Muscular System TEST

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What are the three types of muscle tissues

Skeletal, smooth, cardiac

How do they all differ

cell structure, body location, how they are stimulated to contract

The ability to contract depends on what?

Myofilaments, Actin and Myosin

What is the structure of a skeletal muscle?

Attaches to the skeleton 

Cigar-shaped 

Largest muscle fiber  

Striated  

Multinucleate  

Voluntary control, contracts rapidly with force --> tires easily 

What CT sheath wraps skeletal muscle fibers?

endomysium

What coarser, fibrous CT sheath wraps multiple skeletal muscle fibers?

perimysium

fascicle

What is a bundle of muscle fibers called?

Epimysium

What are multiple fascicles bound by?

What is the structure of smooth muscle?

No Striations 

Involuntary 

Found in the walls of hollow organs --> Stomach, bladder, respiratory passages  

Spindle shaped 

Single nucleus  

Arranged in sheets/layers that alternately contract/relax = movement of food through digestive tract 

--> one circularly and one longitudinally 

What is the structure of cardiac muscle?

FOUND IN THE HEART ONLY 

Striated 

Involuntary 

Cushioned by soft CT arranged in spiral/figure-8 shaped bundles  

Connected by intercalated disks 

Contracts set by pace-maker 

What are muscle functions?

1. Movement  

2. Maintains posture 

3. Stabilizes Joints 

4. Generates heat 

Sarcolemma

What is a plasmic membrane that covers nuclei of muscle?

Myofibrils

Cytoplasm is filled w/ long ribbon like organelles

Light and dark bands

What gives myofibrils their stripped appearance?

sarcomeres

What are myofibrils are made up of CONTRACTILE units called?

Myofilaments

What are sarcomeres made up of?

Myosin(thick) and Actin(thin)

What are the two protein myofilaments?

ATPase enzymes that are in Myosin

What splits ATP to generate power for muscle contraction?

regulatory proteins

What prevents and allows myosin cross bridging?

To store calcium and release it upon demand

What is the role of sarcoplasmic reticulum(SR)?

Graded responses

How are contractions regulated?

How are graded responses “graded”?

Changing the frequency of muscle stimulation 

By changing the # of muscle cells being stimulated 

ATP is hydrolyzed

What happens to ATP when a muscle contracts?

Only 4-6 seconds of ATP

How much energy does a muscle store?

ATP

What is the ONLY energy source that can be used to directly power a contraction?

1. Direct Phosphorylation of ADP by Creatine Phosphate  

1. Pos: Muscle cells store 5x as much CP as ATP 

2. Neg: CP are soon exhausted in 20 secs 

1. Aerobic Respiration  

1. Pos: Yields lots of ATP 

2. Neg: Process is slow and requires a steady supply of oxygen and nutrients 

1. Anaerobic Glycolysis + Lactic Acid Fermentation 

1. Pos: 2.5x faster and provides the most ATP for 30-60 secs of strenuous activity  

2. Neg: Uses a lot of glucose for small ATP yield = lactic acid promotes muscle fatigue and soreness 

two points or more

How many points is a muscle attached to bone?

Origin

Muscle is attached to immovable/less moveable bone

Insertion

Muscle is attached to movable bone

What are the most common types of body movement?

Flexion 

Extension 

Rotation 

Abduction 

Adduction 

Circumduction 

What are the special types of body movement?

Dorsiflexion and plantar flexion 

Inversion and eversion 

Supination and pronation 

Fixators  

Skeletal muscle are named according to:

Direction of muscle fibers 

Relative size of muscle  

Location of muscle  

Number of origins 

Location of muscle's origin and insertion 

Shape of muscle  

Action of muscle  

Arrangement of fascicles vary depending on

Muscles with different structures and functions

Fascicles can be:

Circular  

Convergent  

Parallel 

Fusiform 

Pennate( uni, bi, multipennate)