Essentials of Anatomy & Physiology - Ch 7
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84 terms
Terms | Definitions |
|---|---|
 produce movement, maintain posture and position, support soft tissue, guard entrances and exits, maintain body temperature | What are the five functions of muscles? |
| 3 | How many layers of connective tissue make up the muscle? |
| epimysium, perimysium, endomysium | What are the three layers of connective tissue that make up the muscle? |
| epimysium | connective tissue that separates muscle from surrounding tissues and organs |
| perimysium | connective tissue that divides skeletal muscles into bundles of fibers called fascicles |
| endomysium | connective tissue that surrounds each skeletal muscle fiber and ties adjacent fibers together |
| fascicles | bundles of muscle fibers; made up of 10-100 muscle cells |
| fascicles | groups of _____________ make up muscles |
| tendon | all three layers of connective tissue come together at the end of the muscle to form a ______________ |
| skeletal, cardiac, smooth | three different types of muscle |
| produce movement and maintain body position | the two main functions of skeletal muscle |
| origin, insertion, belly | three parts of the larger muscle |
| origin | point of attachment of a muscle which does not change position when muscle contracts |
| insertion | point of attachment of a muscle; the end that is most movable |
| belly | the middle part of the larger muscle |
| sarcolemma | part of the muscle fiber; plasma membrane of cell |
| transverse tubules | channels that extend down into the muscle cells that carry electric signals from surface into the cell |
| sarcoplasmic reticulum | part of the muscle cell that stores calcium |
| myofibrils | bundles of threads within the muscle fiber that are responsible for contractions |
| sarcomeres | muscles cells are divided into sections called ____________ |
| shortens | muscle contraction occurs as the sarcomere __________ |
| thick filaments, thin filaments, z-discs | three elements that make up sarcomeres |
| z-discs | line the ends of sarcomeres |
| thick filament | thread that lies in the center of the sarcomere |
| thin filaments | twisted threads attached to the z-disc at either end of the sarcomere |
| active sites | areas along thin filaments normally covered by tropomyosin |
| cross bridge | formed when the active site of a thin filament is uncovered and the thick filament attached to active site |
| sliding filaments | principle where thin filaments move inward over thick filaments, pulling z-discs inward, and causing sarcomeres to shorten |
| contraction | this occurs when every single sarcomere shortens at the same time |
| excitation | first stage of contraction when and electrical impulse is sent and crosses from nerve to muscle at the neuromuscular junction |
| neuromuscular junction | communication between nervous system and skeletal muscle occurs here |
| acetylcholine | neurotransmitter that helps electric charge to pass from nerves to muscles |
| spreads down the sarcolemma and into the transverse tubules | What happens to the electrical signal in the first step of excitation? |
| transverse tubules carry the signal to the sarcoplasmic reticulum | During excitation, what happens after the electrical impulse reaches the transverse tubules? |
| sarcoplasmic reticulum releases calcium | During excitation, what happens when the electrical impulse reaches the sarcoplasmic reticulum? |
| active sites of the thin filaments are uncovered | During excitation, what happens once calcium is released? |
| contraction | repeating sequence of events that causes the thick and thin filaments to move past each other |
| exposure of active site, crossbridge formation, power stroke, crossbridge detachment, re-activation | What are the five steps of the contraction cycle? |
| crossbridge formation | During the contraction cycle, what happens once active sites are exposed on the thin filaments? |
| power stroke | During the contraction cycle, what happens after the thick filament attaches to the thin filament? |
| power stroke | the pulling of the active sites toward the middle of the sarcomere |
| crossbridge detachment | During the contraction cycle, what happens after the thick filaments attach and pull the thin filaments toward the center of the sarcomere? |
| ATP | During the contraction cycle, what is needed in order for crossbridge detachment to occur? |
| re-activation | What happens after the crossbridges detach? |
| re-activation | In this step of the contraction cycle, myofibrils reset and realign to prepare for another contraction. |
| muscle tone | resting tension of the muscle |
| muscle tone | involuntary contraction of small number of muscle cells that keeps the muscles firm when relaxed and allows for the maintenance of posture |
| atrophy | wasting away of muscles due muscles not being regularly stimulated |
| disuse atrophy | wasting away of muscles due to lack of use |
| denervation atrophy | wasting away of muscles due to nerve damage |
| connective tissue | in late stages of atrophy, muscle is converted to _________ and cannot be reversed |
| hypertrophy | increase in diameter of muscle fibers caused by forceful repetitive muscle activity |
| myofibrils, sarcoplasmic reticulum | hypertrophy is caused by an increase in the number of ___________ and ___________ in each cell |
| isotonic contraction | type of contraction that occurs when tension rises and skeletal muscle length changes |
| isotonic contraction | type of contraction that occurs while lifting, walking, or running |
| concentric | type of isotonic contraction where muscle shortens to produce movement |
| eccentric | type of isotonic contraction where muscle lengthens to maintain force and movement |
| isometric contraction | type of contraction where the muscle as a whole does not change length; the tension produced never exceeds resistance |
| isometric contraction | type of contraction that maintains posture and supports objects in a fixed position |
| ATP | muscles need ____________ to produce movement and activity |
| ATP, creatine phosphate, anaerobic cellular respiration, aerobic cellular respiration | What are the four sources of energy for muscles? |
| 2 seconds | Small amounts of ATP stored in the muscles will produce ____________ of muscle contraction. |
| creatine phosphate | chemical produced during energy transfer that can provide energy for the creation of ATP |
| creatine phosphate | energy stored in ____________ is used to recharge ADP back to ATP |
| 15 seconds | Creatine phosphate will produce __________ of muscle contraction. |
| glycolysis | the breakdown of glucose to pyruvic acid in the cytoplasm of the cell yielding ATP; occurs in the absence of oxygen |
| anaerobic cellular respiration | process that produces ATP in the absence of oxygen |
| 130 seconds | Glycolysis can produce ____________ of muscle contraction. |
| lactic acid | a toxic byproduct of glycolysis |
| lactic acid | excess levels of this chemical may lower pH and alter the normal functioning of key enzymes causing the muscle to no longer contract normally |
| muscle fatigue | a build up of lactic acid causes this condition |
| aerobic cellular respiration | process that produces ATP through mitochondria in oxygen-rich environment |
| aerobic cellular respiration | produces more ATP than any other method |
| 40 minutes | Aerobic cellular respiration can produce ____________ of muscle contraction. |
| anaerobic cellular respiration | If you have been contracting your muscles for two minutes, you are using ______________ to produce the contraction |
| aerobic cellular respiration | If you have been contracting your muscles for 30 minutes, you are using ______________ to produce the contraction |
| creatine phosphate | If you have been contracting your muscles for 8 seconds, you are using ____________ to produce the contraction |
| red muscle fibers | types of muscle fibers that contain more myglobin, blood vessels, and mitochondria producing longer contractions |
| red muscle fibers | types of muscle fibers that help to maintain posture |
| white muscle fibers | types of muscle fibers that contain less blood vessels and less mitochondria producing rapid, shorter contractions |
| white muscle fibers | types of muscle fibers that help move arms and legs |
| location, shape, action | muscles names are based on these three things |
| oxidative | types of red muscle fibers that use aerobic pathways |
| glycolytic | types of red muscle fibers that use anaerobic pathways |
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