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What are the general characteristics of the
endocrine system?
- releases hormones into the bloodstream
- regulate metabolic processes
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What is a hormone?
- substance secreted by an endocrine gland and transported in the blood
- organic compound
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What is the basic function of a hormone?
stimulate changes in target cells even in extremely low concentrations
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What are paracrine substances?
- synthesized from a type of fatty acid in cell membranse
- produce liver, kidney, heart, lungs, thymus gland, pancreas, brain and reproductive organ cells
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What are autocrine substances?
affect only secreting cells
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Define steroid hormones
- derived from cholesterol
- include sex hormone
- secretions from adrenal cortex
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Define nonsteroid hormones?
- called amines
- derived from amino acid tyrosine
- synthesized in the adrenal medulla
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How do steroid and nonsteroid hormones affect their target cells?
- steroid:combine with specific protein receptors
- nonsteroid: combines with specific receptor molecules
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What are prostaglandins?
paracrine substances, are potent and present in small amounts
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How do prostaglandins function?
- they are not stored, they are synthesized just before they are released
- regulate cellular responses to hormones
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How does the nervous system aid in the regulations of hormones?
- directly stimulates some glands
- adrenal medulla
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How does the hypothalamus aid in the regulation of hormones?
controls the anterior pituitary gland's releade of tropic hormones, which stimulate other endocrine to glands release hormones
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How does the internal environment aid in the regulation of hormones?
- group of glands responds directly to changes in environment
- (blood glucose rises, pancreas secretes insulin)
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Describe the negative feedback system
mechanism that restores a biochemical or other balance in which build up of a product suppresses its synthesis
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at the base of the brain
attached to the hypothalamus
lies in the stella turcica
pituitary gland
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vascular structure that consists of two large lateral loves connected by a broad isthmus
below the larynx on either side and anterior to the trachea
thyroid gland
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on the posterior suface of the thyroid gland
usually 4 of them
parathyroid glands
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a gland sits atop each kidney like a cap and is embedded in the mass of adipose tissue that encloses the kidney
adrenal gland
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elongated, somewhat flattened organ posterior to the stomach and behind the parietal peritoneum
pancreas
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small oval structure deep between the cerebral hemispheres, attached to the upper portion of the thalamus
pineal gland
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Growth hormone
prolactin
thyroid stimulating hormone
adrenocorticotropic hormone
follic-stimulating hormone
luteinizing hormone
antidiuretic hormone
oxytocin
pituitary gland
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thyroxine
triiodothyronine
calcitonin
thyroid gland
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secretes the protein parathyroid hormone
parathyroid gland
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epinephrine aka adrenalin
norepinephrine aka noradrenalin
sex hormones
adrenal glands
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aldosterone
cortisol
adrenal androgens
adrenal cortex
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glucagon
insulin
somatostatin
pancreas
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lies in the mediastinum posterior to the sternum and between the lungs
thymus
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thymosins
(hormones)
thymus
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stimulates increase in size and rate of division of body cells; enhances movement of amino acids
Growth Hormone (GH)
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sustains milk production after birth; amplifies effect of LH in males
Prolactin (PRL)
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controls secretion of hormones from the thyroid gland
thyroid stimulating hormone (TSH)
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controls secretion of certain hormones from the adrenal cortex
adrenocorticotropic hormone(ACTH)
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development of egg-containing follicles in ovaries; stimulates follicular cells to secrete estrogen;in males, stimulates production of sperm cells
follicle-stimulating hormone (FSH)
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promotes secretion of sex hormones; release egg cells in females
Luteinizing hormone(LH)
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causes kidneys to reduce water excertion; in high concentration, raises blood pressure
antidiuretic hormone(ADH)
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contracts muscles in uterine wall and those associated with milk secreting glands
oxytocin(OT)
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increases rate of energy release from carbohydrates; increases rate of protein synthesis; accelerates growth; stimulates activity in nervous system
Thyroxine (T4)
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increases rate of energy release from carbohydrates; increases rate of
protein synthesis; accelerates growth; stimulates activity in nervous system.....5 times more potent
Triiodothyronine (T3)
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lowers blood calcium and phosphate ion concentrations by inhibiting release of calcium and phosphat ions from bones
calcitonin
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helps regulate the concentration of extracellular electrocytes by conserving sodium ions and excreting potassium ions
aldosterone
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decreases protein synthesis, increases fatty acid release and stimulates glucose synthesis from noncarbohydrates
cortisol
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supplement sex hormones from the gonads; may be converted into estrogens
adrenal androgens
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stimulates the liver to break don glycogen and convert noncarbohydrates into glucose; stimulates breakdown of fats
glucagon
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promotes formation of glycogen from glucose, inhibits conversion of noncarbohydrates into glucose and enhances movement of glucose through adipose and muscle cell membranse
insulin
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helps regulate carbohydrates
somatostatin
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insufficient secretion of human growth hormone during childhood produces
hypopituitary dwarfism
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high metabloic rate, sensitivity to heat; restlessness, hyperactivity, weight loss, protruding eyes, goiter
hyperthyroidism
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autoantibodies bind TSH receptors on thyroid cell membrans, mimicking action of TSH, overstimulating gland and goiter
Graves Disease
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autoantibodies attack thyroid cells, resulting in hypothyroidism
hashimoto disease
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cretinism-stunted growth, abnormal bone formation, mental retardation, low body temperature, sluggishness
hypothyroidism (infantile)
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myxedema-low metabolic rate; sensitivity to cold, sliggishness, poor appetite, swollen tissues, mental dullness
hypothyroidism(adult)
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deficiency of thyroid hormones due to iodine deficiency; because no thyroid hormones inhibit pituitary release of TSH, thyroid is ocerstimulated and enlarges but functions below normal
simple goiter
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fatigue, muscle weakness, painful joints, altered mental functions, depression, weight loss, bone weakening, increased PTH secretions overstimulaates osteoclasts
hyperparathyroidism
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muscle cramps and seizures, decreased PTH secretion reduces osteoclast activity, diminishing blood calcium ion concentration
hypoparathyroidism
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decreased blood sodium, increased blood potassium, low blood glucose level, dehydration, low blood pressure, frequesnt infections, fatigue nasuea and vomitting, increased skin pigmentation
addisons disease
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the pancreas can not produce insulin
symptoms begin before age twenty
juvenile of insulin dependent)
Type 1 diabetes mellitus
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non-insulin dependent
ususally in people over 40
cells lost insulin receptors and are less able to respond to insulin
Type II diabetes mellitus
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impars ADH regulation of water balance
diabetes imsipidus
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Which part of the brain controls your response
to stress?
hypothalamus
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threatens tissues, extreme heat or cold, decreased oxygen concentration, infections, injuries, prolonmges heavy exercise
physical stress
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results from thoughts about real or imagined dangers, personal losses, unpleasent social interactions
psychological stress
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Which hormones are involved in the stress response?
- epinephrine
- corticotropin releasing hormone
- ACTH
- Cortisol
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Which systems are affected by stress?
autonomic nervous system
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List some the life span changes seen in the endocrine system.
endocrine glands shrink and accumulate fibrous connective tissue, fat and lipofuscin
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hormone the adrenal medulla secretes during times of stress
epinephrine
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neurotransmitter released from the axons of some nerve fibers
norepinephrine
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