involuntary contraction regulates blood flow in blood vessels.
-Appearance: cell narrow , tapered, DOES NOT have STRIATIONS, UNInucleated (one cell).
-sustains long contractions and does not fatigue easily.
– does NOT require nervous system for RHYTHMIC contraction.
– Nervous System that supply heart affect heart RATE & STRENGTH of contraction.
– appearance: STRIATED, cylindrical, branched cells, UNInucleated (one cell).
– intercalated discs contain: Gap Junctions & Adhesion junctions allow for quick contraction response to surrounding muscles
-usually attached to skeleton
– blood capillaries and nerve cells reach each muscle cell (fibers) by way of___________
ME:fascicles look like flesh tubs that hold many smaller tubs within it, these “smaller tubes within” are the actual muscle cells.
– muscle itself is covered by a connective layer called________.
-lies on top of the outer coverings of the deep Fascia( which incases the
– tissue that serves to divide protect and cover various organs, including the different layers of muscle.
2.Make bones & body parts move: allows for movement of limbs, eye movement, facial expressions and breathing.
3.Helps maintain body temperature: contraction causes ATP to break down releasing heat this occurs continuously 21.
4.Assist fluid movement in cardiovascular and lymphatic vessels: the squeezing of skeletal muscles keeps blood moving in cardiovascular veins and lymph moving in lymphatic vessels.
5. help protect bones and internal organs /stabilize joints: muscles pad the bones, muscular wall in abdominal region protect internal organs, muscle tendons help hold bones together at the joint.
– can be very long
– under voluntary control.
– cells arranged in sheets
– no striations
– not easily fatigued
– term for the chains of (primarily) Actin and Myosin that pack a muscle fiber. These are the force generating structures.
-gives muscles it’s reddish-brown color
-is synthesized IN muscle cells
– are cylindrical in shape, run the length of a muscle cell.
– within the ______ are many Sarcomeres
1.Thick Filament: made out of Protein Myosin, is “bulkier” than thin filament.
2.Thin Filament: made of Actin thin and “pearl strand” like.
-each _______is separated by two dark vertical (“wavy” or “Z”up& down) the lines,
*reminds me of black “crimped” hair
-responsible for the striations in the skeletal muscle.
-allows for connection to the next adjacent sarcomere.
-appearance of two”golf clubs” twisted together.
pearls made up of three proteins:
1.Actin (globular cupped pearls) contains myosin-binding sites.
Tropomyosin: “gates”Cover actin filament sites, can only move if troponin bind with calcium
3. Troponin: “locks” actins entry site it can only be unlocked with Ca2+
Actin and Myosin slide under one another, causing sarcomere to shorten. NOTE the individual Myofilaments do not change length themselves but instead OVERLAP each other to shorten the Sarcomere.
1. when Myosin is at rest ADP(Adininetriphosphate) & P (Phosphate) molecules are attached to the nubs
2. when we decide to move, calcium is released from the sarcoplasamic reticulem it attaches to Troponin on Actin Filament, troponin moves tropomyosin “gate” this move exposes Actins moyosin-binding sites.
3.once exposed Myosin nubs release, a single Phosphate Molecule flies off Myosin and allows for a Cross Bridge to occur.
4. the ADP molecule left behind is then used to form a Power Stroke (which is when the Myosin nubs pull the actin inwards contracting the muscles).
5. once the left behind ADP is used up ATP then attaches itself to the myosin heads, this molecule ATP makes nubs release themselves from the Actins Myosin-binding sites.
6. once Myosin releases itself (rests) the ATP is Immediately converted to ADP & P molecule once again
-it overlaps adjacent sarcomeres
-is contains overlapping THICK & THIN filaments
-________ appears when sarcomere is relaxed, at this point the center will ONLY contain Myosin filaments (thick filaments)
-the axon of one Motor Neuron has several branches and can stimulate many muscles at once to react/contract.
The Axon Terminal of a Motor Neuron releases *Acetylocholine (Ach) into the *Synaptic Cleft or gap where it binds to receptors on the *Sarcolemma of the Muscle fiber(cell).The electrical impulses are carried into the muscle fiber by the *Transverse or T Tubules. the electrical impulses cause the release of *Calcium from its storage site in the *Sarcoplasmic Reticulum. calcium binds to the protein *Troponin in the thin filaments. This causes the protein *Tropomyosin to move aside allowing access to myosin binding sites on the *Actin molecules. The crossbridges of *Myosin(thick filaments) attach to the binding site, and a power stroke pulls filaments toward the center of the sarcomere.
-Anaerobic,supplies APT w/o consuming oxygen.
– high energy compound built up when muscle is resting.
– does not directly participate in muscle contraction instead gives P (phosphate) to ATP
– occurs during sliding filaments:
regenerates ATP by transferring it’s phosphate to ADP.
– creatine phosphate is rebuilt when muscle is resting.
-completed in mitochondria provides most of muscles ATP.
-uses glycogen and fatty acid’s from fat as fuel to produce ATP if OXYGEN available.
-Anaerobic, supplies ATP w/o consuming oxygen.
– occurs in the sarcoplasm produces ATP necessary for short bursts of exercise.
– glucose broken down to lactate (lactic acid)
-accumulation of of lactate in muscle cells makes sarcoplasm acidic, eventually ATP depletes muscles cramp and fatigue sets in.
– oxygen debt obvious when person breaths heavily after exercising.
– muscles greatest asset, is the ability to run up oxygen debt
– repay debt requires replenishing creatine phosphate, Lactic acid changed back to Pyruvate so Mitochondria can completely metabolize.
– the number of mitochondria increase in people who work out so fermentation is not needed to produce ATP, therefore Glucose is spared and used to feed the brain.
– a marathon runner is not exhausted due to oxygen debt instead has used up all muscles glycogen supply and livers glycogen supply as well( a high carb diet for 2 days is needed to replenish areas)
-Tend to be a Aerobic
-have more endurance
– have many mitochondria
-dark in color because they contain Myoglobin
-high resistance to fatigue.
-Tend to be Anaerobic
-designed for strength
– few mitochondria & little myoglobin
-have fewer blood vessels then fast twitch fibers -vulnerable to accumulation of lactic acid.
– easily fatigued.
-Lies over the frontal bone
– puckers the lips as forming a kiss
-A ring like band of muscle that encircles the eye
– allows eye to close tightly or blink.
– closes jaw
– Closes Jaw
– muscle “fans” the temporal bone
-Muscles originate on an inferior ribs & insert on a superior rib
-Muscles depress rib cage during forced expiration.
– primary muscle used for respiration
-Separates the thoracic cavity from abdominal cavity
-Originates at base of skull
-Insertion: clavicle and scapula
– adduct scapula when the shoulders are pullback, also helps extend head.
– abducts arm
– insertion: acromion processes, spine of scapula, clavicle, tuberosity of humorous.
– bulges when forearm arm is flexed.
– originates at the scapula inserts on the radius.
– originates from the scapula and humorous.
– muscle joins tendon that inserts on Ulna.
– muscle extends arm.
-Largest muscle in the body covers a large part of butt
– originates at the ileum and sacrum
-inserts on the femur
-prime mover of thigh extension( climbing, jumping, crouching)
-stabilizes patella and the knee joint, extends leg
– flexes leg
– forms a large part of calf
– walking or running or stand on tiptoe.
– Insertion:arises from femur; distally the muscle joins the strong calcaneal tendon
-is caused by an increase in the number of myofibrils in the muscle cells
-occurs when muscles contract to > 75% of maximum tension
-the presence of myoglobin in muscle cells
-the presence of many mitochondria in muscle cells