ENDOCRINE ENDOCRINE SYSTEMSYSTEM

HormonesHormones• Self-regulating system• Production

– Extremely small amounts– Highly potent

• Affect:– Growth– Metabolism– Behavior

• Two categories:– Lipid (Steroid)– Amino acid

PituitaryPituitary• Also known as hypophysis• Located beneath brain• Divided into two lobes:

– Anterior•Releases six hormones

– Posterior•Releases two hormones

Thyroid and ParathyroidsThyroid and Parathyroids

• Thyroid gland– Located on either side of larynx and

upper trachea– Two lobes – Secretes mixture of hormones

• Parathyroid glands– Located at posterior surface of

thyroid– Affect calcium metabolism

Adrenal GlandsAdrenal Glands• Hormones produced involved in body’s

response to stress• Located atop each kidney• Divided into two regions

– Outer cortex produces:• Steroid hormones• Cortisol• Aldosterone• Sex hormones

– Inner medulla produces• Epinphrine• Norepinephrine

PancreasPancreas• Islet cells produce two hormones:

– Insulin•Increases cellular use of glucose•Decreases sugar levels in blood

– Glucagon•Decreases cellular use of glucose•Increases sugar levels in blood

Other Endocrine TissuesOther Endocrine Tissues• Thymus

– Secretes thymosin• Gonads

– Secrete sex hormones• Prostaglandins

– Group of hormones produced by many cells

– Variety of effects• Uterine contractions• Inflammatory response• Vasomotor activities

Clinical Aspects of Endocrine Clinical Aspects of Endocrine SystemSystem

• Endocrine diseases result from:– Hypersecretion – Hyposecretion– Secretion at wrong time– Failure of target tissue to respond

• Causes may originate:– In gland itself– With hypothalamus or pituitary failing

to release proper amount of hormone stimulators

PituitaryPituitary• Pituitary adenoma usually increases

secretion of growth hormone– Excess in children causes gigantism– Excess in adults causes acromegaly

• Treatment– Surgery– Drugs to reduce hormone level in blood

Pituitary (con’t)Pituitary (con’t)

• Panhypopituitarism– Hypofunction of pituitary– Caused by tumor or interruption of gland’s

blood supply– Widespread effects

• Lack of ADH– Results in diabetes insipidus

• Kidneys with diminished ability to conserve water

• Symptoms include:– Polyuria – Polydipsia

ThyroidThyroid• Deficiency of thyroid hormone causes:

– In infants• Physical retardation• Mental retardation• Congenital hypothyroidism

– In adults• Myxedema

• Hyperthyroidism– Common form is Graves disease– May result in goiter (enlarged thyroid)

• Not always results from thyroid malfunction

ParathyroidsParathyroids• Overactivity causes high level of calcium in

blood– Calcium obtained from bones– Possible development of kidney stones

• Underactivity results in decreased calcium– May cause:

• Tingling• Numbness• Tetany

AdrenalsAdrenals• Addison disease = hypofunction of

adrenal cortex– Caused by:

• Autoimmune destruction of gland• ACTH deficiency

– Results in:• Water loss• Low blood pressure• Electrolyte imbalance• Weakness• Nausea• Increase of brown pigmentation

Adrenals (cont’d)Adrenals (cont’d)• Cushing syndrome = excess of adrenal

cortisol hormones– Caused by:

• Therapeutic administration of steroid hormones• Tumor

– Results in:• Moon-shaped face• Localized obesity• Weakness• Hirsutism• Fluid retention

Pancreas and DiabetesPancreas and Diabetes

• Diabetes mellitus– Most common endocrine disorder– Failure to use glucose effectively– Excess glucose causes hyperglycemia– Two types:

• Type 1 (juvenile-onset or insulin-dependent)• Type 2 (adult-onset or non-insulin dependent)

Type 1 DiabetesType 1 Diabetes• Usually appears in children and

teenagers• Caused by failure of pancreatic

islets to produce insulin• For proper management:

– Monitor blood sugar levels– Give insulin in divided doses– Regulate diet

Type 2 DiabetesType 2 Diabetes• Initiated by cellular resistance to insulin• May result in:

– Metabolic syndrome– Hypoglycemia– Insulin shock

• Diagnosed by measuring levels of glucose in blood plasma

• Most cases linked to obesity• Another form is gestational diabetes

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