Functional Anatomy Exam 4

Angle of Insertion

Angle that the muscle’s tendon attaches to the bone, can increase or decrease through motion

What does angle of insertion allow?

More range of motion

Line of Pull

Line from the origin and insertion of a muscle

Angle of Pennation

Shortening of oblique muscle fibers in relation to tendons, has more force generation

What can muscles be named for?

Location, shape, action, # of divisions, attachment points, fiber orientation, and size

Location

Rectus Femoris and External Oblique

Shape

Deltoid and Rhomboid

Action

Erector Spine, Supinator, and Extensor Digiti Minimi

# of divisions

Biceps Brachii and Triceps Brachii

Attachment Points

Coracobrachialis and Extensor Hallucis Longus

Fiber Orientation

External Oblique

Size

Gluteus Maximus and Teres Minor

What are the three roles of muscle?

Agonist, antagonist, synergist

Agonist

Primary movers with the muscles most involved, causes joint motion through a specified plane when contracting concentrically

Antagonist

Located opposite of agonist and has opposite concentric action, works in cooperation with agonist muscles by relaxing and allowing movement

Synergist

Assist with action of agonist, they are guiding muscles

What are the three types of muscle contractions?

Isometric, isotonic, isokinetic

Isometric Contraction

Muscle is contracting without joint movement, resistance and effort torques are balanced

Isotonic Contraction

Concentric contraction is shortening and is the effort phase. Eccentric contraction is lengthening and is the return phase

Isokinetic Contraction

Joint movement at a consistent speed based on the force put in

Normal Resting Length

Length of muscle when it’s not directly altered by active contraction or application of external forces

Tension

Force built up within a muscle

Tone

Tension that is present in a muscle at all times

Excursion

Distance from max lengthening to max shortening

Optimal Length

When a muscle is at a slight strength, but not overstretched. Maximum interface between actin and myosin with some passive muscle tension.

Active Insufficiency

Point at which a muscle cannot shorten any further

Passive Insufficiency

Muscle can’t be lengthened further without damage

What can poor posture do to muscle tissue?

Cause tissues on one side of joint to lengthen and tissues on the other side to shorten

What are the four functions of muscle tissue?

Create movement, stabilize posture, assist circulation of fluids, and perform thermogenesis

What is the way motion can be described?

Muscles are the force, bones are the levers, joints are axes

What has to happen for movement?

Activation from motor unit/nerves

What are the three types of muscle tissue?

Cardiac, smooth, skeletal

What are the four properties of muscle tissue?

Irritability, contractibility, extensibility, elasticity

Irritability

Must be able to respond to stimulus from a nerve, which results in a contraction

Contractibility

Must be able to contract and generate force when an adequate stimulus is applied

Extensibility

Must be able to stretch and lengthen when a force is applied

Elasticity

Must be able to return to normal after stretching/shortening

Sarcomere

Unit that shortens and lengthens

What are the two main parts of a sarcomere?

Actin is the thin filaments and myosin is thick filaments

Sliding Filament Theory

Myosin hooks into actin and shortens towards M line, pulling actin with it

Concentric Contraction

Muscle shortens, myosin exerts pulling force on actin to pull together

Eccentric Contraction

Muscle lengthens, actin and myosin bond doesn’t release, they are pulled apart/lengthened

Type 1-Slow Twitch 

Muscle fiber that is smaller in diameter, responds less quickly, doesn’t fatigue as fast, and has sustained longer contractions

Type 2-Fast Twitch

Muscle fiber that is larger in diameter, responds quickly, fatigues quickly

What are three main parts of muscle attachment?

Tendons, musculotendinous junction, tenoperiosteal junction

Origin

Proximal attachment point

Insertion

Distal attachment point

Parallel Muscles

Have increased range of motion, fibers are arranged parallel to length of muscle

What are the 5 types of parallel muscles?

Strap, flat, fusiform, triangular, circular

Flat muscles

Have aponeurosis to connect

Fusiform muscles

Spindle shaped, with muscle in the middle and tendons on the ends

Triangular muscles

somewhat flat, can have a spiral on one end

Circular muscles

Strap muscles, but form a circle

Oblique Muscles

Produce more force and have shorter fibers

What are the 3 types of oblique muscles?

Unipennate, bipennate, multipennate

What are the two types of muscle arrangements?

Parallel and oblique

Unipennate muscles

Fibers branch off one side

Bipennate muscles

Fibers branch off two sides

Multipennate muscles

Has fibers coming out multiple sides and angles