4 Muscular System Flashcards
Muscle Function
- Produce Movement
- Maintain Posture and Body Position
- Stabilize joints
- Generate heat
- additional functions
Skeletal muscle fibers are packaged into organs called _ that attach to the skeleton
skeletal muscles
Skeletal Muscle cover our _ , they help form the smooth contours of the body.
bone and cartilage framework
physical structure of
Skeletal muscle fibers
- large
- cigarshaped
- multinucleate cells
Skeletal muscle is also known as _ and as
voluntary muscle
striated muscle
Connective Tissues wrapping
wraps entire muscle
epimysium
Connective Tissues wrapping the Muscle Fibers
wrapped in endomysium
muscle fiber
Connective Tissues wrapping the Muscle Fibers
wrapped in perimysium
fascicle
no striations and is
involuntary
smooth muscle
found mainly in the walls of
hollow (tubelike) organs
smooth muscle
- are spindle-shaped, uninucleate, and surrounded by scant endomysium and are arranged in two layers (circular and longitudinal)
- single, fusiform, no striations
smooth muscle
- is striated, uninucleated and under involuntary control
- branching chains of cells
Cardiac Muscle
are cushioned by small amounts of endomysium and are arranged in spiral or figure 8–shaped bundles
cardiac cell
Cardiac muscle fibers are branching cells joined by special gap junctions called _
intercalated discs
connective tissue components of skeletal muscle
- epimysium
- perimysium
- endomysium
connective tissue components of cardiac muscle
endomysium attached to the fibrous skeleton of the heart
connective tissue components of smooth muscle
endomysium
regulation of contraction of skeletal muscle
voluntary via nervous system controls
regulation of contraction of cardiac muscle
- involuntary
- internal heart pacemaker
- nervous system controls
- hormones
regulation of contraction of smooth muscle
- involuntary
- nervous system controls
- hormones
- chemicals
- stretch
speed of contraction of skeletal muscle
slow to fast
speed of contraction of cardiac muscle
slow
speed of contraction of smooth muscle
very slow
rhythmic contraction of skeletal muscle
no
rhythmic contraction of cardiac muscle
yes
rhythmic contraction of smooth muscle
yes, in some
Microscopic Anatomy of Muscle
- sarcomeres
- myofilaments
- sarcoplasmic reticulum
Microscopic Anatomy of Muscle
structural and functional units of skeletal muscle
sarcomeres
Microscopic Anatomy of Muscle
are the precise arrangements of even smaller structures within sarcomeres - thin and thick myofibrils
myofilaments
Microscopic Anatomy of Muscle
interconnecting tubules and sacs that is used to store calcium and to release it on demand when the muscle fiber is stimulated to contract
sarcoplasmic reticulum
Special functional properties of muscle fibers
- irritability
- contractility
- extensibility
Skeletal Muscle Fiber Activity
- aka responsiveness
- ability to receive and respond to stimulus
irritability
Skeletal Muscle Fiber Activity
the ability to forcibly shorten when adequately stimulated
contractility
Skeletal Muscle Fiber Activity
the ability of muscle fibers to stretch, whereas elasticity is their ability to recoil and resume their resting length after being stretched
extensibility
Muscle Contraction
Skeletal muscle fibers must be stimulated by _
nerve impulses
Muscle Contraction
- _ may stimulate a few muscle fibers or hundreds of them, depending on the particular muscle and the work it does
- A _ consists of one neuron and all the skeletal
muscle fibers it stimulates
- One motor neuron (nerve cell)
- motor unit