Biology: Ch. 13
ACTH
(Adrenocorticotropic hormone) -Stimulates adrenal cortex to release glucocortids (cortisol)
FSH and LH
(Gonadotropins) -Stimulate reproductive organs of ovaries and testes -Not produced until about age 10-13 (puberty) -Increase in production initiates sexual maturation and development of puberty.
TSH
(Thyroid-Stimulating Hormone) -Acts on thyroid gland, promoting release of thyroid hormones
Anterior pituitary
-ACTH, TSH, FSH, LH, PRL, and GH -Releasing and inhibiting hormones from hypothalamus travel to pituitary through pituitary portal system -The release of each interior pituitary hormone is controlled, at least partially, by the hypothalamus
Posterior pituitary hormones: nonsteroidal
-Antidiuretic hormone (ADH) -primary target cells in kidneys -maintains water balance in body Oxytocin -Causes uterine contractions during labor and milk ejection through neuroendocrine reflex
Growth hormone
-Has widespread effects on body -Most obvious in bone and muscle -most of its growth-promoting effects occur during childhood and adolescence
Diabetes insipidus
-Hyposecretion of ADH results in inability to conserve water appropriately -Causes excessive urination, dehydration, thirst
Pituitary dwarfism
-Hyposecretion of growth hormone -Treated by administration of GH throughout childhood
Insulin
-Lowers blood sugar -Promotes uptake of sugar by cells in liver, muscle, and adipose tissue -Promotes conversion of glucose into glycogen, proteins, and fat.
Glucagon
-Raises blood sugar -Causes breakdown of glycogen to glucose in liver
Mineralocorticoids (Aldosterone is an example)
-Regulate sodium and potassium -Acts on kidneys promoting sodium reabsorption and potassium excretion
Mineralocorticoids
-Regulate sodium and potassium -Acts on kidneys, promoting sodium reabsorption and potassium excretion
Glucocorticoids
-Secretion mediated through hypothalamus-pituitary secretions -Regulate blood glucose levels during prolonged fasting -Surpresses inflammatory responses
Glucocorticoids (Cortisol is an example)
-Secretion mediated through hypothalamus-pituitary secretions -Regulate blood glucose levels during prolonged fasting -Surpresses inflammatory responses
Nonsteroid hormones
-Water soluble -Bind to surface on target cell membranes -Work through intermediate mechanisms to cause changes in membrane protein -May involve a "second messenger" within the cell such as cyclic AMP (cAMP) -FASTER action than steroid hormones; seconds to minutes
Steroid hormones
1) Lipid soluble ,chemically derived from cholesterol 2) Bind to intracellular receptor 3) Takes minutes to produce specific proteins 4) Slower acting than Nonsteroid hormones; minutes to hours
Pituitary gland
1) Master gland 2) secretes 8 different hormones that regulate other endocrine organs 3) two lobes: posterior and anterior
Hypothalamus
1) Small region of the brain 2) link to nervous system and endocrine gland 3) produces two hormones of its own 4) monitors and controls hormone secretion of the pituitary gland
Steroid hormones
1) Structurally related to cholesterol 2) Lipid soluble
Nonsteroid hormones
1) Structurally related to proteins 2) Lipid insoluble
Negative feedback loop involving hormones includes the following:
1) endocrine gland serves as the control center 2) hormone is the pathway between the control center and the effectors 3) Target tissues or organs are the effectors
Endocrine cells in islets of Langerhans within the pancreas secrete the following three hormones
Alpha cells: secrete glucagon Beta cells: secrete insulin Delta cells: secrete somatostatin
Endocrine system
Collection of specialized cells, and tissues that produce and secrete hormones
Acromegaly
Excessive growth hormone over a long period in adults
Posterior pituitary is connected to hypothetical mess by Neuro endocrine cells
Hormones (ADH and oxytocin) made in cell bodies in the hypothalamus are transported down axons to axon endings and posterior pituitary for storage and release
Gigantism
Hyper secretion of growth hormone in childhood
Somatostatin
Inhibit secretion of glucagon and insulin, regulates other hormones
Adrenal medulla
Inner layer of adrenal gland -Epinephrine (adrenaline) Norepinephrine (noradrenaline)
Endocrine and nervous systems
Interact
Thyroid &Parathyroid
Involved in regulating calcium balance. Thyroid itself is involved in controlling metabolism. Also located below larynx in neck.
Pancreatic islets of Langerhans
Involves in regulating blood glucose levels
Adrenal cortex
Outer layer of adrenal gland -Glucocorticoids, such as cortisol -Mineralocorticoids, such as aldosterone
Endocrine control is
Slower
Prolactin
Stimulates development of mammary glands and production of milk
The pancreas has both exocrine and endocrine functions
True
