Essentials Of A & P:chap 7 Muscular System

Front 1

Epimysium surrounds (fascia)

Back 1

skeletal muscle.

Hint 1

158

Front 2

Endomysium surrounds

Back 2

muscle fiber

Hint 2

158

Front 3

List characteristics of skeletal muscle

Back 3

1. Contractility-the ability of to shorten with force.
2. Excitability-the ability to respond to a stimulus.
3. Extensibility-stretchable
4. Elasticity-ability to recoil back to original position.

Hint 3

157-158

Front 4

muscle fasciculi

Back 4

a muscle composed of numerous visible bundles.

Hint 4

158

Front 5

perimysium

Back 5

loose connective tissue covering muscle fasciculi.

Hint 5

158

Front 6

A fasciculus is composed of

Back 6

several muscle cells or muscle fibers.

Hint 6

158

Front 7

sarcoplasm

Back 7

The cytoplasm of each muscle fiber.

Hint 7

158

Front 8

Sarcoplasm contains numerous

Back 8

myofibrils, which extends from one end of the muscle fiber to the other. The two major kind are actin and myosin myofilaments.

Hint 8

158

Front 9

Troponin molecules

Back 9

Attach at specific intervals along the actin myofilaments and provide calcium binding sites on the actin myofilament.

Hint 9

158

Front 10

Tropomyosin filaments

Back 10

Are located along the groove between the twisted strands of actin myofilament subunits. They expose attachment sites on the actin myofilament when calcium is bound to troponin, and they cover attachment sites of the actin myofilaments site for actin myofilaments.

Hint 10

158

Front 11

sarcolemma

Back 11

The cell membrane of the muscle fiber.

Hint 11

158

Front 12

transverse, or T tubules

Back 12

Are located at regular intervals along the muscle fiber and wrap around sarcomeres where the actin and myosin myofilaments overlap, The T tubules are associated with a highly organized, smooth endoplasmic reticulum called sarcoplasmic reticulm. T tubules connect the sarcolemma to the sarcoplasmic reticulum. The sarcoplasmic reticulum has relatively high concentration of calcium ions, which play a major role in muscle contractions.

Hint 12

158

Front 13

Resting membrane potential

Back 13

The charge difference across the membrane of a resting cell. The outside of most cell membranes is positively charged compared with the inside of the cell membrane.

Hint 13

158

Front 14

What are the two reasons for resting membrane potential?

Back 14

1. The concentration of K+ inside the cell membrane is higher than the outside the cell membrane.
2. The cell membrane is more permeable to K+ than it is to other ions, including negatively charged molecules, such as protein, located inside the cell. This occurs because some K+ channels are open, wheres as other ion channels, such as those for Na + are closed.

Hint 14

158

Front 15

action potential

Back 15

The rapid depolarization and repolarization of the cell membrane.
Depolarization when the Na+ channel is open briefly and a few positively Na+ diffuse down their concentration gradient into the cell, causing the inside of the cell membrane to become more positively charge than the outside.
Repolarization when the Na+ channels close and additional K+ channels open. Causing less Na+ to enter the cell and K+ to leave the cell. This causes the inside of the cell to become more negative than the outside once again.

Hint 15

160

Front 16

synapse

Back 16

The cell-to-cell junction between a nerve cell and either another nerve cell or an effector cell, such as a muscle or gland cell.

Hint 16

162

Front 17

presynaptic terminal

Back 17

An enlarged axon terminal.

Hint 17

162

Front 18

synaptic cleft

Back 18

The space between the presynaptic terminal and the muscle fiber membrane.

Hint 18

162

Front 19

postsynaptic membrane

Back 19

The muscle fiber membrane.

Hint 19

162

Front 20

synaptic vesicles

Back 20

small vesicles which contain acetylcholine, which functions as a neurotransmitter, a molecule released by a presynaptic nerve cell that stimulates or inhibits a postsynaptic cell.

Hint 20

162

Front 21

muscle twitch

define and list and explian in brief the three phases

Back 21

The contraction of a muscle fiber in response to a stimulus.
The three phases are lag phase, contraction phase, and relaxation phase.
The lag phase is the time between the application of a stimulus and the beginning of contraction. The contraction phase is the time of contraction, and the relaxation phase is the time during which the muscle relaxes.

Hint 21

167

Front 22

The force of contraction produced by a muscle is increased in two ways:

Back 22

1. summation, which involves increasing the force of contraction of the muscle fibers within the muscle and 2. recruitment, which involves increasing the number of muscle fiber contracting.

Hint 22

167

Front 23

Tetanus

Back 23

A sustained contraction that occurs when the frequency of stimulation is so rapid that there is no relaxation.

Hint 23

167

Front 24

Muscle fibers cannot stockpile ATP, however...

Back 24

muscle fiber can store another high-energy molecule, creatine phosphate, which provides a means of storing energy that can be used rapidly to help maintain an adequate amount of ATP in the contracting muscle fiber. This creatine phosphate is accessed quickly to produce ATP, which is used in muscle contraction and to restore ATP reserves.

Hint 24

168

Front 25

ATP is produced by both _________ and _______ _______ resptation.

Explain

Back 25

anaerobic and aerobic cellular respiration

Anaerobic respiration does not require O2, results in the breakdown of glucoses to yield ATP and lactic acid.
Aerobic respiration requires O2 and breaks down glucose to produce ATP, CO2, and H2O.

Hint 25

168

Front 26

psycholigical fatigue

Back 26

The most common type of fatigue, involves the CNS rather than the muscle themselves. The muscles are still able to contract, however the individual "perceives" that continued muscle contraction is impossible.

Hint 26

169

Front 27

muscle fatigue results when

Back 27

ATP is used during muscle contraction faster than it can be produced in the muscle fibers and lactic acid builds up faster than it can be removed. As a consequence, ATP falls too low for muscle fibers to produce their maximum force of contraction, and contractions become weaker and weaker.

Hint 27

169

Front 28

physiological contracture

Back 28

When there is too little ATP to bind to myosin myofilaments. Because binding of ATP to myosin heads is necessary for cross-bridge release between the actin and myosin, the cross-bridges between the actin and myosin myofilaments cannot be broken, and the muscle cannot relax.

Hint 28

169

Front 29

Explain the difference between isomertric or isotonic muscle contration

Back 29

In isometric contrations, the amount of tension increases during the contraction process, but the length of the muscle does not change. Isometric contractions are responsible for constant legth of the postural muscles of the body, such as the muscles of the back. (equal distance)

Isotonic contraction, the amount of tension produced by the muscle is constant during contraction, but the length of the muscle decreases. Movement of the arms or fingers are predominantly isotonic contraction. (equal tension)

Most muscle contraction are a combination of both in which the muscles shorten some distance and degree of tension increases.

Hint 29

169

Front 30

Muscle tone

Back 30

The constant tension produced by muscles of the body over long periods of time. It is responsible for keeping the back and legs straight, the head held upright, and the abdomen from bulging.

Hint 30

169