Module 4 Quiz Flashcards
What are the 3 types of muscle tissue?
Cardiac
Smooth
Skeletal
Function of muscle?
Contract and create a pulling force
What are the 2 types of tissue found in skeletal muscle?
Skeletal muscle tissue
Fibrous fascial connective tissue
What are the major structural and major functional units of a muscle?
Muscle cells (make up majority of muscle and they do the contracting)
What is the function of fascial connective tissue?
Structural framework for muscle and becomes tendon.
Transfers force of muscle contraction to bone
Why are there nerves in skeletal muscle?
Carry motor messages from CNS to muscle
Carry sensory messages from muscle to CNS
Why are there blood vessels in skeletal muscle?
Bring needed nutrients to the muscle tissue and drain away waste products of muscle metabolism
What are muscle fibers?
Muscle cells
Length of muscle fibers (cells)?
0.5 inch to 20 inches
What is the classic appearance of muscle cells?
Striated
What is a fascicle?
Bundles of muscle fibers (up to 200)
What is muscular fascia made of?
Mostly collagen, some elastin
What is the fibrous fascia that surrounds each individual muscle fiber?
Endomysium
What is the fibrous fascia that surrounds a group of muscle fibers, dividing the muscle into fascicles?
Perimysium
What is the fibrous fascia that surrounds an entire muscle?
Epimysium
What is lateral force transmission?
Force of contraction of fiber A will transfer to fiber B even though it was not stimulated to contract.
Occurs through connections of endo-, peri-, and epimysia
What is a tendon?
Muscular fascia that attaches the muscle to a bone or soft tissue (round and cord-like)
What is an aponeurosis?
Muscular fascia that attaches the muscle to bone or soft tissue (broad and flat)
Because tendons and aponeuroses are an integral part of the muscle, muscles are referred to as…
myofascial units
What is intermuscular septa?
Thick muscular fascia that separates muscles of the body and provide a site of attachment for adjacent muscles
What are aponeurotic sheets?
Muscular fascia that expands over large groups of muscles
Where are the nerves and blood vessels located in skeletal muscle?
Within muscular fascia
What are the cellular microstructures in muscle cells?
Cytoplasmic organelles
Why are muscle cells multinucleate?
Muscle fibers developed from multiple stem cells grouping together
Why are muscles rich in mitochondria?
Mitocondria create adenosine triphosphate (ATP) molecules aerobically
What is myoglobin?
oxygen-binding molecule in muscle similar to hemoglobin but has greater ability to bind oxygen
What are myofibrils?
Cytoplasmic organelles that runs the length of the fiber - composed of sarcomeres (that lay side by side)
What is a Z-line?
boundary of a sarcomere
Each sarcomere contains protein filaments called
Actin
Myosin
Where are the actin and myosin filaments within the sarcomere?
Actin filaments are attached to the Z-lines at both ends
Myosin filaments are located in the center of the sarcomere
What causes muscle striation?
Overlapping of actin and myosin filaments
What is the functional unit of skeletal muscle?
Sarcomere (performs the contraction)
What is the physiologic process of a sarcomere celled?
Sliding filament mechanism (also called ratchet theory)
Where does the energy that drives the sliding filament mechanism come from?
Adenosine triphosphate (ATP) molecules
What are the 2 steps of the sliding filament mechanism that require ATP?
- Energy for myosin-actin cross-bridges to break
2. Reuptake of calcium into sarcoplasmic reticulum when contraction done
What are the 4 steps in which ATP molecules are supplied
- Stored ATP
- Regeneration of ATP from stored creatine phosphate
- Regeneration of ATP from anaerobic breakdown of glucose
- Regeneration of ATP from aerobic breakdown of glucose
Breakdown of glucose first occurs aerobically or anaerobically?
Anaerobically
Where does anaerobic breakdown of glucose occur?
Within the sarcoplasm of muscle cell
Where does aerobic breakdown of glucose occur?
Within mitochondria
How does aerobic breakdown of glucose exercise the heart?
Requires oxygen which requires increased circulation which increases demand on heart
How does the lack of ATP account for rigor mortis?
ATP required to break myosin-actin cross-bridges.
- Muscles in state of contraction at death
- Calcium leaks into sarcoplasmic reticulum and triggers cross-bridges (continues until tissue breaks down)
How is ATP expenditure related to trigger points?
Trigger points squeeze blood vessels, diminish blood flow, and decrease delivery of glucose to muscle cells –> deficiency of ATP production
Decreased ability to break cross-bridges and reuptake calcium
What is the energy crisis hypothesis?
ATP deficiency leading to formation and persistence of trigger points
What is glycolysis?
Anaerobic breakdown of glucose
For each molecule of glucose broken down by glycolysis, what is formed?
2 ATP molecules Lactic acid (waste)
What is the Kreb’s cycle
Aerobic breakdown of glucose
For each molecule of glucose broken down by Kreb’s cycle, what is formed?
36 ATP
Carbon dioxide
Water
What is oxygen’s role in aerobic metabolism?
Bonds to the carbon atoms created when glucose molecule is broken down to create CO2 which can be easily carried away in the bloodstream and eliminated via the lungs
What is oxygen debt?
When anaerobic metabolism is relied on, lactic acid is a waste product; this is sent to the liver to be turned into glucose
Sending it to the liver requires oxygen - explains why person may continue to breathe deeply after exercise is completed
What is muscle innervation?
When peripheral nerve has ability to direct muscle to contract
What is the small space between muscle fiber and motor neuron?
Synaptic cleft; synaptic gap; synapse
What are neurotransmitters
Molecules released by motor neuron into synapse which transmit neural message for contraction to muscle fiber
What is the neurotransmitter released between motor neurons and muscle fibers?
Acetylcholine
What happens when neuron no longer secretes acetylcholine?
Neurotransmitter left in synapse is removed by acetylcholinesterase enzyme and muscle relaxes