Muscle tissue Flashcards
What are the three types of muscles?
Skeletal
Cardiac
Smooth
Which type of muscle has many nuclei per cell?
Skeletal
Which muscle types use involuntary control?
Cardiac
Smooth
Which types of muscles produce the most heat?
Skeletal
What are the four characteristics of muscle tissue?
Excitability
Contractility
Extensibility
Elasticity
What’s the name of the CT layer between skin and muscle?
superficial fascia
What are the functions of the superficial fascia?
Stores water and fat
Preserves heat
Protects and cushions underlying tissues
What does the deep fascia do?
Holds functional groups of muscles together
Allows each muscle to move
Fills spaces between muscles
The [???] is the CT layer that wraps a whole muscle
epimysium
The [???] is the CT layer that wraps muscle fascicles
perimysium
The [???] is the CT layer that wraps each muscle fiber
endomysium
What type of CT are tendons made of?
Dense regular
What’s the plasma membrane of a skeletal muscle cell called?
Sarcolemma
What’s the cytoplasm of a skeletal muscle called?
Sarcoplasm
What’s the name of the organelle running the length of the cell that’s made up of sarcomeres?
Myofibril
What are sarcomeres made of?
Myofilaments
What causes muscle striation?
The arrangement of myofilaments
What are the two types of myofilaments?
Thick filaments
Thin filaments
What proteins are thick filaments made of?
Myosin
What proteins are thin filaments made of?
Actin
What does the sarcoplasmic reticulum do?
Stores calcium and releases it when signaled by a nerve impulse
What do cross bridges do?
Stick out of thick filaments and bind with thin filaments
What do T-Tubules do?
Continuations of the sarcolemma that carry nerve impulses to deeper region of muscle fiber
Explain the Sliding Filament Mechanism
When nerve impulse signals muscle cell calcium is released from sarcoplasmic reticulum. This allows myosin to bind to actin and pull the thin filaments toward the center of the sarcomeres.
What’s a motor unit?
One motor neuron plus all the muscle fibers it innervates
Delicate muscles have [more/fewer] fibers per motor unit.
Fewer
What’s the area called where the neuron meets a muscle fiber?
Neuromuscular junction
What’s the gap between a neuron and a muscle fiber called?
Synaptic cleft
What’s the name of the neurotransmitter that’s released at the neuromuscular junction?
Acetylcholine
What are the structural/functional types of skeletal muscle fiber?
Red slow twitch/slow oxidative
White fast twitch/fast glycolytic
Intermediate fast twitch/fast oxidative
Which types of muscle fibers are smallest?
Red slow twitch
Which muscle fiber types are more common in postural muscles?
Red slow twitch/slow oxidative
which 2 kinds of muscle fibers can convert to the other?
White fast twitch
Intermediate fast twitch
Where are intercalated discs found?
Between cells in cardiac muscle
What are intercalated discs made of?
Desmosomes to resist stretch
Gap junctions allow ions to carry between cells
Order the 3 muscle fiber types by length
Smooth - 30-200 mm long
Cardiac - 100 mm long
Skeletal - cenimeters long
What are the 2 main types of smooth muscle?
Multiunit (in specific places) Single unit (most)
Skeletal muscle contracts through sliding filament, where smooth muscle does what?
Scrunching criss-crossed filaments
