Skeletal System

Question 1

What composes the axial skeleton?

Answer 1

80 bones including the skull, spinal column, and ribcage + hyoid bone and ear ossicles.

Question 2

What composes the Appendicular skeleton?

Answer 2

126 bones; all bones of upper and lower libs and pectoral and pelvic girdles

Question 3

How are bones classified?

Answer 3

Based on their shape

Question 4

What are long bones?

Answer 4

Cylindrical shaped bones where length is greater than width.

Question 5

Which bones function as levers and move muscles when they contract?

Answer 5

Long bones

Question 6

What bones provide stability and support?

Answer 6

Short bones

Question 7

What bones are cube like in shape and are found in carpals of wrist and tarsals of ankles?

Answer 7

Short bones

Question 8

What bones are attachment points of muscles and often protect internal organs?

Answer 8

Flat bones

Question 9

What are examples of flat bones?

Answer 9

Skull bones, shoulder blades, sternum, and ribs.

Question 10

What bones have a spongy interior

Answer 10

flat bones

Question 11

What is the function of irregular bone?

Answer 11

Complex shapes help support spinal cord from compressive forces.

Question 12

What is the function of seamoid bones?

Answer 12

protect tendons by helping them overcome compressive forces, patellas are the only bones found in common.

Question 13

Sutural/Wormian bones occur where?

Answer 13

Within a joint of the skull

Question 14

What are the two forms of bone classification based on internal structure?

Answer 14

Trabecular Bone
Compact Bone

Question 15

What is trabecular bone?

Answer 15

50-90% porous and metabolically active

Question 16

What is Compact bone?

Answer 16

10% porous and provides strength an support
constitutes 80% of adult skeleton

Question 17

What is the ephysis?

Answer 17

Wider section at ends of bones (red bone marrow)

Question 18

What is the diaphysis?

Answer 18

tubular shaft that runs between each ephysis (yellow bone marrow)

Question 19

What is hematopoiesis and where does it occur?

Answer 19

The production of red blood cells, white blood cells and platelets that occurs in the red marrow

Question 20

What type of tissue does yellow marrow contain?

Answer 20

Adipose tissue

Question 21

Where does ephysis and diaphysis meet?

Answer 21

metaphysis

Question 22

What is contained in the metaphysis?

Answer 22

Epiphyseal plate (growth plate) and a layer of hyaline cartilage in growing bone

Question 23

What happens to metaphysis is adulthood?

Answer 23

The cartilage is replaced by osseous tissue and the ephyseal plate becomes an epiphyseal line.

Question 24

Where is compact bone found?

Answer 24

In the diaphysis of long bones

Question 25

What is the microscopic structural unit of compact bone and what is it composed of?

Answer 25

Osteon; rings of calcified matrix called lamellae.

Question 26

What does the canaliculi of the lacuna do?

Answer 26

Connects to one another so that nutrients and wastes can be transported to and from osteocytes. Permits communication between osteocytes.

Question 27

Where are osteocytes located?

Answer 27

Within the lacuna

Question 28

What is the Haversian canal?

Answer 28

A canal that contains blood vessels, lymphatic vessels, and nerves.

Question 29

What is the periosteum

Answer 29

Outer sheath that contains blood vessels, nerves, and lymphatic vessels that nourish compact bone.

Question 30

Where do tendons and ligaments connect to on the bone?

Answer 30

periosteum

Question 31

What cells are in the periosteum?

Answer 31

Osteoblasts, fibroblasts, and osteogenic cells (skeletal stem cells). Osteocytes trapped in matrix.

Question 32

What cells are in the endosteum?

Answer 32

Osteoblasts, skeletal stem cells, and osteoclasts.

Question 33

How is spongy bone arranged?

Answer 33

With trabeculae that form a matrix of spaces that provide support and strength.

Question 34

How is blood and nerves supplied to the spongy bone?

Answer 34

Blood nutrients enter and leave through nutrient foramen

Question 35

What types of cells are found in bone tissue?

Answer 35

Osteoblasts Osteocytes Osteogenic Cells Osteoclasts

Question 36

What are the steps to form a osteocyte?

Answer 36

Osteogenic cell to osteoblast to osteocyte

Question 37

What do osteoblasts do?

Answer 37

Synthesize and secrete collagen matrix and calcium salts, once the outside calcifies, it becomes an osteocyte.

Question 38

Where do osteoclasts originate from?

Answer 38

Monocytes and macrophages (WBC)

Question 39

What cells break down old bone, while what cells form new bone?

Answer 39

Osteoclast break down and osteoblast form new bone.

Question 40

What is intramembranous ossification?

Answer 40

Flat bone formation where compact and spongy bone develop from sheets of mesenchymal areolar connective tissue

Question 41

What do mesenchymal cells differentiate into?

Answer 41

Specialized cells such as capillaries or osteogenic cells then fibroblasts.

Question 42

What is the ossification center?

Answer 42

Where early osteoblasts cluster

Question 43

What is the result of intramembranous ossification?

Answer 43

Osteoid results in trabecular matrix while osteoblasts on the surface of spongy bone become periosteum.

Question 44

What is endochondral ossification?

Answer 44

After 6-8 weeks after conception, some mysenchemal cells differentiate into chondrocytes (cartilage cells) that form the precursor to bones

Question 45

What is the perichondrium?

Answer 45

Membrane that covers cartilage

Question 46

As more matrix is produced, what happens to chondrocytes?

Answer 46

As chondrocytes in center of cartilaginous model grow in size, the ones that are far in don't receive nutrients and die.

Question 47

When blood vessels invade the spaces chondrocyte what happens?

Answer 47

The spaces eventually become the medulalry cavity and the penetration of capillaries initaites transformation of perichondrium to bone producing periosteum.

Question 48

How does bone keep growing?

Answer 48

Chondrocytes and cartilage continue to grow at the ends of the bones (future ephysis).