Endocrine System

Function Maintain Homeostasis (Balance) Example of Imbalance? Communicates and coordinates physiological responses Example of Imbalance?

Hormones Chemical messengers How do hormones travel? Stimulate physiological responses in other cells Target Cells How do hormones travel?

Hormone Production and Distribution Endocrine Glands Gland: an organ specialized to produce secretions Distribution Relies on blood circulatory system How does this compare to nervous system?

Endocrine Glands Hypothalamus Pituitary Thyroid Parathyroid Pancreas Adrenal Gonads

Hypothalamus Location- Base of brain case Functions- Regulation of Primitive or Basal activities such as sex drive and water balance 9 hormones- 7 act on anterior lobe of pituitary gland (Tropic) 2 stored in posterior lobe

Hypothalamo-hypophyseal portal system What type of vessels comprise a portal system? What is unique about a portal system?

Hypothalamo-hypophyseal portal system and tract Location- Pituitary Stalk (Infundibulum) Link the hypothalmus to the pituitary gland Portal- Capillary beds connect to anterior lobe Tract- Neurons connect to posterior lobe

Pituitary gland Location- Sphenoid bone of the skull Anterior Lobe Produces Six hormones that Regulate Reproduction Growth Activity of the Thyroid Gland Posterior Lobe No hormone production only storage of hypothalamic hormones

Thyroid Largest endocrine gland Location- Wrapped around anterior and lateral sides of Trachea, just below Larynx Hormone- Thyroid Hormone Function- Increases Metabolic Rate

Parathroid Glands Location- Four glands imbedded on posterior surface of Thyroid Hormone- Parathyroid Hormone Function- Calcium Regulation

Adrenal Glands Cortex Medulla Location- 2 glands one superior to each Kidney. Cortex Zona Glomerulosa: Outer layer Zona Fasciculata: Middle Layer Zona Reticularis- Inner Layer Medulla

Adrenal Glands Medulla- (Fight or Flight Response) Epinepherine and Norepinephrine Cortex- Zona Glomerulosa Mineralocorticoids- Regulate Kidney Na+ and K+ excretion Zona Fasiculata Glucocorticoids- Stress and immune supression Zona Reticulata- Sex steroids- androgens precursor to sex hormones

Pancreas Location- Inferior and posterior to Stomach Pancreatic Islets Clusters of endocrine cells Function- Glucose Regulation

Gonads Male- Testes Female- Ovary Secrete Androgens such as Testosterone Female- Ovary Secrete Estrogen and Progesterone

Homeostatic Control Metabolic Rate Growth Hormone Blood Glucose Levels Blood Calcium Levels Water Retention Stress

Metabolic Rate Gland Hormones Hypothalamus Thyrotropin Releasing Hormone (TRH) Pituitary Gland Thyroid Stimulatory Hormone (TSH) Thyroid Thyroxine (T4) and Triiodothyronine (T3)

Interactions between Metabolic Hormones T4 & T3

Metabolic Rate Hormones released in response to a decrease in T3 blood levels Affects: All cells in the body except brain, spleen, testes, uterus and the thyroid gland Results: Increase in basal metabolic rate, oxygen consumption and heat production

Disorders Hypothyroidism (Creatinism) Goiter Children: mental retardation, development abnormalities Adults: lethargy, obesity Goiter Hyperthyroidism (Graves’ Disease) Weight loss, sweating, nervousness, sleeplessness Goiter -----a hypertrophy of the thyroid gland resulting from iodine deficiency

Growth Gland- Pituitary Gland Hormone- Effects Growth Hormone: increases mitosis and cellular differentiation. Secreted in response to Sleep, Trauma, Exercise, High protein meals, and Low blood sugar Effects Directly: Liver Indirectly: Bone, Muscle, and Cartilage

Disorders Pituitary Dwarfism- Insufficient secretion of Growth Hormone Gigantism- Over-secretion of Growth Hormone

Blood Glucose Levels Gland- Pancreas Hormones Insulin- increases uptake of glucose by cells Glucagon- increases release of glucose by cells and increases liver glucose production Released in response to… Insulin: high blood glucose levels Glucagon: low blood glucose levels Effects- Systemic Liver

Disorders Diabetes Mellitus- Disruption of Metabolism due to lack of insulin or lack of response to insulin. Symptoms- Excessive Urine, Intense Thirst, and Ravenous Hunger Type I- (Juvenile of Insulin Dependant) Destruction of Insulin Producing Cells Type II- (Adult or Noninsulin Dependant) Target cells resistant to Insulin

Blood Calcium Levels Gland- Parathyroid Hormone- Parathyroid hormone Released in response to low calcium levels Effects Kidneys- Retain Calcium Bones- Release Calcium

Disorders Hyper- or Hypo-parathyroidism Hyper-parathyroidism: Over Secretion Soft, Fragile Bones Kidney stones Hypo-parathyroidism: Under Secretion Rapid Decline of Blood Calcium Fatal

Water Retention Gland- Hypothalamus Hormone- ADH Effects? Stored and released by posterior pituitary Hormone- ADH Released in response to Dehydration and High Osmolarity (thickening) of blood Effects?

Disorders????

Stress Gland- Adrenal Cortex Hormones Glucocorticoids Effect- Systemic

Disorders Cushing Syndrome Cause: Excess Glucocorticoids Disrupts Protein and Fat Metabolism Symptom is abnormal fat deposits, fatigue and exhaustion

Cushing Syndrome (cont.) After Surgery