Chapter 10 Flashcards
types of muscle tissue
skeletal muscle, cardiac muscle, smooth muscle
skeletal muscle
striated (banded)
attached to bones
voluntary
cardiac muscle
striated and branching
walls of the heart
involuntary controlled
smooth muscle
non-striated
walls of hollow organs (digestive organs)
involuntary controlled
functions of muscle tissue
movement (moving blood, food) maintenance of posture joint stabilization heat generation (exercising)
functional characteristics of muscle tissue
contractibility, excitability, extensibility, and elasticity
contractibility
can forcibly shorten
excitability
can be stimulated by nerve impulses
extensibility
can be stretched
elasticity
can recoil after it has been stretched
connective tissue coverings
epimysium, perimysium, endomysium
epimysium
dense irregular CT that surrounds an entire muscle
perimysium
fibrous CT tissue that surrounds fascicles (groups of muscle fibers)
endomysium
fine CT layer that surrounds each muscle fiber in a fascicle
skeletal muscle (contains)
muscle tissue
nerves
blood
connective tissue coverings
muscle attachments
can either attached to bones directly or indirectly
origin (attachment point)
-the less movable attachment of a muscle
insertion
-the more movable attachment of a muscle
microscopic anatomy of skeletal muscle tissue
skeletal muscle fibers
- contain myofibrils, the organelles that are responsible for the contraction of the cell - enclosed by the sarcolemma (the plasms membrane of a muscle fiber)
sarcomeres
the segments that make up a myofibril
important structures associated with the sarcomeres
Z discs (lines) thin (actin) filaments thick (myosin) filaments A bands (dark bands) I bands (light bands) H bands (halfway) M lines (midline)
muscle contraction
sliding filament theory
- contraction of a muscle cell occurs when the myosin heads (of the thick filaments) attach to the actin (thin) filaments and pull the thin filaments to the center of the sarcomere
- the Z discs move closer together as the muscle cell contracts
- this process is repeated many times as contraction continues
microscopic anatomy (largest to smallest )
muscle fascicle muscle fiber myofibril sarcomere myofilaments
sarcoplasmic reticulum
a specialized type of endoplasmic reticulum
surrounds each myofibril
stores and releases calcium ions (Ca2+) which allow the filaments to attach and slide past each other
T tubules
extensions of the sarcolemma that wrap around the myofibrils
help to conduct the nerve impulses deep into the muscle fiber
intercalated discs
complex junctions between cardiac muscle cells
allow the cells of the heart to beat simultaneously
cardiac muscle
located in the heart wall
involuntary controlled
fibers striated and branching
contains a large abundance of mitochondria
smooth muscle
located in: inside the eye walls of the circulatory vessels respiratory tubes digestive tubes urinary organs reproductive organs non-striated involuntarily controlled
contraction of smooth muscle
fibers contain actin and myosin filaments but NO SARCOMERES
peristalsis
(this motion will propel substances through organs)
peristalsis
when smooth muscle contracts it causes waves of contraction and relaxation through the surrounding connective tissues