Today in Human Anatomy…

Week #8 (9/8-9/12)Warm Up – Mon, 9/8:- None

Have out:NothingPick up:Nothing

Agenda:1. Patch Adams movie

Homework:1. Guest Speaker

Thank You – Fri, 9/12

2. Osseous Tissue Quiz #1 – Tues, 9/16

Anatomy Fun Fact:The hardest bone in the human body is the jawbone.

Histology of the Skeletal System: Osseous Tissue

Learning Goal:Students can describe the basic

histology of the Skeletal System. 

Students will be able to:Describe the 5 major functions of bone

Identify the 6 classifications of bones

Explain the functions & relationships of osteocytes, osteoblasts, osteoprogenitor cells &

osteoclasts

Describe the important effects of hormones & nutrition on bone health

Osseous Tissue Latin Roots• Oss/osteo- = bone• Hema(o)- = blood• -poie = to make• Coxa = hip• Carp- = relating to the wrist• Tars- = ankle• Dia- = apart, through• Epi- = on top of• Peri- = around• Endo- = within, inside

• Phys- = nature, movement• Dipl- = twofold, double• Pro- = for, forward• Gen- = birth• -cyte = cell• -blast = cell with a nucleus, 

embryo• -clast = broken• -oid = like, similar to

Why is Bone considered an Organ?

• Bones are organs (organ level of organization) because they contain different types of tissue – Osseous – Nervous– Blood– Cartilage

Functions of Bones• Support – hard framework

that supports body & cradles soft organs

• Protection – fused bones of skull, vertebrae, rib cage

• Movement – skeletal muscles use bones as levers

• Mineral Storage – calcium & phosphate

• Blood Cell Formation (hematopoiesis) – RBC & WBC forms within red marrow cavities of certain bones

Week #8 (9/8-9/12)Warm Up – Tues, 9/9:- Show US your Osseous Tissue Index Cards!!!

Have out:Osseous Tissue Index Cards Bone diagramOsseous Tissue PPT notesPick up:Skeletal Sys. Outline

Agenda:1. Osseous Tissue lecture – Classification,

Anatomy & Bone Histology2. Bones recap

Homework:1. Guest Speaker

Thank You – Fri, 9/12

2. Osseous Tissue Quiz #1 – Tues, 9/16

Anatomy Fun Fact:The hardest bone in the human body is the jawbone.

Classification of Bones• Classified according to shape:

– Long Bones – has a shaft & 2 ends; made mostly of compact bone but may contain spongy bone in its interior• Ex. Femur, tibia, fibula, humerus,

fingers of hand– Short Bones – cube-like & contain

mostly spongy bone; compact bone provides thin surface layer• Ex. Bones of carpus (wrist) & tarsus

(ankle)• Sesamoid Bones – small, flat, shaped

like sesame seed; develop in tendons located near joints – Ex. Knee cap (patella)

Classification of Bones• Classified according to shape:

– Flat Bones – thin, flattened & usually a bit curved; have 2 relatively parallel compact bone surfaces • Ex. Sternum, ribs, skull• Sutural Bones – small, flat, irregular

shaped bones of skull– Irregular Bones – bones that do

not fit above classification • Ex. Vertebrae & os coxa (pelvis)

Long Short Flat Irregular

Anatomy of Long Bones• Diaphysis (shaft) – composed of a thick collar of

compact bone that surrounds a central medullary cavity (marrow cavity) • “dia” – passing through

• Epiphyses – bone ends• “epi” – on top of• Exterior made up of compact

bone• Interior is spongy bone

• Why are the exterior & interior regions of the epiphyses structured this way?

• Joint surface of each epiphysis is covered with thin layer of articular cartilage (cushion)

Anatomy of Long Bones• Periosteum – outer surface of diaphysis

• Richly supplied with nerve fibers & blood vessels• Endosteum – a delicate covering of internal bone

structures• Why are there 2 wrappings

found within long bone structure?

Anatomy of Short, Irregular & Flat Bones

• Thin plates of periosteum-covered compact bone on outside

• Endosteum-covered spongy bone (called diploe in flat bones) on inside

Anatomy of Bones• All bones contain external compact bone &

internal spongy bone filled with red or yellow bone marrow

Hematopoetic Tissue in Bones

• Hematopoeisis: formation of blood cells• “hema” – blood• “poiesis” – production or formation of

• Infants• Medullary cavity & all spongy bone

contain red marrow• Adults

• Diaphysis is usually filled with fatty (adipose) yellow marrow

• Majority of hematopoiesis in long bones occurs in head of the femur & humerus

• Most important blood production occurs in diploe of flat bones (sternum) & in some irregular bones (hip bone)

Week #7 (9/4)Warm Up – Friday 9/4:- Osseous Cells Relationships Review

Have out:Osseous Cells diagramOsseous Latin index cardsSkeletal Sys. Pre-TestPick up:Osseous Tissue PPT notes Pt 2

Agenda:1. Osseous Tissue lecture – Bone Growth/

Cartilage, Effects of Nutrition & Hormones on Bone & Bone Fractures/Repair

Homework:1. Osseous Tissue

Quiz #1 on Wednesday 9/9

Anatomy Fun Fact:Humans & giraffes have the same number of bones (8) in their necks. Giraffe neck vertebrae are just much, much longer!

What classification would this bone fall under?

Name the identified regions or coverings of a long bone.

Name a function of bone.

What is formed in the medullary cavity of a long bone?

5 (space)6 (stuff)

4

3       (use anatomical direction term)

2

1       (use anatomical direction term)

8 (covering)

7 (covering)

Bone Histology

Now what level of organization are we talking about?

• Bone contains specialized cells & a solid, sturdy matrix (calcium salts deposited around collagen protein fibers)

• Osteocytes: mature bone cells that occupy a lacuna (osseous cell “bed”)• “osteo” – bone• “cyte” - cell

Bone Histology• Bone cells are arranged in

cylindrical patterns throughout bone around thin tubes called Haversian canals that contain nerves & blood vessels that nourish the osteocytes.

• Tiny cytoplasmic extensions called canaliculi (little canals) connect the osteocytes to one another & the Haversian canals. Osseous Cells relationships (~4:13)

Functions of Osteocytes• Maintain the protein

& mineral content of the matrix• Secrete chemicals that

dissolve old matrix & then stimulate the depositing of calcium crystals

• Assist in the repair of damaged bone• If released from lacunae,

osteocytes can become an osteoblast or an osteoprogenitor cell

Osteoprogenitor Cells• Stem cells that undergo mitosis,

producing daughter cells that differentiate into osteoblasts• Aid in repair of

bone fractures • Located in the

periosteum