Chapter 11 Endocrine System Endocrine System What is

Chapter 11 : Endocrine System

Endocrine System: What is it? l l system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body Hormones affect other endocrine glands or body systems

ES and Homeostasis l Homeostasis

STIMULUS Hypothalamus Releasing Hormone (Release-Inhibiting Hormone) Pituitary Stimulating Hormone Gland Hormone Target

Basic Structure of Feedback Loop l l l Environmental Stimulus Stimulates Control Center (Brain-hypothal. ) Hypothalamic hormones stim. Pituitary hormone stim. Target area produces change Change acts negatively or positively on the cycle.

A. Positive Feedback l l Not common Classic example: Action of OXYTOCIN on uterine muscle during birth.

Positive Feedback l l l Baby pushes on cervix Nervous signal to Hypothalamus Hypothal. manufactures OXY transported to POSTERIOR PITUITARY & released OXY stimulates uterine contraction Loop stops when baby leaves birth canal

Negative Feedback: Thyroid

IV. Specific Endocrine Events A. B. C. D. Thyroid Hormone Growth Hormone Adrenal Cortex Hormones Sex Steroids

Endocrine System: Team Players l l l l The Pituitary Gland Thyroid Gland Parathyroid Glands Adrenal Glands Pancreas Thymus Pineal Gland Gonads

Pituitary/ Hypophysis l Pituitary gland: a small gland located on a stalk hanging from the base of the brain l “The Master Gland” – – – Primary function is to control other glands. Produces many hormones. Secretion is controlled by the hypothalamus in the base of the brain. l Anterior Secretions: – – – – TSH ACTH FSH LH ISCH LTH GH/ STH MSH l Posterior Secretions: – – ADH Oxytocin

Thyroid Gland l Thyroid Gland: butterfly shaped, left and right halves fused by an isthumus. On either side of the larynx l l Secretions: “The Weight Gland” – Controls metabolism, iodine uptake, blood calcium levels – – – T 3: metabolism regulation T 4: metabolism regulation Calcitonin: promotes absorption of calcium from blood and bones

Adrenal Glands l l Adrenal Glands: Located cranial to the kidney. Each gland has 2 parts: cortex and medulla “The Reaction Gland” – Regulates electrolytes, metabolism, sexual functions, injury response l Cortex Secretions (Steriods): – – – l Mineralocort icoids Glucocortico ids Androgens Medulla Secretions: – – Epinephrine Noreeprinephrine

Pancreas l Pancreas: aggregation of cells located near the proximal duodenum l “The Sugar Regulation Gland” – (Endocrine FXN) secretion of bloodglucose regulation l Endocrine Secretions: – – Insulin Glucagon

Gonads: gamete production l Ovary Secretions: Stimulated by h. CG which is secreted by placenta – Estrogen l – 2 ndary sex characteristics Progesterone l Maintains preg l Testes – Testosterone l 2 ndary sex characteristics

Common Procedures l l l Assays: tests amount of hormone present Thyroid Stimulation Test: blood analysis of thyroid levels ACTH Stimulation Test: blood analysis of cortisol levels in the blood

Common Ailments l l l Acromegaly: enlargement of extremities due to over active growth Cushing’s Disease/ Hyperandrenocorticism: excessive adrenal cortex production resulting in increased urination, drinking, and distribution of body fat Diabetes Mellitus: metabolic disorder, of inadequate secretion of insulin