Do Now

1. Do Now • Use the Socrative App to answer the questions! • Room # 981663

2. Objectives • Identify the different structures and fuctions of the Skeletal system. • Label a long bone and internal structures of bone. • Explain bone development and growth. • Apply knowledge of homeostatic mechanisms to explain the regulation of blood calcium levels.

3. Skeletal System Chapter 7

4. Skeletal System Components • Bone • Tendons- connect bones to muscle • Ligaments- connect bones to bones

5. Functions • Muscle attachment • Protection • Contain blood-producing cells • Storage of inorganic salts • Passageway for nerves & blood vessels

6. Bone Classification • Long • Ex: • Humerus • Femur • Ulna • Radius • Clavicle • Phalanges

7. Bone Classification • Short • Wrist bones • Foot bones

8. Bone Classification • Flat

9. Bone Classification • Irregular

10. Bone Classification • Sesmoid

11. Long Bone Anatomy

12. Microscopic Structure • Compact (Cortical) Bone: osteocytes and layers of ECM are concentrically clustered around a Haversian Canal (Osteon). • Haversian Canals contain blood vessels and nerve fibers which nourish the bone cells.

13. Microscopic Structure

14. Bone Development • Intramembranous Bones: • Originate between sheetlike layers of connective tissue. • Endochondral Bones: • Begin as masses of cartilage that bone tissue replaces.

15. Bone Development • Bone Development Animations • Bone Development Explanation (YouTube)

16. Bone Development • Intramembranous Ossification: 1. Connective tissue appears a the sites of future bones. 2. Connective tissue cells differentiate into osteoblasts. 3. Osteoblasts deposit bony material around themselves and form spongy bone. 4. Membranous tissue cells give rise to the periosteum. 5. Osteoblasts inside the periosteum form compact bone.

17. Bone Development • Endochondral Ossification (Condensed Version): • Cartilage breaks down in the center of the diaphysis. (primary ossification center) • Periosteum forms around the developing dipahysis from connective tissue. • Blood vessels and osteoblasts from periosteum invade the cartilage and form spongy bone. • Epiphysis remain cartilaginous and later secondary ossification centers appear and form spongy bone. • Epiphyseal plate undergoes mitosis and produces new cells which enlarge , while calcium salts accumulate in the extracellular matrix, they calcify, and the cartilage cells die. • Osteoclasts secrete acid that dissolves part of the calcified matrix and osteoblasts deposit new bone tissue in place of the calcified cartilage. • Bone continues to grow at the epiphyseal plate until adulthood.

18. Endochondral Ossification

19. Do Now • Complete the questions using Socrative (you will get participation points for this so make sure you do it! Use someone’s phone when they are done or the computer if necessary)

20. Objectives • To explain the different functions of bone in detail. • To apply your knowledge of homeostasis and negative feedback loops to explain hormonal regulation of bone calcium resorption and deposition.

21. 7.4- Bone Function • Aside from movement and protection, bones are involved in… • Red blood cell formation • Storage of inorganic salts

22. Hematopoiesis • Hematopoeiesis=Red blood cell formation • RBC’s form in the liver, spleen, and bone marrow • Red Marrow: • Found in infants as well as in spongy bone of skull, ribs, sternum, clavicles, vertebrae, and hip bones of adults • Produces red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. • Yellow Marrow: • In adults • Stores fat • *doesn’t produce RBC’s

23. Inorganic Salt Storage • ECM of bone is rich in calcium • Calcium is required for muscle contraction, nerve impulse conduction, blood clotting, and other physiological processes. • Our bodies must maintain a sufficient blood-calcium level using a homeostatic mechanism.

24. Calcium Regulation • How is calcium regulated?

25. Calcium Regulation

27. Low calcium levels • Causes Parathyroid Hormone (PTH) to be released • PTH causes stored calcium in bone to be released • PTH causes calcium reabsorption in the kidney (not excreted in urine) • PTH causes the synthesis of Vit. D. which increases Ca+ absorption in the small intestines.

28. High calcium levels • Causes the release of calcitonin from the thyroid gland • Calcitonin Inhibits Ca2+ absorption by the intestines • Inhibits osteoclast activity in bones • Inhibits renal tubular cell reabsorption of Ca2+ allowing it to be excreted in the urine

29. Hypo vs. Hypercalcemia • Hypocalcemia: can cause muscle stiffness and seizures • Hypercalcemia: too much calcium, causes kidney stones or even kidney failure, could cause heart problems

30. Quiz on Friday! • There will be a quiz on 7.1-7.4 on Friday. This will include the main bones of the skull as well as the notes we have covered so far. • #’s 1-13 (not the features just bones!)

31. Do Now • If you have not done so already, complete the quiz on socrative! • If you have already completed it, come up with 3 questions you might see on your quiz that you did not see on the practice quiz.

32. Objectives • To Identify the major bones of the skull. • To label the major features of the bones of the skull.

33. The Skull!!

34. Frontal Bone

35. Parietal Bone(s)

36. Occipital

37. Temporal

38. Ethmoid (The Orange)

39. Sphenoid

40. Mandible

41. Maxilla

42. Zygomatic

43. Volmer

44. Palatine

45. Nasal

46. Lacrimal (The Green)

47. Hyoid

48. Coloring Activity • *Color all of the bones that we just covered!