Test Prep 2 Flashcards
Smooth Muscle?
- Non striated
- Involuntary
- Found in walls of hollow internal structures, such as blood vessels, airways, and most hollow organs
- Function include peristalsis, blood pressure, pupil size, erect hairs
Skeletal Muscle?
- Striated, multi nucleated, fibers run parallel
- Voluntary
- Found along skeleton
- Functions include movement, heat generation, posture
Cardiac Muscle?
- Striated, one central nucleus
- Involuntary
- Found in the heart
- Pumps blood
General Functions of Muscle Tissue?
- Body movements
- Stabilizing body position- posture
- storing and moving substances within the body
- Generating Heat
Properties of Muscle Tissue?
- Excitable
- Contractibility
- Extensibility
- Elastisity
Plasma membrane of Muscle?
Sarcolemma
Within the Sarcolemma there is..
Sarcoplasm (fluid). Sarcoplasm contains myoglobin (red pigmented protein)
Layers of covering of a muscle?
From deep to superficial:
myofilaments: actin and myosin, make up the myofibril-inside sarcoplasm
sarcoplasm is inside the sarcolemma, covered by the endomysium. Makes up a fasicle, covered in the perimysium
muscles are covered by the epimysium
What is a compartment?
A functional group of skeletal muscles that work together and are wrapped together by a container
In limbs, a group of skeletal muscles, associated blood vessels, associated nerves all of which have a common function
Fascia Lata?
Thickening of epimysium to envelope the quads and hamstrings
Aponeurosis?
Thick fascia
What does Sarcoplasmic Reticulum do?
Adjacent to t-Tubules, stores calcium
Actin?
The thin filament. Has a myosin binding site
Titin?
Structural protein that connects Z disc to M line of sarcomere. Lets muscle return to original shape
What is the A Band?
Part of the sarcomere with the myosin
I Band?
Part of sarcomere without myosin, changeable in length
H Zone
Only myosin, no actin
What does “iso” mean?
Same
Isotonic muscle contraction?
The tension in the muscle remains constant while the muscle changes its length. Used for body movements and for moving objects. Two types of Isotonic contractions, eccentric and concentric
2 types of Isotonic Contraction?
Eccentric and Concentric
Concentric Contraction?
tension generated is great enough to overcome the resistance of the object to be moved, and the muscle shortens and pulls on another structure, such as a tendon, to produce movement and reduce the angle at a joint. Example is picking up a book- concentrated isotonic contraction of the biceps brachii
Eccentric Contraction?
Think the lowering part of a squat. The muscle lengthens in a controlled manner while it continues to contract. Lowering the book is a eccentric isotonic contraction
Isometric Contraction?
The tension generated is not enough to exceed the resistance of the object to be moved, and the muscle stays the same. No change in length, no movement.
Example is holding a book out. Energy is still being used, but no change in length or movement
What does hydrolyze mean?
ATP had water added to it
What is a motor unit comprised of?
The motor unit is comprised of the lower motor neuron plus all the muscle cells that it innervates.
Sequence of structures that AP follows?
Starts at Neuromuscular junction
follows axon to motor end plate
-acetylcholine is released
-sodium moves through ligand channels
-potassium is moved through voltage gated channels
-leak channels move both sodium and potassium
-threshold of -55 reached
-muscle AP follows through T tubules
-T tubules open voltage gated calcium channels
-Calcium binds to troponin on the thin actin filament
-Exposes myosin binding sites
-if myosin heads are ready, they attach, pull actin filaments toward m line
-ATP needed to release myosin heads
-ATP needed to open the calcium active transport pumps- restore calcium levels in sarcoplasm
-tropomyosin slides back, muscle relaxes
What is motor unit recruitment?
the process in which the number of active motor units increases is called motor unit recruitment. Responsible for smooth movements instead of jerks. Uses motor units to increase tension in a muscle.
Autorhythmic Muscle Fibers?
Myocardial muscle cells- form the conduction system of the heart
2 places ATP is used?
- bring calcium back into Sarcoplasmic reticulum
- Bring myosin off tropomyosin heads
How are skeletal muscles classified?
By structure and function
Skeletal Muscles by Structure?
by Structure:
Red- dark meat, have high myoglobin content, more mitochondia, more energy stores (glycogen) and more blood supply
White- Have less myoglobin, less mitochondria and less blood supply
Skeletal Muscle by Function?
Slow Oxidative Fibers: small, red fibers, least powerful, very fatigue resistant, used for endurance- like postural muscles
Fast Oxidative- glycolic Fibers: are intermediate in size, appear dark red, are moderately resistant to fatigue. Used for walking
Fast-glycolic fibers: are large, white and powerful. Suited to intense anaerobic activity for short duration
What is hyperplasia?
too much change in the number of cells. Its an extra number of cells