidus, the kidneys fail to reabsorb water.

_ Too little growth hormone in childhood results in dwarfism.

_ Myxedema is the result of hyperthyroidism.

_ Addison’s disease is the result of too little corticosteroid.

_ Cushing’s disease is the result of too little ACTH.

_ Cretinism is an extreme form of hyperthyroidism present at birth.F

In Summary

34.1 Endocrine glands are ductless glands,

releasing hormones directly into the

bloodstream and tissues

The organs of the endocrine system produce hormones that regulate the chemical

of organs, tissues, and other cells

Hormone levels are controlled by positive and negative feedback loops

In Summary (cont.)

34.2 The pituitary gland releases: GH, MSH, ACTH, TSH,

FSH, LH, PRL, ADH, and OT The thyroid gland releases calcitonin, T 3, and T 4 The parathyroid gland releases PTH The adrenal medulla secretes epinephrine and norepinephrine The adrenal cortex produces aldosterone and cortisol The hormone-

releasing of cells in the pancreas release glucagon and insulin The pineal body releases melatonin; the thymus releases thymosin and thymopoietin; ovaries release estrogen and progesterone (females); and the testes (males) release testosterone The kidneys produce erythropoietin, and the heart produces atrial natriuretic peptide

In Summary (cont.)

34.3 Stressors are stimuli that produce a stress

response, a physiologic response to the stimulus that changes the body’s functioning in

some way

34.4 The diseases and disorders of the endocrine

system are as varied as the organs and hormone dysfunctions that cause them An

overview of these conditions is found in Table

34-2