skeletal system 1

Question 1

The primary function for the skeletal system is what?

Answer 1

For supporting the body and protecting vital organs

Question 2

How many bones are we born with? How much is left when we age?

Answer 2

270

206 named bones

Question 3

What are bones made up of?

Answer 3

Bones are made up of a complex arrangement of inorganic minerals and a variety of tissues including bone, bone marrow, nerves, blood vessels, endothelial, and cartilage

Question 4

What are the functions of bones?

Answer 4

1. Protection - of organs (skull protects the brain, ribs protects the heart, etc)
2. Support and framework for the human body
3. Movement - by providing attachment points for muscles
4. pH balance - of the blood by absorbing or releasing bone minerals
5. Hematopoiesis - (blood production) in blood marrow
6. Fat storage - in yellow bone marrow
7. Sound transduction - through small bones located in the ear canal
8. Storage of growth factor in bone matrix
9. Removal of heavy metals or foreign chemicals - to detoxify blood and release slowly for excretion
10. Mineral storage - of calcium and phosphorous
11. Production of hormones - such as ostocalcin

Question 5

What are bone minerals mostly made of?

Answer 5

Calcium and phosphorous

Question 6

Bone mineral is created by what? And it allows what?

Answer 6

Osteoblasts

Allows bones to withstand large amounts of compressional force

Question 7

What is the other major component of bone matrix?

Answer 7

Organic collagen, which is a protein that gives bone the ability to withstand stretching forces

Question 8

What are the major cells that contribute to building and breaking down bone matrix and bone structure?

Answer 8

Osteoblasts, osteocytes, and osteoclasts

Question 9

Osteoblasts are responsible for what?

Answer 9

Responsible for creating bone matrix, and therefore building bone

Question 10

When does osteoblasts become osteocytes?

Answer 10

Once osteoblasts have become trapped in the bone matrix they have created, they become osteocytes

Question 11

What is the function of osteocytes?

Answer 11

Maintain the bone matrix and calcium homeostasis
Osteocyte, a cell that lies within the substance of fully formed bone. It occupies a small chamber called a lacuna, which is contained in the calcified matrix of bone. Osteocytes derive from osteoblasts, or bone-forming cells, and are essentially osteoblasts surrounded by the products they secreted.

Question 12

Where are osteocytes located?

Answer 12

Lacunae

Question 13

What are osteoclasts?

Answer 13

Large cells that are capable of reabsorbing bone minerals, and therefore remodeling bone structure
They also remove minerals to the bloodstream for a variety of bodily functions, such as muscle contraction

Question 14

Bone matrix can be arranged into what classifications?

Answer 14

1. Compact bone

2. Trabecular bone

Question 15

Define compact bone

Answer 15

Also known as dense or cortical bone, is extremely hard and compact with very little space
Bone mineral in compact bone is arranged into tight circles called osteons, with nerves and blood vessels passing through the center. Compact bone accts for 80% of the total bone mass

Question 16

Define trabecular bone

Answer 16

Also known as spongy or cancellous bone, is porous and more like a network that allows nerves, blood vessels, and bone marrow to easily fill trabecular bone
Stress on trabecular bone causes it to create new and stronger networks, making it extremely adaptable
Accts for 20% of the total bone mass, it has a greater surface area than compact bone

Question 17

What are the five main types of bone based on their shape?

Answer 17

1. Long bones - bones that are longer than they are wide and made up of primarily compact bone (e.g. arm bones, leg bones, and phalanges)
2. Short bones - cube-shaped with a thin layer of compact bone (e.g. wrist and ankle bones)
3. Sesamoid bones - bones embedded in tendons. (e.g. patella and pisiform)
4. Flat bones - thin and curved with parallel layers of compact bone. (e.g. sternum and bones of the skull)
5. Irregular bones - bones that do no fit in any of the other categories. (e.g. vertebra and bones of the sinus)

Question 18

What does collagen fibers allow bones to do?

Answer 18

The presence of collagen fibers allow bone to endure stretching forces

Question 19

What does mineral salts allow bones to do?

Answer 19

Allow bones to endure compression forces

Question 20

How is the bone construction similar to reinforced concrete?

Answer 20

Similar in that steel rebar allows concrete to resist strecthing forces, while the cement resists compression

Bone structure is somewhat similar to reinforced concrete that contains structural metal reinforcement rods or bars. These metal reinforcements are commonly called rebar. Protein strands make up the rebar of bone. Calcium and phosphorus mineral crystals deposited around the protein strands are somewhat like the concrete poured around the rebar in reinforced concrete. The protein strands provide the tensile strength that holds everything together and the minerals provide the solid structure. If bones were made only of protein, they would be too flexible. If bones were made solely from minerals, the skeleton would be too brittle.

Question 21

What is the function of osteons?

Answer 21

Allows the bone to resist greater amounts of force

Question 22

The bone construction does not resist what?

Answer 22

Does not tend to resist twisting forces, and in fact is the primary cause of bone fractures

Question 23

What are the two main components of extracellular matrix?

Answer 23

Mineral salts and collagen

Question 24

What types of force do collagen and bone mineral resist?

Answer 24

Bone mineral resist compression forces

Collagen fibers resist tension forces

Question 25

What chemicals make up the organic portion of the bone extracellular matrix?

Answer 25

Made up of proteoglycans, water, minerals, and fibrous proteins

Question 26

What chemicals make up the inorganic portion of the bone extracellular matrix?

Answer 26

Consists of hydroxapatites or minerals salts, primarily calcium phosphate

Question 27

What portion of the bone extracellular matrix is most responsible for bone flexibility?

Answer 27

Collagen contribute to the flexibility and tensile strength of the bone

Question 28

What portion of the bone extracellular matrix is most responsible for bone hardness?

Answer 28

The mineral salts are responsible for hardness

Question 29

What passes through the Haversian canal?

Answer 29

The Haversian canal contains its own blood vessels, which supply nutrients to the bone cells of the osteon and its own nerve fibers

Question 30

What is created in red bone marrow?

Answer 30

It produces red blood cells, white blood cells, and platelets

Question 31

Where are the blood vessels found in compact bone?

Answer 31

In the Haversian canal

Question 32

Where are the blood vessels found in spongy bone?

Answer 32

In between the trabulcae

Question 33

number of axial bones

Answer 33

80

Question 34

number of skull bones

Answer 34

29

Question 35

Cranium bones

Answer 35

Frontal Parietal Temporal Occipital Sphenoid Ethmoid

Question 36

forehead, eyebrows, superior eye orbit

Answer 36

Frontal bone

Question 37

superior and lateral walls of cranium

Answer 37

parietal bones

Question 38

parts of temporal bones

Answer 38

``` external acoustic meatus styloid process zygomatic process mastoid process internal acoustic meatus ```

Question 39

canal that leads to eardrum and middle ear

Answer 39

external acoustic meatus

Question 40

most posterior bone of cranium

Answer 40

occipital bone

Question 41

hole at the base of the skull where spinal cord enters skull

Answer 41

foramen magnum

Question 42

Types of bone fractures

Answer 42

Closed (simple) fracture: break that does not penetrate the skin Open (compound) fracture: broken bone penetrates through the skin

Question 43

Stages in healing bone fracture

Answer 43

Hematoma (blood-filled swelling) is formed Fibrocartilage callus forms Cartilage matrix, bony matrix, collagen fibers splint the broken bone Bony callus replaces the fibrocartilage callus Osteoblasts and osteoclasts migrate in Bone remodeling occurs in response to mechanical stresses

Question 44

Skull and associated bones include

Answer 44

cranium 8, face 14 Auditory ossicles 6, hyoid 1

Question 45

Thoracic cage includes

Answer 45

sternum 1 , ribs 24 bones

Question 46

Vertebral column includes

Answer 46

Vertrebrae, 24, Sacrum 1, Coccyx 1

Question 47

Pectoral girdle (4) includes

Answer 47

Clavicle 2, Scapula 2,

Question 48

Upper limbs include (60)

Answer 48

Humerus (2), Radius (2), Ulna (2), Carpal bones (16), Metacarpal bones (10), Phalanges (proximal, middle, distal 28 bones total)

Question 49

Pelvic girdle (2) includes

Answer 49

Hip bone (Coxal bone 2)

Question 50

Lower limbs (60)

Answer 50

femur (2), Patella (2), Tibia (2), Fibula (2), Tarsal bones (14), metatarsal bones (10), phalanges (28)

Question 51

The axial skeleton is divided into

Answer 51

``` Divided into three parts Skull Vertebral column Bony thorax Forms the longitudinal axis of the body ```

Question 52

The skull is made up of

Answer 52

Two sets of bones Cranial (8) – encloses and protects the brain Facial bones (14) – hold the eyes, facial muscles in place Bones are joined by sutures Only the mandible is attached by a freely movable joint

Question 53

cranium is composed of

Answer 53

``` Composed of 8 large flat bones 1. Frontal bone 2. Occipital bone 3. Ethmoid bone 4. Sphenoid bone 5–6. Parietal bones (pair) 7–8. Temporal bones (pair) ```

Question 54

Facial bones

Answer 54

``` 14 bones in total – 12 are pairs, two are single Key facial bones: Maxillae 2 bones fused together, forms the upper jaw Mandible Single bone, forms the lower jaw Nasal Forms the nose ``` ``` There are 14 facial bones. All are paired except for the single mandible and vomer. 1–2. Maxillae (upper jaw) 3–4. Zygomatics 5–6. Palatines 7–8. Nasals (nose) 9–10. Lacrimals 11–12. Inferior nasal conchae 13. Mandible (lower jaw) 14. Vomer ```

Question 55

Paranasal sinuses

Answer 55

Hollow portions of bones surrounding the nasal cavity

Question 56

Associated bones of the skull

Answer 56

Hyoid bone Attachment site for muscles of larynx, tongue, pharynx Aids in swallowing and speech Auditory ossicles Enclosed in temporal bone Play a role in conducting vibrations to inner ear

Question 57

The fetal skull _______

Answer 57

The fetal skull is large compared to the infant’s total body length Fetal skull is 1/4 body length compared to adult skull which is 1/8 body length

Question 58

Fontanels

Answer 58

Fontanels - fibrous membranes connecting the cranial bones Aids with delivery, Allows the brain to grow, Convert to bone within 24 months after birth, Can feel pulse over the fontanels, Largest is the diamond shaped one called the anterior fontanel, The smaller is triangular shaped and called the posterior fontanel

Question 59

The vertebral column

Answer 59

26 bones (24 vertebrae, sacrum, coccyx) separated by discs Provides column of support – transfers body's weight to lower limbs Protects spinal cord Maintains upright position

Question 60

Vertebral regions

Answer 60

``` Cervical (7 vertebrae – C1 to C7) Thoracic (12 vertebrae – T1 to T12) Lumbar (5 vertebrae – L1 to L5) Sacral (5 fused vertebrae – S1 to S5) Coccygeal (3 – 5 fused vertebrae) ```

Question 61

Vertebral Canal

Answer 61

Encloses spinal cord Spaces between successive vertebrae – intervertebral foramina Passageway for nerves and blood vessels

Question 62

Normal curves of the vertebral column

Answer 62

The spine has a normal curvature Primary curvatures are the “C”-shaped spinal curvatures of the thoracic and sacral regions - present from birth Secondary curvatures are the “S”-shaped spinal curvatures of the cervical and lumbar regions - develop after birth

Question 63

Intevertebral discs

Answer 63

Each single vertebrae is separated by pad of flexible fibrocartilage called a disc Disc Cushion / shock absorption Spinal flexibility Composed primarily of water (90%) Reduced water content with age

Question 64

The bony thorax

Answer 64

``` Forms a cage to protect major organs Sternum Manubrium Body Xiphoid process Ribs True ribs (pairs 1–7) False ribs (pairs 8–12) Floating ribs (pairs 11–12) Intercostal spaces (ICS) are between the ribs Thoracic vertebrae - attachment for the ribs ```

Question 65

The appendicular skeleton is composed off

Answer 65

Composed of 126 bones subdivided into 3 parts: Pectoral girdle Pelvic girdle Limbs (appendages)

Question 66

The pectoral girdle is composed of

Answer 66

Made of two bones which connect upper limbs to trunk Clavicle Scapula These bones allow the upper limb to have exceptionally free movement at expense of stability