EXAM 4 - Muscle Tissue: Types of Contractions/LT Relationship/Recruitment/Movement/Metabolism/Fibers
What is treppe?
Additional stimuli applied after muscle relaxation
Define: atrophy Define: hypertrophy
Decrease in muscle mass Increase in muscle mass
PRECISE MOVEMENT: Example Size of motor unit (More/less) muscle fibers for each motor neuron
Eye muscle Small Less
At compressed or stretched length of sarcomere, which (greater/lesser) interaction occurs between myosin head & actin? What is the result?
Less interaction Force of contraction decreases
Define: Isotonic contraction Tension of muscle Length of muscle Is movement produced? Examples
Move a constant load through the range of motion possible at a joint Constant Changing Yes Chewing, talking, walking, etc.
MUSCLE METABOLISM
Muscle contraction requires energy, but little ATP present in muscles. Additional ATP must be produced for extended strenuous exercise to take place
Define: Isometric contraction Tension of muscle Length of muscle Is movement produced? Examples
Muscle does not or cannot shorten, but the tension on the muscle increases greatly Changes Constant No Maintain posture & body position
What is complete tetanus? Is there a relaxation period? Causes movement?
Muscle stimulated at higher rate where muscle contraction is sustained No Yes
What is incomplete tetanus?
Muscle stimulated at rate where only PARTIALLY RELAXES
What are the causes of muscle fatigue? (3) How is lactic acid created?
(1) Depletion of ATP (2) Lack of oxygen (3) Build-up of lactic acid Glucose → pyruvic acid (lack of sufficient oxygen) → lactic acid
What are the types of movement? (2)
(1) Precise movement (2) Gross movement
What is a motor unit?
A motor neuron and all the muscle fibers it innervates
What are the types of muscle contractions? (5)
(1) Twitch contraction (2) Wave summation (3) Incomplete tetanus (4) Complete tetanus (5) Treppe
(ISOTONIC & ISOMETRIC CONTRACTIONS) MOVEMENT
...
(LENGTH OF MUSCLE FIBERS) LENTH-TENSION RELATIONSHIP
...
(NUMBER OF MUSCLE FIBERS CONTRACTING) RECRUITMENT
...
TYPES OF MUSCLE CONTRACTION
...
TYPES OF SKELETAL MUSCLE FIBERS
...
GROSS MOVEMENT: Example Size of motor unit (More/less) muscle fibers for each motor neuron
Calf muscle Large More
With little stored ATP in muscle fibers, what molecule transfers its high-energy phosphate? To which molecules does phosphocreatine transfer?
Creatine phosphate (phosphocreatine) ADP → ATP
When supply of creatine phosphate is depleted, what molecule is catabolized to generate ATP? Where does glucose come from? (2)
Glucose (1) Blood (facilitated diffusion) (2) Breakdown glycogen within muscle fibers
During aerobic respiration, what happens to glucose? How many ATP as a result?
Glucose + 6O₂ → 6O₂ + H₂O + 36ATP 36 ATP
At optimal length of sarcomere, which (greater/lesser) interaction occurs between myosin head & actin? What is the result?
Greater interaction Powerful contraction
Define: Recruitment What are the results of the patter of activity-when some motor units are active and other inactive? (2)
Increasing the number of ACTIVE motor units (1) Prevents muscle fatigue (2) Produces smooth movement
Fast oxidative (Type IIA) fibers - fast-twitch Diameter Packed myofibrils Amount of mitochondria Geared to _________ respiration Contraction produced Fatigue Color Example
Large Densely packed Few mitochondria Anaerobic cellular respiration Powerful contraction Fatigue easily Pale in color Eye muscles
What is a twitch contraction? What produces twitch? Cause movement?
One contraction period followed by one relaxation period Single AP in motor neuron No
Fast oxidative (Type I) fibers - slow-twitch Diameter Packed myofibrils Amount of mitochondria Geared to _________ respiration Contraction produced Fatigue Color Example
Small Loosely packed Many mitochondria Aerobic cellular respiration Extended period of time contraction Fatigue resistant Red in color = high content of myoglobin Calf muscle
What is wave summation? Result [Will second contraction be stronger than first?]
Two stimuli applied where second stimuli is after refractory period, but before muscle fiber finishes relaxing Stimuli arrive at different times → larger contractions [Yes]
