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141 Cards in this Set
- Front
- Back
How does the endocrine system influence cells?
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by releasing hormones into the blood
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What does the brain do other than regulate organ systems?(4)
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-Integration of senses (sight, smell, hearing)
-Emotions, thoughts, memories, dreams -able to devise complex technology -is ignorant of itself (we have no idea how our brain works!) |
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What are the general fxns of the nervous system? (4)
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-Sensory input
-Integration -Motor output -Has ability to store experiences (memory) and learn |
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2 main divisions of Nervous System. . .
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CNS - brain & spinal cord
PNS - everything else |
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2 divisions of PNS
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-Sensory (afferent)
-Motor (efferent) |
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2 divisions of efferent
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Somatic Nervous System
Autonomic Nervous System |
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2 divisions of Autonomic NS
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Sympathetic NS
Parasympathetic NS |
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Another word for Sympathetic NS?
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fight or flight
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Another word for Parasympathetic NS?
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rest and digest
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What does the somatic division do?
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conveys impulses to skeletal muscle
VOLUNTARY CONTROL |
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What does the autonomic division do?
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carries impulses to smooth and cardiac muscles & glands
INVOLUNTARY CONTROL |
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What is a neuroglial cell?
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nonexcitable cell that supports, insulates and protects
reproduces throughout life don't transmit electrical impulses |
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What is a neuron?
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excitable nerve cells that recieve and transmit electrical impulses
Amitotic |
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What does a neuron depend on?
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oxgenated blood supply
b/c: -can't store glycogen -can't use anaerobic metabolism |
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Neurons have 2 common features, what are they?
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-Cell body (soma)
-Processes (dendrites, axon) |
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What are the 2 common features of the neuron?
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Cell body (soma)
Processes (dendrites & axon) |
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What is a soma?
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an enlarged portion of the neuron containing the nucleus
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What are processes of the neuron?
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fibers extending from the cell body
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-"recieving end" of neuron
-recieve signals from other neurons & transmits them to cell body -neurons may have hundreds |
Dendrites
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-generates and transmits nerve impulses away from cell body
-neurons usually only have 1 -may be microscopic to 4 ft long |
Axon
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Distal end of axon branches profusely into
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axonal terminals
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when impulses reach axonal terminals they stimulate the release of chemicals called
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neurotransmitters (secreted into extracellular space)
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axon terminal is seperated from the next neuron or effector by
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a tiny gap & synaptic cleft (neurons don't touch eachother)
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the junction between neurons is called
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a synapse
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most axons are
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myelinated
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white, fatty sheath covering axons
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myelin sheath
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what does the myelin sheath do?
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-protects and insulates neurons from other neurons
-speeds transmission rate of nerve impulse |
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gaps in the myelin sheath r called
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Nodes of Ranvier
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myeling sheath around axons r destroyed; they become sclerotic (hardened & nonfunctional; ability to use muscles lost; autoimmune disease; PRO in myelin sheath is attacked; not curable
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Multiple Sclerosis
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What can help multiple scerosis?
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oral doses of bovine myelin
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a cluster of cell bodies in the CNS
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nucleus
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a cluster of cell bodies in the PNS
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ganglion
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cluster of fibers in the CNS
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tract
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cluster of fibers in the PNS
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nerve
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cell body is damaged when cell body dies because
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neurons don't go through cell division
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a collection of myelinated fibers (a tract)
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white matter
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a collection of cell bodies & myelinated fibers
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gray matter
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a nerve impulse causes a
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muscle action potential
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what are the steps to a muscle action potential?
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1) release of acetylcholine
-arrival of the acion potential causes exocytosis of synaptic cleft -liberating Ach, which diffuses across cleft 2)Activation of Ach receptors -Ach binds to its receptor -Na+ channels in sarcolemma open and Na rushes into the muscle 3)Production of muscle action potential -influx of Na+ causes depolarization of the muscle cell -triggers a muscle action potential & contraction 4)Termination of Ach activity -Ach is rapidly broken down by an enzyme called Acetylcholinesterase (AChE) which is present in the synaptic cleft |
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Several drugs & toxins block events in the . . .
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Neuromuscular Junction (NMJ)
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One of the most lethal chemicals known; produced by bacteria that proliferates in improperly canned foods; blocks exocytosis of synaptic vesicles at the NMJ; Ach isn't released, muscle contraction doesn't occur; tiny amts cause death by paralyzing the diaphragm
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Butulinium Toxin
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How does botulinium Toxin kill you?
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It blocks exocytosis of synaptic vesicles @ the NMJ; Ach isn't released so muscle contraction doesn't occur; will easily paralyze your diaphram and you will suffocate
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a plant derivative; is used by South American Indians on darts; binds to and blocks the Ach receptor but sarcolemma premeability to Na isn't changed; no influx of Na+, no muscle contraction; paralysis; often used during surgery to relax muscles
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Curare
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autpimmune disease; antibodies bind to and block Ach receptors; causes shortage of functional Ach receptors @ the motor end plate; as disease progresses more Ach receptors are affected; muscles become increasingly weaker and may stop functioning; death may occur due to paralysis of the respiratory muscles
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Myasthenia Gravis
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Which disease is derived from a plant?
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Curare
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Inhibits acetylcholinesterase; it slows removal of Ach from the synaptic cleft so more Ach is available to bind with receptors
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Anticholinesterase agents
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What do anticholinesterase agents do?
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1) treats Myasthenia gravis
2) reversal of curare poisoning |
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what is a reflex arc?
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the neural pathway over which a reflex occurs
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Simple reflex arc
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1) receptor
2) sensory (afferent) neuron 3) integration center (CNS) 4) motor (efferent) neuron 5) effector organ |
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when the reflux activates skeletal muscle it is a ________ reflex
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somatic
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when the reflux activates smooth or cardiac muscles or glands r activated it is a _______ reflex
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autonomic (visceral) reflex
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What r nerves?
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-a bundle of nerve fibers (axons) w/ their CT wrappings
-found outside CNS |
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what is are mixed nerves?
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both motory and sensory fibers
(they go both directions) |
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what do the nervous and endocrine systems do together?
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they regulate functions of other body systems by chemical means
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Hormones travel everywhere blood goes. . .what does that mean?
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they're nonspecific
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secrete their products through a duct onto a body surface; "secretions" NOT hormones; ex: mucous, seat, oil, saliva etc)
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exocrine glands
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r ductless, secrete hormones into surrounding tissure fluid; have a rich vascualr supply to recieve hormones
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endocrine glands
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What's a hormone?
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a chemical messenger secretes into the extracellular fluid and then picked up by the blood
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What do hormones do?
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regulate the metabolic functions of he cells throughout the body
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What r the 2 major types of hormone?
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1) amino acid based hormones
2) steroid hormones |
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may be simple amino acid derivatives, peptides or PRO
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amino acid based hormone
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made from cholesterol; sex hormones (gonadal), the hormones produced by the adrenal cortex
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steroid hormones
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Hormones circulate through the blood but only affect certain tissue cells or organs called
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target cells or target organs
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the target cell/organ must have a specific PRO recepto for that hormone, either . . .
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-on its plasma membrane
-in its interior |
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When hormone binds to its target it. . . .
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alters the cells activity
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What are the ways hormones change cell activity? (4)
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1) changes in plasme membrane permeabilty or electrical state
2) synthesis of PRO or NZs in cell 3) activation/inactivation of NZs 4) stimulation of mitosis |
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Steroid Hormone Action
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-diffuse through plasma membrane
-enter nucleus -bind to specific receptor PRO -hormone & receptor then bind to specific sites on DNA -activates certain genes to transcribe mRna -mRna moves to cytoplasm resulting in the synthesis of new PRO |
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Amino Acid Based Hormone Action
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-bind to their specific recepto PRO in the plasma membrane
-this causes an NZ to be activated -which catalyzes a Rxn that produces a 2nd messenger inside the cell -causes additional intracellular changes |
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Blood levels of hormones are regulated by
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Negative feedback mechanisms
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3 types of stimuli that activate endocrine organs. . .
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1) hormonal stimuli
2) humoral stimuli 3) neural stimuli |
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Hormonal Stimuli
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-hormones from other gland stimulate an endocrine gland
-many hypothalamic hormones stimulate the pituitary |
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Humoral Stimuli
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-changing blood levels of nutrients and some ions
-low blood Ca levels causes the parathyroid gland to secrete |
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Neural Stimuli
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some endocrine glands r stimulated by nerves to secrete
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What are the 2 hormones the hypthalamus synthesizes?
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1) Oxytocin
2) Antidiuretic Hormone |
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Oxytocin and ADH hormone are stored and released from the
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posterior lobe of the pituitary gland
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Which hormone is only released during childbirth & in nursing women?
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Oxytocin
- Uterus (stimulates labor contractions) - Breasts (initiates milk ejection) |
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The target organ for ADH is
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the kidneys
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pea-shaped gland hanging by a stalk from the hypothalamus; Suspended in the sella tursica of the sphenoid bone
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Pituitary Gland
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what does the posterior pituitary lobe do?
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stores and releases hypothalamic homrones
-not a true gland b/c it doesn't synthesize hormones |
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What does the anterior pituitary lobe do?
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synthesizes and secretes 6 hormones
-all r PRO -all r regulated by hormonal stimuli & usually by neg. feedback |
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What r the 4 tropic hormones of the pituitary gland?
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1) thyroid stimulating hormone (TSH) or Thyrotropin
2) Adrenocorticotropic Hormone (ACTH) 3) Follicle Stimulating Hormone (FSH) 4) Luteinizing Hormone (LH) |
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-Thyrotropic
-Stimulates growth & activity of the thyroid |
TSH - Thyroid Stimulating Hormone or thyrotropin
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-Corticotropic
-Stimulates the adrenal cortex to release corticosteroids |
ACTH - Adrenocorticotropic Hormone
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-Gonadotropic
-Stimulates te gonads (ovaries & testes) |
FSH - Follicle Stimulating Hormone
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What does FSH stimulate in the ovaries?
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-Stimulates follicle maturation & ovulation
-follicle produces estrogen |
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What does FSH stimulate in the testes?
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Sperm production
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Luteinizing Hormones are
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Gonadotropic
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What does LH do for the ovaries?
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-Promotes estrogen & progesterone production & secretion
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What does LH do for teh testes?
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-Stimulates testosterone secretion
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Hyposecretion of Growth Hormone or Somatotropin during childhood causes. . .
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dwarfism
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Hypersecretion of GH or Somatotropin causes . . .
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Gigantism
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Hypersecretion of GH or Somatotropin in adults causes. . .
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Acromegaly
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Hypersecretion of GH or Somatotropin usually results from
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a tumor in the organ
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What are the 2 non-tropin hormones in the pituitary gland?
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1) growth Hormone (GH) or Somatotropin
2) Prolactin |
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What are the major targets of GH?
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-Bones - long bone growth (epiphyseal plate)
-Skeletal muscles - increased muscle mass |
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What does prolactin stimulate?
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milk production
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When is prolactin stimulated?
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secretes immediatley after child birth & while nursing
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What does the thyroid gland secrete?
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thyroid hormone
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What kind of hormone are GH and Prolactin?
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PRO hormones
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what happens when you have hypthyroidism?
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-physical/mental sluggishness
-low body temp treatment - oral doses of thyroxin |
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What happens if you have hyperthyroidism?
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-high metabolic rate
-weight loss -nervous, agitated, hot -rapid heart rate |
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What is the treatment for hyperthyroidism?
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-removal of part of the thyroid
-administer radioactive iodine to destroy cells |
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Thyroid gland secretes. .
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-thyroid hormone
-calcitonin |
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Calcitonin is secreted in response to
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-high blood Ca levels
-causes Ca to be deposited to bones -may be diminished in the aged |
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Where is the parathyroid gland located?
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behind the thyroid
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Which hormone does the parathyroid secrete?
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Parathyroid hormone
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What does parathyroid hormone or parathormone do?
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increases blood Ca levels
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What does parathyroid hormone stimulate?
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-osteoclasts to resorb bone & releas Ca to blood
-kidneys to inhibit urinary Ca excretion -Intestinal cells to increase absorption of Ca |
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What is the inner region of the Adrenal glands called?
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adrenal medulla
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What is the outer region of the adrenal glands called?
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adrenal cortex
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The adrenal cortex stimulates how many steroid hormones?
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25+
-which are called corticosteroids -derived from cholesterol |
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3 categories of coticosteroids
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-Mineralcoticoids
-Glucocorticoids -Gonadocorticoids |
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Mineralcorticoids are secreted when. . .
And stimulates. . . |
Na blood level is low
stimulates kidneys -promote Na retention -increase water retention -promotes K secretion |
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Principal hormone for mineralcoticoids is
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Aldosterone
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Glucocorticoids are secreted. . .
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In response to ACTH & to stress
-causes rise in blood levels of glucose and fatty acids -encourages use of fats for NRG needs -Saves glucose for brain -anti-inflammatory effects |
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What r the principal hormones for glucocorticoids?
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-Cortisol
-Corisone |
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Gonadocorticoids are
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weak sex hormones, mainly androgens
-amts. insignificant FXN UNCLEAR |
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Pancrea is located
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below and behind the stomach
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Endocrine cell clusters are called
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Pancreatic islets
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Pancreas secretes 5 pancreatic hormones but the 2 most important are:
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-Insulin
-Glucagon |
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Insulin is secreted by
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Beta Cells
-in response to a "fed" state -stimulates transport of glucose into cells -lowers blood glucose |
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Glucagon is secreted by
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Alpha cells
-in response to "fasting" state -stimulates fat breakdown & release into the blood -increase blood glucose levels |
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Gonads secrete. . .
and fxn @. . . |
steroid sex hormones
Puberty |
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Steroid sex hormones are stimulated by
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gonadotropic hormone from the anterior pituitary (FSH/LH)
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Pineal Gland is located
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in the center of the brain
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Main secretion of pineal gland is
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Melatonin
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Melatonin
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FXn unclear
blood levels peak at night -large in children, shrinks as we age |
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Thymus gland is located under
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the sternum
-large in children & reduces with age |
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The main hormone secreted by the thymus is
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Thymosin
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Thymosin is
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essential for normal immune response
-regulates activation of T lymphocytes (disease fighting blood cells) |
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According to structure what are the 3 types of neurons?
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-multipolar
-bipolar -unipolar |
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According to FXN, what are the 3 types of neurons?
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-afferent
-efferent -interneurons |
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Neurons are:
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-irritable (rspond to a stimulus)
-conductive (conduct electrical impulse down the axon -secretory (secrete chemicals) |
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saltatory conduction is when
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action potentials jump over myelin (node to node)
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When axons are unmyelinated it makes conduction
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much slower
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Skeletal muscles must be
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-innervated
-stimulated by a motor neuron |
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the NMJ synapse is between
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a somatic motor neuron & muscle fiber
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Axon terminal contains
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tiny synaptic vesicles
-membrane-bound sacs -contain the neurotransmitter |
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The neurotransmitter at the NMJ is
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Acetylcholine
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What does the adrenal medulla secrete?
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epinephrine and noneepinephrine
|
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What do epinephrine and nonepinephrine do?
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-increse blood glucose levels
-increse heart rate -blood vessels constrict, diveting blood from nonessential organs TObrain, heart & skeletal muscle |