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