Histlo lab 5

Muscle tissue

•Is a type of tissue in the human body that is responsible for producing heat, force and motion and maintaining posture.

•Makes up ~40% of body weight along with connective tissue.

40%

Muscle makes up how many % of body weight

•Skeletal Muscle

•Cardiac Muscle

•Smooth Muscle

•There are three types of Muscle Tissue:

"skeletal muscle"

•Named _______ because most attach to bones, but some attach to skin or connective tissue sheets.

•Voluntary

•Each muscle cell = muscle fiber.

•Fiber count remains constant after birth.

•Muscles grow by increasing fiber size, not fiber number.

•Exercise enlarges muscle fibers, not their quantity.

Bundles

Skeletal muscle fibers are arranged in

sarcoplasm

The cytoplasm of muscle cells is called

sarcolemma

surrounding cell membrane or plasmalemma of muscle

is called

actin and myosin

two types of contractile protein filaments

Epimysium

Outer sheath covering the whole muscle

Perimysium

Surrounds fascicles, contains blood vessels and nerves

Endomysium

Covers individual muscle fibers, supports nerves & blood vessels

Tendons

Formed by the merging of these connective tissue, layers, attaching muscle to bone

Perymisum
Endomysium

Connective tissue organization

Muscle spindle

•Encapsulated sensory organ

•Connective tissue capsule (8) from adjacent perimysium

Contains intrafusal fibers

Intrafusal fibers

•Specialized stretch receptors in nearly all skeletal muscles

•Detect changes in muscle fiber

sarcomeres

Myofibrils consist of repeating units called ____

sarcomeres

are the contractile elements of striated muscle

Cardiac muscle

•Share characteristics with skeletal muscle fibers

•Exhibit cross-striations

•Contain branching fibers with little change in diameter

•Shorter fibers than skeletal muscle

•Single, centrally located nucleus (some binucleate fibers)

•Perinuclear sarcoplasm (clear zones around nuclei)

•Myofibrils visible in transverse sections

•Involuntary

Smooth muscle

•Found in hollow organs (e.g., intestines, blood vessels)

•Involuntary and controlled by the autonomic nervous system

•Capable of sustained, low-force contractions