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
