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]