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What two systems work together to maintain homeostasis?
endocrine and nervous systems
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What is the name of the system made up of these two systems?
Neuroendocrine system
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What are the 3 functions of the neuroendocrine system?
- 1. Communication
- 2. Integration
- 3. Control
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What does the endocrine system do?
Secretes hormones to specific target cells
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Endocrine glands are:
Ductless glands
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Ductless glands dump their product:
directly into blood stream
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Hormones than those of neurotransmitters.
work slowly and last longer
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Hormones are released as:
inactive but can be activated when needed
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Hormones can be classified by and .
general function and chemical structure
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Which hormones target other endocrine glands and stimulate their growth and secretion?
Tropic hormones
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Which hormones target reproductive tissues?
Sex hormones
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Which hormones stimulate anabolism in target cells?
Anabolic hormones
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What are the 2 types of hormones classified by their chemical structures?
- Steroid hormones
- Nonsteroid hormones
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What is true about steroid hormones?
- synthesized from cholesterol
- Lipid-soluble and can easily pass thru phospholipid membranes of target cells
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Cortisol, aldosterone, estrogen, progesterone, and testosterone are all examples of:
steroid hormones
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hormones do not enter the cell directly.
Non-steroid
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Insulin and parathyroid hormones are:
protein hormones (non-steroid)
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Non-steroid hormones are synthesized primarily from:
amino acids
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Amino acid derivative hormones:
are each derived from a single amino acid molecule
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epinephrine and norepinephrine are:
amine hormones
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Hormones signal a cell by:
binding to the target cell's specific receptors in a "lock and key" mechanism
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What is synergism in relation to hormones?
Combinations of hormones acting together to have a greater effect
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What is permissiveness in relation to hormones?
when one hormone permits, or enables, a second hormone to have its full effect
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What is antagonism in relation to hormones?
- when one hormone produces the opposite effects of another hormone.
- Used for fine tuning
- Ex: insulin and glucagon
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What happens to unused hormones?
It is quickly excreted thru kidneys or broken down.
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Steroid hormones are:
lipid soluble
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The amount of steroid hormones present determines:
- the magnitude of a target cell's response.
- The more hormones the faster and stronger it'll work
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The second messenger mechanism is also known as the:
fixed-membrane-receptor model
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Explain how the second messenger mechanism works.
- Non-steroid hormone acts as first messenger and delivers its chemical message to receptors
- The message is then passed by G protein into cell where it triggers cellular changes
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How is hormonal secretion controlled?
Negative feedback loop called endocrine reflexes
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What is up-regulation?
increased number of receptors being filled which increase sensitivity
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What is down-regulation?
decreased number of receptors being filled which decreases sensitivity
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What are Prostaglandins (PGs)?
Unique group of lipid hormones called tissue hormones because the secretion is produced in tissue and stays localized
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PGs tend to:
integrate activities of neighboring cells
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What were the first 3 prostaglandins identified?
Prostaglandins A, E, and F
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What gland is known as the master endocrine gland?
Pituitary gland
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What is the function of the pituitary gland?
- Sends hormones to all places in the body
- Produces more hormones than all other glands
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What 2 glands make up the pituitary gland?
- Adenohypophysis (Anterior gland)
- Neurohypophysis (Posterior gland)
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What are the 3 stain types of adenohypophysis?
- (C.A.B)
- Chromophobes- do not stain
- Acidophils- stain with acid stains
- Basophils- stain with basic stains
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What are the 5 functional types of adenohypophysis?
- (S.C.T.L.G)
- Somatotrophs- secrete GH (growth hormone)
- Corticotrophs- secretes ACTH (adrenocorticotropic hormone)
- Thyrotrophs- secretes TSH (thyroid stimulating hormone)
- Lactotrophs- secretes PRL (prolactic)
- Gonadotrophs- secrete LH (luteinizing hormone) and FSH (follicle-stimulating hormone)
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What must be done if a patient's TSH level is elevated?
Meds must be increased because thyroid is not working
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What are 4 characteristics of growth hormones (GH)?
- AKA somatotropin (STH)
- Promotes bone growth
- Stimulates fat metabolism
- Increases blood glucose levels
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What is prolactin's (PRL) claim to fame?
promotes development of the breasts to anticipate milk secretion during pregnancy
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ACTH is responsible for:
homeostasis and fluid balance
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What are considered the mind and body links?
- Pituitary and hypothalmus
- Hypothalmus translates nerve impulses into hormone secretions by pituitary
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Increased stress has what effect on immunity?
Decreases
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Adrenal cortex produces which increases water retention and ultimately BP.
aldosterone
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Aldosterone is a type of:
mineralocorticoids
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Main glucocorticoids:
- maintain blood sugar & BP and norepinephrine & epinephrine productions.
- Affects every cell in the body
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Adrenal medulla contains:
neurosecretory tissue- composed of neurons specialized to secrete their products into the blood.
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What is the only organ composed of both endocrine and exocrine tissues?
Pancreas
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Alpha cells secrete:
glucagon
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Beta cells secrete:
Insulin
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What accounts for 75% of all pancreatic islet cells?
Beta cells
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Delta cells secrete:
somatostatin
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What is the most common use for somatostatin?
cancer that causes fluid imbalance
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What does glucagon do?
- increase blood sugar levels
- stimulates gluconeogenesis in liver cells
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What does insulin do?
lowers blood sugar levels
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Name 2 characteristics of testosterone?
- produced by the testes
- regulated by gonadotropin levels in blood
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What are the primary sex organs in the female?
ovaries
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Ovaries produce:
estrogen and progesterone
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What organ serves as a temporary endocrine gland?
Placenta
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What is true of the thymus?
- Larger in children
- produces thymosin which stimulates development of T cells
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Cells in the mucosal lining of the GI tract:
produce both endocrine and exocrine secretions
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What is grehlin?
- hormone secreted by endocrine cells in gastric mucosa
- stimulates hypothalamus to boost appetite
- slows metabolism and fat burning (may contribute to obesity)
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2 characteristics of the heart:
- Secondary endocrine role
- produce atrial natriuretic hormone (ANH)
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ANH's primary effect is to oppose:
- increases in blood volume/ pressure.
- Also an antagonist to ADH and aldosterone
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