Chapter 10 muscle Flashcards
What are the basic functions of muscle tissue?
- Movement and locomotion, through its direct connection with the skeletal system
- Major parts of organ systems (heart, blood vessels, GI system)
- More subtle movements associated with maintaining posture/vertical position
- Help to generate heat due to catabolic reactions that are associated with muscular activity (such that animals shiver or increase overall movement when body temperature drops)
- Can be modified into other structures, such as electric organs in some fish
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Somatic vs Visceral
· Somatic: move bone or cartilage
· Visceral: control activities of organs, vessels, or ducts
Voluntary vs Involuntary
· Voluntary: conscious control
· Involuntary: autonomic nervous system
nervous system control
Describe skeletal muscle
Skeletal muscle: somatic, voluntary, somites(myotomes), striated
found in bone obviously lmao, provide support and structure to vertebrate body
Describe cardiac muscle
Cardiac muscle: visceral(part of internal organs), involuntary, splanchnic lateral plate mesoderm, striated
Cells connected by intercalated discs; Facilitates contraction of all cells nearly simultaneously; found in heart
Describe smooth muscle
· Smooth: visceral, involuntary, splanchnic lateral plate mesoderm, non-striated(irregular lines)
line organs(guts, glands, blood vessels); in contraction bung up; vasoconstriction and vasodilation
What are the three types of muscle tissue?
skeletal, cardiac, and smooth
Connective tissue
Connective tissue layers extend beyond the ends of the muscle fibers to connect with the periosteum of the bone; transmit muscle force
Fascicle
bundle of muscle cells
Myofibril and Sarcomeres
Myofibril: single structures within endomysium
Sarcomeres: functional unites of myofibrils
What are the 3 connective tissue layers in skeletal muscle?
Epimysium(outside), perimysium (bundle of muscle cells), endomysium(individual muscle cells)
Which layer encases the entire muscle and makes tendons:
epimysium
Which layer encases a bundle of skeletal muscle fibers (cells) into fascicles?
perimysium
Which layer encases individual skeletal muscle fibers (cells)?
endomysium
Describe the basics of how actin and myosin interact to produce contraction.
- Both two types of myofilaments; actin spiral-like and myosin straight thick lines
- Myofilaments interact by binding to produce a sliding movement between the filaments, and that creates tension in the muscle fiber leading to muscle contraction
Origin(proximal insertion)
Relatively fixed attachment; closer to body, not much movement
Insertion(distal insertion)
Relatively movable point of attachment.(also called the distal attachment)
What are motor units and how are they innervated?
Motor Units: A motor unit consists of a single motor neuron and all the muscle fibers it innervates. The motor neuron transmits signals from the central nervous system to the muscle fibers, causing them to contract.
Innervation: The axon of the motor neuron branches out to connect with multiple muscle fibers at neuromuscular junctions. When the motor neuron fires, it simultaneously stimulates all the muscle fibers within its motor unit to contract in unison.
What is the effect of muscle cross-sectional area on the force produced?
The force a muscle can produce is directly proportional to its cross-sectional area. A larger cross-sectional area indicates more muscle fibers packed within a given volume, which means greater force production.
How does muscle fiber orientation affect function?
- Best at moving a light load through a long distance
- All fibers lie along the line of tension generated - fibers are parallel to one another
