bone, muscle

Question 1

What is the skeleton considered as?

Answer 1

An organ that supports movement, structure, and protects internal organs.

Question 2

What minerals are stored in bones?

Answer 2

85% of phosphorus and 99% of calcium.

Question 3

Where does hematopoiesis occur?

Answer 3

In the bone marrow.

Question 4

What are the two types of bone tissue?

Answer 4

Cortical bone and trabecular (cancellous) bone.

Question 5

What is cortical bone?

Answer 5

Dense bone that surrounds the marrow space and provides structural support.

Question 6

What is the function of trabecular bone?

Answer 6

Shock absorption and mineral exchange; highly porous.

Question 7

What is the ECM of bone made of?

Answer 7

Collagen fibrils and embedded minerals.

Question 8

What gives bone strength and flexibility?

Answer 8

Hydroxyapatite (strength) and collagen (flexibility).

Question 9

What is bone remodelling?

Answer 9

The process of repairing and renewing bone to maintain integrity and mineral homeostasis.

Question 10

What are osteocytes?

Answer 10

Cells that reside in bone and signal for remodeling.

Question 11

What are osteoclasts?

Answer 11

Multinucleated cells that break down bone matrix.

Question 12

What are osteoblasts?

Answer 12

Cells that lay down new bone matrix.

Question 13

What signals bone remodeling?

Answer 13

Changes in load, microdamage, or need for calcium.

Question 14

How do osteocytes sense mechanical load?

Answer 14

By detecting fluid flow shifts through their connecting passages.

Question 15

What happens to osteoblasts after laying bone?

Answer 15

They become bone lining cells or osteocytes.

Question 16

What is endochondral ossification?

Answer 16

Bone formation using a cartilage template, seen in long bone growth.

Question 17

Where does longitudinal bone growth occur?

Answer 17

At the growth plate (epiphyseal plate) in long bones.

Question 18

What is the metaphysis?

Answer 18

The region below the growth plate where trabecular bone sits.

Question 19

What is osteoporosis?

Answer 19

A metabolic disease where bone structure is compromised, increasing fracture risk.

Question 20

What causes wedge fractures in vertebrae?

Answer 20

Loss of trabecular structure due to bone compression.

Question 21

How can osteoporosis be managed?

Answer 21

Through weight-bearing exercises to increase bone density.

Question 22

What are some roles of muscles?

Answer 22

Movement of bones, food, blood, thermoregulation, metabolism, endocrine functions.

Question 23

What is sarcopenia?

Answer 23

Age-related loss of muscle mass and strength.

Question 24

What are the four properties of muscles?

Answer 24

Contractility, excitability, extensibility, elasticity.

Question 25

What are the three types of muscle?

Answer 25

Skeletal (voluntary), cardiac (involuntary), smooth (involuntary).

Question 26

What are skeletal muscle fibers composed of?

Answer 26

Muscle → fascicle → cell → myofibril → sarcomere → filaments.

Question 27

What are sarcomeres made of?

Answer 27

Actin (thin) and myosin (thick) filaments.

Question 28

What is the sliding filament mechanism?

Answer 28

Myosin pulls actin to shorten the sarcomere without changing filament length.

Question 29

What is a neuromuscular junction?

Answer 29

The synapse where a motor neuron stimulates a muscle fiber.

Question 30

What triggers muscle contraction?

Answer 30

ATP hydrolysis and calcium release which displaces tropomyosin via troponin.

Question 31

Where is calcium stored in muscle cells?

Answer 31

Sarcoplasmic reticulum.

Question 32

How does calcium trigger contraction?

Answer 32

It binds to troponin, moving tropomyosin and allowing cross-bridge formation.

Question 33

What ends muscle contraction?

Answer 33

Calcium is pumped back into the sarcoplasmic reticulum, and tropomyosin blocks binding.

Question 34

What is the difference between cardiac and skeletal muscle?

Answer 34

Cardiac muscle has central nuclei and does not hypertrophy.

Question 35

What are Type I muscle fibers?

Answer 35

Slow-twitch, red, fatigue-resistant, aerobic metabolism.

Question 36

What are Type II muscle fibers?

Answer 36

Fast-twitch, white, fatigue quickly, anaerobic metabolism.

Question 37

What are the two types of smooth muscle contraction?

Answer 37

Phasic (rapid) and tonic (slow, sustained).

Question 38

How does smooth muscle contract?

Answer 38

Calcium binds to calmodulin, activates MLCK, phosphorylates myosin to form cross-bridge.

Question 39

What triggers smooth muscle relaxation?

Answer 39

Nitric oxide inhibits MLCP and removes phosphate from myosin.

Question 40

What determines contraction strength in smooth muscle?

Answer 40

Calcium concentration.

Question 41

What is a motor unit?

Answer 41

One motor neuron and the group of muscle fibers it innervates.

Question 42

What do small motor units do?

Answer 42

Enable fine control with less force and fatigue resistance.

Question 43

What do large motor units do?

Answer 43

Generate more tension for large movements but fatigue quickly.

Question 44

What is a muscle twitch?

Answer 44

A single contraction from one action potential.

Question 45

What is summation?

Answer 45

Repeated stimulation before complete relaxation, increasing tension.

Question 46

What is tetanic contraction?

Answer 46

Sustained, involuntary contraction from rapid firing of action potentials.

Question 47

What is latch contraction?

Answer 47

Sustained contraction in smooth muscle with low energy use.