Week 5 - The Skeletal System

Question 1

Question

Answer 1

Answer

Question 2

What composes the skeletal system?

Answer 2

All the bones and their associated cartilages, including bone (osseous) tissue, cartilage, dense connective tissue, epithelial tissue, adipose tissue, and nervous tissue.

Question 3

Why is each individual bone considered an organ?

Answer 3

Because it comprises various tissues working together.

Question 4

What are the six functions of the skeletal system?

Answer 4

Support, protection, assistance in movement, mineral homeostasis, blood cell production, triglyceride storage.

Question 5

How does the skeletal system provide support?

Answer 5

It serves as the structural framework for the body, supporting soft tissues and providing attachment points for tendons.

Question 6

How does the skeletal system protect the body?

Answer 6

It shields internal organs from injury, such as the skull protecting the brain and the rib cage protecting the heart and lungs.

Question 7

How does the skeletal system assist in movement?

Answer 7

It provides anchor points for skeletal muscles, allowing for coordinated movements.

Question 8

What is mineral homeostasis, and how does the skeletal system contribute to it?

Answer 8

It involves storing and releasing minerals, particularly calcium and phosphorus, to maintain proper levels in the blood.

Question 9

What is hematopoiesis, and where does it occur?

Answer 9

Hematopoiesis is the production of blood cells, occurring in the red bone marrow.

Question 10

What is stored in yellow bone marrow, and what is its function?

Answer 10

Yellow bone marrow stores triglycerides, serving as an energy reserve.

Question 11

What is the diaphysis of a long bone?

Answer 11

The long, cylindrical shaft of the bone.

Question 12

What are the epiphyses of a long bone?

Answer 12

The proximal and distal ends of the bone.

Question 13

What are the metaphyses, and what do they contain in growing bones?

Answer 13

The regions between the diaphysis and epiphyses; they contain the epiphyseal (growth) plate in growing bones, which becomes the epiphyseal line in adults.

Question 14

What is articular cartilage, and where is it found?

Answer 14

A thin layer of hyaline cartilage covering the epiphyses, reducing friction and absorbing shock at joints.

Question 15

What is the periosteum, and what are its functions?

Answer 15

A tough connective tissue sheath covering the bone’s surface (except at joints), protecting the bone and serving as an attachment point for tendons and ligaments.

Question 16

What is the medullary cavity, and what does it contain?

Answer 16

A hollow space within the diaphysis containing yellow bone marrow, which reduces the weight of the bone.

Question 17

What is the endosteum?

Answer 17

A thin membrane lining the medullary cavity, containing bone-forming cells.

Question 18

What is the composition of the bone’s extracellular matrix (ECM)?

Answer 18

15% water, 30% collagen fibers, 55% crystallized mineral salts.

Question 19

What are osteoprogenitor (osteogenic) cells?

Answer 19

Unspecialized stem cells that divide to produce osteoblasts; found in the periosteum, endosteum, and canals containing blood vessels.

Question 20

What are osteoblasts, and what is their function?

Answer 20

Immature bone cells responsible for bone formation, secreting collagen fibers and other organic components, and initiating calcification.

Question 21

What are osteocytes, and where are they located?

Answer 21

Mature bone cells derived from osteoblasts, located within lacunae; they maintain bone tissue and regulate bone remodeling.

Question 22

What are osteoclasts, and what is their role?

Answer 22

Large cells formed from the fusion of monocytes, responsible for bone resorption and regulating blood calcium levels; found in the endosteum.

Question 23

What is calcification?

Answer 23

The process initiated by osteoblasts in which mineral salts and ions are deposited in a collagen framework, hardening the tissue to form bone.

Question 24

What are the two types of bone tissue?

Answer 24

Compact (cortical) bone and spongy (trabecular or cancellous) bone.

Question 25

What are the characteristics of compact bone?

Answer 25

Dense and strong, composed of osteons (Haversian systems), with central canals containing blood vessels and nerves, surrounded by concentric lamellae.

Question 26

What are osteons, and what are their components?

Answer 26

Structural units of compact bone, consisting of osteonic (Haversian) canals, concentric lamellae, lacunae with osteocytes, and canaliculi for nutrient and waste exchange.

Question 27

What are interstitial lamellae?

Answer 27

Fragments of older osteons that fill the spaces between osteons in compact bone.

Question 28

What are circumferential lamellae?

Answer 28

Lamellae that encircle the bone just beneath the periosteum or around the medullary cavity, providing added strength.

Question 29

What are the characteristics of spongy bone?

Answer 29

Composed of trabeculae, surrounded by red bone marrow, providing structural support, protecting red bone marrow, and reducing bone weight.

Question 30

Where is spongy bone typically found?

Answer 30

In the epiphyses of long bones, the interior of short, flat, and irregular bones, and lining the medullary cavity of long bones.

Question 31

What are the four zones of the epiphyseal growth plate?

Answer 31

Zone of resting cartilage, zone of proliferating cartilage, zone of hypertrophic cartilage, and zone of calcified cartilage.

Question 32

What happens in the zone of resting cartilage?

Answer 32

Chondrocytes anchor the epiphyseal plate to the epiphysis, providing stability.

Question 33

What occurs in the zone of proliferating cartilage?

Answer 33

Chondrocytes divide by mitosis, increasing the number of cells and contributing to bone growth in length.

Question 34

What occurs in the zone of hypertrophic cartilage?

Answer 34

Chondrocytes mature and enlarge, preparing to calcify.

Question 35

What happens in the zone of calcified cartilage?

Answer 35

Cartilage is calcified and replaced by bone tissue, contributing to the lengthening of the diaphysis.

Question 36

What is the process of bone growth in thickness?

Answer 36

Appositional growth, where osteoblasts deposit new bone beneath the periosteum, increasing the diameter, and osteoclasts resorb bone on the endosteal surface, expanding the medullary cavity.

Question 37

What is bone remodeling, and why is it important?

Answer 37

The ongoing replacement of old bone tissue with new bone tissue, maintaining bone strength and integrity, regulating calcium levels, and adapting to stress.

Question 38

What are the key processes involved in bone remodeling?

Answer 38

Bone resorption by osteoclasts and bone deposition by osteoblasts.

Question 39

How is bone remodeling regulated?

Answer 39

By hormones, growth factors, mechanical stress, and local signaling molecules.

Question 40

What is a fracture?

Answer 40

A break in the continuity of the bone, often accompanied by injury to surrounding soft tissues.

Question 41

What are the steps involved in the repair of a bone fracture?

Answer 41

Haematoma formation, soft callus formation, hard callus formation, and bone remodeling.

Question 42

What occurs during haematoma formation?

Answer 42

Blood vessels are disrupted, leading to a clot at the fracture site.

Question 43

What is the role of the soft callus in bone repair?

Answer 43

A fibrocartilaginous callus bridges the fractured ends, providing temporary stabilization and allowing new blood vessels to grow.

Question 44

What happens during hard callus formation?

Answer 44

The soft callus is replaced by a hard, calcified callus of immature bone.

Question 45

What is the final step in bone repair, and how long does it take?

Answer 45

Bone remodeling, which restores the bone's original shape and structure, can take months to years.

Question 46

What is the role of bones in calcium homeostasis?

Answer 46

They act as a reservoir for calcium, releasing or absorbing it to maintain stable blood calcium levels.

Question 47

What are the two main divisions of the adult human skeleton?

Answer 47

Axial skeleton (80 bones) and appendicular skeleton (126 bones).

Question 48

What does the axial skeleton consist of?

Answer 48

Skull, hyoid bone, auditory ossicles, vertebral column, and thoracic cage.

Question 49

What does the appendicular skeleton consist of?

Answer 49

Pectoral girdles, upper limbs, pelvic girdle, and lower limbs.

Question 50

What are the cranial bones, and how many are there?

Answer 50

Frontal (1), parietal (2), temporal (2), occipital (1), sphenoid (1), and ethmoid (1); a total of 8 bones.

Question 51

What are the facial bones, and how many are there?

Answer 51

Nasal (2), lacrimal (2), palatine (2), inferior nasal conchae (2), vomer (1), zygomatic (2), maxillae (2), mandible (1); a total of 14 bones.

Question 52

What are sutures in the skull?

Answer 52

Immovable joints that fuse skull bones together.

Question 53

What are the four main sutures in the skull?

Answer 53

Coronal, sagittal, lambdoid, and squamous sutures.

Question 54

What are the paranasal sinuses, and what is their function?

Answer 54

Air-filled cavities in cranial and facial bones, enhancing voice resonance and helping moisten and cleanse inhaled air.

Question 55

What are fontanels, and what are their functions?

Answer 55

Soft spots in a newborn's skull that allow for skull deformation during birth and brain growth.

Question 56

What is the hyoid bone, and where is it located?

Answer 56

A U-shaped bone in the anterior neck, supporting the tongue and providing attachment sites for muscles.

Question 57

How many vertebrae are in the vertebral column, and what are the regions?

Answer 57

26 vertebrae: cervical (7), thoracic (12), lumbar (5), sacrum (1), coccyx (1).

Question 58

What are the functions of the vertebral column?

Answer 58

Protects the spinal cord, supports the head, and serves as an attachment point for ribs, muscles, and the pelvic girdle.

Question 59

What are the normal curvatures of the vertebral column?

Answer 59

Cervical (convex), thoracic (concave), lumbar (convex), sacral (concave).

Question 60

What are intervertebral discs, and what is their function?

Answer 60

Fibrocartilaginous pads between vertebrae that cushion and allow movement.

Question 61

What are the three main components of a typical vertebra?

Answer 61

Vertebral body, vertebral arch, and processes (transverse, spinous, superior, and inferior articular).

Question 62

What is the thoracic cage composed of, and what is its function?

Answer 62

The sternum and 12 pairs of ribs; it protects thoracic and upper abdominal organs, supports the upper limbs, and assists in respiration.

Question 63

What are the three parts of the sternum?

Answer 63

Manubrium, body, and xiphoid process.

Question 64

What are true ribs, false ribs, and floating ribs?

Answer 64

True ribs (1-7) attach directly to the sternum, false ribs (8-10) attach indirectly, and floating ribs (11-12) have no anterior attachment.

Question 65

What is the pectoral girdle, and what are its components?

Answer 65

A structure that attaches the upper limbs to the axial skeleton; consists of the clavicle and scapula.

Question 66

What is the function of the clavicle?

Answer 66

Provides structural support, protects neurovascular structures, and allows for a wide range of shoulder motion.

Question 67

What is the function of the scapula?

Answer 67

Provides attachment points for muscles and allows for a wide range of shoulder movements.

Question 68

What bones compose the upper limb?

Answer 68

Humerus, ulna, radius, carpals, metacarpals, and phalanges.

Question 69

What is the pelvic girdle, and what bones form it?

Answer 69

A structure that connects the lower limbs to the axial skeleton, composed of the ilium, ischium, and pubis.

Question 70

What are the functions of the pelvic girdle?

Answer 70

Supports the vertebral column and pelvic organs, connects the lower limbs to the axial skeleton, and provides attachment points for muscles.

Question 71

What bones compose the lower limb?

Answer 71

Femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges.

Question 72

What are joints, and what are their main functions?

Answer 72

Points of contact between bones, cartilage and bone, or teeth and bones; they facilitate movement, provide stability, absorb shock, connect bones, allow growth, and provide flexibility and elasticity.

Question 73

How are joints functionally classified?

Answer 73

Based on the degree of movement: synarthrosis (immovable), amphiarthrosis (slightly movable), diarthrosis (freely movable).

Question 74

How are joints structurally classified?

Answer 74

Based on the presence or absence of a synovial cavity and the type of connective tissue binding the bones: fibrous, cartilaginous, synovial.

Question 75

What are fibrous joints?

Answer 75

Joints with no synovial cavity, held together by dense irregular connective tissue, usually allowing little or no movement.

Question 76

What are cartilaginous joints?

Answer 76

Joints with no synovial cavity, bones joined by cartilage, allowing limited movement.

Question 77

What are synovial joints?

Answer 77

Joints with a synovial cavity, permitting a wide range of movements.

Question 78

What are the characteristics of synovial joints?

Answer 78

Synovial cavity, articular cartilage, articular capsule, synovial fluid, accessory ligaments, articular discs, articular fat pads.

Question 79

What are the six types of synovial joints?

Answer 79

Plane, hinge, pivot, condyloid, saddle, ball-and-socket.

Question 80

What are gliding movements at synovial joints?

Answer 80

Movements where flat bone surfaces move back and forth or side to side, with limited range.

Question 81

What are angular movements at synovial joints?

Answer 81

Movements that change the angle between bones, including flexion, extension, hyperextension, abduction, adduction, and circumduction.

Question 82

What is rotation at synovial joints?

Answer 82

A bone revolving around its own longitudinal axis.

Question 83

What are special movements at synovial joints?

Answer 83

Specific movements such as elevation, depression, protraction, retraction, inversion, eversion, dorsiflexion, plantar flexion, supination, pronation, and opposition.

Question 84

What type of movements do plane joints allow?

Answer 84

Plane joints allow gliding movements, such as those in intercarpal joints.

Question 85

What type of movements do hinge joints allow?

Answer 85

Hinge joints allow flexion and extension, such as in the elbow and knee.

Question 86

What type of movements do pivot joints allow?

Answer 86

Pivot joints allow rotation, as seen in the atlantoaxial joint and radioulnar joints.

Question 87

What type of movements do condyloid joints allow?

Answer 87

Condyloid joints allow flexion, extension, abduction, adduction, and circumduction, such as in the wrist joint.

Question 88

What type of movements do saddle joints allow?

Answer 88

Saddle joints allow movements similar to condyloid joints but with a greater range, such as in the thumb joint.

Question 89

What type of movements do ball-and-socket joints allow?

Answer 89

Ball-and-socket joints allow the widest range of movements, including flexion, extension, abduction, adduction, and rotation, such as in the shoulder and hip joints.

Question 90

What are gliding movements at synovial joints?

Answer 90

Gliding movements occur when flat bone surfaces move back and forth or side to side against each other without significant alteration of the angle between the bones. Examples include the intercarpal and intertarsal joints.

Question 91

What are angular movements at synovial joints, and what types are there?

Answer 91

Angular movements involve a change in the angle between articulating bones. Types include flexion (decreasing the angle, e.g., bending the elbow), extension (increasing the angle, e.g., straightening the arm), hyperextension (extension beyond the anatomical position, e.g., bending the head backward), abduction (movement away from the midline, e.g., raising the arm sideways), adduction (movement toward the midline, e.g., lowering the arm to the side), and circumduction (circular movement of a limb, e.g., arm circles).

Question 92

What is rotation, and what are its types?

Answer 92

Rotation involves a bone revolving around its own longitudinal axis. Types include medial (internal) rotation (turning the anterior surface of a limb toward the midline) and lateral (external) rotation (turning the anterior surface of a limb away from the midline).

Question 93

What are special movements at joints?

Answer 93

Special movements are specific to certain joints and include elevation and depression (upward and downward movements, e.g., shrugging shoulders), protraction and retraction (anterior and posterior movements, e.g., jutting the jaw forward and pulling it back), inversion and eversion (movements of the sole of the foot inward and outward), dorsiflexion and plantar flexion (upward and downward movements of the foot, e.g., raising toes and pointing toes), supination and pronation (rotational movements of the forearm, turning the palm up or down), and opposition (movement of the thumb across the palm to touch the other fingers).