Lab 9: Endocrine System

Review Where does pepsinogen come from? Why doesn’t the stomach digest itself? Why can Veggans not eat meat anymore?

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

DVD clip Battling A Giant

Hormones Chemical messengers –Stimulate physiological responses in other cells –Target Cells Tropic (Trophic) Hormones –Hormone whose target is another endocrine gland. How do hormones travel?

Hormone Production and Distribution Production –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 –Zona Glomerulosa: Outer layer –Zona Fasciculata: Middle Layer –Zona Reticularis- Inner Layer Medulla Location- 2 glands one superior to each Kidney.

Adrenal Glands 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 Medulla- (Fight or Flight Response) Epinepherine and Norepinephrine

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

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

DNH- Anatomy

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

Metabolic Rate GlandHormones HypothalamusThyrotropin Releasing Hormone (TRH) Pituitary GlandThyroid Stimulatory Hormone (TSH) ThyroidThyroxine (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) –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- –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 –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

Dissection & Review Cat Questions- –You won’t need to find the specific glands –You will need to know region of the body where found –You will need to know location of organs affected Lab Notes at Library on Reserve Research Papers Next Week Due Reviews for final exam will be in Two Weeks.