1. The Skeletal System
Chapter 5

2. Chapter Overview Functions of Bone
Two kinds of bone tissue – compact and spongy – types of marrow
Development of bone – cartilage model
Hormones and bone growth
Importance of Bone Remodeling; osteoblasts and osteoclasts
Loss of bone density – Osteoporosis
Ligaments and tendons
Overview of Human Skeleton – Axial and Appendicular –KNOW THE NAMES and LOCATIONS OF ALL THE BONES
AXIAL: Skull, ribs, sternum, vertebral column, intervertebral disks
APPENDICULAR: Pectoral girdle -scapula, clavicle, upper limb bones, pelvic girdle, leg, ankle and foot bones
Joints – types of joints and MOVEMENTS at joints – learn all terms
Diseases/disorders –osteoarthritis, rheumatoid arthritis, sprain, bursitis, dislocations, types of fractures, scoliosis, herniated discs
Role of fibroblasts and osteoblasts in repairing bone fractures

3. Bone Functions
The skeleton is a framework of bones and cartilage that performs several functions
Support for soft tissues
Provides a place of attachment for muscles
Protects internal organs
Stores minerals (calcium and phosphorus) and fat
Certain bones produce blood cells in the red marrow

4. There Are Two Kinds of Bone Tissue
Compact bone
Dense tissue
Periosteum – membrane that nourishes the bone
Forms in thin, circular layers around central canals -Osteon
Bone shaft and outer part of the two ends
Spongy bone
Inside long bone’s shaft
Looks lacy; quite strong

6. Figure 5.1 The structure of bone.6

7. Bone Marrow Connective tissue where blood cells are formed Red marrow
Occurs in spongy bone of some bones (ribs, pelvis, backbone, skull, sternum and long bone ends)
Produces blood cells
Yellow marrow
Fills the cavities of adult long bones
Is largely fat and used for energy storage

9. Figure 5.2 The fetal skeleton is first made of cartilage and gradually is replaced by bone.9

10. Figure 5.3 Steps of bone formation in long and short bones, from an embryo into childhood.10

11. Cartilage Model
Web Activity: Bone Growth 11

12. Tuesday, 10/31/17 What are the 5 steps/stages of bone formation?
Do Not look in book or notes……..
Discuss with the person next to you

13. 5 steps of bone formation
Cartilage model
Bone collar formation (osteoblasts) around the shaft of the model
Shaft hollows out, spongy bone fills in; blood vessels penetrate so bone formation expands
Bone formation develop in the ends of bone (secondary centers)
Cartilage remains only on contact surfaces and growth plate

15. Hormones and Bone Growth
Growth hormone stimulates bone growth during childhood
Thyroid hormones ensure that the skeleton grows with the proper proportions
Sex hormones (testosterone and estrogen) prompt and stop the growth spurt of puberty

16. Hormones and Bone Growth
By the end of the teenage years, sex hormones initiate less frequent cell division
Growth plate thins
Ends of the bone fuse with the shaft
Bone can no longer increase in length

18. Stop and Think!
We have discussed the mechanism by which long bones grow and the role of growth hormone in that process.
Why would it be ineffective for a short, middle-aged person to be treated with growth hormone to stimulate growth?
Discuss with person next to you.

20. Bone Remodeling – Osteoblasts and Osteoclasts
Osteoblasts form/deposit/build bone
Osteoclasts BREAK DOWN bone -secrete enzymes that degrade it – release calcium and other minerals that are reabsorbed by the body
In adults, bone building and bone breakdown continue constantly
Calcium is constantly entering and leaving a person’s bones

21. Bone Tissue Is Constantly “Remodeled”
The ongoing calcium recycling is called BONE REMODELING
Keeps bones resilient
Mechanical stress
Repair of broken bones
During growth
Homeostasis of blood calcium levels (interplay of two hormones calcitonin and parathyroid hormone PTH)

22. Monday, 11/6/17 What are the steps of healing in a bone?
Complete the worksheet by numbering the steps in the order that healing takes place.
Give a brief description of what is taking place for each step.

23. Healing Bone Activity PDF

24. The Role of Fibroblasts and Osteoblasts in Repairing Bone Fractures
Nondisplaced fracture: the ends remain aligned
Displaced fracture: the ends must be realigned
When a bone breaks, bleeding occurs and a clot forms
Fibroblasts invade the clot and secrete collagen fibers that form a callus linking the two parts of the bone
Osteoblasts transform this cartilage into bone

25. The Role of Fibroblasts and Osteoblasts in Repairing Bone Fractures
Web Activity: Bone Repair 25

27. Bone Tissue Is Constantly “Remodeled”
The ongoing calcium recycling is called BONE REMODELING
Keeps bones resilient
Mechanical stress
Repair of broken bones
During growth
Homeostasis of blood calcium levels (interplay of two hormones calcitonin and parathyroid hormone PTH)

28. Bone remodeling - the process of bone deposition and breakdown
* also helps regulate blood calcium levels
* calcium plays a role in the functioning of nerves and muscles
as well as blood clotting
Calcitonin and Parathyroid Hormone – help control bone remodeling and regulat-
ing blood calcium levels.

29. Bone Density
As we age, bone tissue may break down faster than it is renewed
Osteoporosis is a progressive deterioration in bone density
May occur when the action of osteoclasts outpaces that of osteoblasts
May also occur as a result of inability to absorb calcium
Calcium and sex hormone deficiency, smoking and a sedentary lifestyle – contribute to osteoporosis
Exercise, dietary calcium and drugs may slow it down

30. In Osteoporosis, Bone Tissue Breaks Down Faster Than It Is Rebuilt

31. Exit Question
Contrast the functions of osteocytes, osteoblasts and osteoclasts.

33. Tuesday 11/7/17
How does calcitonin and parathyroid hormone (PTH) control bone remodeling and blood calcium levels?

34. Bones, Ligaments, and Tendons Are the Basic Components of the Skeleton
Organization of human’s 206 bones
Axial skeleton
Appendicular skeleton
Ligaments (elastic connective tissue – stretchy and resilient)
Connect bones at joints
Tendons – cords/straps of connective tissue packed with collagen fibers
Attach muscles to bones or other muscles

35. Figure 5. 6 Major bones of the human body
Figure 5.6 Major bones of the human body. Bones of the axial skeleton are shown in orange; bones of the appendicular skeleton are shown in light brown. Cartilage is shown in light purple. 35

36. Axial Skeleton
The axial skeleton: protects and supports our internal organs
Components
Skull
Vertebral column
Sternum and rib cage

37. Facial bones (fourteen bones) Support several sensory structures
Figure 5.7 Major bones of the skull and face.
Facial bones (fourteen bones)
Support several sensory structures
Serve as attachment sites for most facial muscles 37

38. Cranial Bones
The cranium which is formed from eight (sometimes more) flat bones
Protect the brain
House the structures of hearing
Provide attachment sites for the muscles of the head and neck

42. Figure 5.8 The skull bones of a human newborn are not fused but are instead connected by fibrous connective tissue.
Before and shortly after birth, the bones of the cranium are connected by membranous areas called fontanels
Allow the skull to be compressed during birth as the baby passes through the birth canal
Allow for the rapid growth of the brain during the fetal period and infancy
Replaced by bone by 2 years of age 42

43. Vertebral Column The vertebral column consists of 26 vertebrae
7 cervical (neck) vertebrae (C1–C7)
12 thoracic (chest) vertebrae (T1–T12)
5 lumbar (lower back) vertebrae (L1–L5)
1 sacrum (formed by the fusion of five sacral vertebrae)
1 coccyx (or tailbone, formed by fusion of four vertebrae)

45. Wednesday 11/8/17 Which bones form the bridge of the nose?
Which bones form the cheekbones in the skull?
What are the interconnected bones that form the backbone?

46. Intervertebral disks separate vertebrae from one another
Figure 5.9 A side view of the vertebral column.
Intervertebral disks separate vertebrae from one another
Pads of fibrocartilage
Become compressed over the years and individuals become shorter as they age 46

47. Label the skeleton

48. Vertebral Column and Scoliosis
“Twisted disease”
Abnormal curvature of the spine
Cause is unknown
Affects over 1.5 million adolescents, primarily females
Treatment may involve a brace or surgery

49. Vertebral Column and Intervertebral Disks
The term “slipped disk” is a misnomer
It is a disk that bulges but does not move out of place
If a disk bulges inward, it can press against the spinal cord and interfere with perception of incoming stimuli and muscle control
If a disk bulges outward, it can press against the sciatic nerve and cause the painful inflammatory condition sciatica

50. Rib cage
12 pairs of ribs attach at the back of the rib cage to the thoracic vertebrae
Upper 10 pairs are attached by cartilage either directly or indirectly to the sternum
Last two pairs do not attach to the sternum and are called “floating ribs”

51. Label the skeleton

52. Appendicular Skeleton
The appendicular skeleton allows movement and interaction with the environment
Components
Pectoral girdle
Pelvic girdle
Limbs

53. Composed of: Function: Scapulae Clavicles Supports the arms
Figure 5.11 The pectoral girdle and arm.
Composed of:
Scapulae
Clavicles
Function:
Supports the arms 53

54. More rigid than the pectoral girdle
Figure 5.12 The pelvic girdle and leg.
More rigid than the pectoral girdle
Composed of:
Two pelvic bones joined in front at the pubic symphysis
Function:
Supports the legs 54

55. Label the skeleton

56. 5.5 Joints: Connections between Bones
Joints are areas of contact or near contact between bones
All joints have some form of connective tissue that bridges the gap between bones

57. Types of Joints Synovial joint (knee, elbow, hips) Synovial fluid
Movement
Cartilaginous joint (vertebrae)
Slight movement
Fibrous joint (teeth-socket)
No cavity
Generally no movement

58. Figure 5.13 The knee is a synovial joint.58

59. Synovial Joints
Synovial joints differ in the type and range of motion they permit
Hinge joints
Motion in only one plane
Example: knee
Ball-and-socket joints
Motion in all planes
Example: shoulder

60. Figure 5.14 Types of movement at synovial joints.60

62. Thursday 11/9/17 Name the three types of joints
Do they have movement?
Where do you find them?
The pectoral girdle is composed of what bones?
The pelvic girdle is composed of what bones?

63. Carpal tunnel syndrome

64. Damage to Joints Sprains Bursitis Injuries to ligaments
Range from slight (caused by overstretching) to serious (caused by tearing)
Example: tearing the anterior cruciate ligament of the knee
Bursitis
Inflammation of the bursae (fluid-filled sacs that surround and cushion joints)
Example: inflammation at the elbow from repeatedly swinging a tennis racket

66. Arthritis Joint inflammation Types Osteoarthritis
Degeneration of joint surfaces over time
Rheumatoid
Autoimmune condition marked by an inflammation of the synovial membrane
Damaged joint may need to be replaced with an artificial joint

67. Rheumatoid Arthritis May Cause Bones to Become Misaligned

68. Friday 11/10/17
Skeletal Lab
Scavenger Hunt

69. Chapter Review Functions of Bone
Two kinds of bone tissue – compact and spongy – types of marrow
Development of bone – cartilage model
Hormones and bone growth
Importance of Bone Remodeling; osteoblasts and osteoclasts
Loss of bone density – Osteoporosis
Ligaments and tendons
Overview of Human Skeleton – Axial and Appendicular –KNOW THE NAMES and LOCATIONS OF ALL THE BONES
AXIAL: Skull, ribs, sternum, vertebral column, intervertebral disks
APPENDICULAR: Pectoral girdle -scapula, clavicle, upper limb bones, pelvic girdle, leg, ankle and foot bones
Joints – types of joints and MOVEMENTS at joints – learn all terms
Diseases/disorders –osteoarthritis, rheumatoid arthritis, sprain, bursitis, dislocations, types of fractures, scoliosis, herniated discs
Role of fibroblasts and osteoblasts in repairing bone fractures