Skeletal System 7 October 2013

What do our bones reveal about us?  Our health, past and current  Trauma, past and current  Age  Gender  Race Significant concept: Our bones are dynamic – constantly changing

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.

What are the functions of the bones? 1.Support - support and anchor the body and organs 2.Protection – protect organs Examples:

What are the functions of the bones? 1.Support - support and anchor the body and organs 2.Protection – protect organs Examples:  Skull protects brain.  Ribs protect heart and lungs.  Vertebrae protect spinal cord. 3.Movement – bones serve as an attachment site for muscles; muscles use bones like levers for movement

What are the functions of the bones? 4.Storage – fat, calcium, and phosphorus storage 5.Blood cell formation – Red and white blood cells develop within the red marrow of long bones and flat bones

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.

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

Classifying Bones by Shape 4 corners Examine all the bones in your group. 1.Do you all agree about the type? 2.Can you guess which bones any of them are?

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.

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.

Structure of a Long Bone Think, Pair, Share: Name two ways the structure of the long bone varies by age. 1)Infants have red marrow in medullary cavity – converts to yellow in adults 2)Growing individuals have epiphyseal plates (cartilage); adults have epiphyseal lines

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

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.

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.

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

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.

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

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

Microscopic Structure: Compact Bone

Osteon lamellae

Microscopic Structure: Spongy Bone All you need to know is that 1)Spongy bone is much less dense 2)Spongy bone contains red marrow, which functions to produce blood.

You Do: Make a concept map, showing connections between the following terms: Group A Terms Lamellae Lacunae Osteocyte Central canal Perforating canal Canaliculi Be prepared to share with the class! Group B Terms Yellow marrow Red marrow Hematopoiesis Medullary cavity Spongy bone Compact bone Diaphysis epiphysis

You Do: Make a concept map, showing connections between the following terms: Group A Terms Lamellae Lacunae Osteocyte Central canal Perforating canal Canaliculi Be prepared to share with the class! Group B Terms Yellow marrow Red marrow Hematopoiesis Medullary cavity Spongy bone Compact bone Diaphysis epiphysis

Closure 1.What were our objectives today and how well did we meet them? 2.What learner profile trait did we focus on and how did we use it? 3.How does what we learned today address our unit question?

Exit Ticket 1.Identify 3 functions of bones. 2.Name two bones and describe their shape. 3.Draw and label picture of either the gross anatomy (overall shape) of a long bone OR the microscopic structure of compact bone.