Muscular System Flashcards
(28 cards)
What is myology?
the study of muscle
What are the functions of the muscular system?
Movement
Posture maintenance
heat protection
only 40% of the energy released is muscle activity is useful at work
the remaining 60% is given off as heat
What are the characteristics of muscle?
Excitability- ability to receive and respond to stimuli- contract
Contractility- the ability to shorten forcibly
Extensibility- the ability to be stretched or extended
Elasticity- ability to recoil and resume the original resting
What are the types of muscle?
Smooth muscle
Skeletal muscle
Cardiac muscle
What are the characteristics of smooth muscle?
Spindle shaped cells
cells contain a single nucleus
No striations
Contain actin (thin) and myosin (thick) filaments
Have less developed endoplasmic reticulum
Involuntary
What are the types of Smooth muscle?
Multiunit smooth muscles
Visceral smooth muscles
What are the characteristics of multiunit smooth muscle?
Less organized
Functions as individual muscle units
Found in the wall of blood vessel (increase or decrease blood pressure)
What are the characteristics of Visceral smooth muscle?
More organized
Show rhythmicity and peristaltic movements (waves of motion)
mostly found in the wall of the GI tract, uterus, urinary bladder
What are the characteristics of skeletal muscle?
cells are elongated like fibers-called muscle fibers
multinucleated cells
Striated
Voluntary
attached to the bone- associated with posture and movement
Which muscle tissue has spindle shaped cells?
Smooth Muscle
What are the characteristics of cardiac muscles?
cells are elongated and branched
cells are single or multiple nuclei (mostly single)
have intercalated discs
cells are striated
involuntary
muscle fibers contract as a unit
contract for longer time period due to Endoplasmic Ret. having extra calcium
self exciting and rhythmic
EX) Heart muscle
Histology: Each muscle cell is a ?
Myofiber (when elongated)
What is Plasmalemma called in the muscular system?
Sarcolomma
What is cytoplasm called in the muscular system?
Sarcoplasm
What is Endoplasmic reticulum called?
sarcoplasmic reticulum
Each myofiber consists of several cylindrical structures called?
Myofibrils
Each myofibril consists of?
thick and thin myofilaments
Thick myofilaments are?
myosin (protein) filament
Thin myofilaments are?
actin (protein) filament
Overlapping of thick and thin filaments form?
A- band (anisotropic band) Also known as dark band
Each myofibril is divided into compartments called?
sarcomeres
Thin myofilaments form?
I-Band (isotropic band) also called light band
Sarcomeres are separated from one another by?
Z-line
Part of the A-Band that contains think myofilaments ONLY is the?
H-zone
