Chapter 10 muscle

Question 1

What are the basic functions of muscle tissue?

Answer 1

• 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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Question 2

Somatic vs Visceral

Answer 2

· Somatic: move bone or cartilage
· Visceral: control activities of organs, vessels, or ducts

Question 3

Voluntary vs Involuntary

Answer 3

· Voluntary: conscious control
· Involuntary: autonomic nervous system
nervous system control

Question 4

Describe skeletal muscle

Answer 4

Skeletal muscle: somatic, voluntary, somites(myotomes), striated

found in bone obviously lmao, provide support and structure to vertebrate body

Question 5

Describe cardiac muscle

Answer 5

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

Question 6

Describe smooth muscle

Answer 6

· Smooth: visceral, involuntary, splanchnic lateral plate mesoderm, non-striated(irregular lines)

line organs(guts, glands, blood vessels); in contraction bung up; vasoconstriction and vasodilation

Question 7

What are the three types of muscle tissue?

Answer 7

skeletal, cardiac, and smooth

Question 8

Connective tissue

Answer 8

Connective tissue layers extend beyond the ends of the muscle fibers to connect with the periosteum of the bone; transmit muscle force

Question 9

Fascicle

Answer 9

bundle of muscle cells

Question 10

Myofibril and Sarcomeres

Answer 10

Myofibril: single structures within endomysium
Sarcomeres: functional unites of myofibrils

Question 11

What are the 3 connective tissue layers in skeletal muscle?

Answer 11

Epimysium(outside), perimysium (bundle of muscle cells), endomysium(individual muscle cells)

Question 12

Which layer encases the entire muscle and makes tendons:

Answer 12

epimysium

Question 13

Which layer encases a bundle of skeletal muscle fibers (cells) into fascicles?

Answer 13

perimysium

Question 14

Which layer encases individual skeletal muscle fibers (cells)?

Answer 14

endomysium

Question 15

Describe the basics of how actin and myosin interact to produce contraction.

Answer 15

• 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

Question 16

Origin(proximal insertion)

Answer 16

Relatively fixed attachment; closer to body, not much movement

Question 17

Insertion(distal insertion)

Answer 17

Relatively movable point of attachment.(also called the distal attachment)

Question 18

What are motor units and how are they innervated?

Answer 18

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.

Question 19

What is the effect of muscle cross-sectional area on the force produced?

Answer 19

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.

Question 20

How does muscle fiber orientation affect function?

Answer 20

• 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