Chapter 46-The Endocrine System and Chemical Regulation Flashcards
Paracrine regulators
-many types, nearly all cells in body secrete one type or another, act only at short distances on neighboring cels with complementary receptors
Neurotransmitters
- most secreted by neurons into synapses, transmits nerve impulse across chemical sunapse
- some neurontransmitters distributed by blood and act as a hormone (norepinephrine)
neurohormones
hormones made by neurons that are transmitted by blood (ex. antidiuretic hormone)
Endocrine Hormones
Regulatory chemicals that are secreted by special glands into extracellular fluid and carried by the blood to target tissues/organs
3 Classes of Endocrine Hormones
- Peptide and Proteins (hydrophilic)
- glycoproteins - Amino acid derivatives (hydrophilic)
- thyroid hormones
- meltonin - Steroids (hydrophobic)
- sex steroids
- corticosteroids
Lipophilic Hormones
- non polar, fat soluble
- steroid and thyroid hormones
- travel in blood, attached to transport proteins
- bind to intracellular receptors
- act over brief time period
Hydrophilic Hormones
polar, water soluble
- all hormones except steroids and thyroids
- freely soluble in blood
- bind to extracellular receptors, activate kinase cascades
- longer active period
Hypothalamus
- Releasing Hormones, Inhibiting Hormones
- Target tissue=adenhoypophysis
- Principle action=acitvate/inhibit release of adenohypophyseal hormones
Posterior Pituitary Gland
- Secretes hormones produced by hypothalamus neuron bodies
- Antidiuretic Hormone, Oxytocin
- Target Tissue=kidneys, uterus, mammary glands
- Actions=conserves water (ADH), stimulates contraction, stimulates milk ejection (in that order for hormones/tissues)
Anterior Pituitary gland
- Produces 7 essential hormones, act on and regulate other endocrine glands
- controlled by hypothalamus
- -negative feedback inhibition
- Peptide hormones
1. ACTH-Adrenal Cortex-Stimulates secretion of adrenal hormones
2. MSH-SKin-stimulates color change in reptiles - Protein hormones
3. Growth Hormone-many organs-stimulates bone growth, protein synthesis - Glycoprotein Hormones
4. Thyroid Stimulating Hormone-Thyroid gland-stimulates thyroxine secretion
5. Luteinizing hormone-gonads-stimulates ovulation
6. Prolactin-mammary glands- milk production
7. Follicle stimulating hormone-gonads-stimulates spermatogensis in males, development of ovarian follicles in females
Thyroid Gland
- Thryroid Hormones-most cells-stimulates metabolic rate
2. calcitonin-bone-inhibits loss of calcium from bone
Parathyroid Gland
- Parathyroid Hormone-bone, kidneys, digestive tract-raises blood calcium level, stimulates calcium reabsorption in kidneys
- 4 small glands attached to thyroid
Adrenal Medulla
- inner portion of Adrenal Glands
- Epinephrine and Norepinephrine-muscle-initiates stress response
Adrenal Cortex
Stimulated by anterior pituitary hormone
- Glucocorticoids-many organs-raises blood glucose level
- Mineralocorticoids-kidney tubules-maintains proper balance of NA+ and k+ in blood
Pancreas
Exocrine and Endocrine Gland
- secretes insulin-liver-lowers blood glucose levels
- glucagon-liver-raises blood glucose levels
Pineal Gland
- located in roof of third ventricle of brain
- melatonin-gonads, brain, pigment-regulates biological rhythms
Testis
-testosterone-stimulates development of sex organs, stimulates secondary sex characteristics in males
Ovaries
Progesterone-uterus-completes preparation for pregnancy, stimulates development
Pituitary gland
-Master gland-consists of anterior pituitary, posterior pituitary
Anterior Pituitary Disorders
- growth hormone
- Hypersecretion=gigantism
- hyposecretion-pituitary dwarfism
Diabetes Mellitus
- Diabetics cannot take up glucose from blood
- type 1=individuals lack insulin secreting beta cells, treated by daily injections of insulin
- type 2=very low number of insulin receptors, treated by diet and exercise
What are the 5 steroid hormones
- minerocorticoids (aldosterone)
- glucocorticoids (cortisol)
- estradiol
- progesterone
- testosterone
