The Endocrine System Are your hormones runnin’ wild?

Glands  Exocrine - Secrete into ducts or onto a free surface - sweat, sebaceous, mucous, digestive  Endocrine - secrete into cellular space then into blood - hormones

Hormones  Hormones are chemical messages  Regulate the chemical composition and volume of the internal environment  What are some examples of regulation of chemical composition of blood. How about volume  Glucose, Water  Regulated by insulin and a hormone called ADH (antidiuretic hormone)

Hormones  Help regulate organic metabolism and energy balance  Thyroid gland  Help body cope with emergency environmental demands - infection, trauma, emotional stress, dehydration, starvation, hemorrhage, and temperature extremes.  Adrenaline (epinephrine)  Fight or flight syndrome  Sympathetic

 Hormone producing cells are sent information from sensing and signaling systems - permit regulation of amount and duration of hormone release  Examples: Blood glucose, Na+, K+, Ca++, O2

 Target cells - cells that are affected by specific hormones  Receptors - most cells have receptors that bind to one or more hormones  There are about 50 different hormones - cells only respond to specific hormones  Once a hormone binds to a cell’s receptors, there is a set of reactions within the target cell to produce the desired effects

Feedback Systems  “Circular situation in which information about the status of something is continually reported (fed back) to a central control region.”  Like a thermostat.  Negative feedback system - reverses the direction of the initial condition  Negative - response is opposite to the stimulus

ThalamusHypothalamus Pituitary Gland Thyroid Parathyroids Pancreas Thymus Adrenals Ovaries Testes

Posterior Pituitary  ADH (Anti-Diuretic Hormone)  Controls Kidneys  Oxytocin  Stimulates mammary glands to produce milk  Stimulates uterine contractions

Anterior Pituitary  HGH (Human Growth Hormone)  Stimulates cell division, protein synthesis, bone growth  Prolactin  Milk production  MSH (melanocyte-stimulating hormone)  Skin color in lower verts, unknown in humans

Anterior Pituitary  TSH (Thyroid Stimulating Hormone)  Stimulates thyroid  ACTH (adrenocorticotropic hormone)  Stimulates adrenal cortex  Gonadotropic Hormones  Gamete and sex hormones

Thyroid  Thyroxin  Increases metabolic rate  regulates growth and development  Calcitonin  Lowers blood Calcium levels

Parathyroid  PTH  Raises blood Calcium levels

Adrenal Medulla  Epinepherine and Norepinephrine  Adrenaline  Cardiac and other muscles

Adrenal Cortex  Glucocorticoids  Raise blood glucose level, stimulates breakdown of protein  Mineralcorticoids  Stimulates kidneys to reabsorb sodium and excrete potassium  Sex Hormones  puberty

Pancreas  Insulin  Lowers blood glucose  Promotes formation of glycogen, proteins, fats  Glucagon  Raises blood glucose  Promotes breakdown of glycogen, proteins, fats

Gonads  Testes  Androgens (Testosterone)  Stimulates spermatogenesis  Develop and maintain male characteristics  Ovaries  Estrogen and Progesterone  Growth of uterine lining  Develop and maintain female characteristics

Thymus  Tymosins  Stimulates maturation of T Lymphocytes

Disorders of Endocrine Glands  Diabetes Mellitus: Insulin Lack and Insensitive Cells  Symptoms:  Sugar in urine  Frequent urination  Abnormal thirst  Rapid Weight Loss  Itching  Visual Disturbances  Skin disorders - boils, infections

Diabetes  Sugar is not being metabolized  Liver fails to store glucose as glycogen  Cells fail to utilize glucose efficiently  Body turns to breakdown of protein and fats