Chapter 6

Why is it important for skeletal muscles to have an extensive blood supply network in the epimysium and perimysium?

Supply large amounts of oxygen and nutrients. Carry away metabolic wastes generated by active skeletal muscle

Isometric

Tension in the muscle increases (push against a wall with bent elbows)

How forcefully a muscle contracts depends to a large extent on

The number of cells stimulated

Perimysium

The sheath of connective tissue surrounding a bundle of muscle fibers

Three classes of levers

1st class: seesaw (head off chest) 2nd class: wheelbarrow (tiptoe) 3rd class: tweezer (elbow)

What is a muscle fascicle and what is contained inside it?

A bundle of skeletal muscle fibers surrounded by perimysium, a type of connective tissue.

Aponeurosa

A large sheetlike tendon

Agonist

A muscle who contraction moves a part of the body directly

Antagonist

A muscle whose action counteracts that of another specified muscle

Sarcomere

A structural unit of a myofibril in striated muscle

Epimysium

A thin sheath of fibrous elastic tissue surrounding a muscle.

What are thin filaments called? Thick filaments?

Actin is thin, Myosin is thick

Aerobic, Anaerobic

Aerobic - with air Anaerobic - without air

The energy provided for muscle contraction comes from

Aerobic respiration

Adduction

Movement of a limb toward the midline

What are the major functions of skeletal muscle?

Movement, posture, heart, digestion, body heat

How are skeletal muscle fibers different from your typical cell?

Multinucleated

Synergist

Muscle that aids a prime mover in a movement and helps prevent rotation

Sliding filament theory

Muscles contracting

Isotonic

Myofilaments are able to slide past each other during contractions. The muscle shortens and movement occurs (bending the knee, rotating the arm)

The propagated action potential makes the sarcolemma permeable to this ion moving into the cell.

Na+

Oxygen Debt

Not having enough oxygen

Origin vs. Insertion

Origin: The place or point where a muscle arises Insertion: Attaches to and tends to be moved by the contraction of the muscle

What is a muscle twitch

Single, brief contraction

Put in order from smallest to largest the following: muscle fiber, myofibril, fascicle, skeletal muscle, actin, and myofilament.

Skeletal Muscle, Fascicles, Muscle fiber, Myofibrils, Myofilaments, Actin & Myosin

Generating ATP during muscle contraction

Stored ATP (4-6 secs) CP (15 secs) Cellular respiration (6O2) Lactic acid fermentation ( 2ATP)

Resting Muscle

+ on the outside, - on the inside

Dorsiflexion

Back of foot facing the shin

Flexion

Brings two bones closer together

Just following the action potential, K ion gates are

Closed

Endomysium

Connective tissue surrounding the individual muscle fibers within the smallest bundles

This high-energy molecule is found in only muscle cells

Creatine phosphate

When the myosin heads link to the thin filaments they are called

Cross bridges

Sarcoplasm

Cytoplasm of striated muscle cells

Fascicles are bound together by this tough connective tissue.

Endomysium

Doing a medial rotation of the hand from anatomical position supinates the hand. T/F?

False

Pronation

Forearm rotates laterally so the palm faces the outside

Supination

Forearm rotates laterally so the palm faces the sides

This muscle is a prime mover in flexion of the thigh.

Iliopsoas

These structures are unique to cardiac muscle.

Intercalated discs

Contractions in which the muscles do not shorten are called

Isometric

The sodium-potassium pumps in the sarcolemma pump

K+ in, Na+ out

Grouping of muscles

Location Shape Size

When a muscle is relaxed, the level of Ca ions in the cell is

Low

Circumduction

Movement in a circle

Rotation

Movement of a bone around its longitudinal axis

Abduction

Movement of a limb away from the midline

This muscle dorsiflexes the foot

Tibialis anterior

Plantar flexion

Toes face downwards

Sarcolemma

Transparent tubular sheath that envelops the fibers of muscle

In a resting skeletal muscle, this chemical blocks the length of the thin filament (actin).

Tropomyosin

Extension

Typical straightening the elbow or knee

Muscle Fatigue

Unable to contract even with a stimulus