MD Endocrine System MD Describe the structures of the endocrine system. MD Analyze the function of the endocrine system.

 ENDOCRINE GLANDS  Secrete hormones directly into bloodstream  Ductless  EXOCRINE GLANDS  Secrete substances through a duct  Sweat, salivary, lacrimal and pancreas

Function of the Endocrine System  To secrete hormones  Hormones are chemical messengers that coordinate and direct target cells and organs.

Hormonal Control  The secretion of hormones is controlled by either  Negative feedback  Nervous control

NEGATIVE FEEDBACK  Drop in hormone level triggers a chain reaction to increase secretion, for example 1.Blood level of the hormone falls 2.Brain gets message and sends out a hormone to stimulate gland 3.Gland produces more hormone 4.When blood levels of the hormone increase, the brain hormones tell the gland to stop production.

NERVOUS CONTROL  In some cases, sympathetic nervous system causes direct release of hormone from gland  for example, when stress causes the adrenal medulla to secrete adrenalin.

PITUITARY GLAND  Tiny structure the size of a grape  Located at the base of the brain  Connected to the hypothalamus  Divided into anterior and posterior lobes  The “Master Gland”

PITUITARY GLAND

Pituitary-Hypothalamus Interaction  Release of hormones from the anterior pituitary are controlled by “releasing factors” from the hypothalamus.  While hypothalamus is part of the nervous system, it produces two hormones that are stored in the posterior pituitary

Anterior Pituitary Lobe  Anterior lobe of Pituitary Gland secretes 7 hormones.  Growth Hormone  Prolactin  Thyroid-stimulating Hormone  Adrenocorticotropic Hormone  Follicle-stimulating Hormone  Luteinizing Hormone  Interstitial Cell-stimulating Hormone

Anterior Pituitary Lobe

GROWTH HORMONE (GH)  SOMATOTROPIN  Responsible for growth and development.

PROLACTIN PROLACTIN  Develops breast tissue  Stimulates production of milk after childbirth

THYROID-STIMULATING HORMONE – TSH  Stimulates growth of thyroid gland and production of thyroxine.

ADRENOCORTICOTROPIC HORMONE – ACTH  Stimulates growth of adrenal cortex and secretion of adrenocorticoids

FOLLICLE-STIMULATING HORMONE – FSH  Stimulates growth of graafian follicle and production of estrogen in females, sperm in males.

LUTEINIZING HORMONE – LH  Stimulates ovulation and formation of corpus luteum, which produces progesterone in females

INTERSTITIAL CELL- STIMULATING HORMONE – ICSH  Production of testosterone by interstitial cells of testes in male.

Posterior Pituitary Lobe  Stores 2 hormones produced by the Hypothalamus.  Vasopressin  Oxytocin

VASOPRESSIN  Converts to ADH (antidiuretic hormone) in the bloodstream  Acts on kidney to concentrate urine and preserve H2O in the body

OXYTOCIN  Released during childbirth causing contractions of the uterus.

Pituitary Gland Disorders  Hyperfunction of Pituitary  Too much growth hormone.  In preadolescent causes overgrowth of long bones which leads to excessive tallness. GIGANTISM

Gigantism Twelve-year-old boy with pituitary gigantism measuring 6'5" with his mother. Note the coarse facial features and prominent jaw.

Pituitary Gland Disorders  Hyperfunction of Pituitary  too much growth hormone  In adulthood causes overdevelopment of bones in face, hands and feet  Attacks cartilage – so the chin protrudes, lips nose and extremities enlarge called ACROMEGALY  Rx – drugs to inhibit growth hormone, radiation

Acromegaly

Pituitary Gland Disorders  Hypofunction of pituitary (too little growth hormone.)  Occurs in childhood (DWARFISM)  Small size, but body proportions and intellect are normal  Sexual immaturity  Rx – early diagnosis, injection of growth hormone

Dwarfism These girls are sisters. The girl on the left lacked growth hormone. In this picture she was 18cm shorter than her sister, despite being one and a half years older.

Pituitary Dwarves and “Little People”  Most “little people” do not have pituitary dwarfism.  They have ACHONDROPLASIA.  Pituitary dwarves have very short stature, but normal body proportion.

Pituitary Dwarves and “Little People”  Achondroplasia is caused by a genetic defect and may be passed on to children.  Body is disproportionate.  Legs and arms are short compared to trunk.  Prominent forehead, protruding jaw, and flat depressed area between eyes.  Legs are bowed, hands are short and stumpy and feet are short, flat and broad.

Achondroplasia

Other Pituitary Disorders  DIABETES INSIPIDUS  Drop in amount of ADH from posterior pituitary, excessive loss of water  Symptoms  Polyuria  Polydipsia

THYMUS GLAND  Endocrine gland and lymphatic organ  Located behind the sternum, above and in front of the heart  Begins to disappear at puberty  Secretes a large number of hormones  Major hormone THYMOSIN which stimulates lymph cells to produce T- lymphocytes

THYMUS GLAND

THYROID GLAND  Butterfly-shaped mass of tissue  On either side of larynx, over trachea  H-shaped

THYROID GLAND  Main hormone – THYROXINE – is controlled by the secretion of TSH  Thyroxine controls the rate of metabolism  Also secretes CALCITONIN  Controls calcium ion concentration in the body  Prevents hypercalcemia

Thyroid Gland Disorders  HYPERTHYROIDISM  Overactive thyroid gland  Too much thyroxin secreted leading to enlargement of gland  People with this disease consume large quantities of food but lose body fat and weight

Thyroid Gland Disorders  HYPERTHYROIDISM  Most pronounced symptoms are enlargement of gland (GOITER) and bulging of eyeballs (EXOPHTHALMOS)  Rx – total or partial removal of thyroid gland, drugs to reduce thyroxin, radiation

HYPERTHYROIDISM

Thyroid Gland Disorders  HYPOTHYROIDISM  Not enough thyroxine secreted  May be due to lack of iodine (simple goiter)  Major cause of other types is inflammation of thyroid which destroys the ability of the gland to make thyroxine  Symps – dry and itchy skin, dry and brittle hair, constipation, muscle cramps at night

Thyroid Gland Disorders  HYPOTHYROIDISM  MYXEDEMA ( a form of hypothyroidism)  Hypothyroidism left untreated in adults  Face gets swollen, weight increases  Rx – daily medication of thyroxine

MYXEDEMA Before and after treatment

Thyroid Gland Disorders  HYPOTHYROIDISM  CRETINISM  Hypothyroidism in early infancy or childhood  Lack of mental and physical growth causes mental retardation and very small stature  Rx – thyroid extract – damage cannot be undone but treatment can halt progression

PARATHYROID GLANDS  Four glands, each the size of a grain of rice  Attached to posterior thyroid  Produce PARATHORMONE which helps control blood calcium level, prevents hypocalcemia

PARATHYROID GLANDS

Parathyroid Gland Disorders  TETANY  In hypoparathyroidism, decreased calcium levels affect function of nerves  Convulsive twitching develops, person dies of spasms in the respiratory muscles  Rx – Vitamin D, calcium and parathormone

Parathyroid Gland Disorders  HYPERPARATHYROIDISM  Excessive levels of Parathormone  Causes elevated blood calcium levels which can lead to kidney stones  Calcium is drawn from bones causing deformity and weakness of the bones

Blood Calcium Levels  Adequate blood calcium is necessary for proper muscle contractions (especially cardiac muscle)  Blood calcium levels are controlled by two endocrine system hormones.  Calcitonin from the thyroid gland prevents calcium concentration from getting too high.  Parathormone from the parathyroid prevents calcium concentration from getting too low.

ADRENAL GLANDS  Located on top of each kidney  Adrenal gland has 2 parts:  Cortex (outer)  Medulla (inner )  Adrenal glands are controlled by ACTH from the pituitary.

ADRENAL GLANDS  Adrenal cortex secretes hormones known as corticoids – (natural steroids)  They are: mineralcorticoids, glucocorticoids, and sex hormones.

ADRENAL GLANDS  Mineralcorticoids  Affects the amount of sodium and potassium excreted by the kidneys.  Also involved in amount of water retained by the kidneys.

ADRENAL GLANDS  Glucocorticoids  Increase amount of glucose in blood. Uses stored glycogen (a liver protein) and converts it to glucose.  Decreases inflammation and reduces pain.  Body’s natural anti-inflammatory agents.

ADRENAL GLANDS  Androgens  Male sex hormones.  Work with other male hormones to produce masculine characteristics.  Synthetic versions of androgens are used (illegally) by athletes in enhance their performance.

ADRENAL GLANDS  Adrenal medulla secretes epinephrine (adrenalin) and norepinephrine  ADRENALIN is a powerful cardiac stimulant – “fight or flight” hormones that prepare the body for an emergency situation  Adrenalin is also called epinephrine.

ADRENAL GLANDS Adrenal Gland Kidney Kidney

Adrenal Gland Disorders  CUSHING’S SYNDROME  Hypersecretion of adrenal cortex  May be caused by adrenal cortical tumor or prolonged use of prednisone  Symptoms – high blood pressure, muscle weakness, obesity, poor healing, tendency to bruise, hirsutism (excessive hair growth), menstrual disorders Rounded moon face and buffalo hump  Rx – surgical removal of tumor

CUSHING’S SYNDROME Note moon face and hirsutism of chin. Buffalo hump

Adrenal Gland Disorders  ADDISON’S DISEASE  Hypofunction of adrenal cortex  Symps – bronzing of skin, hypoglycemia, hypotension, etc.  Rx – replace deficient hormones

ADDISON’S DISEASE Note hyperpigmentation or bronzing of skin.

Steroid Abuse in Sports  Anabolic steroids (androgens) can help build bigger, stronger muscles  Risks far outweigh temporary improvements – males have liver changes, atrophy of testicles, breast enlargement, and cardiovascular disease  Female risks include amenorrhea, abnormal placement of body hair, baldness, voice changes

GONADS (Sex glands)  Ovary in female. Produces ova and female hormones  Estrogen – development of female reproductive organs, secondary sex characteristics  Progesterone – plays a part in the menstrual cycle

GONADS (Sex glands)  Testes in male. Produces sperm and testosterone  Testosterone – male reproductive organs and secondary sex characteristics

PANCREAS  Located behind the stomach  Endocrine and exocrine functions  Involved in production of INSULIN by ISLETS OF LANGERHANS

PANCREAS  Insulin – promotes utilization of glucose by the cells, fatty acid and amino acid transport, and facilitates protein synthesis  Other cells in islets of Langerhans secrete glucagon, action may oppose that of insulin (increase glucose in bloodstream)

Extra credit…..  Research the name “Langerhans”.  Next class-Turn in a note card stating:  Who Langerhans was  Why the area of the pancreas that secretes insulin is named for him.  Where and when he did his work.  3 points on next test.

PANCREAS

Disorders of Pancreas  DIABETES MELLITUS  Caused by  secretion of insulin  Can be insulin dependent (juvenile) or non-insulin dependent  Symptoms – polyuria, polyphagia, polydypsia, weight loss, blurred vision, and possible diabetic coma

DIABETES MELLITUS  If not treated, excess glucose in blood (hyperglycemia) and glucose secreted in urine (glycosuria)  Since glucose not available for cellular oxidation, body starts to burn up protein and fat  Treatment involves giving patient insulin through some type of injection.

Insulin administration using syringe

Insulin administration by pump

DIABETES MELLITUS  If too much insulin is given, blood sugar may go too low (hypogycemia  insulin shock)  Must give patient some type of fast acting sugar.  If blood sugar gets too high – hyperglycemia  diabetic coma

DIABETES MELLITUS  Type II (non-insulin dependent) is most common, usually familial, occurs later in life, controlled with oral hypoglycemic drugs and diet  Tests for Diabetes – blood sample measured in glucometer – done by patient in home – normal blood sugar mg

Glucose monitor

Glucose monitor and insulin pump

How the pancreas regulates blood sugar levels

PINEAL GLAND  located in 3 rd ventricle in brain, produces melatonin  may also help prevent early puberty  Amount of light entering eye stimulates a group of nerve cells which then stimulates the pineal gland  The less light the more melantonin

PINEAL GLAND

Disorders of Pineal Gland  SEASONAL AFFECTIVE DISORDER  Also called “cabin fever”, “winter blues” or “sunshine disorder.”  Depression or anxiety people feel during dark days of winter  Cause – may be due to increase in melatonin from pineal gland  Rx - sunshine

Other Hormones  PROSTAGLANDINS  tissue hormones  can cause constriction of blood vessels, muscle contractions.  Can be used to induce labor.