Chapter 10 Flashcards
(20 cards)
List all the muscle tissue functions.
- producing body movements
- stabilizing body positions
- storing/moving substances within the body (food/blood)
- generating heat (shivering)
- communication (facial muscles)
How is muscle tissue different from the other 3 tissue types?
Functions : mostly for movement
Types : skeletal, smooth, cardiac
Structure : Muscle fibers are elongated and packed with actin and myosin, which are arranged in a way that allows for contraction
Cell Arrangement : muscle fibers are organized in bundles
What are the 3 classes of muscle tissue?
- Smooth
- Skeletal
- Cardiac
Define Smooth Muscle.
- non striated
- involuntary
-fusiform (spindle) shape
Define Skeletal Muscle.
- striated
- voluntary
- myofibers
Define Cardiac Muscle.
- striated
- involuntary
- branched
- cardiocytes
What are the levels of muscle structure (muscle tissue)? Superficial to Deep.
- whole muscle
- fascicles - smaller bundles
- MYOfibers - individual cells
- MYOfibrils - cluster of protein inside the cell
- MYOfilaments - contractile proteins
What are the levels of skeletal muscle structures (wrappings/CT)? Superficial to Deep.
- Superficial fascia - hypodermis
- Deep fascia - dense connective tissue
- Epimysium - dense irregular connective tissue
- Perimysium - bundles of fibers
- Endomysium - muscle cell
What are the levels of skeletal muscle structure (whole)? Superficial to Deep.
- Superficial Fascia
- Deep Fascia
- Epimysium
- Whole Muscle
- Perimysium
- Fascicle
- Endomysium
- Myofibers
- Myofibrils
- Myofilaments
What structures would you find inside the muscle cell?
- Myofibrils
- Sacromeres
- Sarcoplasm (cytoplasm)
- Sarcoplasmic Reticulum (SR)
- Transverse Tubules (T Tubules)
- Mitochondria
- Nucleus
What is inside the myofibril?
Bonding striations from thick and thin myofilaments.
- I bond
- A bond
- M line
- H zone
- Z disc
- sarcomere (each repeating unit is a sarcomere)
What are the thin myofilaments made of?
ACTIN
- double stranded actin
- has binding sites for myosin
- sites covered by tropomyosin
What are thick myofilaments made of ?
MYOSIN
- bundles of myosin
- each myosin molecule has a head and tail
The myofiber also has…
T Tubules
- deep investigations of sarcolemma that extends across the cell
Sarcoplasmic Reticulum (smooth E.R)
- stores the calcium needed for contraction
- dilated terminal cisterns contact T tubules
What about Sarcoplasmic Reticulum?
- The sarcoplasm of the myofiber is full of myofibrils.
- The sarcoplasmic reticulum, which stores calcium surrounds the myofibrils.
- Calcium needs to be released into the sarcoplasm in order for muscles to contract
- without calcium, myosin and actin cannot bind
What makes skeletal muscles contract ?
- Neurons communicate with skeletal muscle fibers to get them to contract.
Define N.M Junction ?
Neuromuscular Junction (NMJ)
- the synapse between a motor neuron and a skeletal muscle fiber
Neurotransmitter = acetylcholine (ACh)
How does the neuron activate contraction in the myofiber?
- Action Potential Growth
- Release of Acetylcholine
- Binding to receptors
- Depolarization
- Calcium Release
- Contraction Mechanism
- Cross - Bridge Cycling
- Relaxation
Define muscle relaxation.
- stops the electrical impulse from a neuron
- removes the neurotransmitter - ACh
- returns the calcium to storage in the SR
Define a motor unit.
- 1 somatic motor neuron + all the fibers it innervates
- each fiber has one neuron, BUT one neuron can innervate many fibers
if a stronger contraction is needed…
- more units will be recruited
