Chapter 10: Muscle Tissue Part 1

movement, maintaining posture, protection & support, regulating elimination of materials, producing heat

what are some functions of skeletal muscle?

excitability

define the characteristics of skeletal muscle tissue

ability to respond to a stimulus by changing electrical membrane potential

conductivity

define the characteristics of skeletal muscle tissue

involves sending an electrical change down the length of the cell membrane

contractility

define the characteristics of skeletal muscle tissue

exhibited when filaments slide past each other

contractility

what characteristic of skeletal muscle enables the muscle to cause movement?

extensibility

define the characteristics of skeletal muscle tissue

ability to be stretched

elasticity

define the characteristics of skeletal muscle tissue

ability to return to original length following a lengthening or shortening

organ

each skeletal muscle is a(n) ____________ with multiple types of tissues working together

fasicle

define the park of skeletal muscle:

bundle of muscle fibers

muscle fibers

define the park of skeletal muscle:

individual muscle cells

epimysium

define the concentric layer of wrapping in skeletal muscle

dense irregular connective tissue wrapping WHOLE MUSCLE

epimysium

which layer of skeletal muscle wraps the whole muscle?

perimysium

define the concentric layer of wrapping in skeletal muscle

dense irregular connective tissue wrapping FASCICLE

perimysium

which layer of skeletal tissue houses blood vessels and nerves?

endomysium

areolar connective tissue wrapping INDIVIDUAL FIBER

endomysium

which layer of skeletal tissue is delicate, used for electrical insulation, capillary support, and binding of neighboring cells?

tendon

define the skeletal muscle component that attaches muscles to bone/skin

cordlike structure of dense regular connective tissue

aponeurosis

define the skeletal muscle component that attaches muscles to bone/skin

thin, flattened sheet of dense irregular tissue

deep fascia

define the skeletal muscle component

• made of dense irregular CT

• superficial to epimysium

• separates individual muscles; binds muscles with similar functions

superficial fascia

define the skeletal muscle component

• made of areolar and adipose CT

• superficial to deep fascia

• separates muscles from skin

vascularized

skeletal system is _____________ (has extensive blood vessels)

somatic motor neurons

what is the skeletal muscle innervated by?

sarcoplasm

define the part of muscle cell (fiber)

• the cytoplasm

• is multinucleated

sarcolemma

define the part of muscle cell (fiber)

• the plasma membrane

• voltage-gated ion channels that allow for the conduction of electrical signals

• has T-tubules

T-tubules

what are the tubular foldings in sarcolemma that facilitate transmissions from electrical impulses?

myofibrils

define the part of muscle cell (fiber)

bundles of myofilaments enclosed in sarcoplasmic reticulum

terminal cisternae

define the part of muscle cell (fiber)

blind sacs of sarcoplasmic reticulum

• stores calcium

triad

define the part of muscle cell (fiber)

consists of a T-tubule and 2 terminal cisternae

myofilaments

define the component in myofibrils

• the contractile proteins within myofibrils

• has thick and thin version

myosin

define the component in myofibrils

the contractile protein that makes up the THICK filaments of muscle fibers

actin

define the component in myofibrils

the contractile protein that makes up the THIN filaments of muscle fibers

myosin

which filament is made up of one tail and two heads (actin and ATP heads)?

actin

which filament is twisted with F-actin & G-actin monomers and has regulatory proteins present?

tropomyosin

what is a regulatory protein in muscle cells that covers the myosin binding site during rest?

troponin

what is the regulatory protein in muscle cells that binds calcium?

sarcomere

define the organization of a sarcomere

the overall contractile unit of a muscle fiber that makes myofilaments

Z discs

define the organization of a sarcomere

separate one sarcomere from the next

• made of thick and thin filaments

• each sarcomere has 2

A band

define the organization of a sarcomere

the dark area of striation

• made of dense filaments (both thick and thin)

H zone

define the organization of a sarcomere

made of only thick filaments and disappears during muscle contraction

• central portion of the A band

M line

define the organization of a sarcomere

middle of sarcomere that anchors thick filaments

I band

define the organization of a sarcomere

the light area of striation

• only has thin filaments

connectin

define the organization of a sarcomere

protein that stabilizes the thin filaments in the I band

dystrophin

define the organization of a sarcomere

anchors some myofibrils to sarcolemma proteins

muscular dystrophy

define the diagnosis

• caused by defective or insufficient dystrophin

• sarcolemma is damage during muscle contraction

symptoms: walking difficulties, muscle atrophy, postural issues

myoglobin

define the term:

an oxygen-storing, pigmented protein in muscle cells; used for aerobic ATP production

glycogen

define the term:

the storage form of glucose

creatinine phosphate

define the term:

can quickly lose its phosphate group to replenish the ATP supply

motor unit

define the part for the innervation of skeletal muscle fibers

a motor neuron and all the muscle fibers it controls

small motor unit

which motor unit has less than 5 muscle fibers

small motor unit

which motor unit allows for precise control of force output?

large motor unit

which motor unit consists of thousands of muscle fibers?

large motor unit

which motor unit allows for the production of large amounts of force?

neuromuscular junction

define the part for the innervation of skeletal muscle fibers

point of contact between a motor neuron and a muscle cell

synaptic knob

define the component in the neuromuscular junction

• expanded tip of the motor neuron axon

• houses synaptic vesicles

• has calcium pumps and voltage-gated calcium channels in the sarcolemma

synaptic vesicles

what are the saclike structures found inside the synaptic knob which contain the neurotransmitter acetylcholine?

synaptic cleft

define the component in the neuromuscular junction

narrow, fluid-filled space that separates the synaptic knob from the motor end plate

• houses acetylcholineterase

acetylcholinesterase

what is the enzyme the breaks down ACh molecules?

motor end plate

define the component in the neuromuscular junction

specialized region of sarcolemma with numerous folds

• has many acetylcholine receptors

• has protein channels that allow sodium entry and exit

resting membrane potential

what is the electrical charge of a neuron when it is not active?

• established by leaky channels and Na+/K+ pumps

• voltage-gated channels are closed

- 90 mV

what is the resting membrane potential of a muscle cell?

excitation of a skeletal muscle

what is the first event in skeletal muscle contraction?

excitation-contraction coupling

what is the second event in skeletal muscle contraction?

crossbridge cycling

what is the third event in skeletal muscle contraction?

skeletal muscle relaxation

what term includes some of the following events?

• Termination of nerve signal and ACh release from motor neuron

• Hydrolysis of ACh by acetylcholinesterase

• Closure of ACh receptor causes cessation of end plate potential

• No further action potential generation

• Closure of calcium channels in sarcoplasmic reticulum

• Return of Ca2+ to sarcoplasmic reticulum by pumps

• Return of troponin to original shape

• Return of tropomyosin blockade of actin's myosin binding sites

• Return of muscle to original position due to its elasticity

tetanus

define the diagnosis

• spastic paralysis

•caused by toxin from Clostridium tetani

• blocks release of inhibitory neurotransmitters in the spinal cord, resulting in overstimulation of muscles

• prevented by vaccines

botulism

define the diagnosis

• muscular paralysis

•caused by toxin from Clostridium botulinum

• prevents the release of ACh at synaptic knobs

• can be treated with careful injections