Anatomy and Physiology 2 Exam 1 1 1 What are the different types of muscles Cardiac muscle is only found in the heart thus the name and it is an involuntary muscle Contraction of this muscle propels blood form the ventricles throughout the body It is uninucleated and it is also striated meaning if you are viewing it from a microscope there are clearly defined repeating segments These are the sacromeres contractile unit Smooth muscle is also involuntary and has one nucleus like cardiac muscles It differs in that it is not striated Smooth muscle surrounds most organs and is used to transport material For example the esophagus propelling food or the large intestine moving food by peristalsis Skeletal muscle is the only voluntary muscle type in the body and it is also striated like the cardiac muscle It has many nuclei unlike cardiac and smooth muscle 2 Define and identify the anatomy of a sarcomere within skeletal muscle and explain the sliding filament theory leading to muscle contraction The sacromere is the unit of the muscle that is involved in the contraction There are three types of muscles in the human body and they are cardiac smooth and skeletal So everything is in layers for example the outside covering of the muscle is called the epimysium Then the perimysium is the name for a group of muscle fibers and the endomysium is an individual fiber Now that we got down to the fiber we look further at it and it contains the proteins actin and myosin The saromere is the smallest contractile unit of the fiber and it repeats many times along the muscle and this gives origin to the striated patterns Now to the mechanism of the contraction For contraction to occur the myosin protein head attaches to the actin and essentially pulls the actin to contraction Normally though the actin is covered by another protein called tropomyosin and this has to be moved for the myosin to do its job The process of contraction starts with an action potential and this propagates and depolarizes the sacroplasmic reticulum stores Ca 2 Then once the SR depolarizes Ca 2 is released and this binds with troponin which is another protein on the actin Once it binds to troponin tropomyosin is signaled to Tony Berardi 2 move from the actin so the myosin head can bind Once attached the head pulls the filaments together This is called excitation contraction coupling 3 Define and distinguish between the types of muscle fibers and explain the possibilities or lack there of of hyperplasia and fiber type morphology So the sarcomere is the smallest contractile unit of the muscle fiber and there are three types of fibers Type 1 is what is called the slow twitch fibers meaning they are fatigue resistant endurance In order to have the endurance they have a lot of mitochondria to supply all its energy and a high capillary density because more capillaries mean more blood and more blood means more oxygen for energy Type 2x is the fast twitch fiber and is used to power and shorts bursts of energy They would have few mitochondria since they don t supply energy as long as type 1 Type 2a is an intermediate of both types Now muscle gain is due to hypertrophy which is an increase in the size of the fiber Hyperplasia means muscle fibers grow in number and this DOES NOT happen in humans The only hyperplasia that happens in the body is with adipose tissue You can lose muscle fibers with age and it s called sarcopenia 4 State the different types of skeletal muscle contraction and the functions and characteristics of skeletal muscle All muscles share the same characteristics and these are excitability contractility elasticity and extensibility The functions are obviously to produce movement heat to stabilize and to maintain posture Now for the different functions that a muscle can produce There is concentric movement which means the muscle is shortening There is also Eccentric movement which is when the muscle lengths Some other terms are isometric meaning same length isotonic meaning same tension and isokinetic meaning same velocity Occlusion training is a technique to train that involves cutting off the blood flow to the muscle so it gets fatigued faster Highly effective with hypertrophy If you want to know more email me Tony Berardi 3 5 What is a motor unit And how are motor units recruited according to the size principle A motor unit is a neuron that and all the muscle fibers it is innervated to so when that neuron sends its action potential to the fibers they all contract Now to go over the size principle This just means that no matter what the activity is the motor unit with the fewest fibers fires first 6 What are the different types of fascicle arrangements Also what determines a muscles power and ROM The different types of fascicles refer to the arrangement of the muscle in the body These are convergent parallel unipennate circular multipennate fusiform and bipennate Depending on how the fascicles are arranged the ROM and power of the muscle will be affected Basically the muscle with the most fibers is the strongest 7 Describe the 3 classes of levers and apply the knowledge to uses of mechanical advantage and muscle insertions to determine lever classes in the body Every skeletal movement in the human body is performed by a lever system with the bones There are three different levers that are based on the type of movement To visualize the levers you have to think of the bone as being the lever the joint as being the fulcrum the muscle insertion point being the effort remember the insertion is the end of the muscle that can move freely and the weight that you are moving as the load These three levers cleverly named 1 2 and 3rd class are either considered power or speed levers Power levers are when the load weight is close to the fulcrum joint and the effort movable insertion point is far from the fulcrum These layouts will allow the load to be moved with little effort Speed levers are when the load is far from the fulcrum and the effort is close to the fulcrum This requires more effort to move the load and Is not ideal at a mechanical disadvantage 1st class lever is when the fulcrum is in the middle of the load and the effort Think of a see saw and moving the head up and down is an example Load is the head fulcrum is the occipital joint in neck and the effort is the neck muscles 2nd class levers are when the effort is at one end load is in the middle and the fulcrum is at the other end Standing on your toes is an example
View Full Document
Unlocking...