muscle tissues

what are the three types of muscle tissue?

1. skeletal

2. cardiac

3. smooth

what type of muscle is voluntary?

skeletal

what type(s) of muscle is/are striated?

1. skeletal

2. cardiac

what are the functions of skeletal muscle?

1. contract and cause movement

2. generate heat via shivering

3. prevent excess movement of bones and joints

4. maintain skeletal stability

5. prevent skeletal structure damage or deformation

where is skeletal muscle located in the body?

openings of internal tracts

what are the layers of connective tissue that enclose muscle?

1. epimysium

2. perimysium

3. endomysium

what does the epimysium surround?

the entire muscle; outermost layer

what is the composition of epimysium?

dense irregular tissue

what is the function of epimysium?

1. allows muscle to contract without completely falling apart

2. separates muscle from other tissues to allow independent movement

what does the perimysium surround?

each individual bundle of muscle fiber

fascicles

a group of muscle fibers surrounded by perimysium

endomysium location

inside the fasicle

what does the endomysium encase?

each individual muscle fiber in a layer of collagen and reticular fibers

what components are included in skeletal muscle fiber structure?

1. sarcolemma

2. sarcoplasm

3. sarcoplasmic reticulum

4. sarcomere

sarcolemma

plasma membrane of muscle fibers

sarcoplasm

cytoplasms of muscle fibers

where are nuclei located in skeletal muscle?

several nuclei located peripherally within sarcoplasm

sarcomere

portion of myofibril that extends between two z-lines

what is the functional unit of a skeletal muscle?

sarcomere

sarcomere structure

arrangement of contractile myofilaments

myofibril

connects individual sarcomeres together in a long chain which then attaches to the sarcolemma at its end

myofibrils are bundled together within the…

sarcoplasm

where are mitochondria and sarcoplasmic reticulum found in the sarcomere?

between myofibrils

what creates the striations in muscle?

density differences between myofilaments

thick filaments are composed of…

myosin

thin filaments are composed of…

1. actin

2. troponin

3. trypomyosin

what are the skeletal muscle fiber types?

slow oxidative muscle fibersfast glycolytic muscle fibersfast oxidative-glycolytic fibers

what are slow oxidative muscle fibers adapted for?

slow contractions over long periods of time without fatigue

composition of slow oxidative muscle fibers

have many mitochondria surrounding myoglobin and capillaries

which skeletal muscle fiber type is small in diameter?

slow oxidative muscle fiber

what are fast glycolytic muscle fibers specialized for?

rapid short-term contraction

what does fast glycolytic muscle fibers depend on?

anaerobic metabolism of glucose derived from stored glycogen because these fibers have few mitochondria

what is the appearance of fast glycolytic muscle fibers?

white

why do rapid contractions lead to rapid fatigue in fast glycolytic muscle fibers?

lactic acid accumulates from glycolysis

what skeletal muscle fiber has large diameters?

fast glycolytic muscle fibers

what is the correct order of muscle tissue from the smallest unit to the largest unit?

1. myofilament

2. myofibril

3. muscle fiber

4. fascicle

what type(s) of muscle(s) is/are non-striated?

smooth muscle

what is the appearance of smooth muscle?

bundles of elongated fusiform cells with tapered endsnuclei located in center

what type(s) of muscle(s) is/are involuntary?

1. smooth muscle

2. cardiac muscle

what supports the individual fibers of smooth muscle?

reticular fibers with collagen and elastic fibers

what are the components of smooth muscle?

1. contractile apparatus of thick and thin filament

2. cytoskeleton of desmin and viment in intermediate filaments

3. dense bodies

what is the function of dense bodies in smooth muscle?

provide attachment site for thick and thin filamentsallo force for contraction

what is the location of smooth muscle?

1. urinary bladder

2. uterus

3. small intestines

4. blood vessels

what type of muscle is responsible for changing the pupil size in the eye?

smooth muscle

what muscle is responsible for making the hair stand erect on skin if in fear or cold?

smooth muscle

what is smooth muscle specialized for?

slow and prolonged contraction

what is smooth muscle under the influence of?

1. hormones

2. autonomic nervous system

cardiac muscle location

make up the walls of the heart (myocardium)

what is the appearance of cardiac muscle?

• short fibers

• one centrally placed nucleus

• cells may contain mitochondria

intercalculated discs

densely-staining cross bands present in cardiac muscle

what is the function of intercalculated discs?

allow muscle to contract in a coordinated fashion

intercalculated discs are part of…

sarcolemma

intercalculated discs contain…

1. gap junctions

2. desmosomes

what is the function of gap junctions?

allow for quick transmission of action potential in the heart for coordinated contraction

what is the function of desmosomes?

anchor fibers in the heart so cells do not pull apart during individual fiber contraction

how is skeletal muscle regenerated?

1. mesenchymal cells within the external lamina of muscle fiber are activated

2. cells proliferate and fuse to form new skeletal muscle fibers

how does smooth muscle tissue regenerate?

small mononucleated cells undergo mitosis and replace damaged tissues

how does cardiac muscle regenerate

lacks satellite cells so damaged cells will be replaced by proliferating fibroblasts which typically will result in myocardial scars

rank the best to worst regenerative muscle tissues

1. smooth muscle

2. skeletal muscle

3. cardiac muscle

What structures in the muscle contain numerous gap junctions, desmosomes, and adherens junctions?

intercalculated discs

What characteristic is unique to cardiac muscle?

it is branched

what are other stimuli that the smooth and cardiac muscle specifically can respond to?

1. catecholamines from the blood

2. hormones local stimuli