Ch. 48 Endocrine System (Unit 5) Flashcards
Hormones
Chemical substances produced in the body that control and regulate the activity of certain target cells or organs.
Negative feedback
Most common type of endocrine feedback system that results in the gland increasing or decreasing the release of hormone.
Positive feedback
Regulates hormone synthesis and release.
Circadian rhythm
Endogenous 24-hour rhythm that can be driven and altered by sleep-wake or dark-light 24-hour cycles
Tropic hormones
Hormones that control the secretion of hormones by other glands
Growth Hormone
Affects the growth and development of all body tissues. Has a role in protein, fat, and carbohydrate metabolism.
Antidiuretic hormone
Regulates fluid volume by stimulating reabsorption of water in the renal tubules. It is a potent vasoconstrictor.
Oxytocin
Stimulates ejection of milk into mammary ducts during lactation and contraction of the uterus; it may also affect sperm motility.
Melatonin
Secretion is increased in response to exposure to the dark and decreased in response to light.
Thyroxine (T4)
Thyroid hormone that accounts for 90% of production by the thyroid gland.
Triiodothyronine (T3)
Thyroid hormone that is more potent and has greater metabolic effects than T4
Iodine is necessary for the synthesis of both
T3 and T4
Calcitonin
Produced by C cells of the thyroid gland in response to high circulating calcium levels. `
Catecholamines
Neurotransmitters epinephrine, norepinephrine, and dopamine.
Corticosteroid
Promote metabolism; increase in response to stress; anti-inflammatory
Thyroid-stimulating hormone (TSH)
Stimulates the thyroid gland to secrete thyroid hormones
Adrenocorticotropic Hormone (ACTH)
Stimulates the adrenal cortex to secrete corticosteroids
Follicle-Stimulating hormone (FSH)
Stimulates secretion of estrogen and the development of ova in women and sperm development in men.
Luteinizing Hormone (LH)
Stimulates ovulation in women and secretion of sex hormones in both men and women.
Cortisol
Most abundant and potent glucocorticoid, is necessary to maintain life and protect the body from stress.
Aldosterone
Potent mineralocorticoid that maintains extracellular fluid volume. It acts on the renal tubule to promote renal reabsorption of sodium and excretion of potassium and hydrogen ions.
Islets of Langerhans
The hormone-secreting portion of the pancreas. Consists of 4 types of hormone-secreting cells: alpha, beta, delta, and F cells
Alpha cells
produce and secretes the hormone glucagon
Beta Cells
produce and secrete insulin and amylin
Delta cells
produce and secrete somatostatin
F cells
Secrete pancreatic polypeptides
Glucagon
Synthesized and released from pancreatic alpha cells and the gut in response to low levels of blood glucose, protein ingestion, and exercise.
Insulin
Principal regulator of metabolism and storage of ingested carbohydrates, fats, and proteins.
Somatostatin
Inhibits insulin and glucagon secretion
Pancreatic polypeptide
Influences regulation of pancreatic exocrine function and metabolism of absorbed nutrients
Androgens
Promote growth spurt in adolescence, secondary sex characteristics, and libido in both sexes
Hypothalamus
- 2 important groups of hormones: releasing hormones and inhibiting hormones
- Contains neurons, which receive input from the CNS, including brainstem, limbic system, and cerebral cortex. -Neurons from the hypothalamus create a circuit to facilitate coordination of the endocrine system and autonomic nervous system.
- Coordinates the expression of complex behavioral responses, such as anger, fear, and pleasure
Pituitary
- Connected to the hypothalamus by the infundibular stalk. Stalk relays information between the hypothalamus and the pituitary
- 2 major parts: Anterior pituitary and posterior pituitary
