Module 12: The Endocrine System Flashcards
Water soluble hormones
Amines
Peptides and proteins
Eicosanoids
Lipid soluble hormones
Steroid
Thyroid
Gas
Amino-based hormones
Consist of proteins or protein derivatives
Most hormones belong to this group
React with receptors on the surface of the cell
Rapid reaction
Steroid hormones
Synthesized from cholesterol
Sex hormones and those hormones from the adrenal cortex
React with receptor sites inside a cell
Slow reaction
Pituitary gland (hypophysis)
Master gland
Controls the activity of many other endocrine glands
Activity controlled by hypothalamus
Anterior pituitary gland – (adenohypophysis)
Posterior pituitary gland – (neurohypophysis)
Hypothalamus
Major link between nervous and endocrine systems
Adenohypophysis
Anterior pituitary gland
Secretions regulated by hypothalamus
Neurohypophysis
Posterior pituitary gland
Two hormones produced in the hypothalamus and sent into a capillary bed in the neurohypophysis where they are stored and released
Growth hormone (GH)
Also called somatotropin
Target: most body tissues
Stimulates growth by promoting protein synthesis
Thyroid-stimulating Hormone (TSH)
Also called thyrotropin
Target: thyroid gland
Stimulates production of thyroid hormones
Adrenocorticotrophic Hormone (ACTH)
Target: Cortex of the adrenal glands
Stimulates production of hormones in the adrenal cortex
Follicle-stimulating hormone (FSH)
Target: testes and ovaries
Stimulates production of sperm in the male
Stimulates maturation of ova and production of estrogen by the ovaries
Luteinizing hormone (LH)
Target: reproductive organs
Stimulates the production of testosterone in the testes Stimulates the production of estrogen and progesterone by the ovaries
Also stimulates ovulation
Prolactin (PRL)
Target: mammary glands
Stimulates milk production (lactation)
Oxytocin
Target: uterus, mammary glands
Stimulates uterine contractions and initiates labor
Stimulates ejection of milk
Antidiuretic hormone (ADH)
Also called vasopressin
Target: kidneys
Increases water reabsorption in the kidney to reduce water loss
T3 (triiodothyronine) and T4 (thyroxine or tetraiodothyronine)
Target: most body cells Regulates energy balance Increases rate of protein synthesis Regulates growth Most T4 is converted to T3 (the more active form) in the target tissues
Calcitonin
Target: bone tissue
Regulates calcium blood levels by inhibiting the release of calcium from bone tissue to blood (decreases blood calcium)
Parathyroid glands
Four small glands (some individuals have as many as 8) embedded in the posterior thyroid
Have nothing to do with the thyroid gland
Parathyroid hormone (PTH)
Also called parathormone
Target: bones, intestines, kidneys
Increases blood calcium levels
Adrenal glands
Located above each kidney
Also called the suprarenal glands
Outside layer (fibrous capsule) is surrounded by a cushion of fat
Two functional layers: cortex and medulla
Mineralocorticoids
Secreted by adrenal cortex
Most common is aldosterone
Target: kidneys
Regulate water balance in the body
Glucocorticoids
Secreted by adrenal cortex Most common is cortisol Target: most cells Increase blood sugar levels Inhibit inflammation and immune response
Gonadocorticoids (androgens)
Target: ovaries and testicles
Increase female sex drive