Mader’s Understanding Human Anatomy & Physiology Chapter 7 Muscular system

Smooth Muscle
Smooth Muscle
-Blood Vessels:
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.

Cardiac Muscle
-Involuntary muscle forms the heart wall.
– 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

Skeletal Muscle
Skeletal Muscle
STRIATED, MULTInucleated cells
-usually attached to skeleton
-is VOLUNTARY

connective tissue coverings: 1.ENDOmysium
connective tissue coverings: 1.ENDOmysium
-thin layer of Areolar connective tissue that surrounds each Muscle Cell.
– blood capillaries and nerve cells reach each muscle cell (fibers) by way of___________

Perimysium
Perimysium
-Connective tissue coverings that incases the fascicles.

ME:fascicles look like flesh tubs that hold many smaller tubs within it, these “smaller tubes within” are the actual muscle cells.

EPImysium
EPImysium
-Layer of fibrous tissue that surrounds a set of muscles.
– muscle itself is covered by a connective layer called________.

Superficial Fascia: 5.
Superficial Fascia: 5.
-synonymous with Hypodermis
-lies on top of the outer coverings of the deep Fascia( which incases the

Fascia:
-a thin sheath of fibrous tissue enclosing a muscle or other organ.
– tissue that serves to divide protect and cover various organs, including the different layers of muscle.

Tendons
Tendons
Connective tissue covering that connects the muscle to the bone.

5 Functions of skeletal muscles
1. support the body: allows us to remain upright, some skeletal muscles serve the this purpose even when relaxed.

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.

1. Choose the phrase you could use when describing skeletal muscle
-multinucleate
– can be very long
– under voluntary control.

2. Choose the phrase you could use when describing smooth muscle.
-uninucleate
– cells arranged in sheets
– no striations
– not easily fatigued

Order of connective tissue covering from superficial to deep
Epimysium
perimysium
endomysium

Myofilaments
Myofilaments
Microscopic view of cells internal parts
– term for the chains of (primarily) Actin and Myosin that pack a muscle fiber. These are the force generating structures.

Sarcolemma
Sarcolemma
the fine transparent tubular sheath that envelops the fibers of skeletal muscles.

Sarcoplasm
Sarcoplasm
-the cytoplasm of striated muscle cells.

Sarcoplasmic reticulum
Sarcoplasmic reticulum
The sarcoplasmic reticulum is a specialized type of smooth ER that regulates the calcium ion concentration in the cytoplasm of striated muscle cells.

Glycogen
Glycogen
A polysaccharide that stores energy for muscle contraction

Myoglobin
– can pull oxygen out of blood and make it available to muscle mitochondria that are carrying on cellular respiration.
-gives muscles it’s reddish-brown color
-is synthesized IN muscle cells

T (transverse) tubule
T (transverse) tubule
___________ STICKS OUT of the SARCOLEMMA (phospholipid bi-layer) into the muscle cell and conveys nerve signals that release CA 2+ from the sarcoplasmic reticulum into the sarcoplasm

Myofibril
Myofibril
-“innards” of muscle cells
– are cylindrical in shape, run the length of a muscle cell.
– within the ______ are many Sarcomeres

Sarcomeres
Sarcomeres
Structure of the myofibril consisting of:

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,

Z lines
two dark vertical (“wavy” or “Z”up& down) lines,
*reminds me of black “crimped” hair
-responsible for the striations in the skeletal muscle.
-allows for connection to the next adjacent sarcomere.

Thick Filaments
Thick Filaments
-Thick filaments are formed from a protein called Myosin.
-appearance of two”golf clubs” twisted together.

Thin Filaments
Thin Filaments
– “cupped double helix pearls” (where Myosin Thick Filament connects)

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+

Sliding Filaments theory
Sliding Filaments theory
Contraction of skeletal muscles occur when:
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

I Band
I Band
in EACH sarcomere it is the light colored ONLY THIN filaments attached on both sides of the adjacent Z Lines
-it overlaps adjacent sarcomeres

A Band
A Band
-is the dark region of the sarcomere located in the center BTW the I Band on both sides .
-is contains overlapping THICK & THIN filaments

H Zone
H Zone
-located directly in the center of the A Band.
-________ appears when sarcomere is relaxed, at this point the center will ONLY contain Myosin filaments (thick filaments)

Skeletal Muscle Contraction
Skeletal Muscle Contraction
Muscle Cells(fibers) are Innervated: meaning they contract when the axon from the nerve cell (neuron) sends signal to react.
-the axon of one Motor Neuron has several branches and can stimulate many muscles at once to react/contract.

How does contraction occur in a skeletal muscle?
(teacher handout)
How does contraction occur in a skeletal muscle?
(teacher handout)
when we decide to move:
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.

Neuromuscular Junction
the entire region where: Synaptic Cleft: small gap btw the axon Terminals and the Muscle cells sarcolemma ACh receptors are, is the ________.

Creatine phosphate breakdown
-ATP PRODUCTION
-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.

Cellular Respiration:
-ATP PRODUCTION
-completed in mitochondria provides most of muscles ATP.
-uses glycogen and fatty acid’s from fat as fuel to produce ATP if OXYGEN available.

Fermentation
-ATP PRODUCTION
-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
– occurs when muscle uses fermentation to supply ATP
– 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)

The portion of a muscle cell membrane that extends into the muscle conveys nerve signals is called the?
Transverse (T) Tubules

Thin filaments are composed of which three proteins?
1.Actin
2.Troponin
3.Tropomyosin

Which of the following is the process in a muscle cell that requires oxygen to produce ATP energy
Cellular Respiration

Hypertrophy
Increase muscle size

Atrophy
Decrease in muscle size

Slow twitch fibers
Slow twitch fibers
-(type 1 fiber)
-Tend to be a Aerobic
-have more endurance
– have many mitochondria
-dark in color because they contain Myoglobin
-high resistance to fatigue.

Fast twitch fibers
Fast twitch fibers
– (type 2 fibers)
-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.

Frontalis
Frontalis
Muscles of facial expression
-Lies over the frontal bone
-raises eyebrows.

Orbicularis Oris
Orbicularis Oris
-Muscles of facial expression
-Incircles mouth
– puckers the lips as forming a kiss

Obicularis oculi
Obicularis oculi
-Muscles of facial expression
-A ring like band of muscle that encircles the eye
– allows eye to close tightly or blink.

Masseter
Masseter
-Muscles of mastication
– closes jaw

Temporalis
Temporalis
-Muscles of mastication
– Closes Jaw
– muscle “fans” the temporal bone

External intercostals
External intercostals
-Muscles of the trunk
-Muscles originate on an inferior ribs & insert on a superior rib
-Muscles depress rib cage during forced expiration.

Diaphragm
Diaphragm
-Muscles of the trunk
– primary muscle used for respiration
-Separates the thoracic cavity from abdominal cavity

Trapezius
Trapezius
-Muscles of the shoulder
-Originates at base of skull
-Insertion: clavicle and scapula
– adduct scapula when the shoulders are pullback, also helps extend head.

Deltoid
Deltoid
-Muscles of the shoulder
– abducts arm
– insertion: acromion processes, spine of scapula, clavicle, tuberosity of humorous.

Biceps of Brachii
Biceps of Brachii
Muscles of the arm
– bulges when forearm arm is flexed.
– originates at the scapula inserts on the radius.

Triceps brachii
Triceps brachii
-Only muscle of the posterior arm.
– originates from the scapula and humorous.
– muscle joins tendon that inserts on Ulna.
– muscle extends arm.

Gluteus maximus
Gluteus maximus
-Muscles that move the thigh
-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)

Quadriceps femoris
Quadriceps femoris
-4 part thigh muscle
-stabilizes patella and the knee joint, extends leg

Hamstrings
Hamstrings
-posterior muscle
– flexes leg

Gastrocnemius
Gastrocnemius
-Muscles that move the ankle/ foot

– 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

A nerve cell together with all of the muscle fibers it innervates is called a ___.
motor unit

An increase in muscle size ___.
-is called hypertrophy
-is caused by an increase in the number of myofibrils in the muscle cells
-occurs when muscles contract to > 75% of maximum tension

The attachment of a muscle that moves a bone is called the ___.
insertion

Which arm muscle extends the forearm?
triceps brachii

Which of the following helps to maximize ATP production in skeletal muscle cells?
-glycogen storage in muscle cells
-the presence of myoglobin in muscle cells
-the presence of many mitochondria in muscle cells

Muscle cells are grouped into bundles called fascicles. The fascicles have a sheet of connective tissue called_______
Perimysium

Skeletal Muscle voluntary, locomotion/movement. we control them. striated. Cardiac Muscle intercalated discs. involuntary. only found in heart. WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write my sample Smooth Muscle involuntary. digestive, …

A Band the dark-staining zone of a sarcomere, whose center is traversed by the H band. Acetycholine (Ach) chemical transfer substance released by some nerve endings WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR …

Ligament strong connective tissue that holds bones together in movable joints Tendon the strong connective tissue cords that attach skeletal muscles to bones WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write …

Tendons Composed of dense fibrous connective tissue. Binds muscle to periosteum. Point of Insertion more movable bony attachment of the muscle, is pulled toward the origin WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR …

Movement A function of the muscular system, coordinated function of bones, joints, nerves, and muscles Support A function of the muscular system, holding body upright and strengthening skeleton WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR …

sarkos flesh mys muscle WE WILL WRITE A CUSTOM ESSAY SAMPLE ON ANY TOPIC SPECIFICALLY FOR YOU FOR ONLY $13.90/PAGE Write my sample epimysium surrounds entire muscle. layer of collagens perimysium divide skel muscles into fasicles/muscle fibers fasicles muscle fibers …

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