Skeletal Muscle Contraction

Question 1

What are the factors that influence muscle strength?

Answer 1

Pennation (angle of muscle)

Cross sectional area

Fiber type

Length of muscle

Speed of contraction

Type of contraction

Question 2

7 factors influence muscle soreness. What are they?

Answer 2

1) Mini tears in muscle

2) Osmotic pressure change

3) Muscle spasms

4) Overstretching

5) Acute inflammation

6) Alteration in cell’s mechanism for calcium regulation

7) Combination of all other factors

Question 3

What is the basic functional unit of a muscle fiber?

Answer 3

Sarcomere

Question 4

Myocyte is a _______.

Answer 4

Muscle fiber

Question 5

Myofibril is a _________________.

Answer 5

bundle of sarcomeres

Question 6

What type of neuron changes the spindle’s length?

Answer 6

Gamma-motor neurons

Question 7

What are the 8 steps of muscle contraction?

Answer 7

1) EPSP reaches muscle fibril and AP propogates

2) Sarcolemma releases Calcium

3) Calcium binds to troponin exposes the binding site

4) Actin and myosin cross-bridge causing contraction

5) ATP is bound in myosin

6) ATP is released= power stroke

7) New ATP joins = breaks cross-bridge

8) ATP is hydrolyzed= myosin bends again

Question 8

The first step in the process of muscle contraction is for Calcium to bind to ______________.

Answer 8

Troponin

Question 9

Once calcium binds to troponin, _______ slides away from the binding sites on actin.

Answer 9

Tropomyosin

Question 10

During cross-bridge cycle, when is myosin in high-energy?

Answer 10

BEFORE the power stroke

Question 11

When a muscle is sore, what can cause edema around the muscle?

Answer 11

Osmotic pressure changes

Question 12

Describe what could cause muscles to feel sore

Answer 12

Changes in calcium regulation

Osmotic pressure changes

Overstretching

Spasms

Minute tears

Question 13

Pyramidal tract disorder aka

Answer 13

Upper motor neuron syndrome

Question 14

What are signs and symptoms of pyramidal tract disorder?

Answer 14

Babinski Sign

Hypertonic Spasticity

Clonus

Hyper-reflexia

Loss of fine motor skills

Muscle wastes due to non-use

Question 15

Neurons in Extrapyramidial tract originate in _________.

Answer 15

The brainstem

Question 16

The 2 main categories of Extrapyramidial disorders are _________.

Answer 16

Parkinsons (Akinetic rigid syndrome)

Dykinesias
-Tremor
-Chorea
-Tics
-Dystonia

Question 17

Which type of muscle fiber will be recruited first?

Answer 17

Type 1 (endurance/red) since it is smaller

Question 18

What is the largest sensory organ in the body?

Answer 18

Muscles

Question 19

Golgi tendon organs detect _________________.

Answer 19

Change in muscle
-length, pressure, force

Question 20

Intrafusal fibers of muscle spindles are innervated by________.

Answer 20

Gamma-motor neurons

Question 21

Primary spindle afferents respond to ____________.

Answer 21

dynamic change in LENGTH

Tendon tap/vibration

Question 22

Secondary spindle afferents respond to ____________.

Answer 22

static change in posture

Question 23

What are the 2 things that could cause the stretch of intrafusal fibers?

Answer 23

Gamma motor neuron activation

Passive changes in length due to being attached to extrafusal muscle fibers

Question 24

True/False: Golgi Tendon organs are sensitive

Answer 24

True! They are very sensitive

Question 25

Most of the sensory endings in a muscle are made up of _________.

Answer 25

Free nerve endings