Muscular Tissue

What are the steps of the contraction cycle?

1. ATP hydrolysis. 2. Attachment of myosin to actin to form cross-bridges. 3. Power stroke. 4. Detachment of myosin from actin.

What are the properties of muscle tissue?

1. Electrical excitability 2. Contractility 3. Extensibitliy 4. Elasticity

What are the functions of muscular tissue?

1. Producing body movements. 2. Stabilizing body positions. 3. Storing and moving substances within the body. 4. Generating heat.

What are the three types of muscular tissue?

Skeletal, Cardiac and Smooth

Actin

Thin filament of protein found in muscles

tendon

a cord of dense regular connective tissue that attaches muscle to the periosteum of bone

Acetylcholine

a neurotransmitter that, among its functions, triggers muscle contraction

Myocin

a protien that forms Thick Myofilaments

endomysium

a sheath of areolar connective tissue that wrapes around individual skeletal muscle fibers

recovery oxygen uptake

amount of oxygen needed to restore the body's metabolic conditions back to resting levels after exercise

I band

area in the sarcomere where only thin filaments are present

H zone

area of only thick filaments

subcutaneous layer

areolar and adipose connective tissue that separates muscle from skin

twitch contraction

brief contraction of all the muscle fibers in a motor unit of a muscle in response to a single action potential in its motor neuron

fascicles

bundle of muscle fibers

What are the characteristics of cardiac muscle tissue?

cardiac muscle is striated, involuntary and forms most of the heart wall

M line

composed of supporting proteins holding thick filaments together at the H zone

aponeurosis

connective tissue elements extended as a broad, flat layer

eccentric isotonic contraction

contraction in which muscle lengthens

isometric contraction

contraction in which muscle tension is generated without shortening of the muscle

concentric isotonic contraction

contraction in which the muscle shortens

sarcoplasm

cytoplasm of muscle fibers

fascia

dense irregular connective tissue that lines the body wall and limbs and hold functional muscle units together

perimysium

dense irregular connective tissue that separates a muscle into groups of individual muscle fibers

the sliding filament theory

explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement.

sarcomere

functional unit of muscle contraction

muscle fatigue

inability of a muscle to maintain its strength of contraction or tension during prolonged activity

What are the characteristics of fast oxidative fibers?

intermediate in diameter, appear dark red due to large amounts of myoglobin and blood capillaries, can generate ATP by aerobic cellular respiration as well as by anaerobic glycolysis (due to high intracellular glycogen levels), and fast speed of contraction

transverse tubules

invaginations of the sarcolemma from the surface toward the center of the muscle fiber

wave summation

larger contractions resulting from stimuli arriving at different times

What are the characteristics of fast glycolytic fibers?

largest in diameter, generate the most powerful contractions (contain most myofibrils), appear white in color due to a low amount of myoglobin, blood capillaries, and mitochondria, generate ATP by glycolysis (contain large amounts of glycogens), and contract strongly and quickly

A band

middle area in the sarcomere where thick and thin filaments are found

muscle fiber

muscle cell

satellite cells

myoblasts that persist in mature skeletal muscle

What are the characteristics of skeletal muscle tissue?

skeletal muscle is striated, voluntary and move bones of the skeleton

What are the characteristics of slow oxidative fibers?

smallest in diameter, least powerful. appear dark red due to large amounts of myoglobin and blood capillaries, generate ATP (contain many large mitochondria) by aerobic cellular respiration, and have a slow speed of contraction

What are the characteristics of smooth muscle tissue?

smooth muscle is smooth (non-striated), involuntary, located in the walls of hollow internal structures and is also found in the skin

fused (complete) tetanus

sustained contraction of a muscle, with no relaxation between stimuli

unfused (incomplete) tetanus

sustained, but wavering contraction with partial relaxation between stimuli

neuromuscular junction

synapse between a motor neuron and a muscle fiber

Acetylcholinesterase

the enzyme that breaks down acetylcholine in the synaptic cleft

epimysium

the outermost connective tissue layer that encircles an entire skeletal muscle

Synaptic transmission

the process of transferring information from one cell to another at a synapse

stress-relaxation response

the smooth muscle action that allows the fibers to maintain their contractile function even when stretched

sarcoplasmic reticulum

Ca 2+ storing tubular system similar to the endoplasmic reticulum

myoglobin

oxygen-building protein found only in muscle fibers

sarcolemma

plasma membrane of the muscle fiber

motor unit recruitment

process of increasing the number of activated motor units

muscle tone

produced by the continual involuntary activation of small number of skeletal muscle motor units; results in firmness in skeletal muscle

Z discs

separates the sarcomeres from each other