Chapter 9 -- Muscle and Muscle Tissue

Type of tissue that is packaged in skeletal muscles, has obvious stripes called striations, and is controlled voluntarily

Skeletal Tissue

Type of tissue found in walls of hollow organs, and moves involuntarily

Smooth Tissue

Type of tissue only found in the heart, has striations, but moves involuntarily

Cardiac Tissue

Protective Sheath that surrounds entire muscle

Epimyseum

Protective sheath that surrounds each muscle fiber

Endomyseum

Protective sheath that surrounds each group of muscle fibers

Perimyseum

Level of organization that is a bundle of fascicle

Muscle

Level of organization that is a bundle of muscle fibers

Fascicle

Level of organization that is a bundle of myofibrils

Muscle Fiber

Level of organization that is a bundle of myrofilaments

Myrofibril

Horizontal unit of myrofilaments

Sacromere

Part of sarcomere that is the length of myosin

A band

Part of sarcomere that separates successive sarcomeres

Z line

Part of sarcomere that is the space between the ends of myosin (thick protein)

I band

Part of sarcomere that is the space between the ends of actin (thin protein)

H zone

Part of sarcomere that is the middle part

M line

Sleeve of longitudinal/perpendicular tubules the regulates intracellular calcium levels

Sarcoplasmic Reticulum

Pathway fro nerve impulses to travel deep into muscle

Transverse Tubules

Thin protein made up of troponin and tropomyosin

Actin

Thick protein with a head and a tail

Myosin

Steps of Nerve Impulse Transmission into muscle: Nerve impulse reaches end of an axon

Step 1

Steps of Nerve Impulse Transmission into muscle: Channels open to allow Ca+ into axon

Step 2

Steps of Nerve Impulse Transmission into muscle: Ca+ triggers release of ACH from synaptic vessels

Step 3

Steps of Nerve Impulse Transmission into muscle: ACH diffuse quickly across synapse, binding to muscle fiber membrane

Step 4

Steps of Nerve Impulse Transmission into muscle: AP is regenerated at muscle fiber, then into transverse tubules

Step 5

Theory that explains how muscles contract, where thick myosin filaments use energy from ATP to repeatedly bind, pull, and release thin actin filaments, causing muscle fiber to shorten and force to be generated.

Sliding Filament Theory

Steps of SFT: Nerve impulse arrives at muscle and triggers electrical signal across muscle fiber

Step 1

Steps of SFT: Signal travels down transverse tubules and arrives at Sarcoplasmic Reticulum

Step 2

Steps of SFT: Sacroplasic Reticulum releases Ca+ ions into muscle

Step 3

Steps of SFT: Ca+ binds to troponin, shifting tropomyosin, and exposing active site of actin

Step 4

Steps of SFT: Myosin reaches out to exposed actin sites, allowing a “cross bridge” to form (BIND)

Step 5

Steps of SFT: Stored energy is released from myosin head, causing actin and myosin to slide together (SLIDE)

Step 6

Steps of SFT: New ATP binds to myosin, releasing cross-bridge (RELEASE)

Step 7

One of two ways muscles contract, this one being a quick one time contraction; 1 AP = 1 cycle of contraction

Twitch

One of two ways muscles contract, this one being for most muscle actions, where many AP’s are needed

Graded muscle response

Graded muscle response where multiple AP’s are sent back to back, causing successive contractions to occur more quickly

Summation

Graded muscle response where repeated quick summation leads to increased strength of twitch, due to Ca+ buildups in SR

Incomplete Tetanus

Graded muscle repose where AP’s occur so quickly, longer relaxation periods exist between contractions; resulting in smooth muscle contraction

Complete Tetanus

Factor where small motor units happen first, then larger motor units happen last

Recruitment

Factor where initial is weaker, but the repeated is stronger,

Strength over time

Factor where optimal force of contraction is generated when muscle is moderately stretched.

Length-Tension Relationship

Energy method where we regenerate ATP, giving energy for about 10-15 seconds

Creatine Phosphate System

Energy method where we breakdown glucose, yielding more ATP

Anaerobic Glycolysis

Energy method where a sequence of chemical reactions in mitochondria use 1 glucose to make 38 ATP.

Aerobic Respiration

Muscle fiber type that requires contraction time, and O2; yields a longer lasting, but weaker, contraction

Slow Twitch (Type 1)

Muscle fiber type that has a faster contraction time, and doesn’t require oxygen; shorter lasting, but stronger contractions

Fast Twitch (Type 2)