endocrine system chapter 13. 2 endocrine system overview endocrine system –consists of ductless...

Endocrine System

CHAPTER 13

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Endocrine System Overview

• Endocrine system– Consists of ductless glands

• Secrete hormones directly into bloodstream

– Affect the function of specific body organs• Regulates many intricate body functions

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Pituitary Gland

• Referred to as “master gland”– Secretes hormones that control functions of

other glands– Known as hypophysis– Has two distinct lobes with specific functions

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Pituitary Gland • Anterior Pituitary Gland = Adenohypophysis

– Secretes Growth Hormone (GH) • Also called Somatotropic Hormone (STH)• Regulates growth of bone, muscle, and other body

tissues

– Secretes Adrenocorticotropic Hormone (ACTH)• Stimulates normal growth and development of

adrenal cortex and secretion of corticosteroids

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Pituitary Gland• Anterior Pituitary Gland

– Secretes Thyroid-Stimulating Hormone (TSH)• Promotes and maintains normal growth and

development of the thyroid gland• Stimulates secretions of the thyroid hormones

– Secretes Lactogenic Hormone (LTH) • Also called Prolactin• Promotes development of breasts during

pregnancy• Stimulates secretion of milk from breasts after

delivery of baby

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Pituitary Gland• Anterior Pituitary Gland

– Secretes Follicle-Stimulating Hormone (FSH)• Stimulates secretion of estrogen and production of

eggs in the female ovaries• Stimulates production of sperm in the male testes

– Secretes Luteinizing Hormone (LH)• Stimulates female ovulation and the secretion of

testosterone in the male– Melanocyte-Stimulating Hormone (MSH)

• Controls intensity of pigmentation in pigmented cells of the skin

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Pituitary Gland• Posterior Pituitary Gland = Neurohypophysis

– Secretes Antidiuretic Hormone (ADH)• Decreases excretion of large amounts of urine • Increases reabsorption of water by the renal tubules

– Secretes Oxytocin (OT) • Stimulates contraction of the uterus during childbirth• Stimulates release of milk from the breasts of lactating

women in response to the suckling reflex of the infant

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Pineal Gland• Tiny, pinecone-shaped gland

– Located behind dorsal aspect of midbrain region

– Plays a part in supporting body’s biological clock• Regulation of patterns of eating, sleeping, and

reproduction

– Secretes melatonin• Induces sleep

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Thyroid Gland

• Located in front of the neck just below the larynx, on either side of the trachea– Consists of a right and left lobe

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Thyroid Gland• Secretes Triiodothyronine (T3)

– Helps regulate growth and development of body

– Helps control metabolism and temperature– Secretes Thyroxine (T4)

• Helps maintain normal body metabolism

– Secretes Calcitonin• Helps regulate the level of calcium in the blood

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Parathyroid Glands

• Four tiny rounded bodies located on dorsal aspect of thyroid gland– Secrete Parathyroid Hormone (PTH)

• Also known as parathormone• Regulates level of calcium in blood

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Thymus

• Single gland located in mediastinum near the middle of the chest, just beneath sternum– Large in fetus and infants, shrinks with age– Secretes thymosin and thymopoietin

• Stimulates production of T cells that are involved in the immune response

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Adrenal Glands

• Two small glands, one positioned atop each kidney

• Also known as suprarenal glands– Consists of an adrenal cortex and an adrenal

medulla• Each has independent functions

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Adrenal Glands• Adrenal cortex secretes corticosteroids

– Mineralocorticoids• Regulate how mineral salts (electrolytes) are

processed in the body– Glucocorticoids

• Influence metabolism of carbohydrates, fats, and proteins in the body

• Necessary for maintaining normal blood pressure• Have an anti-inflammatory effect on the body• Increase glucose available during “fight-or-flight”

responses by the body

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Adrenal Glands

• Adrenal cortex secretes – Gonadocorticoids

• Sex hormones secreted in small amounts• Contribute to secondary sex characteristics in

males and females

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Adrenal Glands• Adrenal medulla secretes catecholamines

– Epinephrine = adrenaline• Sympathiomimetic agent• Increases heart rate and force of heart muscle

contraction• Dilates bronchioles in the lungs• Decreases peristalsis in the intestines• Raises blood glucose levels by causing the liver to

convert glycogen into glucose

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Adrenal Glands

• Adrenal medulla secretes – Norepinephrine = noradrenaline

• Known as a sympathomimetic agent• Produces a vasoconstrictor effect on the blood

vessels, thereby raising blood pressure

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Pancreas

• Elongated gland located in upper left quadrant of the abdomen– Behind the stomach

• Extends horizontally across the body– Beginning at first part of small intestines and

ending at edge of spleen

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Pancreas• Islets of Langerhans secrete:

– Glucagon• Increases blood glucose levels by stimulating liver

to convert glycogen into glucose when blood sugar is extremely low

– Insulin• Makes it possible for glucose to pass from blood

through cell membranes to be used for energy• Promotes conversion of excess glucose into

glycogen for storage in the liver for later use

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Ovaries

• Female sex glands = female gonads– Pair of almond shaped glands

• Located in upper pelvic cavity, on either side of lateral wall of uterus

• Near fimbriated ends of the fallopian tubes

– Responsible for producing mature ova and releasing them at monthly intervals during ovulation

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Ovaries• Hormones secreted by the ovaries

– Estrogen• Promotes maturation of ovum in the ovary• Stimulates vascularization of uterine lining each

month to prepare for implantation of a fertilized egg• Contributes to secondary sex characteristic

changes in female with onset of puberty– Progesterone

• Primarily responsible for changes within the uterus in anticipation of a fertilized ovum

• Responsible for development of maternal placenta after implantation of a fertilized ovum

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Testes• Testes = male gonads = testicles

– Two small ovoid glands located in scrotum– Primary organs of male reproductive system– Responsible for production of sperm and

secretion of androgens (male steroid hormones)

– Secrete testosterone• Responsible for secondary sex characteristic

changes that occur in male with onset of puberty• Responsible for maturation of sperm

PATHOLOGICAL CONDITIONS

Pituitary Gland

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Acromegaly

• Pronounced– (ak-roh-MEG-ah-lee)

• Defined– Chronic metabolic condition characterized by

the gradual, noticeable enlargement and elongation of the bones of the face, jaw, and extremities, due to hypersecretion of the human growth hormone after puberty

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Diabetes Insipidus

• Pronounced– (dye-ah-BEE-teez in-SIP-ih-dus)

• Defined– Deficiency in secretion of antidiuretic hormone

(ADH) by posterior pituitary gland• Characterized by large amounts of urine and

sodium being excreted from the body

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Dwarfism• Pronounced

– (DWARF-ism)• Defined

– Generalized growth retardation of body due to deficiency of human growth hormone

– Also known as congenital hypopituitarism or hypopituitarism

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Gigantism

• Pronounced– (JYE-gan-tizm)

• Defined – Proportional overgrowth of body’s tissue due

to hypersecretion of human growth hormone before puberty

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Hypopituitarism

• Pronounced– (high-poh-pih-TOO-ih-tah-rizm)

• Defined – Complex syndrome resulting from absence or

deficiency of pituitary hormone(s)


Thyroid Gland

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Cancer, Thyroid Gland

• Pronounced– (CAN-sir, THIGH-royd gland)

• Defined– Malignant tumor of the thyroid gland– Leads to dysfunction of gland and inadequate

or excessive secretion of thyroid hormone

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Goiter, Simple; Nontoxic

• Pronounced– (GOY-ter simple; nontoxic)

• Defined– Hyperplasia of thyroid gland

• Results from a deficient amount of iodine in diet, required for synthesis of T3 and T4, thyroid hormones produced by the thyroid gland

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• Pronounced– (high-per-THIGH-royd-izm)

• Defined– Hypertrophy of thyroid gland resulting in

excessive secretion of thyroid hormone• Causes extremely high body metabolism, thus

creating multisystem changes

Graves’ Disease (Hyperthyroidism)

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Graves’ DiseaseHyperthyroidism

• Three distinguishing characteristics– Hyperthyroidism– Thyroid gland enlargement (goiter)– Exophthalmia

• Unnatural protruding of the eyes

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Hypothyroidism• Pronounced

– (high-poh-THIGH-royd-izm)• Defined

– Condition in which there is a shortage of thyroid hormone causing an extremely low body metabolism due to a reduced usage of oxygen

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Hypothyroidism

• Most severe form known as myxedema– Water retention all over body in connective

tissues– Person has puffy appearance and thick

tongue– Reduced metabolic rate

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Thyroiditis(Hashimoto’s)

• Pronounced– (thigh-royd-EYE-tis)– (HASH-ee-moh-TOZ)

• Defined– Chronic inflammation of the thyroid gland,

leading to enlargement of the thyroid gland

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Thyrotoxicosis(Thyroid Storm)

• Pronounced– (thigh-roh-toks-ih-KOH-sis)

• Defined– Acute, sometimes fatal, incident of

overactivity of the thyroid gland resulting in excessive secretion of thyroid hormone


Parathyroid Gland

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Hyperparathyroidism(Hypercalcemia)

• Pronounced– (high-per-pair-ah-THIGH-royd-izm)– (high-per-kal-SEE-mee-ah)

• Defined– Overactivity of any one of the parathyroid

glands– Leads to high levels of calcium in blood and

low levels of calcium in bones

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Hypoparathyroidism

• Pronounced– (high-poh-pair-ah-THIGH-royd-izm)

• Defined– Decreased production of parathyroid hormone

resulting in hypocalcemia– Characterized by nerve and muscle weakness

with muscle spasms or tetany


Adrenal Glands

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Addison’s Disease• Pronounced

– (AD-ih-sons dih-ZEEZ)• Defined

– Life-threatening disease process due to failure of the adrenal cortex to secrete adequate mineralocorticoids and glucocorticoids • Resulting from an autoimmune process, a

neoplasm, an infection, or a hemorrhage in the gland

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• Pronounced– (PRYE-mary al-doss-STAIR-ohn-izm)

• Defined– Condition characterized by excretion of

excessive amounts of aldosterone• Leads to an increased volume of blood and

hypertension• Causes body to retain extra sodium and excrete

extra potassium

Conn’s Disease(Primary Aldosteronism)

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Cushing’s Syndrome

• Pronounced– (CUSH-ings SIN-drom)

• Defined– Cluster of symptoms in the adrenal gland as a

result of an excessive amount of cortisol or ACTH circulating in blood

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Cushing’s Syndrome• Cushing’s Syndrome

– Symptoms• Central obesity• Round “moon” face• Edema• Hypertension• Supraclavicular fat pads (buffalo hump)• Muscular weakness and wasting• Skin infection• Poor wound healing• Low potassium level• Emotional changes

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Pheochromocytoma• Pronounced

– (fee-oh-kroh-moh-sigh-TOH-mah)• Defined

– Vascular tumor of adrenal medulla– Produces extra epinephrine and

norepinephrine– Leads to persistent or intermittent

hypertension and heart palpitations

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Virilism

• Pronounced– (VEER-il-izm)

• Defined– Development of male secondary sex

characteristics in the female due to the excessive secretion of adrenocortical androgens from the adrenal cortex

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Virilism• Virilism

– Symptoms• Excessive hair on the body and face (hirsutism)• Absence of menstruation• Deepening of the voice• Acne• Oily skin• Muscular hypertrophy• Atrophy of the breasts and uterus• Ovarian changes


Pancreas

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Diabetes Mellitus• Pronounced

– (dye-ah-BEE-teez MELL-ih-tus)• Defined

– Disorder of pancreas in which beta cells of islets of Langerhans of the pancreas fail to produce an adequate amount of insulin• Results in body’s inability to appropriately

metabolize carbohydrates, fats, and proteins

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Diabetes Mellitus• Classifications

– Type I Diabetes – Formerly known as Insulin-Dependent

Diabetes Mellitus (IDDM)• Usually occurs before age of 30• Sudden onset• Controlled with insulin injections • Individuals are prone to developing ketosis

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Diabetes Mellitus• Classifications

– Type II Diabetes – Formerly known as Non-Insulin-Dependent

Diabetes Mellitus (NIDDM)• Usually appears in adults after age of 40• Majority of these individuals are obese• Usually controlled through diet and exercise

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Diabetic Retinopathy• Pronunciation

– (dye-ah-BET-ik ret-in-OP-ah-thee)• Defined

– Disorder of blood vessels of retina in which capillaries of the retina undergo localized areas of bulging (microaneurysms), hemorrhages, leakage, and scarring• Consequence of 8-10 year duration of diabetes

mellitus

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Gestational Diabetes• Pronounced

– (jess-TAY-shun-al dye-ah-BEE-teez)• Defined

– Disorder in which women who are not diabetic before pregnancy develop diabetes during the pregnancy• Inability to metabolize carbohydrates• Results in hyperglycemia

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Pancreatic Cancer

• Pronounced– (pan-kree-AT-ik CAN-sir)

• Defined– Life-threatening primary malignant neoplasm

typically found in head of pancreas

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Pancreatitis• Pronounced

– (pan-kree-ah-TYE-tis)• Defined

– Acute or chronic destructive inflammatory condition of the pancreas• Creates symptoms that vary from mild self-limiting

pancreatic edema to massive necrotizing hemorrhagic pancreatitis

Diagnostic Techniques, Treatments, and Procedures

Endocrine System

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• Thyroid function tests– Tests that measure blood levels of hormones

T3, T4, and TSH• Thyroid-Stimulating Hormone (TSH) Blood

Test – Measures concentration of TSH in blood

• Used to differentiate primary hypothyroidism from secondary hypothyroidism


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• Fasting Blood Sugar (FBS)– Blood glucose sample taken usually early in

the morning after the person has been without food or drink since midnight


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• Glucose Tolerance Test (GTT)– Test that evaluates person’s ability to tolerate

a concentrated oral glucose load by measuring glucose levels:• Prior to glucose administration• 30 minutes after glucose administration• 1, 2, and 3 hours after glucose administration


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• Radioactive Iodine Uptake (RAIU) Test– Thyroid function test – Evaluates function of thyroid gland– Administers radioactive iodine – Places gamma ray detector over thyroid

gland – Determines percentage of radioactive iodine

absorbed by gland over specific time periods


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• Serum Glucose Tests– Tests that measure amount of glucose in

blood at time sample was drawn• Thyroid Echogram (Ultrasound)

– Examination to distinguish solid thyroid nodules from cystic nodules

Diagnostic Techniques,Treatments, and Procedures

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• Thyroid scan– Examination to determine position, size,

shape, and physiological function of thyroid gland through use of radionuclear scanning


endocrine system chapter 13. 2 endocrine system overview endocrine system –consists of ductless...

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