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physiology exam 2
| Question | Answer |
|---|---|
| describe skeletal muscle | voluntary, multinucleated, striated |
| describe cardiac muscle | intercalated discs, single nucleus, striated, nonvoluntary |
| describe smooth muscle | no striations, nonvoluntary, single nucleus |
| run length of the cell, bundle of thick and thin fibers | myofibrils |
| repeating units of myofilaments (functional unit of skeletal muscle( | sarcomere |
| thick filaments | myosin |
| thin filaments | actin |
| 2 parts of actin | troponin and tropomyosin |
| which bands get reduced during skeletal muscle contraction | I band and H band |
| area where thick and thin filaments do not overlap | H band |
| area where thick and thin filaments overlap | A band |
| area in the middle of the A band | M line |
| bindline between two thin filaments | Z line |
| what does troponin do | binds to both tropomyosin and actin, has a Ca2+ binding site, when Calcium binds there tropomyosin gets moved out of the way of actins myosin binding site |
| what does tropomyosin do | binds to actin and covers myosin binding sites (troponin keeps tropomyosin in place) |
| globular molecule arranged as 2 twisted chains, each molecule has one binding site for myosin | actin |
| complex molecule with many molecules, each molecules has 2 twisted cables with a tail and a head | myosin |
| the activation of the force generating sites within muscle fibers | contraction |
| following contraction, the mechanisms that generate force are turned off and tension declines | relaxation |
| the neurons whose actions innervated skeletal muscle fibers are | alpha motor neurons |
| cell bodies of motor neurons are located | in the brain and spinal cord |
| are the axons of motor neurons myelinated | yes |
| a single motor neuron innervates many muscle fibers T or F | T |
| each muscle fiber is controlled by a branch from multiple motor neurons T or F | F |
| together a motor neuron and the muscle fibers it innervates | motor unit |
| region of the muscle fiber plasma membrane that lies directly under the terminal portion of the axon | motor end plate |
| junction of an axon terminal with the motor end plate | neuromuscular junction |
| low Ca = | relaxed muscle |
| high Ca = | activated muscle |
| explain excitation contraction coupling | action potential flows into t-tubules causes the dihydropyridine receptor to activate the ryanodine receptor, Ca flows out from SR, Ca binds to troponin causing tropomyosin to stop blocking actin. myosin binds to actin, Ca is transported back into the SR |
| sequence of events that occur b/w the time a cross-bridge binds to a thin filament, moves, and repeats | cross bridge cycle |
| describe the cross bridge cycle | actin and myosin tightly joined, ATP binds to myosin head. ATP hydrolysis (ADP and P released) energizes myosin cross bridge, energized cross bridge can now bind to actin, calcium binds to troponin. ADP and P released and cross bridge moves. |
| two functions of ATP in the cross bridge cycle | energy released from ATP hydrolysis provides the energy for cross-bridge movement, ATP binding to myosin breaks the link b/w actin and myosin during the cycle |
| roles of myosin in muscle contraction | 1. myosin release of actin 2. energy for cross-bridge movement 3. removal of Ca from troponin 4. Na/K pump |
| 3 ways ATP is produced in skeletal muscle | creatine phosphate, oxidative phosphorylation, glycolysis |
| describe creatine phosphate | stored in muscle, donates P to create ATP, creatine left over |
| describe glycolysis | glucose from blood + glycogen from the body creates ATP. By products are lactic acid and oxidative phosphorylation |
| describe oxidative phosphorylation | uses ox, fatty acids, and amino acids to create ATP |
| first way ATP is produced in the muscle | creatine phosphate |
| where does creatine phosphate take place | cytosol |
| where does oxidative phosphorylation take place | mitochondria |
| how many ATP molecules are produced in OP | 64 (36)for 1 glucose |
| how many ATP molecules are produced in glycolysis | 2 ATP for 1 glucose used |
| where does glycolysis occur | cytosol |
| which types of ATP synthesis in skeletal muscle are anaerobic and aerobic | glycolysis - anaerobic, OP and CP are aerobic |
| 3 types of skeletal muscle fiber | Slow Oxidative (SO), fast oxidative-glycolytic (FOG), fast glycolytic (FG) |
| which type of muscle fiber is good for posture and antigravity | slow oxidative |
| which type of muscle fiber is good for aerobic exercise activities | Fast oxidative glycolytic |
| which type of muscle fiber is good for high power activities | fast glycolytic |
| endurance training develops what type of muscle | oxidative/red muscle - adds myoglobin, mitochondria and capillaries |
| weight lifting develops what type of muscle | glycolytic/white muscle -stimulates glycogen storage, stimulates glycolytic enzymes, increases actin and myosin filaments |
| motor unit size smallest to largest | SO, FOG, FG |
| whole muscle tension is determined by: | force developed in single muscle fibers and the total number of muscle fibers contracting at once |
| force developed in a single muscle fiber can be determined by: | # of action potentials, fiber lengths, fiber diameter or type, state of fatique |
| the total number of muscle fibers contracting at once can be determined by | motor unit size - legs have more muscle fibers that innervate = contracts more |
| where can smooth muscle be found | walls around cavities, tubes, and iris of eye |
| what are thick and thin filaments held in place by in smooth muscle | dense bodies |
| characteristics of smooth muscle | spindle shaped, interconnected, no t-tubules, no troponin, poorly developed SR so relies on Ca from both inside and outside the cell |
| what is smooth muscle innervated by | the symp and parasymp |
| steps in smooth muscle contraction | Symp and parasymp release NT's, NT's bind to Na ligand gated ion channel depol membrane, triggers opening of Ca channels, Ca binds to calmodulin and activates it, calmodulin activates myosin light chain kinase, MLCK uses ATP to phosphorylate myosin, cbc |
| smooth muscle can also be activated by | hormones, nitric oxide, and paracrine substances |
| in smooth muscle action potentials are mediated by - | Ca not Na like skeletal muscle |
| main neurotransmitter in skeletal muscle | ACh |
| main neurotransmitter in smooth muscle | ACh, NE, Epi |
| major functions of hormones | maintain homeostasis, coordinate growth and development, assure reproduction |
| secretion of an endocrine gland or cell that is carried by the blood to a target cell with specific receptor for it | hormone |
| hormones can structurally be | steroids, amino acids, or proteins |
| exocrine vs endocrine secretions | exocrine - exit the body or connect to the lumen endocrine- enter interstitial fluid and diffuse into the blood |
| 3 paths of endocrine hormones | hormone circulating blood - excreted in urine or feces, inactivated by metabolism, or activated by metabolism, target cells |
| relate hormones from the hypothalamus and posterior pituitary gland | hormones produced in hypothalamus but released and stored from posterior pituitary gland |
| 2 posterior pituitary hormones | ADH (vasopressin) and Oxytocin |
| what does ADH hormone do | stimulates water reabsorption in kidney tubules and collecting ducts, stimulates constriction of smooth muscle cells in arterioles (increased BP) |
| what does oxytocin do | stimulates uterine contractions during labor, stimulates smooth muscle contractions in mammary glands during lactation |
| how are hormones released from the anterior pituitary gland | hormones travels from hypothalamus via hypothalamo-pituitary portal vessles |
| hormone secretion by the anterior pituitary gland is controlled by | hypophysiotropic hormones released by hypothalamic neurons, and reach the APG by way of the hypothalamo-hypophyseal, the portal vessels, the hypophysiotropic hormones stimulate the anterior pituitary cells to release their hormones |
| hormone system for cortisol | 1. hypothalamus releases CRH, ant pit. releases ACTH, adrenal cortex releases cortisol |
| effects of cortisol | stimulates adrenal cortex to secrete: glucocorticoids |
| production of cortisol increased during: | stress |
| excessive amounts of cortisol can lead to: | loss of protein, strength, ability to heal, and reduced immune system function |
| adrenal hormones released from the medulla | epinephrine and norepinephrine (sympathetic system) |
| what do epinephrine and norepinephrine increase | respiratory rate, heart, blood flow, synthesis of new glucose, promotes lipolysis |
| a disease that is caused by high cortisol | Cushing's disease (usually due to an ACTH secreting tumor of the anterior pituitary gland) |
| symptoms of Cushing's disease | uncontrolled metabolism, loss of bone mass, muscle mass, skin becomes thin and easily bruised, immunosuppression, redistribution of fat (face, trunk, back of neck), high blood pressure |
| a tumor that causes high ACTH secretion would effect what else in the system of cortisol production | high cortisol but low CRH |
| thyroid hormone required for | development of nervous system and normal adult mental activity |
| what happens to cortisol secretion if CRH is low | cortisol secretion will be low |
| what happens to CRH secretion if cortisol is low | will increase |
| what happens to ACTH secretion when cortisol is high | will decrease |
| pathway of thyroid hormone secretion | hypothalamus - TRH Anterior pituitary gland - TSH Thyroid gland - TH (thyroid hormone) |
| what does TH stimulate | metabolic rate via oxidative phosphorylation |
| what does TH increase | rate of activity of mitochondria, O2 consumption, glucose metabolism, promotes growth, rate of protein synthesis |
| high TH levels | hyperthyroidism |
| low TH levels | hypothyroidism |
| hyperthyroidism symptoms | wieght loss, increased appetite, increased sensitivity to heat, tachycardia, diarrhea, anxiety/irritability, increaed hair and nail growth/increased sweating |
| hypothyroidism symptoms | weight gain, decreased appetite, increased sensitivity to cold, bradycardia, constipation, fatigue/depression, hair loss and thin nails/dry skin |
| disease caused by hyperthyroidism | grave's disease |
| what is grave's disease | an autoimmune attack on the thyroid gland that leads to overproduction of thyroid horomones |
| iodine deficiency can cause | hypothyroidism |
| overstimulation of the thyroid gland can produce | goiters |
| a disease that can be caused by hypothyroidism | cretinism |
| what is cretenism | congenital iodin deficiency syndrome, a condition present at birth marked by impaired physical and mental development due to insufficient thyroid hormone production |
| how does increased TH effect epinephrine | causes increased epinephrine by putting more beta receptors on cells so that more epinephrine can bind |
| increased epinephrine causes | increased heart rate and blood pressure |
| why would beta blockers aid in the treatment of hyperthyroidism? | reduces the effects on the heart by blocking b cells |
| the name given to the repeating functional units that cause stritations in skeletal muscle myofibril is sarcomere | true |
| during skeletal muscle contraction, the distance b/w the z lines of a sarcomere decreases because of shorteing of the thick and thin filaments | false |
| during concentric contractions of skeletal muscle the I band and H zone shorten but the A stays the same | True |
| what protein is the principle component of skeletal muscle thick filaments | myosin |
| muscle cells divide to increase muscle size as one grows | false |
| troponin does what: | binds with calcium to allow sarcomere shortening |
| the energy for cross bridge cycling during muscle contraction is provided by | ATP |
| lactic acid is a waste product | glycolysis |
| this is the first from of metabolism used in a cell | creatine phosphate pathway |
| this is the most efficient type of metabolism | oxidative phosphorylation |
| this metabolism occurs in the mitochondria | oxidative phosphorylation |
| makes 2 ATP per glucose molecule | glycolysis |
| energy in a resting muscle is stored as ATP | false |
| glycolysis occurs in the cytosol | true |
| oxidative phosphorylation relies on O2, amino acid and proteins | true |
| increased calcium is a key step for excitation contraction coupling in | smooth and skeletal muscle |
| troponin is presents in what muscle | skeletal |
| uses atp to power cross bridge cycling : | skeletal and smooth |
| t-tubules present | skeletal |
| regulates blood flow and blood pressure because it makes the wall of blood | smooth |
| has dense bodies | smooth |
| relies on Ca from both inside and outside of the cell | smooth |
| has striations | skeletal |
| smaller motor units are associated with finer control of muscle tension, and coarse, powerful movements are associated with muscles with large motor units | true |
| you would find more FG fibers in the eye muscles compared to leg muscles | false |
| the force that a whole muscle (not a muscle fiber) exerts is based on | amount of motor units recruited, the stimulation frequency of each fiber, the total number of fibers contracting at once, and the state of fatique of individual muscle fibers |
| where would you not find smooth muscle: uterus, hands, bladder, iris of eye | hands |
| if the adrenal glands were removed from a patient, his plasma cortisol levels would ______, secretion of CRH by the _____ would _____, and secretion of ACTH by the ______ would _______ | decrease, hypothalamus would increase, and secretion of ACTH by the anterior pituitary gland would increase |
| cortisol is released from the cortex of the adrenal glands, and epinephrine and norepinephrine are released from the medulla | true |
| TH is produced by the thyroid gland but it gets stimulated by high levels of TSH in plasma | true |
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