Skeletal & Muscular System

Question 1

What are the main functions of the skeletal system?

Answer 1

Support, protection, movement, mineral storage, blood cell production, and energy storage.

Question 2

What are the two main parts of the human skeleton?

Answer 2

Axial skeleton and appendicular skeleton.

Question 3

What bones are included in the axial skeleton?

Answer 3

Skull, vertebral column, and thoracic cage.

Question 4

What bones are included in the appendicular skeleton?

Answer 4

Limbs and girdles (pectoral and pelvic girdles).

Question 5

What are the four main types of bones by shape?

Answer 5

Long bones, short bones, flat bones, and irregular bones.

Question 6

Give an example of a long bone.

Answer 6

Femur.

Question 7

What is an example of a flat bone?

Answer 7

Sternum.

Question 8

What is the diaphysis of a bone?

Answer 8

The shaft or central part of a long bone.

Question 9

What is the epiphysis?

Answer 9

The end part of a long bone, initially growing separately from the shaft.

Question 10

What is the medullary cavity

Answer 10

The central cavity of bone shafts where marrow is stored.

Question 11

What covers the outer surface of bones?

Answer 11

Periosteum.

Question 12

What are the two main types of bone tissue?

Answer 12

Compact bone and spongy bone.

Question 13

What is compact bone?

Answer 13

Dense and solid bone tissue that forms the outer layer of bones.

Question 14

What is spongy bone?

Answer 14

Porous bone tissue found at the ends of long bones and inside flat bones.

Question 15

What are osteoblasts?

Answer 15

Cells that build new bone tissue.

Question 16

What are osteoclasts?

Answer 16

Cells that break down bone tissue.

Question 17

What are osteocytes?

Answer 17

Mature bone cells that maintain bone tissue.

Question 18

What is ossification?

Answer 18

The process of bone formation.

Question 19

What are the two types of ossification?

Answer 19

Intramembranous and endochondral ossification.

Question 20

Where does intramembranous ossification occur?

Answer 20

In flat bones like the skull.

Question 21

Where does endochondral ossification occur?

Answer 21

In most bones of the body, especially long bones

Question 22

What is a joint?

Answer 22

A place where two or more bones meet.

Question 23

What are the three functional classifications of joints?

Answer 23

Synarthroses (immovable), amphiarthroses (slightly movable), and diarthroses (freely movable).

Question 24

What are the three structural classifications of joints?

Answer 24

Fibrous, cartilaginous, and synovial joints.

Question 25

Give an example of a synovial joint.

Answer 25

Knee joint.

Question 26

What fluid is found in synovial joints?

Answer 26

Synovial fluid.

Question 27

What is osteoporosis?

Answer 27

A condition where bones become weak and brittle due to loss of bone mass.

Question 28

What is arthritis?

Answer 28

Inflammation of the joints causing pain and stiffness.

Question 29

What type of muscles are under voluntary control and responsible for body movement?

Answer 29

Skeletal muscles.

Question 30

What type of muscle propels materials through the digestive, cardiovascular, urinary, and reproductive systems?

Answer 30

Smooth muscle.

Question 31

What is the main function of cardiac muscle?

Answer 31

To pump blood by contracting the heart.

Question 32

What common feature is shared by all muscle tissues?

Answer 32

Contraction.

Question 33

Which muscle type is primarily responsible for body movement and posture?

Answer 33

Skeletal muscle

Question 34

How do skeletal muscles aid in communication?

Answer 34

They control facial expressions, speaking, writing, typing, and gesturing.

Question 35

How do muscles contribute to body temperature?

Answer 35

Muscle contraction releases heat as a by-product, helping maintain body temperature.

Question 36

How does smooth muscle help in the function of internal organs?

Answer 36

It causes constriction to propel and mix contents in organs and regulate blood flow.

Question 37

What role does cardiac muscle play in circulation?

Answer 37

Its contraction causes the heart to beat, propelling blood throughout the body.

Question 38

What are the three types of muscle tissue?

Answer 38

Skeletal muscle, smooth muscle, and cardiac muscle.

Question 39

What percentage of body mass is skeletal muscle?

Answer 39

Approximately 40%.

Question 40

What is unique about the structure of skeletal muscle cells?

Answer 40

They are multinucleated with nuclei located on the periphery under the plasma membrane.

Question 41

What are skeletal muscles attached to?

Answer 41

Bones

Question 42

Where is smooth muscle found?

Answer 42

In walls of hollow organs and tubes like blood vessels and glands.

Question 43

What is the shape and structure of a smooth muscle cell?

Answer 43

Spindle-shaped, single nucleus, and no visible striations.

Question 44

Where is cardiac muscle found?

Answer 44

In the heart

Question 45

How are cardiac muscle cells connected to contract in unison?

Answer 45

Through intercalated discs that allow wave-like contraction.

Question 46

What is a defining structural feature of cardiac muscle cells?

Answer 46

They are branched, have one nucleus, and are connected electrically and physically.

Question 47

Q19: What is a muscle fascicle? A19: A bundle of skeletal muscle fibers within a muscle.

Question 48

What connective tissue surrounds each fascicle?

Answer 48

Perimysium.

Question 49

What surrounds the entire muscle?

Answer 49

Epimysium.

Question 50

What layer surrounds individual muscle fibers?

Answer 50

Endomysium.

Question 51

What is the sarcolemma?

Answer 51

The plasma membrane of a muscle fiber.

Question 52

What is the sarcoplasm?

Answer 52

The cytoplasm of a muscle fiber.

Question 53

What is the sarcoplasmic reticulum (SR)?

Answer 53

Specialized smooth ER that stores and releases calcium ions.

Question 54

What is the sarcomere?

Answer 54

The functional unit of a muscle fiber, made of actin and myosin filaments.

Question 55

What initiates skeletal muscle contraction?

Answer 55

Stimulation from the neuromuscular junction.

Question 56

What role does calcium play in muscle contraction?

Answer 56

It binds to troponin, exposing actin's binding sites for myosin.

Question 57

What forms when actin and myosin bind?

Answer 57

A cross-bridge

Question 58

What energy molecule powers the myosin movement during contraction?

Answer 58

ATP

Question 59

What causes voltage-gated Ca²⁺ channels to open in the presynaptic terminal?

Answer 59

An incoming action potential.

Question 60

What neurotransmitter is released to stimulate muscle contraction?

Answer 60

Acetylcholine (ACh).

Question 61

What enzyme breaks down ACh in the synaptic cleft?

Answer 61

Acetylcholinesterase.

Question 62

What happens when Na⁺ enters the postsynaptic cell?

Answer 62

Depolarization occurs, possibly generating an action potential.

Question 63

How is the sarcolemma involved in contraction?

Answer 63

It conducts the action potential along the muscle fiber.

Question 64

What triggers calcium release from the SR?

Answer 64

Depolarization of the T tubules.

Question 65

What protein does calcium bind to for contraction to occur?

Answer 65

Troponin.

Question 66

What happens when the active sites on actin are exposed?

Answer 66

Myosin heads bind to actin to form cross-bridges and initiate contraction