Endocrine System** Flashcards
What is the function of the endocrine system?
Maintain homeostasis by releasing hormones and control prolonged continuous processes
How does the endocrine and nervous system work together?
Coordinate and direct the activity of the body’s cells and to maintain homeostasis
What kind of cells are in the endocrine system?
Glandular epithelium
What kind of chemical signals does the endocrine system have?
Hormones
What is the specificity of response in the endocrine system?
Receptors on target cells
What is the speed of onset in the endocrine system?
Seconds to hours
How long is the duration of action in the endocrine system?
May be brief or may last for days if secretion ceases
Release their products at the body’s surface (epithelium) or into body cavities through ducts; ducted
Exocrine Glands
What are some examples of exocrine glands?
Sweat, oil, saliva, pancreas, liver
Produce hormones that release into the blood or lymph; ductless
Endocrine glands
What are some examples of endocrine glands?
Pituitary, thyroid, pancreas, thymus
Chemical messengers released into the blood to be transported leisurely throughout the body
Hormones
Cells with specific receptors on which hormones exert their effect
Target cells
Where must protein receptors be present so the hormone can attach?
Plasma membrane
What does a hormone depend on so it could interact with its customers’ receptors?
Molecular structure
Made from cholesterol; can pass straight through the target cell’s membrane and cytoplasm and into its nucleus
Steroid
What are steroid hormones soluble in?
Lipids
What are steroid hormones insoluble in?
Water
Amino acid based molecules; activates/deactivates enzymes that trigger the desired change to the cell’s activities
Non-steroid hormones
What prompts the endocrine glands to release or not release their hormones?
Negative feedback
What is hormone secretion activated by?
Internal or external stimulus
What do rising hormones inhibit?
Further hormone release
Endocrine organs are prodded into action by other hormones
Hormonal stimuli
What are some examples of hormonal stimuli?
Hypothalamus stimulates the anterior pituitary gland to secrete its hormone
Changing blood levels of certain ions and nutrients
Humoral stimuli
What are some examples of humoral stimuli?
Decreasing calcium levels stimulates the parathyroid ormone
Nerve fibers stimulate hormone release
Neural stimuli
What are some examples of neural stimuli?
Adrenal medulla releases norepinephrine and epinephrine during periods of stress
What types of chemicals can hormones be?
Steroids, peptides, amines, proteins, glycoproteins
Locally-produced lipids that affect the organ in which they are produced with a variety of effects
Prostaglandins
What are some effects of Prostaglandins?
Relax or contract smooth muscle, stimulate secretion, influence blood pressure
Hormones that have another endocrine gland as their target
Tropic hormones
What 2 hormones does the anterior pituitary produce?
Growth hormones, prolactin
Stimulates body cells to grow and reproduce
Growth hormone
What factors influence growth besides GH?
Nutritional status
What hormones from the hypothalamus control the levels of GH?
GH-releasing and GH-inhibiting
What disorders may result from a lack/too much GH?
Gigantism, dwarfism
Promotes milk production in lactating women
Prolactin
What hypothalamic hormones affect prolactin?
PRL releasing hormone
Controls secretions of the thyroid gland
Thyroid stimulating hormone
What hypothalamic hormone affects the release of the thyroid stimulating hormone?
TRH
What hormone does ACTH affect the release of?
Cortisol
What is the name of te hormone that controls ACTH’s release?
Corticotropin releasing hormone
Hormone that makes testes produce sperm and ovaries to produce eggs and release estrogen
Follicle stimulating hormone
What hormone from the hypothalamus controls the release of follicle stimulating hormone?
Gonadotropin releasing hormone
Causes ovulation and formation of corpus luteum in the ovary which releases estrogen and progesterone
Luteinizing hormone
What controls the relase of luteinizing hormones?
Gonadotropin releasing hormone
What structure actually produces the hormones released by the posterior pituitary?
Hypothalamus
Cause kidneys to conserve water
Antidiuretic hormone
What disease can occur if not enough antidiuretic hormone is released?
Diabetes
What 2 hormones does the posterior pituitary produce?
Oxytocin, antidiuretic hormone
Causes contractions of the uterus wall and milk letdown during breastfeeding
Oxytocin
What 2 hormones does the thyroid gland produce?
Thyroxine and Triiodothyronine
Regulates metabolism
T4 and T3
Lowers blood levels of calcium and phosphate ions
Calcitonin
Increases blood calcium levels by stimulating osteoclasts to break down bone tissue and release calcium into blood and influences kidneys to conserve calcium ions
Parathyroid Hormone
What 2 hormones are produced by the adrenal medulla?
Epinephrine and Norepinephrine
What effects do epinephrine and norepinephrine have on the body?
Similar effects to those of the sympathetic division of the autonomic nervous system
What 3 hormones are produced by the adrenal cortex?
Aldosterone, Glucocorticoids, sex hormones
Controls the levels of sodium ions by conserving them in the kidneys
Mineralcorticoids
Influence the metabolism of glucose, protein, and fat
Glucocorticoids
Supplement hormones released by the gonads and may stimulate early development of reproductive organs
Sex hormones
What hormone does the pancreas produce?
Glucagon
Increases the blood levels of glucose by stimulating the breakdown of glycogen and the conversion of noncarbohydrates into glucose
Glucagon
What does the pineal gland secrete?
Melatonin
Involves the regulation of circadian rhythms in the body
Melatonin
What does the thymus gland secrete?
Thymosin
Affect production and differentiation of T lymphocytes that are important in immunity
Thymosin
What 2 hormones do the ovaries produce?
Estrogen and progesterone
What 4 hormones does the placenta produce?
Estrogen, progesterone, Human chorionic gonadotropin, relaxin
What hormone does the testes produce?
Testosterone
Secrete hormones associated with the processes of digestion
Digestive gland
Secretes atrial natriuretic peptide affecting sodium
Heart
Secrete erythropoietin for blood cell production
Kidneys
What do salivary glands secrete?
Amylase
Active in breaking down starches
Amylase
Releases when food passes through the pyloric sphincter
Gastrin
Produced by the liver and stored in the gall bladder until it is released into the small intestine to break down lipids
Bile
Released when acidic food enters the first part of the small intestine (duodenum)
Secretin
Causes mother’s pelvic ligaments and the pubic symphysis to relax and become more flexible
Relaxin
Prepare breasts for lactation
Human placental lactogen
Produced by the embryo & then by the fetal part of the placenta
Human chorionic gonadotropin
What 4 hormones does the anterior pituitary release?
Thyroid stimulating hormone, ACTH, follicle stimulating hormone, luteinizing hormone
