muscular system (zoology lec)

muscular system

responsible for all types of body movement

Skeletal muscle

Cardiac muscle

Smooth muscle

Three basic muscle types are found in the body

smooth and skeletal

what muscle cells are elongated

contraction

the movement of microfilaments

myo & mys

prefixes that refers to the muscle

sarco

Prefix that refers to “flesh”

Skeletal muscles

muscles attached to the bones

Axial & Appendicular

two kinds of skeletal muscle

non-skeletal

muscle that is not attached to the bones

cardiac muscle

muscles in the walls of the heart

smooth muscle

muscles in walls of hollow visceral organs (other than heart)

skeletal muscle

Single, very long, cylindrical, multinucleate cells with very obvious striations

cardiac muscle

Branching chains of cells; uninucleate, striations; intercalated discs

smooth muscle

Single, fusiform, uninucleate; no striations

Epimysium, perimysium, and endomysium

CT components of skeletal

Endomysium attached to the fibrous skeleton of the heart

CT components of cardiac

Endomysium

CT componentss of smooth

Endomysium

_______ attached to the fibrous skeleton of the heart

Voluntary; via nervous system controls

regulation of contractions in skeletal muscle

Involuntary;

regulation of contractions in cardiac muscle

pacemaker

the heart has a ________

hormones

nervous system controls?

Slow to fast

speed of contraction in skeletal muscle

slow

speed of contraction in cardiac muscle

very slow

speed of contraction in smooth muscle

somatic

muscles used in moving from one place to another

visceral

muscles that regulate internal environment

integumentary

muscles that move the skin; facial expression

Myotome – epimere – mesoderm

origin of myotomic

Splanchnic – hypomere – mesoderm

origin of splanchnic

parietal

Skeletal, voluntary, straited, somatic, myotomic

visceral

on-skeletal, involuntary, smooth, visceral, splanchnic

Branchiomeric

Skeletal, voluntary, striated, visceral, splanchnic

integumentary

Non-skeletal, voluntary, striated, integumentary, myotomic or splanchnic

Levator

Raises an opening

Depressor

Lowers an opening

Sphincters

Regulates an opening

Tendons

cord-like structures, Mostly collagen fibers

tendons

Often cross a joint due to toughness and small size

Aponeuroses

sheet-like structures that is Attach muscles indirectly to bones, cartilages, or connective tissue coverings

• Bones

• Cartilages

• Connective tissue coverings

Sites of muscle attachment

submucosa

thick layer of loose or dense irregular connective tissue in the gastrointestinal tract

mucosa

lines body cavities and hollow organs open to the external environment, such as the digestive, respiratory, and reproductive tracts

• Produce movement

• Maintain posture

• Stabilize joints

• Generate heat

Skeletal Muscle Functions

sarcomere

contractile unit of a muscle fiber

Myofilaments

threadlike protein filaments that make up myofibrils inside muscle cells

myosin filaments

Thick filaments

actin filaments

Thin filaments

myosin filaments

Has ATPase enzyme, Composed of the protein myosin

actin filaments

Composed of the protein actin, Anchored to the Z disc

myofilaments

otagnization of sarcomere

neurotransmitter

chemical released by nerve upon arrival of nerve impulse

acetylcholine (ACh)

chemical released by nerve upon arrival of nerve impulse

sarcolemma

Acetylcholine attaches to receptors on the

sodium

Sarcolemma becomes permeable to

action potential

Sodium rushes into the cell generating an?

binding sites on the thin filament

Activation by nerve causes myosin heads (cross bridges) to attach to?

towards the center of sarcomere

Myosin heads then bind to the next site of the thin filament and pull

sliding of the myosin

This continued action causes a _______ along the actin

contracted

The result is that the muscle shortened

all or none

Muscle fiber contraction is

the same interval

Within a skeletal muscle, not all fibers may be stimulated during

differing response

Within a skeletal muscle, not all fibers may be stimulated during

Graded responses

Different combinations of muscle fiber contractions may give

The frequency of muscle stimulation & number of muscle cells being stimulated at one time

Graded responses can be produced by changing

twitch

type of graded response that is a brief, single contraction and relaxation cycle in a muscle fiber caused by a single action potential from a motor neuron

summing

The process where individual sub-threshold graded potentials combine together over space and time rather than acting in isolation

unfused

a type of graded muscle contraction that happens when a skeletal muscle is stimulated repeatedly in rapid succession

fused

smooth, sustained, maximal muscle contraction that occurs when motor neurons deliver action potentials at a high frequency

fibers stimulated

Muscle force depends upon the number of?

greater muscle tension

More fibers contracting results in

energy

Muscles can continue to contract unless they run out of

stored ATP

muscles use ______ for energy

Adenosine Triphosphate

what is atp?

atp bonds

it is broken to release energy

4-6 sec

seconds worth of ATP is stored by muscles

fatigued

When a muscle is______, it is unable to contract even with a stimulus

oxygen deficit

Oxygen must be “repaid” to tissue to remove

accumulated lactic acid

Oxygen is required to get rid of

Increasing acidity (from lactic acid) and lack of ATP

these causes the muscle to contract less

Isotonic contractions

Myofilaments are able to slide past each other during contractions

isometric contraction

contraction where tension in the muscles increases

relaxed muscle

Some fibers are contracted even in a

muscle tone

Different fibers contract at different times to provide

involuntary control

The process of stimulating various fibers is

muscle size, strength, and endurance

Exercise increases

excercise

it increases muscle size, strength, and endurance

endurance

Aerobic is for

greater resistance to fatigue

Aerobic (endurance) exercise (biking, jogging) results in stronger, more flexible muscles with ___________

stronger, more flexible muscles

Aerobic (endurance) exercise (biking, jogging) results in _____________ with greater resistance to fatigue

resistance excercise

it increases muscle size and strength

aerobic excercise

Makes body metabolism more efficient

aerobic excercise

Improves digestion, coordination

flexion

Decreases the angle of the joint

flexion

Brings two bones closer together

extension

Increases angle between two bones