类别 全部 - muscles - anatomy - contraction - exercise

作者:Heather Carter 10 年以前

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Muscular System Anatomy

The muscular system is integral to various body functions, including movement, posture maintenance, joint stabilization, and heat generation. It consists of three types of muscles: skeletal, cardiac, and smooth.

Muscular System Anatomy

Muscular System Anatomy

Types of Exercise

Resistance
increases size of muscles

weightlifting

Isometric
tension in muscles increases

no movement occurs

pushing against concrete wall

Isotonic
muscles shorten

movement occurs

normal exercise

Aerobic
uses oxygen

produces 36 molecules of ATP

Shortcoming: requires continuous supply of oxygen and fuels

makes body more flexible and resistant to fatigue

Anaerobic
does not use oxygen

produces 2 molecules of glucose

Shortcoming: uses a lot of glucose and produces little ATP

increases strength

Types of muscle responses

Tetanus
one contraction immediately followed by another

muscle never completely returns to a relaxed state

effects are compounded

Twitch
not normal function
single, brief contraction
Graded Responses
how skeletal muscles react to stimuli

a. speed or b. number of cells stimulated

Factors when naming muscles

1. Size
2. Location

3. Movement/action it causes

4. Number of origins

5. Location of origin and insertion

6. shape

7. Direction of muscle fibers

Shapes of Muscle

Circular
mouth, eyes
Flat
diaphragm, forehead
Spindle
arms, legs
Triangular
shoulder, neck

5 Golden Rules of Muscle Activity

1. All cross at least 1 joint
2. bulk lies proximal to joint crossed

3. All have at least 2 attachments: origin & insertion

4. Muscles can only pull, they never push

5. During contraction, the insertion moves towards origin

Functions

Produces movement
maintains posture

stabilizes joints

generates heat

Types of Muscle

Smooth
found in viscera

not striated, 1 nucleus

Cardiac
found in heart

striated, 1 nucleus

involuntary, regulated by ANS

Skeletal
found in limbs

striated, multinucleated

voluntary, regulated by CNS