1. name three muscles in the upper body, and describe their location. (anterior, posterior, etc.)
2. what type of muscle tissue is found in the heart? compare the distinguishing
properties of this muscle to other muscle tissue types.
3. compare skeletal and smooth muscle tissue in terms of structure and function.
4. explain the role of calcium ions (ca2+) in the sliding filament theory of muscle
contraction? explain the importance of the proper function of atp in this process.
theorize what may happen if there were a breakdown of atp production.
5. in the “energizing stage” of the sliding filament theory of muscle contraction, atp
breaks down and releases energy to cause the myosin head to tilt about 45 degrees.
describe what happens and the stages that occur next. theorize what might happen if
atp was not present.

1) - The coracobrachialis and pectoralis major muscles connect the humerus anteriorly to the scapula and ribs, flexing and adducting the arm toward the front of the body when you reach forward to grab an object.
- On the posterior side of the arm the teres major and latissimus dorsi extend and adduct the arm towards the scapula and vertebra when you pull an object down off of a shelf above your head.
- The deltoid and supraspinatus muscles run superiorly between the scapula and humerus to abduct as well as flex and extend the arm.

These muscles allow us to raise our arm in the air or swing the arm as in throwing a ball underhand.

2) cariac muscle makes up the heart, its involuntary, striated muscle that is found in the walls and histological foundation of the heart, specifically the myocardium. Cardiac muscle is one of three major types of muscle, the others being skeletal and smooth muscle.

3) Smooth muscles are composed of elongated, spindle shaped cells and are commonly involved in involuntary motions. Skeletal muscles allow movement by being attached to bones in the body.  Skeletal muscles control voluntary movements which can be consciously controlled.

4) Calcium is a crucial part of muscle contraction. The ionic element is released from muscles during contraction and relaxation. The release of calcium helps propagate the muscle contraction and relaxation stages. An adenosine triphosphate molecule stores energy that is released and used by energy-consuming reactions, such as muscle contraction, transmission of nerve impulses and formation of other molecules. ATP is found in cells and is made from the breakdown of food. It is composed of oxygen, hydrogen, phosphorus and carbon atoms. The energy in an ATP molecule is locked within phosphate bonds, which hold its phosphate groups together.

5) The muscle would neither contract nor relax if ATP was'nt there. It would stay in the same state because ATP is required for contraction as well relaxation of muscle. That is why dead bodies become very stiff.

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