Unformatted text preview:

Alexis Rice Summary Chapter 13Endocrine System: Collection of specialized cells, and tissues that secrete hormones.-Hormones have access to every cell-Each hormone acts only on specific cells (target cells)-Only specific cells have receptors for specific hormones -Endocrine control is slower than nervous system-Endocrine and nervous systems interactEndocrine Glands: Ductless organs that secrete hormones into blood, interstitial fluid, lymphHormones: - Chemical messengers secreted by endocrine glands-Circulate in the bloodstream-Act on specific cells in the bodySteroid Hormones: - Structurally related to cholesterol-Lipid soluble, chemically derived from cholesterol-Activate specific genes to produce specific proteins-Slower acting than non-steroid hormones; minutes to hoursNon-steroid Hormones: - Structurally relates to proteins-Lipid insoluble-Water soluble-Bind to receptors on target cell membranes -Work through intermediate mechanisms to activate existing enzymes-Faster action than steroid hormones; seconds to minutesNegative Feedback Loops of Hormones: -Many hormones participate in internal homeostatic control mechanisms-Negative feedback loop involving hormones includes the following:-Endocrine gland serves as the control center-Hormone is the pathway between the control center and the effectors -Target tissues or organ are effectorsHypothalamus: - Homeostatic control center of the brain-Links nervous system and endocrine system-Produces two hormones of its own-Monitors and controls hormone secretions of the pituitary glandPituitary Gland: - “Master” gland-Secretes eight different hormones that regulate other endocrine organs-Two lobes: posterior and anteriorPosterior Pituitary: - Connection to hypothalamus by neuroendocrine cells-Hormones made in hypothalamus, stored in posterior pituitary-Hormones (ADH and oxygen) made in cell bodies in hypothalamus are transported down axons to axon endings in posterior pituitaryPosterior pituitary hormones non-steroidal: -Antidiuretic hormone (ADH)-Conserves water in kidneys-Regulates water balance in body-Oxytocin-Causes uterine contractions during labor and milk ejection through neuroendocrine reflex.Anterior Pituitary:-Controlled by hypothalamus-Releasing and inhibiting hormones from hypothalamus travel to pituitary throughpituitary portal system -The release of each anterior pituitary hormone is controlled, at least partially, bythe hypothalamusAnterior Pituitary Hormones:-ACTH (adrenocorticotropic hormone)-Stimulates adrenal cortex to release glucocorticoids (cortisol)-TSH (thyroid-stimulating hormone)-Acts on thyroid gland, promoting release of thyroid hormones -FSH and LH (gonadotropins)-Stimulate growth, development, and function of ovaries and testes-Not produced until about age 10-13 (puberty)-Increase in production initiates sexual maturation and development at puberty-Prolactin-Stimulates development of mammary glands and milk production-Growth Hormone-Has widespread effects on body-Major effects on bone, muscle-Most of its growth-promoting effects occur during childhood and adolescencePituitary Disorders: Hypersecretion and Hyposecretion -Diabetes Insipidus-Hyposecretion of ADH results in inability to conserve water appropriatley-Causes excessive urination, dehydration, thirst -Gigantism-Hypersecretion of growth hormone in childhood -Acrosmegaly-Excessive growth hormone over a long period in adults-Pituitary Dwarfism-Hyposecretion of growth hormone over a long period in adultsPancreas Secretes Glucagon, Insulin, and Somatostatin:-Pancreas: has both exocrine and endocrine functions-Pancreatic hormones are involved in regulating blood glucose levels -Endocrine cells in Islets of Langerhans within the pancreas secrete the followingthree hormones: -Alpha cells: secrete glucagon-Beta cells: secrete insulin-Delta cells: secrete somatostatin-Glucagon-Raises blood sugar-Causes breakdown of glycogen to glucose in liver-Insulin-Lowers blood sugar-Promotes uptake of sugar by cells in liver, muscle, and adipose tissue-Promotes conversion of glucose into glycogen, proteins, fat-Somatostatin-Inhabits secretion of glucagon and insulin, regulates other hormonesAdrenal Glands:-Adrenal Cortex: outer layer-Adrenal medulla: inner layerAdrenal Cortex: Glucocorticoids and Mineralocorticoids-Glucocorticoids (Cortisol is an example)-Secretion mediated through hypothalamus pituitary secretions-Maintain blood glucose levels during prolonged fasting-Suppress inflammatory responses-Mineralocorticoids (Aldosterone is an example)-Regulate sodium, potassium, water balance-Act on kidneys, promoting sodium reabsorption and potassium excretionAdrenal Medulla: Epinephrine and Norepinephrine-Adrenal Medulla-Neuroendocrine organ -Secretion stimulated by-Sympathetic nervous system-Hormones: Nonsteroidal-Epinephrine and norepinephrine-Enhance function of sympathetic nervous system-(fight-or-flight response)Thyroid and Parathyroid Glands·Thyroid located just below larynx in neck·Parathyroid glands embedded in back of thyroid·Both thyroid and parathyroid involved in calcium balance·Thyroid also involved in regulating metabolismThyroid Gland: Thyroxine Speeds Cellular Metabolism-Secretion: mediated through hypothalamus pituitary secretions-Steroidal hormones-Thyroxine (T4) and Triiodothyronine (T3)-Both regulates production of ATP from glucose, affect metabolic rate-Calcitonin-Lowers blood calcium levels-Decreases rate of bone resorption by inhibiting osteoclasts-Stimulates uptake of calcium by bonesParathyroid Hormone (PTH) Controls Blood Calcium Levels-Secretion-Response to lowered blood calcium levels-Action-Removes calcium and phosphate from bone-Increases absorption of calcium by the digestive tract-Causes kidneys to retain calcium and excrete phosphate-Major regulator of blood calcium concentration in adultsTestes Produce Testosterone-Functions of testosterone and other androgens-Before birth – responsible for development of external male genitalia-At onset of puberty-Regulates development and normal functioning of sperm, male reproductive organs, and male sex drive.-Regulates development of male secondary sex charachteristics-Small amounts of androgens produced by adrenal glands in both sexesOvaries Produce Estrogen and Progesterone-Hormones: steroidal-Estrogen-Initiates development of secondary sex characteristics-Regulates menstrual cycle-Progesterone-Regulates menstrual cycleOther Glands and Organs Also Secrete Hormones-Thymus:

View Full Document

OHIO BIOS 1030 - Summary Chapter 13

Download Summary Chapter 13
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...

Join to view Summary Chapter 13 and access 3M+ class-specific study document.

We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Summary Chapter 13 2 2 and access 3M+ class-specific study document.


By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?