1. Skeletal System
1-2 October 2015

2. Our bones are window to our health, revealing secrets about our lives past & current.
Relate to overall unit question: Our bodies require care to function properly. Our bones keep a record of the care we provide, across our lifetime. For this reason, they are often used by forensic biologists and medical examiners.

3. What do our bones reveal about us?
Our health, past and current
Trauma, past and current
Age
Gender
Race
By the end of the mini unit, you will know how our bones change due to sex hormones, age, and disease.

4. What are the functions of the bones?
Support - support and anchor the body and organs
Protection – protect organs
Examples:

5. What are the functions of the bones?
Support
Protection
Examples:
Skull protects brain.
Ribs protect heart and lungs.
Vertebrae protect spinal cord.
Movement – bones serve as an attachment site for
muscles; muscles use bones like levers for movement
Storage – fat, calcium, and phosphorus storage
Blood cell formation – Red and white blood cells develop within the red marrow of long bones and flat bones

6. What are the functions of the bones?
Storage – fat, calcium, and phosphorus storage
Blood cell formation – Red and white blood cells develop within the red marrow of long bones and flat bones

7. Classifying Bones by Shape
Sesamoid bones are bones embedded within tendons. The patella is the largest example.
Sesamoid bones are a type of short bone.
Fun fact: The number and size of sesamoid bones vary in different people.
Short bones = cube shaped (wrist, ankles), patella
flat are flat, thin, usually curved (sternum, ribs, skull
Irregular: vertebrae, hip

8. Classifying Bones by Shape
4 corners Determine which type of bone you have & move to the appropriate corner of the room.

9. Classifying Bones by Shape
4 corners
Examine all the bones in your group.
Do you all agree about the type?
Can you guess which bones any of them are?

10. Structure of a Long Bone
The diaphysis is the shaft.
The epiphyses are the ends
Epiphyseal plates are plates of hyaline cartilage found near the ends of growing bones. In adults, this cartilage is completely replaced by bone, forming the epiphyseal line.
The epiphyses are covered with articular cartilage – provides a smooth, surface for joints.
25 min to start of structure

11. Structure of a Long Bone
The diaphysis is covered with the periosteum, a fibrous connective tissue
Inside the diaphysis is the medullary cavity.
In adults, the medullary cavity is filled with yellow marrow (function: to store fats)
In infants, the medullary cavity is filled with red marrow (function: to produce blood)
Fun fact: In adults, the yellow marrow of the medullary cavity can convert to red marrow in cases of severe anemia.

12. Structure of a Long Bone
Think, Pair, Share:
Name two ways the structure of the long bone varies by age.
Infants have red marrow in medullary cavity – converts to yellow in adults
Growing individuals have epiphyseal plates (cartilage); adults have epiphyseal lines

13. Classifying Bones by Tissue Type
There are two types of bone tissue: spongy bone and compact bone.

14. Classifying Bones by Tissue Type
There are two types of bone tissue: spongy bone and compact bone. Most bones contain both tissues types, in different locations.
In irregular, flat, and short bones, the compact bone is exterior and the spongy bone is interior.

15. Classifying Bones by Tissue Type
There are two types of bone tissue: spongy bone and compact bone. Most bones contain both tissues types, in different locations.
Long bones are mostly compact; in long bones the spongy tissue is found only in the ephiphyses (ends) of the bones.

16. Microscopic Structure: Compact Bone
Even compact bone is not solid! It has many, many channels for blood vessels, nerves, nutrients and wastes.

17. Microscopic Structure: Compact Bone
Basic unit of structure: Osteon
Consists of a central (Haversian) canal and lamellae (rings of calcium salts)
Between lamellae are cavities called lacunae. The osteocytes (mature bone cells) are found in the lacunae.

18. Microscopic Structure: Compact Bone
Transport system:
Blood vessels and nerves grow through central canals (long axis) and perforating canals (short axis)
Canaliculi (tiny channels) branch from central canals to all lacunae

19. Microscopic Structure: Compact Bone
Think, Pair, Share: Explain why an excellent transport system is vital to the functioning of bone.

20. Microscopic Structure: Compact Bone

21. Microscopic Structure: Compact Bone

22. Microscopic Structure: Compact Bone
lamellae
Osteon

23. Microscopic Structure: Spongy Bone
All you need to know is that
Spongy bone is much less dense
Spongy bone contains red marrow, which functions to produce blood.

24. Which ones do you need to know?
Bones of the skeletal system
Which ones do you need to know?
Diagram 5.6 (page 125)
Diagram 5.7 (page 126)
Diagram 5.11 (page 129)
Diagram 5.14 (page 131)
Diagram 5.19 (page 135)
Diagram 5.23 (page 142)

25. Human Skeleton Some hints for memory .. .
Radius is thumb side; ulna is pinky side
Its tibia and fibula
The cuff of your sleeve is by your carpals. The tarsals are in your foot.
Knowing the major bones will help you learn the muscle names!

26. Lateral view of human skull
Sutures are immovable fibrous joints that connect the bones of the skull.
Processes are projections that act as sites for muscle and ligament attachment.
A meatus is a canal. External auditory meatus leads to the ear drum.
Knowing the bones of the skull will help you learn the lobes of the brain!

27. anterior view of human skull
Foramen are small openings in bone for the passage of nerves and blood vessels.
A ramus is an arm-like projection of a bone that helps form a joint.

28. The vertebral column
The vertebral column consists of 33 bones that protect the spinal cord and bear the weight of the body.
The vertebral column is divided into different regions. The regions have different curves and different shapes to the vertebrae.
The individual cervical, thoracic, and lumbar vertebrae are separated by fibrocartilage pads called intervertebral discs
A slipped (herniated) disc occurs when an intervertebral disc slides out of place, pressing on a nerve

29. The bony thorax What bone shape is the sternum? Flat
… so what kind of marrow does it have?
red
In order to diagnose certain blood disorders, doctors perform a sternal puncture by inserting a needle into the sternum to obtain red marrow.
Consists of ribs, sternum, and thoracic vertebrae
Sternum is three bones fused together.
Has important ‘landmarks’
Jugular notch
Sternal angle
Have students palpate jugular notch. Its at level of third thoracic vertebrae.
Sternal angle can also be palpated. Helps doctors count ribs so know where to listen for different heart sounds.

30. The bony thorax There are three types of ribs.
True ribs connect directly to the sternum by a cartilaginous joint.
False ribs connect indirectly to the sternum (or not at all). The last two false ribs are called ‘floating ribs’ because they do not connect to the sternum at all.

31. Pelvic Girdle
The pelvic girdle is composed of two hip bones, sacrum, and coccyx.
Each hip bone is composed of three different bones:
Ilium (most lateral bone – the ‘hips’)
Pubis (most anterior – these fuse at a joint called pubic symphysis
Ischium – most inferior

32. Male vs Female Pelvic Girdle
WHY?
Female pelvises…
have a larger, more circular inlet
Is shallower / more spread out
Has a larger pubic arch (80-85o)
Male pelvises…
have a smaller, heart shaped inlet
Is deeper / more upright
Has a smallerr pubic arch (50-60o)

33. How do you know? Thumbs up for girls! Male! Pelvis is deep
Inlet is heart-shaped & narrow
Pubic arch is degrees
How do you know?

34. How do you know? Thumbs up for girls! Male!
Inlet is heart-shaped & narrow
Pubic arch is degrees
How do you know?

35. How do you know? Thumbs up for girls! Female! Inlet is large and round
Pubic arch is degrees
How do you know?