Lesson 4.1

2. Chapter 4: The Skeletal System Lesson 4.1 Bone as a Living Tissue

3. Functions of the Skeletal System • Support • Our bones form the internal support system that provides shape and support to our trunk and limbs. • Protection • Our bones surround and support the body’s delicate internal organs. E.X. the ribs protect the heart and lungs in the thoracic cavity. • Movement • When muscles contract or shorten, they pull on the attached bones causing movement. • Storage • Bones also serve as a storage repository for minerals, such as phosphorous and calcium. • Blood cell formation (hematopoiesis) • Occurs in the red bone marrow in medullary cavity

4. Structures and Classifications of Bones • Composition of bones • Osteocytesmature bone cells • 60–70% of bone weight comes from its mineral content; Calcium Carbonate and Calcium Phosphate. • 30–40% of bone weight comes from collagen, (protein that provides bone’s flexibility) and water. • Organization of bones • Bone is structurally organized into two different types of tissue • Cortical: relatively dense • Trabecular: also known as spongy bone, is relatively porous, with a honeycomb structure

5. Shape Categories of Bones • Bones are traditionally divided into four categories: • Long bones • Long, round shaft, with bulbous knobs at both ends. • Shafts enclose the central hollow medullary cavity or canal. • Major bones of the arms and legs. • Short bones • Shaped like a cube. • Bones of the wrists and ankles. • Flat bones • Thin, large in surface area, and generally curved • The scapula and bones of the skull • Irregular bones • All other bones • Bones of the spinal column and hip girdle

6. Anatomical Structure of Long Bones • Diaphysis of a long bone, the hollow shaft, is composed of cortical bone. A fibrous connective, periosteum, surrounds and protects the diaphysis. • Periosteum contains blood and lymph vessels, as well as nerves. It is involved in bone growth, repair, and nutrition. • The hollow center of the diaphysis, is filled with yellow bone marrow, (from the age of 5) with a rich supply of blood vessels and is a storehouse for fat.

8. Anatomical Structure of Long Bones • The bulbous endings of the long bones are known as epiphyses. • contain red marrow, which participates in the formation of red blood cells, and some white blood cells • Each epiphysis is surrounded by a protective covering of articular cartilage. • Canaliculi and lacunae provide a matrix for the supply of nutrients and the removal of waste products.

9. Growth and Development of Bones • Osteoblasts • build new bone tissue • Osteoclasts • break down weakened or damaged bone tissue • Bone formation • Skeleton of early-developing embryos is composed mainly of a flexible tissue called hyaline cartilage. • This cartilage is replaced by bone as the fetus develops by a process called ossification. • As an adult, cartilage still forms parts of the nose, ribs and some joints.

10. Growth and Development of Bones • Longitudinal growth • Bones grow in length at the epiphyseal plates, located close to the ends of long bones • Circumferential growth • Most bone growth occurs during childhood, bones actually grow in diameter throughout most of life • Adult bone development • Aging results in a progressive loss of collagen (which provides elasticity) and increase in bone brittleness • Bone mineral deposition normally peaks • In women at about 25 to 28 years of age • In men at about 30 to 35 years of age. Thereafter, bone mass is progressively lost

11. Review and Assessment Match these words with 1–4 below: flat, osteocytes, osteoblasts, storage. 1. Build bone tissue 2. One example of bone shape 3. A function of the skeletal system 4. Mature bone cells Osteoblasts Flat Storage Osteocytes

12. Chapter 4: The Skeletal System Lesson 4.2 The Axial Skeleton

13. The Axial Skeleton • The skull • The vertebral column • The thoracic cage

14. The Skull • The 22 bones of the skull are divided into two groups: • The cranium • Surround and protects the brain • The facial bones • Protect the front of the head, give our faces their individual shapes, protect and orient the eyes, and allow chewing of food. • Most of the bones of the skull and face are joined together by irregularly shaped, interlocking, and immovable joints called sutures.

15. The Cranium • The cranium includes eight bones. • There are four sets of paired (left and right side) bones; • The rest are single bones. • frontal bone • Parietal bones (2) • Temporal bones (2) • Occipital bones • Ethmoid bone (2) • Sphenoid bone (2)

16. The Facial Bones • A total of fourteen bones form the face. • There are six pairs (left and right) of bones. • The other two are single bones • Maxillary bones (2) • Palatine bones (2) • Zygomatic bones (2) • Lacrimal bones (2) • Nasal bones (2) • Vomer • Inferior concha bones (2) • Mandible

17. The Vertebral Column • Thirty-three (33) stacked, individual bones called vertebrae comprise the spine. • The vertebrae differ in size and shape in the different regions of the spine to best fulfill their respective functions

18. The Vertebral Column • Regions of the spine • Cervical • Upper 7vertebrae • Nodding the head up and down, • Rotation to the right and left. • Atlas is the first cervical vertebrae • Axis is the second cervical vertebrae • Thoracic • Next 12 vertebrae, which extend through the chest region and articulate (connect) with the ribs • Lumbar • 5 vertebrae found in the lower back KNOW!!

19. The Vertebral Column • Sacrum • 5 fused vertebrae that form the posterior portion of the pelvic girdle. • Coccyx (tailbone) • 4 fused vertebrae at the bottom of the spine. • Curves of the spine • The alternating curves make the spine stronger and better able to resist potential injuries than if it were straight. • Cervical curve • Thoracic curve • Lumbar curve • Sacral curve

20. Abnormal Spinal Curvatures • Abnormal spinal curvatures can develop due to genetic or congenital abnormalities or when the spine is habitually subjected to asymmetrical forces • Lordosis • Exaggeration of the lumbar curve • Kyphosis • Accentuation of the thoracic curve • Scoliosis • lateral deviation of the spine

21. The Intervertebral Discs • Intervertebral discs are composed of fibrocartilage provide cushioning between all of the articulating vertebral bodies that are not fused. • They are located between vertebrae • They serve as shock absorbers and allow flexibility

22. The Thoracic Cage • The ribs, sternum, and thoracic vertebrae are collectively known as the thoracic cage • Sternum consist of: • Manubrium • Body of the sternum • Xiphoid process • 12 pairs of ribs: • First 7 pairs (1-7), true ribs, attach directly to the sternum • Next 3 pairs (8-10), false ribs, have cartilaginous attachments to the cartilage of the 7th rib rather than the sternum • Lowest 2 pair (11 & 12), floating ribs, they do not attach to bone or cartilage in front of the body KNOW!!!

23. Review and Assessment True or False? 1. All ribs are true ribs. 2. The facial bones surround the brain. 3. The sphenoid bone is part of the cranium. 4. There are 4 regions in the spine. 5. Intervertebral discs allow spinal flexibility. False False True False True

24. Chapter 4: The Skeletal System Lesson 4.3 The Appendicular Skeleton

25. The Upper Extremity • The shoulder complex also called the shoulder girdle or pectoral girdle. • Scapula (shoulder blade) • Clavicle (collar bone) • The arm • Humerus • Radius • Ulna

26. The Upper Extremity • The wrist and hand • Collectively, there are 54 bones in the wrists and hands: 27 on the left and 27 on the right. • Large number of bones enables a wide range of precise movements including ability to grasp objects. • Carpals (8) - Wrist • main function is to provide a base for the bones of the hand • Metacarpals (5) – palm • Phalanges (14) – fingers & thumb

27. The Lower Extremity • The pelvic girdle • Shelters the reproductive organs, bladder, and part of the large intestine. • The female pelvis is wider than the male pelvis to enable pregnancy and childbirth. • Ilium • Ischium • Pubis • The leg • Femur • Longest & strongest bone • Tibia • Fibula • Patella (kneecap)

28. The Lower Extremity • The ankle and foot • Tarsals (7) • Metatarsals (5) • Phalanges (14)

29. Chapter 4: The Skeletal System Lesson 4.4 Joints

30. Immovable Joints • Joints are where dense, fibrous tissue (ligaments) binds the bones together. • Sutures • Bones of the skull • Syndesmoses • Coracoacromial joint – top of the shoulder • Distal tibiofibular joint – between tibia and fibula

31. Slightly Movable Joints • Joints that permit only slight motion. • Synchondroses, articulating bones are held together by a thin layer of hyaline cartilage • Sternocostal joint – between the sternum and the ribs • Epiphyseal plates – growth plates • Symphyses, thin plates of hyaline cartilage separate a disc of fibrocartilage from the bones • Vertebral joints • Pubic symphysis

32. Freely Movable Joints • Also called synovial joints • Surrounded by synovial membrane (tendon sheaths) lining that secretes a lubricant known as synovial fluid • Gliding joint • Hinge joint • Pivot joint • Condylar joint • Saddle joint • Ball – and – socket joint

33. Freely Movable Joints

34. Freely Movable Joint Structures • Bursae • Separate tendons from bone, reducing the friction on the tendons during joint motion. • Tendon sheaths • Double-layered synovial structures surrounding tendons • Articular tissues • Articular fibrocartilage • Tendons • Ligaments

35. Chapter 4: The Skeletal System Lesson 4.5 Common Injuries and Disorders of the Skeletal System

36. Fractures • A fracture is a break or a crack in a bone • Greenstick • Stress • Comminuted • Spiral

37. Epiphyseal Injuries • These are injuries to the • Epiphyseal plate ( growth plate) • Articular cartilage (covers the ends of bones) • Apophysis (site where tendon attaches to bone)

38. Osteoporosis • This is a condition in which bone mineralization and strength are so abnormally low that regular, daily activities can result in painful fractures. • Age-related osteoporosis • Osteoporosis occurs in most elderly individuals, with earlier onset in women. • The female athlete triad • Occurs in female athletes at the high school and collegiate levels who strive to maintain an excessively low body weight. • Disordered eating • Amenorrhea (no menses) • Osteoporosis

39. Common Joint Injuries • Sprains • Caused by abnormal motion of the articulating bones that result in overstretching or tearing of ligaments, tendons, or other connective tissues crossing a joint. • Most common site of a sprain is the ankle. • Dislocations • When one of the articulating bones is displaced from the joint socket. • Common dislocation sites are: shoulders, fingers, knees, elbows, and jaw • Bursitis • Inflammation of bursae (fluid-filled sacs that provide cushioning) due to overuse leading to irritation. • Most commonly experienced by runnersbetween the Achilles tendon and the calcaneus (heel bone)

40. Arthritis • Commonly associated with aging and is characterized by joint inflammation accompanied by pain, stiffness, and sometimes swelling. • Over one hundred different types of arthritis have been identified • Rheumatoid arthritis • Autoimmune disorder in which the body’s own immune system attacks healthy joint tissues. • It is the most debilitating and painful form of arthritis. • Osteoarthritis • Non-inflammatory, degenerative disease of articular cartilage

41. Review and Assessment True or False? 1. A torn ligament causes a sprain. 2. Low strength bones easily break. 3. Immune system attack causes amenorrhea. 4. Greenstick is a type of fracture. 5. Bursitis is an inflammation of bursae. True True False True True