Nervous + Muscular system

Question 1

what is actin?

Answer 1

a thin filament protein involved in muscle contraction

Question 2

what is myosin?

Answer 2

a thick filament protein involved in muscle contraction

Question 3

what is an A band?

Answer 3

the dark band in a sarcomere representing where myosin filaments are present

Question 4

what is an I band?

Answer 4

the light band in a sarcomere representing where actin filaments are present

Question 5

describe aerobic exercise

Answer 5

physical activity that uses oxygen to produce energy, promoting cardiovascular health and endurance

Question 6

define contractility

Answer 6

the ability of muscle tissue to shorten and generate force

Question 7

define elasticity

Answer 7

the ability of a muscle tissue to return to its original length after being stretched

Question 8

define endomysium

Answer 8

sheath of connective tissue that surrounds each muscle fiber

Question 9

define epimysium

Answer 9

a sheath of connective tissue that surrounds the entire muscle

Question 10

define perimysium

Answer 10

a sheath of connective tissue that surrounds a fascicle

Question 11

define Golgi tendon organ (GTO)

Answer 11

a sensory receptor located in tendons that detects changes in muscle tension

stops contraction/mm relaxation

Question 12

define irritability/responsivity

Answer 12

the ability of muscle tissue to respond to stimuli, typically from the nervous system

Question 13

define an isometric contraction

Answer 13

no movement occurs
ex: holding a plank position

Question 14

define an isotonic contraction

Answer 14

movement occurs
concentric vs eccentric
ex: lifting a box or squatting

Question 15

explain the 5 golden rules of skeletal muscle activity

Answer 15

• With a few exceptions, all muscles cross at least 1 joint
• The bulk of a muscle mass lies proximal to the joint it crosses
• All skeletal muscles have an origin and insertion
• During contraction, the insertion moves toward the origin
• All skeletal muscles can only pull, never push

Question 16

tendons vs ligaments

Answer 16

Tendons: connect muscle to bone
Ligaments: connect bone to bone

Question 17

define muscle spindle

Answer 17

Skeletal muscle (intrafusal fibers)
- Measures: muscle stretch and length
- Reflex: resist stretch

Question 18

what are the 4 muscle movers and what do they do?

Answer 18

• Agonist: prime mover
• Antagonist: opposes prime mover
• Synergists: assists prime mover, reduces undesirable movements
• Fixators: specialized synergist, stabilizes to allow the prime mover to move the insertion point

Question 19

describe cardiac muscle type

Answer 19

• branching chains, uninucleate, striations, intercalated discs
• involuntary, slow contraction
• controls pacemaker (SA node) and nervous system

Question 20

describe skeletal muscle type

Answer 20

• single, long and cylindrical, multinucleate, striations
• voluntary contraction, speed varies
• controls the nervous system

Question 21

describe smooth muscle type

Answer 21

• single, fusiform, uninucleate, no striations
• involuntary contraction, speed varies
• controls nervous system, hormones, chemicals, and stretch

Question 22

what are the 4 skeletal muscle functions?

Answer 22

• Produce movement
• Maintain body posture and position
• Stabilize joints
• Produce heat

Question 23

describe the 4 skeletal muscle fiber properties

Answer 23

• irritability/responsivity
• Contractility
• Extensibility
• Elasticity

Question 24

describe the key components of a neuromuscular junction

Answer 24

The neuromuscular junction is where a motor neuron communicates with a muscle fiber. It includes the axon terminal of the neuron, the synaptic cleft, and the motor end plate (specialized region of the sarcolemma) on the muscle fiber.

Question 25

What is a motor unit and why is it considered the functional unit of skeletal muscle?

Answer 25

The neuromuscular junction is where a motor neuron communicates with a muscle fiber. It includes the axon terminal of the neuron, the synaptic cleft, and the motor end plate (specialized region of the sarcolemma) on the muscle fiber.

Question 26

Briefly summarize the sliding filament theory.

Answer 26

The sliding filament theory explains that muscle contraction occurs when the protein filaments actin and myosin slide past each other. This overlapping shortens the sarcomere, the basic unit of muscle contraction, leading to overall muscle shortening.

Question 27

What is the primary cause of Amyotrophic Lateral Sclerosis (ALS) and how does it affect muscle function?

Answer 27

ALS is caused by the degeneration of motor neurons, the nerve cells responsible for transmitting signals from the brain and spinal cord to muscles. This disrupts nerve impulses to muscles, leading to progressive muscle weakness and paralysis.

Question 28

State the typical prognosis for an individual diagnosed with ALS and explain why.

Answer 28

The typical prognosis for ALS is a life expectancy of 3-5 years. This is primarily because the muscles involved in breathing eventually become affected, leading to respiratory failure and suffocation.

Question 29

Explain how Myasthenia Gravis leads to muscle weakness.

Answer 29

Myasthenia Gravis results in muscle weakness because the communication between nerves and muscles is disrupted. This occurs due to a shortage of acetylcholine receptors or antibodies attacking these receptors at the neuromuscular junction, preventing effective muscle stimulation.

Question 30

What are the two main causes of the disruption at the neuromuscular junction in Myasthenia Gravis?

Answer 30

The two main causes of disruption at the neuromuscular junction in Myasthenia Gravis are:
1) a shortage of acetylcholine (ACh) receptors on the muscle fiber membrane and
2) the presence of antibodies that attack and block existing ACh receptors.