Muscle Physiology - Winden Flashcards
What are the functions of skeletal muscle?
Provides movement, generates heat, stores nutrient reserves, supports soft tissues, maintain posture and body position, guards entrances and exits
What are the three different types of CT associated with skeletal muscle?
epimysium
perimysium
endomysium
What does epimysium cover?
Covers the entire muscle
Connects to the deep fascia
What does the perimysium cover?
Covers the fascicle
What does the endomysium cover?
Covers the muscle fiber
Describe the difference between a tendon and a aponeurosis
Tendon is the extensions of all the CT from the muscle that is attached to the bone
Aponeurosis is a sheet of the CT extension (ie. on the head)
What are characteristics of skeletal muscle?
Voluntary Striated Multinucleated Long and can be large Develop from the fusion of myoblasts
Name from smallest to largest the units of skeletal muscle
Myofilament, myofibril, myofiber, fascicle, muscle
What is the triad consist of?
Two terminal cisternae and T-tubule
What is distinct about the A band?
Length of the thick filament (dark)
What is distinct about the I band?
Length between the ends of each thick filament (light)
What is distinct about the M line?
Middle of the sarcomere and the center of the A band
What is distinct about the H band?
The area of ONLY thick filaments
What is distinct about the Z lines?
The center of the I band
What is nebulin?
In the thin filament
Holds the two strands of F-actin together
What is tropomysosin?
Two strands that block the active sites on the globular actin
What is troponin?
Moves tropomyosin when binding with Ca
What is titin?
Recoils myosin after contraction
What are the components of myosin?
Head and Neck
Has active sites for both actin and ATP
What is the sliding filament theory
Thin filaments move toward the M line
Width of the A band stays the same
Z lines move closer together
What does contraction duration depend on?
Duration of neural stimulus
Amount of Ca
Avaliability of ATP
What occurs with rigor mortis?
After a body has died, there is no ATP but abundant Ca
Cannot rest muscles
Twitches have 3 phases:
What are they?
latent- Ca release
contraction- Ca binding
relaxation - Ca decrease
What is Treppe?
Repeated stimulation right after relaxation
What is Wave?
Stimuli arrives before relaxation has completed
What is Tetanus and the two types?
Repeated stimuli with little or no relaxation
Incomplete- little relaxation
Complete- no relaxation
What does skeletal muscle tension depend on?
internal and external tension
total number of muscle fibers
What is a motor unit?
All the muscle fibers that are controlled by a single neuron
What would you do to get a smooth contraction?
Recruitment
What is muscle tone?
The firmness and tension of the muscle fiber at rest
What is the difference between isotonic and isometric contraction?
Isotonic (same tension)- muscle changes length
Isometric (same measure)- changes in tension but not in length
What is the difference between concentric and eccentric movement?
concentric- tension is larger than the load and muscle lengthens
eccentric- tension is less than the load and the muscle shortens
What is the difference between slow and fast fibers?
Slow fibers- are red aerobic fibers that are slow to contract and slow to fatigue; contain lots of myoglobin and mitochondria
Fast fibers are white anaerobic fibers that are fast to contract and fast to fatigue
