Term
| List the anatomical components that make up a muscle fiber. |
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Definition
| Plasmalemma, Sarcolemma, Satellite Cells, Sarcoplasm, Transverse Tubules, Sarcoplasmic Reticulum, Myofibrils |
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Term
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Definition
| plasma membrane; part of the sarcolemma |
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Term
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Definition
| composed of the plasmalemma and the basement membrane |
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Term
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Definition
| btw. plasmalemma and basement membrane; involved in growth and development of skeletal muscle |
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Term
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Definition
| fluid part of muscle fiber; contains dissolved proteins, minerals, glycogen, fats, and necessary organelles |
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Term
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Definition
| extensions of the plasmalemma laterally through a muscle fiber; interconnected; allow nerve impulses to be transmitted to individual myofibrils |
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Term
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Definition
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Term
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Definition
| made up of basic contractile elements of skeletal muscle |
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Term
| Components of a motor unit |
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Definition
| The alpha motor neuron and all of the muscle fibers it innervates |
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Term
| What are the steps in excitation-contraction coupling? |
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Definition
1)Action potential (AP) starts in brain
2)AP arrives at axon terminal, releases acetylcholine (ACh)
3)ACh crosses synapse, binds to ACh receptors on plasmalemma
4)AP travels down plasmalemma, T-tubules
5)Triggers Ca2+ release from sarcoplasmic reticulum (SR)
6)Ca2+ enables actin-myosin contraction |
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Term
| What is the role of Ca2+ in muscle contraction? |
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Definition
| Ca2+ binds to troponin on the thin filament, Troponin-Ca2+ complex moves tropomyosin, Myosin binds to actin, Contraction can occur |
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Term
| Describe the sliding muscle filament theory. |
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Definition
1)Ca2+ binds to troponin
2)Troponin-Ca2+ moves tropomyosin out of the way
3)Myosin binds to actin
4)Myosin head pulls actin toward sarcomere center (power stroke)
5)Filaments slide past each other (sarcomeres, myofibrils, muscle fiber all shorten) |
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Term
| How do muscle fibers shorten? |
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Definition
| Filaments slide past each other |
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Term
| Characteristics of Type I muscle fibers |
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Definition
50% of fibers in ave. muscle, peak tension is 110ms (slow twitch), Slower myosin ATPase=slower contraction cycling,
less developed SR, smaller neuron (<300 fibers), high aerobic endurance, recruited for low-intensity aerobic activities, require O2 for ATP production, Efficiently produce ATP |
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Term
| Characteristics of Type II muscle fibers |
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Definition
| peak tension is 50ms (fast twitch), Fast myosin ATPase=fast contraction cycling, more highly developed SR, faster Ca2+ release, larger neuron (>300 fibers), fatigue quickly, Produce ATP anaerobically, Type IIa-more force, short, high-intensity endurance events, Type IIx-seldom used for everyday activities, short, explosive sprints |
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Term
| What is the role of genetics in determine the proportions of muscle fiber types and the potential for success in selected activities? |
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Definition
| Muscle fiber characteristics determined early in life; Alpha-motor neuron determines the muscle fiber type by innervating that muscle fiber; Type I fibers are more suited for prolonged endurance activities and Type II are better suited for high-intensity,short,explosive activities; Intermediate fibers are have the ability to shift to Type I/II based on training; Muscles lose type II motor units as we age |
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Term
| Describe the relationship btw. muscle force development and the recruitment of type I/II motor units |
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Definition
| Less force=fewer/smaller motor units; More force=more/larger motor units; Recruitment->type I->type IIa->type Iix |
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Term
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Definition
| Muscle shortens (sarcomere shortens, filaments slide toward center), joint movement is produced (dynamic contractions) |
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Term
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Definition
| Muscle lengthens (cross-bridges form, but sarcomere lengthens), joint movement (weight lifting->ex: lowering heavy weight) |
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Term
| Isometric/Static Contraction |
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Definition
| Muscle generates force, but length stays the same, joint angle doesn't change, myosin cross-bridges form and recycle-no sliding |
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Term
| What two mechanisms are used by the body to increase force production in a single muscle? |
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Definition
| Length-tension relationship and Speed-force relationship |
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Term
| Length-tension relationship |
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Definition
1)Optimal sarcomere length=optimal overlap
2)Too short or too stretched=little or no force develops |
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Term
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Definition
1)Concentric=max. force development decreases at higher speeds
2)Eccentric=max. force development increases at higher speeds |
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Term
| What is the optimal length of a muscle for maximal force development? |
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Definition
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Term
| What is the relation btw. maximum force development and the speed of shortening (concentric) and lengthening (eccentric) contractions? |
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Definition
| During concentric contractions, max. force development decreases progressively at high speeds. Eccentric contractions allow max. force development to increase progressively at low speeds. |
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Term
| What is ATP and how is it of importance in metabolism? |
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Definition
| ATP=adenosine triphosphate (high-energy compound). It is of importance in metabolism, because it is the useable storage form of energy we derive from food. |
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Term
| What is the primary substrate used to provide energy at rest? |
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Definition
| 50% carbohydrates and 50% fats at rest are used to provide energy |
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Term
| What is the primary substrate used to provide energy during high-intensity exercise? |
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Definition
| During high-intensity exercise we use more carbohydrates |
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Term
| What is the role of PCr in energy production? |
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Definition
| (PCr=phosphocreatine or creatine phosphate); PCr's role in energy production is to regenerate ATP to maintain a relatively constant supply under resting conditions, and recycle ATP during exercise until it's used up. |
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Term
| Describe the relationship btw. muscle ATP and PCr during sprint exercises. |
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Definition
| During a sprint exercise, ATP is at a constant level, PCr declines steadily, because it's used to replenish depleted ATP. |
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Term
| Describe the essential characteristics of the ATP-PCr system. |
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Definition
| Anaerobic, Substrate-level metabolism, 1mol ATP/1mol PCr, 3-15s, Replenishes ATP stores during rest, recycles ATP during exercise until used up, ATP decreases (ADP increases) PCr increases, ATP increases PCr decreases |
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Term
| Describe the essential characteristics of Glycolytic system (glycolysis) |
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Definition
| Anaerobic, 2-3mol ATP/1mol substrate, 15s-2min., breakdown of glucose via glycolysis, Use glucose (1ATP) or glycogen (0ATP) as substrate, starts w/glucose-6-phosphate ends w/pyruvic acid |
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Term
| Cons of the Glycolytic system (glycolysis) |
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Definition
| Low ATP yield, Pyruvic acid converted to Lactic Acid due to lack of O2, Lactic acid impairs glycolysis/muscle contraction |
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Term
| Pros of the Glycolytic system (glycolysis) |
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Definition
| O2 is limited-still allows muscle to contract, sustain short-term, higher-intensity exercise than oxidative metabolism |
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Term
| Describe the essential characteristics of the Oxidative system (oxidative phosphorylation) |
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Definition
| Aerobic, 32-33ATP/glucose, 100+ATP/1FFA, steady supply for hrs., most complex, occurs in Mitochondria |
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Term
| Why are the ATP-PCr and glycolytic energy systems considered anaerobic? |
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Definition
| Considered anaerobic, because they contribute energy during short-burst activities lasting up to 2min.and during the early min. of longer high-intensity exercise |
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Term
| What role does O2 play in the process of aerobic metabolism? |
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Definition
| O2 helps to breakdown substrates which intern provides more energy |
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Term
| Describe the by-products of energy production from the ATP-PCr system |
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Definition
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Term
| Describe the by-product of energy production from the Glycolysis system |
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Definition
| 2-3mol ATP/1 mol substrate (glucose/glycogen) |
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Term
| Describe the by-products of energy production from the Oxidative system |
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Definition
| 32-33mol ATP/1 glucose; 100+ATP/1 FFA |
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Term
| Describe the by-products of energy production from the Oxidative Glycolysis system |
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Definition
| ATP yield the same; In presence of O2 pyretic acid is converted to Acetyl CoA |
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Term
| Describe the by-products of energy production from the Oxidative Krebs-cycle system |
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Definition
1)1molecule glucose->2Acetyl CoA
2)1molecule glucose->2complete Krebs cycles
3)1molecule glucose->double ATP yield
4)2Acetyl CoA->2GTP->2ATP
5)NADH,FADH,H+ |
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Term
| Describe the by-products of energy production from the Oxidative Electron Transport Chain |
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Definition
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Term
| What is Lactic Acid and why is it important? |
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Definition
| Lactic Acid is converted from pyruvic acid. It inhibits muscle contraction |
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Term
| Discuss the interaction among the three energy systems w/respect to the rate at which energy can be produced and the sustained capacity to produce that energy. |
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Definition
1)ATP-PCr: 3-15s
2)Glycolysis: 15s-2min
3)Oxidative: 2min-long term exercise |
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Term
| How do type I muscle fibers differ from type II fibers in their respective oxidative capacities? What accounts for those differences? |
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Definition
| Type I fibers are more aerobic-have more mitochondria and higher concentrations of oxidative enzymes. Type II fibers are better suited for glycolytic energy production. Alpha neurons account for these differences |
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Term
| What are the major divisions of the nervous system? What are their major functions? |
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Definition
1)CNS (brain, spinal cord)
2)PNS - Sensory (afferent; incoming), Motor (efferent; outgoing), Somatic (voluntary, to skeletal muscle)
3)Autonomic - involuntary - to viscera (sympathetic/parasympathetic) |
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Term
| Name the different parts of a neuron |
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Definition
1) Cell body - contains nucleus, cell processes radiate out
2) Dendrites - receiver cell processes, carry impulse toward cell body
3) Axon - sender cell process, starts at the axon hillock, end branches, axon terminals, neurotransmitters |
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Term
| Explain the resting membrane potential |
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Definition
| The difference in electrical charges btw. outside and inside of cell (-70mV) |
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Term
| What causes the resting membrane potential? |
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Definition
| Uneven separation of charged ions (polarized) |
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Term
| How is the resting membrane potential maintained? |
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Definition
1) Permeability of the membrane - more permeable to K+ so it moves more freely
2) Na+/K+ pump - more Na+ on the inside of cells and more K+ on the outside of cell (3 Na+ out for every 2 K+ in) |
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Term
| Describe an action potential |
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Definition
| a rapid and substantial depolarization of the neuron's membrane |
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Term
| What is required before an AP is activated? |
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Definition
| Membrane depolarization must occur and threshold must be reached |
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Term
| Explain how an AP is transmitted from a presynaptic neuron to a post synaptic neuron |
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Definition
1) GP reaches threshold - AP occurs
2) Propagation occurs down axon
3) Reaches axon terminals
4) Synaptic vesicles release neurotransmitters into synaptic cleft
5) Diffuse across synaptic cleft to postsynaptic neurons receptors
6) Binds to postsynaptic receptors |
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Term
| Explain how an AP is transmitted from a presynaptic neuron to a post synaptic neuron |
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Definition
1) GP reaches threshold - AP occurs
2) Propagation occurs down axon
3) Reaches axon terminals
4) Synaptic vesicles release neurotransmitters into synaptic cleft
5) Diffuse across synaptic cleft to postsynaptic neurons receptors
6) Binds to postsynaptic receptors |
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Term
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Definition
| site at which a motor neuron communicates w/a muscle fiber |
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Term
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Definition
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Term
| What brain centers have major roles in controlling movement, and what are these roles? |
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Definition
1) Primary motor cortex (frontal lobe, conscious control of skeletal muscle movement)
2) Basal ganglia (cerebral white matter, help initiate sustained/repetitive movement)
3) Cerebellum (controls rapid and complex movement) |
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Term
| How do the sympathetic and parasympathetic systems differ? |
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Definition
| Sympathetic prepares body for exercise, while parasympathetic opposes sym. (rest/digest) |
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Term
| What is the sympathetic systems significant role in performing physical activity? |
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Definition
| Prepares the body for stress/physical activity and can sustain the body and it's function |
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Term
| What is the parasympathetics role in performing physical activity? |
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Definition
| Helps the body to rest after physical activity |
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Term
| Explain how reflex movement occurs in response to touching a hot object? |
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Definition
1) Stimulus sensed by sensory receptors
2) Sensory AP sent on sensory neurons to CNS
3) CNS interprets sensory info. sends out response
4) Motor AP sent out on alpha motor neuron
5) Motor AP arrives at ske |
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Term
| Describe the role of the muscle spindle in controlling muscle contraction |
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Definition
| Muscle spindle is innervated by gamma motor neurons. It synapses in the spinal cord w/an alpha motor neuron and triggers reflex muscle contraction. Helps to prevent further (damaging) stretch |
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Term
| Describe the role of the Golgi tendon organ in controlling muscle contraction |
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Definition
| When stimulated by excessive tension the golgi tendon organs inhibit agonists and excite antagonists to prevent excessive tension in muscle/tendon to reduce potential for injury |
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Term
| What is an endocrine gland, and what are the functions of hormones? |
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Definition
| Gland that secrets their hormones directly into the blood where they act as chemical signals throughout the body. Functions of hormones to regulate cell/organ activity |
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Term
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Definition
1) Derived from cholesterol, lipid soluble (diffuse through membrane)
2) Receptors are found inside cell (cytoplasm or nucleus)
3) Direct gene activation (Hormone - receptor binds to DNA)
4) Hormone receptor regulates mRNA synthesis (protein synthesis) |
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Term
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Definition
1) not lipid soluble (can't cross membrane)
2) Divided into 2 groups: Protein/peptide hormones-most non steroid hormones, from pancreas, hypothalamus, pituitary gland; A.A. derived hormones-thyroid hormones, adrenal medulla hormones (epinephrine, norepinephrine)
3) Receptors on cell membrane -> second messengers (carry out hormone effects, intensify strength of hormone signal)
4) Common second messengers (cyclic adenosine monophosphate, cyclic guanine monophosphate, Inostiol triphosphate, diacylglycerol) |
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Term
| How can hormones have very specific functions when they reach nearly all parts of the body through the blood? |
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Definition
| Because each cell has specific hormone receptors possessed by the target tissues so they can bind only specific hormones |
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Term
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Definition
| increase number of receptors during high plasma concentration = sensitization |
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Term
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Definition
| decrease the number of receptors during high plasma concentration = desensitization |
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Term
| How do target cells become less sensitive to hormones? |
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Definition
| an increased volume of a specific hormone decreases the number of cell receptors available to it. With fewer receptors there are fewer hormone molecules that can bind. |
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Term
| How do target cells become more sensitive to hormones? |
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Definition
| when there's a prolonged presence of large amounts of a hormone the number of available receptors increases |
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Term
| What are secondary messengers and what role do they play in hormonal control of cell function? |
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Definition
| signal relaying molecules that help intensify the strength of the signal. Can trigger numerous cellular processes |
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Term
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Definition
| stimulates fat metabolism |
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Term
| Triiodothyronine/Thyroxine |
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Definition
1) Increase FFA metabolism
2) Increase in metabolic rate of all tissues
3) Increase protein synthesis
4) Increase number and size of mitochondria
5) Increase glucose uptake by cells
6) Increase rate of glycolysis/gluconeogenesis |
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Term
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Definition
1) short term - stimulates T3/T4
2) Long term - decreases T4 |
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Term
| Epinephrine/Norepinephrine (catecholamines) |
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Definition
1) increase heart rate/contractile force/BP
2) Increase glycogenolysis/FFA
3) increase Blood flow to skeletal muscle |
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Term
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Definition
1) increase gluconeogenesis
2) Increase FFA mobilization/protein catabolism
3) anti - inflammatory, anti - immune |
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Term
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Definition
1) lowers blood glucose
2) increase glucose transport into cells
3) increase synthesis of glycogen, protein, fat, inhibits gluconeogenesis |
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Term
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Definition
| increase water reabsorption at kidneys |
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Term
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Definition
| 1) increase Na+ retention by kidneys/water retention via osmosis/ increase K+ excretion |
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Term
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Definition
| stimulates RBC production |
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Term
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Definition
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