Chapter 10: Muscle Tissue Flashcards
Name the types of muscle tissue
skeletal, cardiac, and smooth
Name all 5 functions of muscle tissue
- Movement
- Stability
- Control of body openings and passages
- Heat production (20-30% of BH at rest)
- Glycemic Control (regulation of blood glucose)
Name and describe all 5 characteristics of muscle tissue
- Excitability: able to respond to a stimulus
- Conductivity: signal for a muscle to contract is spread throughout the entire muscle
- Contractability: the ability to forcefully shorten
- Extensibility: to be stretched
- Elasticity: ability to recoil to the original resting length when tension is released
Characteristics of skeletal muscle fibers
multinucleated, striated, and voluntary
What are connective tissue investments and what is their overall function
they are connective tissue sheaths that surround muscle tissue and organize muscle tissue, provide elasticity, and carry blood vessels and nerves to muscle fibers
Epimysium
covers the surface of muscle, dense connective tissue, and continuous with fascia on outer surface. Extends into perimysium
Fascia
connective tissue sheet that covers epimysium and separates muscles
Perimysium
extension of epimysium into muscle; organizes collections of muscle fibers into fascicles; contains nerves and blood vessels
Endomysium
extensions of the perimysium that surround individual muscle fibers; loose connective tissue; contains capillaries and nerves
Fusiform
muscle shape that is thick in middle and tapers at ends; relatively strong; Ex: biceps brachii and gastrocnemius
Pennate
feather shaped muscle; strongest muscle
Aponeurosis
broad sheet of connective tissue that connects some muscles to bones in some cases of indirect attachment
Mechanical advantage
the closer the load is to the fulcrum and the farther the effort is from the fulcrum, the less effort to move the load in short distances
What is a muscle fiber and what is it made of
an individual skeletal muscle cell; sarcolemma: plasma membrane of cell; Sarcoplasm: cytoplasm of cell; contains myofibrils
myofibrils
cylindrical bundles of protein microfilaments or myofilaments
name types of myofilaments
thin, thick, or elastic
Transverse tubules (T-tubules)
invaginations of the sarcolemma that incircle each myofibril
Sarcoplasmic Reticulum (SR)
Endoplasmic reticulum that stores and releases calcium ions. Lies close to T-tubules
Terminal Cisternae
dilated regions of the SR adjacent to T-tubules
Triad
a T-tubule and two terminal cisternae
Thick Filaments
Composed of contractile protein myosin
Myosin molecules
golf club shaped; tail consisted of two twisted chains; double globular head with actin binding sites
Myosin filament
composed of 200-500 myosin molecules
Name all 3 Thin filaments and functions
- Actin- contractile protein’ G-actin has active sites where myosin heads bind
- Tropomyosin- regulatory protein; blocks active sites of actin in relaxed muscle fibers
- troponin- 3 subunits one of which binds calcium
Why do muscle striations occur?
due to arrangement of thick and thin filaments
I Band
regions of thin filaments that do not overlap thick filaments; wide light bands
A Band
Wide Dark Bands; region of overlapping thick and thin filamentts
H Zone
Narrow light region in the center of A band; only thick filaments
M Line
Dark line in center of H band; region where the two halves of myosin filaments are joined
Z Disks
Dark line in center of I band; proteins anchoring thin filaments of adjacent sarcomeres
sarcomeres
segment of a myofibril extending from one Z-disk to the next.
Nodal tissues
specialized cardiac muscle fibers; spontaneously depolarizes; generates heartbeat
characteristics of cardiac muscle tissue
involuntary, striated, and branched; no regeneration does not divide; intercalated disks which are special junctional complexes between cardiocytes
characteristics of smooth muscle fibers
involuntary, no striations, no branching; spindle shaped; capable of dividing and regenerating; dense bodies that replace Z-disks
