(INFO) 4.1 Introduction to the Anatomy and Physiology of the Endocrine System

endocrine system

controls the secretion of hormones from several glands located throughout the body

glands

• organs that secrete or release hormones into bloodstream

hormones

• transfer information and instructions from 1 area of the body to another

• chemical substances released from glands in small amounts and travel through the blood to other tissues and organs

• growth and development, tissue function, metabolism, homeostasis, sexual function, and mood are all influenced and regulated by hormones

endocrinology

study of endocrine system and a subspecialty of internal medicine

endocrinologist

physician that diagnoses and treats the conditions of the endocrine system.  

adrenals

• abdomen, above the kidneys and 2 parts to it

  • adrenal cortex and adrenal medulla

• regulates sodium/potassium, carbohydrate metabolism, sex hormones, and epinephrine secretion in emergencies

pituitary

• located in the brain

• master gland, regulates other endocrine glands

• can be divided into anterior (adenohyophysis) and posterior (neurohypophysis) sections.

pineal

• located in the brain

• regulates sleep by secreting melatonin and serotonin

pancreas

• epigastric area of the abdomen

• blood glucose regulation

• secrete hormones

thyroid

• larger gland in the neck

• metabolism, growth, and development

• hormones that are secreted include thyroxine (T4), triiodothyronine (T3), and calcitonin.

parathyroid

• located on the thyroid gland in the neck in 2 pairs

  • superior pair and inferior pair

• maintains calcium and phosphate levels

• secretes parathyroid hormone (PTH): MAINTAIN CALCIUM LEVELS AND METABOLISM OF PHOSPHORUS

thymus

• mediastinum in front of the heart

• secretes hormones that regulates the immune system

• hormones: thymosin and thymopoietin

ovaries/testes

• located in the pelvis

• male and female secondary sexual characteristics

• ovary

  • produce estrogen, progesterone (hormones involved in regulation of female sex organs)

• testes

  • produce testosterone (involved in regulation of male sex organs)

• placenta: additional TEMPORARY endocrine organ (produced during pregnancy, secretes hormones involved in growth/development of fetus

adenohypophysis

• secretes different hormones than the posterior portion of the gland

  • growth hormone (GH): REGULATES GROWTH OF ADRENAL CORTEX

  • adrenocorticotropin hormone (TSH): STIMULATES GROWTH OF THYROID GLAND

  • follicle stimulating hormone (FSH) and luteinizing hormone (LH): CONTROL SEX GLANDS

  • prolactin hormone: STIMULATE GROWTH/DEVELOPMENT OF THE MAMMARY GLANDS

  • melanocyte-stimulating hormone: CONTROL SKIN PIGMENTATION

neurohypophysis

• secretes antidiuretic hormone (ADH): REGULATE SECRETION/REABSORPTION OF WATER IN KIDNEYS

• oxytocin: STIMULATE UTERUS TO CONTRACT DURING CHILDBIRTH AND RELEASE OF MILK FROM MAMMARY GLANDS

melatonin

important in the regulation of the bodys sleep wake cycle

serotonin

stimulates nervous system by regulating neurotransmitters, smooth muscles, and gastric secretions

T4 (thyroxine)

maintains regulates the basic metabolic rate of the body, growth, and development of the body, and metabolism of nutrients, water, vitamins, and minerals

T3 (triiodothyronine)

also regulates the basic metabolic rate

calcitonin

involved in bone and calcium metabolism

what does the endocrine portion of the pancreas consist of?

cell clusters called islets of Langerhans

• secret the hormones insulin, glucagon, and somatostatin

insulin

stimulates the cells of body to take in glucose from the bloodstream for metabolism

glucagon

increase blood glucose level by breaking down glycogen into glucose

somatostatin

decreases production of insulin and glucagon

gastrointestinal muscosa

• secretes hormones related to digestion

gastrin, secretin, cholecystokinin, enterogastrone

gastrin

stimulate production of gastric acid in the stomach, which breaks down food

secretin

stimulates secretion of pancreatic enzymes, bile, and other secretions from intestines that are involved in digestion of the food

cholecystokinin

controls the gallbladder

enterogastrone

regulates secretions from the stomach

adrenal cortex

• outer portion of adrenal gland and secretes 3 types of hormones: glucocorticoids, mineralocorticoids, and androgens

glucocorticoids

• involved in carbohydrate metabolism

• main hormones of this are cortisol and corticosterone

mineralocorticoid

• aldosterone main hormone of this which is involved in regulating electrolytes and fluid balance

androgens

• hormones that stimulate development of male sexual characteristics

• main hormones are testosterone and androsterone

adrenal medulla

• inner portion of adrenal gland

  • hormones produced are catecholamines, dopamine, epinephrine, and norepinephrine

catecholamines

involved in nervous system regulation

dopamine, epinephrine, and norepinephrine

3 hormones involved in sympathetic nervous system function