Muscles

Question 1

A single skeletal muscle is called____.

Answer 1

Muscle fiber

Question 2

Each muscle fiber is formed during development by the fusion of a number of undifferentiated mononucleated cells, known as ____

Answer 2

Myoblasts

Question 3

Definition of a muscle?

Answer 3

is a number of muscle fibers bound together by connective tissue (collagen)

Question 4

Muscles are connected to bones by ____.

Answer 4

Tendons (which are made by collagen)

Question 5

What is the relationship between a motor neuron and muscle fibers?

Answer 5

one motor neuron innervates around 100 muscle fibers

Question 6

Definition of a motor unit?

Answer 6

motor neuron and muscle fibers it controls (usually around several hundred)

Question 7

A disease that involves the progressive degeneration of lower motor neurons

Answer 7

Spinal Muscular Atrophy

Question 8

Disease that causes nonprogressive degeneration of upper motor neurons in one cerebral hemisphere:

Answer 8

Stroke

Question 9

Disease that causes the progressive degeneration of neurons in Substantia Nigra

Answer 9

Parkinson’s Disease

Question 10

Synchronous firing of all upper motor neurons

Answer 10

Seizure (epilepsy)

Question 11

Disease that causes progressive degeneration of upper and lower motor neurons in both cerebral hemispheres:

Answer 11

Amyotrophic lateral sclerosis (ALS)

Question 12

Progressive degeneration of myelin in central nervous system

Answer 12

Multiple Sclerosis (MS)

Question 13

The strength of muscle contraction depends on:

Answer 13

1) The number of motor units recruited
2) The frequency of a motor unit discharge
3) The speed of contraction of muscle fibers in the motor unit
4) The nature of a motor unit (whether it is fatigue-resistant or fatigue-prone)

Question 14

Stack many sarcomeres together longitudinally and you have a _____.

Answer 14

Myofibril

Question 15

Name the protein that covers myosin binding sites on actin

Answer 15

Tropomyosin

Question 16

Name Ca2+ sensitive protein that controls cross bridge cycle

Answer 16

Troponin

Question 17

What does troponin do once it is bound to calcium?

Answer 17

It swings tropomyosin away from the rails (actin) from its locomotive (myosin), thus exposing the myosin binding site, allowing a cross bridge to form, and a muscle to contract

Question 18

What keeps muscle from continuous contractile activity?

Answer 18

Tropomyosin is held by Troponin in resting muscle in the position that does not allow myosin to bind to actin

Question 19

Where does calcium come from in a neuron?

Answer 19

Extracellular fluid (EF)

Question 20

Name the muscle length sensors

Answer 20

Muscle spindle

Question 21

Name the muscle tension sensors

Answer 21

Golgi tendon organ