ch 45 post class assignment

During contraction specific regions and subunits of the sarcomere remain unchanged while others do not. From the list below identify the structures and regions that remain constant. 1. A band 2. Actin 3. H zone 4. I band 5 Myosin 6. Z line

1, 2, 5, 6

During contraction specific regions and subunits of the sarcomere remain unchanged while others do not. From the list below, identify the structures and regions that shorten during muscle contraction. 1. A band 2. Actin 3. H zone 4. I band 5 Myosin 6. Z line

3, 4

If you had a sacromere that was composed of 16 myosin heads, after two cycles of contraction how many ATP molecules would be consumed?

32

In an experiment you, the researcher, removes ATP from the system. What would be a likely consequence of the lack of ATP on muscle contraction?

In an experiment you, the researcher, removes ATP from the system. What would be a likely consequence of the lack of ATP on muscle contraction?

In an experiment you, the researcher, removes calcium ions from the system. What would be a likely consequence of the lack of calcium on muscle contraction?

Muscle contraction would not occur because the tropomyosin filament on the actin molecule would block myosin binding sites preventing the formation of cross bridges.

Curare, a poison from a South American shrub, blocks the binding of ACh by muscle cells. What would happen to muscle function if a toxic dose of curare entered the bloodstream?

Paralysis: Action potentials would be impeded at the neuromuscular junction, and the nerve would be unable to trigger the muscle to act.

You are a medical doctor and have a patient in their 50s. The patient is concerned about osteoporosis. What would you suggest as a preventative treatment?

Physical activity along with dietary supplements to provide nutrients

You are describing the role(s) muscle plays in the movement of joints. What does an accurate description include?

Tendons connect muscle to bone. Muscles may pull bones away from or toward one another. The movement of one muscle can be counteracted by the movement of another muscle.

If you were running an experiment and interrupted the interaction between thin and thick filaments, what would be the most likely result on sarcomere contraction?

The sarcomere would not be able to contract therefore the H zone and I band would remain the same in size.

The animation suggests that young women should engage in activities that are weight bearing. What is the benefit of this type of exercise in terms of osteoporosis?

The weight-bearing exercises stress bones and will encourage higher bone density.

Bones in the legs, arms, spine, and pelvis grow

at different rates.

Regarding wings and the lift that is created to produce flight, it is accurate to state that

body size may increase to a point at which it is no longer possible to produce lift. wings are modified forelimbs.

Muscle samples are taken from two groups of men. One group performs regular intense aerobic exercise. The second group is sedentary and does not exercise. When you compare their muscle samples at the microscopic level, you expect to find that the exercising men show greater

capillary density. numbers of mitochondria.

Arthropod exoskeletons are composed primarily of

chitin

Distinguish between the characteristics of each muscle category.

come back after

Match each symptom to the corresponding musculoskeletal disease.

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Distinguish between skeletal muscle fiber types by matching each characteristic to the fiber type it describes. slow-oxidative fibers fast-oxidative fibers fast- glycolytic fibers

come back later

Match each feature to the appropriate skeleton type. Exoskeleton Endoskeleton Hydrostatic skeleton

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Place each locomotion characteristic into the appropriate environment.

come back later

Determine the division of the skeleton to which each bone belongs. Appendicular skeleton Axial skeleton

come back pater

Friction is a more significant obstacle to overcome for locomotion in a terrestrial environment than gravity.

false

Weight bearing activities do not create enough stress to result in bone growth.

false

Factors that may have contributed to the formation of structures used for locomotion include

friction gravity type of environment where organism lives buoyancy

The important function(s) of the skeletal system include

production of blood cells. structural support. locomotion. reservoir for ions.

Which of the following statements about H zones and I bands is TRUE?

the H zones contain only myosin, while the I bands contain only actin

When describing the composition of vertebrate bone, it is accurate to say that

the ratio of organic and mineral components must be in homeostatic balance.

An accurate characterization of calcium's role in muscle contraction would state that

the release of Ca2+ from the sarcoplasmic reticulum is stimulated by a nerve impulse. Ca2+ ultimately allows contractions to occur by facilitating the binding of actin and myosin.

Both myasthenia gravis and muscular dystrophy are autoimmune diseases, but differ in that

the signs and symptoms of MG are not usually apparent until adolescence; those of MD become evident at about 2 to 6 years of age.

During contraction of a muscle, calcium ions bind to...

the troponin molecule.

What is the role of calcium in muscle contractions?

to bind with troponin, changing its shape so that binding sites on the actin filament are exposed

In an aquatic environment, gravity decreases but friction increases compared to a terrestrial environment.

true

In order for locomotion to occur, friction and gravity are both required.

true

The sequence of cross-bridge formation and myofilament movement will be repeated as long as calcium ions are present.

true

When joint movement is the result of antagonistic muscle pairing,

two muscles pull on the joint in opposite directions.

Muscle contraction is caused by

actin filaments sliding past myosin filaments.