Chapter 5

Question 1

What are the functions of the
skeletal system

Answer 1

• Provide structure, support, protection, movement

Question 2

2. Explain the differences between compact
   bone and spongy bone

Answer 2

• Compact Bone – hard, dense, smooth
• Spongy bone – lighter, sponge appearance

Question 3

3. Name the four main classifications of bone
   according to shape.

Answer 3

• Long
• Short (cube shaped)
• Flat
• Irregular

Question 4

4. Name the areas of a long bone

Answer 4

Diaphysis - shaft
Epiphyses – ends of bone
Periosteum – external surface of bone
Articular cartilage - cushions joint
Epiphyseal plate - cartilage in children growing bones

Question 5

5. Describe the microscopic structure of compact bone

Answer 5

• Osteon (Haversian) system – entire circles running down the bone shaft (wooden rings, central canal, and blood vessels/nerves)
• Lamellae – outer wooden rings like a tree
• Interstitial Lamellae – Spaces in between the circles (bone matrix)
• Lacunae - depressions containing osteocytes (bone maintanence cell) look like bugs
• Central canal - centre hole where the blood vessels and nerves run though
  Canaliculus - tunnels going from central canals to osteocytes

Question 6

6. Identify the names and shapes of significant bone markings.

Answer 6

• Bone markings – landmarks where muscles/ blood vessels/ nerves are

o Projections – stick out (T terms)
o Depressions – indentations (F Terms)

Question 7

7. Describe the cells involved in bone formation, growth, and remodeling

Answer 7

• Osteoblasts build new bone.
• Osteoclasts break down bone
• Epiphyseal Plates – allow growth and leave the epiphyseal line behind on the bone

Question 8

8. Describe the significance of epiphyseal plates in bone growth

Answer 8

• Epiphyseal plates (growth plates) – cartilage that will eventually turn into bone at the ends in childhood
  o leaves behind the epiphyseal line

Question 9

9. Explain how appositional growth causes the bone to become thicker and stronger.

Answer 9

• Bones increase in diameter to become wider as well as longer when growing

Question 10

10. Describe the homeostatic regulation of blood calcium, including identifying the
    receptor, control centre, and effector, and apply this knowledge

Answer 10

• Receptor: detect the calcium level in blood.
• Control Center: parathyroid glands (in the thyroid gland).
• Effector: When calcium levels are too low, they release a hormone called parathyroid hormone (PTH) to correct it. If blood calcium is too high, the thyroid gland releases calcitonin, and levels fall.

Question 11

11. Describe how calcitonin and parathyroid hormone maintain the homeostatic balance of blood calcium level, and apply this knowledge

Answer 11

• When calcium levels are low, PTH raises them by taking calcium from the bones and helping the body absorb more from food.
• When calcium levels are high, calcitonin lowers them by storing more calcium in the bones and reducing the amount of calcium absorbed.
• Together, PTH and calcitonin work like a balancing system to keep blood calcium levels within a healthy range.

Question 12

12. Distinguish between the axial and
    appendicular skeletons.

Answer 12

• Axial skeleton along the longitudinal axis of the body
  o It has 3 parts: skull, vertebral column, thoractic cage
  o Green colored on diagram
• Appendicular skeleton – bones of the limbs
  o Shaded gold on diagram
  o Include the pelvic girdle bones (hips) and pectoral girdle bones (shoulders and traps)

Question 13

13. Identify and describe the major bones of the skull (8)

Answer 13

• Frontal bone – forehead/ upper eye
• Parietal bone – top and back/ sides of head
• Occipital bone – base (connects spinal cord to brain)
• Temporal bone – ears
• Nasal – nose bridge
• Zygomatic - cheekbone
• Maxilla – upper jaw
• Mandible – lower jaw

Question 14

14. Describe the function and location of the hyoid bone.

Answer 14

• In the neck, no joint with other bones
• It is a moveable base for the tongue and attachment for neck muscles

Question 15

15. Describe the vertebral column and how many vertebrates do we have?

Answer 15

• The spine supports your weight, protects the spinal cord,
• It has 24 vertebrae total:
  o Cervical vertebrae (7 vertebrae): Located in the neck.
  o Thoracic vertebrae (12 vertebrae): Located in the upper and mid-back.
  o Lumbar vertebrae (5 vertebrae): Located in the lower back.
  2 Sacrum and coccyx fuse together at the bottom of the spine

Question 16

16. Describe the location, parts, and function of the thoracic cage

Answer 16

• The ribcage – made up of bones and cartilage
• Organs inside being protected are heart, lungs, major blood vessels

Question 17

17. Describe the location and parts of the sternum

Answer 17

• Sternum (breastbone) is a flat bone attached to the ribcage (thoracic cage) that fuses 3 bones:
  o Manubrium
  o Body
  o Xiphoid process

Question 18

18. Identify and describe the bones of the shoulder girdle and describe its function

Answer 18

• Clavicle – two collarbones, stabilizes the shoulder by bracing the arm at your side
• Scapula - shoulder blades at back (our “wings), allows movement of arm in many directions

Question 19

19. Identify and describe the bones of the upper limb

Answer 19

• Arm – humerus bone (upper arm), radius and ulna (lower arm)
• Hand – Carpals (wrist), metacarpals (palm), phalanges (fingers)

Question 20

20. Identify and describe the bones of the pelvic girdle and explain its function

Answer 20

• 2 Coxal bones (two hip bones) – ilium, pubis, ischium
• Sacrum – connects coxal to spine

Question 21

21. Describe the three major parts of a coxal
    bone

Answer 21

• Ilium – large flaring bone that is most of the hip
• Ischium – sit down bone at the bottom back of the hip
• Pubis – anterior section of hip

Question 22

22. Identify and describe the bones of the lower limb.

Answer 22

• Thigh – femur bone is the longest, strongest, and heaviest in the body
• Leg - the shin part with two bones: fibula and tibia
• Foot – tarsals (back of foot), metatarsals (medium foot), and phalanges (toes)

Question 23

24. Describe each type of joint movement

Answer 23

• Fibrous (synarthroses) – immovable, fibrous sutures in the skull, interlocked tightly
• Cartilaginous (amphiarthroses)– limited movement, can be epiphyseal in long bones or vertebrae on spine
• Synovial (diarthroses) – freely movable, joints of the limbs, contain synovial fluid

Question 24

What happens to bone from childhood to adulthood? And what is osteoporosis?

Answer 24

Birth to Adulthood:
* Childhood to adulthood is the most dramatic changes
* Long bones are formed from cartilage, Flat bones in skull come from fibrous membranes (fontanels)
* Heads are huge compared to body and grow rapidly because of the brain
Older Adults:
* Bones should be physically stressed to remain healthy
* Osteoporosis is a bone thinning disease that affects older women giving them bone fractures easily
* Weight bearing joints also degenerate, with old people saying “my joints are getting stiff”

Question 25

What is ossification, osteoblasts. Osteoclasts and osteocytes?

Answer 25

Ossification - bone growth Osteoblasts - builder of bone Osteoclasts - break down bone Osteocytes - bone maintanence (mature osteoblasts)

Question 26

True or false: bones are lifeless dry structures that don’t change once long bone growth is complete

Answer 26

False: bones are dynamic and active tissue with a blood supply

Question 27

What is the Sagittal suture, the lambdoid suture and the coronal suture?

Answer 27

Coronal suture - separating frontal and parietal bones Sagittal suture - at top of head separating two parietal bones Lambdoid suture - separating parietal and occipital bone

Question 28

What is a tendon and what is a ligament?

Answer 28

Tendons attach muscle to bone with connective tissue Ligaments attach bone to bone with connective tissue

Question 29

Which 2 minerals are stored in bone matrix?

Answer 29

Calcium and phosphorus

Question 30

There must always be a ready supply of blood calcium to do what 3 things?

Answer 30

1. Conduct nerves 2. Contract muscles 3. Blood clot

Question 31

How many bones are in the adult human body?

Answer 31

206

Question 32

Where and what does red and yellow bone marrow do?

Answer 32

Red marrow: becomes red blood cells Yellow marrow: stores fat Both are found in the centre of bone: the medullary cavity

Question 33

In embryos and young children, what kind of cartilage do they have?

Answer 33

Hyaline cartilage

Question 34

In embryos and young children, what kind of cartilage do they have?

Answer 34

Hyaline cartilage

Question 35

In embryos and young children, what kind of cartilage do they have?

Answer 35

Hyaline cartilage

Question 36

Bones are continuously remodeled based on these 3 things:

Answer 36

1. Blood Calcium level 2. Gravity 3. Exercise

Question 37

The Thyroid gland activates calcitonin when calcium levels are heightened, and they get _______ to deposit calcium in the bone The parathyroid gland hormone activates when blood calcium levels are low and they get __________ to take calcium out of bone

Answer 37

Calcitonin - osteoblasts PTH - osteoclasts

Question 38

What attaches the first 7 pairs of ribs?

Answer 38

Costal (hyaline) cartilage

Question 39

What are the true and false ribs?

Answer 39

1-7 true ribs attached by cartilage 8-12 false ribs 11-12 floating ribs

Question 40

In the anatomical position, the radius is the _______ bone (medial or lateral)

Answer 40

Lateral

Question 41

Is physical stress good for bones?

Answer 41

Yes bones should be pulled by muscles and gravity to remain strong or else they become thin and fragile

Question 42

What are the two functions of joints?

Answer 42

1. Hold the bones together 2. Allow the skeleton to move

Question 43

Where are most synovial joints found, limited movement, and most immovable joints found?

Answer 43

On the axial skeleton is where immovable and limited joints are found for protection of organs On the appendicular skeleton is where the synovial freely moving joints are found

Question 44

What is the true and false pelvis? And what is the difference between a female and male pelvis?

Answer 44

False pelvis - length of one ilium flare True pelvis - hole in pelvis that baby goes through Male pelvis - pubic arch less than 90 degrees, heavier Female pelvis - lighter, larger flare, pubic arch more than 90 degrees

Question 45

What are the only joints in the skull that are freely movable?

Answer 45

Jaw - temporomandibular joints

Question 46

Which skull bones are the keystone of the face?

Answer 46

Maxillae because all facial bones except mandible connect to it

Question 47

What are the 5 main regions of the vertebral column?

Answer 47

Cervival Thoracic Lumbar Sacral Coccyx

Question 48

What make up the primary curvature and secondary curvatures of the spine?

Answer 48

Primary curvature - was there when we were born with a C shape spine, the thoracic and sacral region of spine Secondary curvature - cervical and lumbar region developed later. They centre our weight in the lower limbs.