Chapter 6: Skeletal System Bone Tissue

What are some parts of the body where red bone marrow is most abundant?

Pelvic, ribs, sternum, vertebrae, skull, humerus, femur, and developing bones of fetus.

EPIPHYSES

Proximal and distal ends of bone

EPIPHYSEAL PLATE & FUNCTION

The epiphyseal plate is a hyaline cartilage that is responsible for the growth of the diaphysis.

What are the functions of the bone and skeletal system? (6)

Support (framework and provides attachment points for tendons); Protection; Assistance in movement; Storage and distribution; Blood Cell Production; Triglyceride Storage (yellow bone marrow; potential chemical energy reserve)

What is the term for blood forming tissues?

HEMOPOISES

Where can you find veins that carry blood away from long bones? (3)

1. 1-2 veins w/ nutrient artery exit through diaphysis; 2. vein w/ metaphyseal and epiphyseal veins exit through epiphyses; 3. veins w/ periosteal veins exit through periosteum

Bone formation occurs in what (4) situations?

1. formation of bone from embryo and fetus; 2. growth of bones during infancy, childhood, and adolescence; 3. remodeling of bone (replacement of old bones) throughout life; 4. repair of fracture (breaks in bones) throughout life.

Explain the process of intramembranous ossification.

At the site of ossification (ossification center), mesenchyme cells cluster to form osteogenic cells then osteoblasts -> osteoblasts secret organic e.c matrix of bone until it is surrounded by it -> osteoblasts turn to osteocytes where they reside in lacunae and extend their (legs-cytoplamic processes) into the canaliculi; mineral salts are deposited and e.c matrix hardens (calcifies) ->e.c forms to trabeculae which fuses the calcified e.c matrixes together to form spongy bone around network of blood vessels -> layer of connective tissue forms outside of bone called periosteum which will eventually replace surface by compact bone but middle stays spongy.

What does the skeletal system tissue consists of? (6)

Bone tissue, Adipose tissue (yellow bone marrow), cartilage, blood forming tissue (hemopoiesis), epithelium, dense connective tissue, and nervous tissue.

DIAPHYSIS

Bone's shaft/body (cylindrical shaped)

The process of calcification requires what and explain the process?

Collagen fibers. Mineral salts crystalize between the collagen fibers first then it accumulates around the collagen fibers.

PERIOSTEUM & FUNCTION

Composed of outer fibrous layer of dense irregular connective tissue and an inner osteogenic layer consisting of cells that covers the bone. Protects bone, assist in fracture repair, nourish bone tissue, and provides attachment points for ligaments and tendons. Cells enables the bones to grow in thickness not in length

How does spongy bone differ from compact bone?

Does not have osteons; lighter in weight; is the site red bone marrow and hemopoisis

What happens to our bone marrow as we age?

In newborns, bone marrow is red and continues to undergo hemopoiesis. As we age, bone marrow changes from red to yellow.

Why is bone considered a connective tissue?

It contains cells, extracellular matrix, and protein fibers (collagen fibers).

MEDULLAR CAVITY & FUNCTION

Marrow cavity located within the diaphysis that contains yellow bone marrow and blood vessels in adults. Minimizes weight of bone by reducing bony material where it is least needed.

Explain the process of CALCIFICATION

Mineral salts: Calcium phosphate + Calcium hydroxide = crystals of hydroxyapatite. -> crystals combine with other salts (ex: F, K, S, Mg) -> deposited into framework formed by collagen fibers + e.c. matrix ->crystallize + tissue hardens

What is a bone scan and how is it used?

Nuclear scanning test that finds certain abnormalities of a bone and its metabolic activity (blood flow); radioactive compound is injected through IV and scanning device measures the radiation emitted from bones. Normal bones are gray throughout; dark (hot spots) may indicate cancer, abnormal healing of fractures, or abnormal bone growth; light (cold spots) may indicate decalcified bones, fractures, bone infections, Paget's disease, and rheumatoid arthritis.

What is the term for bone-formation?

Ossification or osteogenesis

METAPHYSES

Region between the diaphysis and epiphyses in which the epiphyseal growth plate is located during bone growth.

ARTICULAR CARTILAGE & FUNCTION

Thin layer of hyaline cartilage that covers the ends of the epiphysis where it forms an articulate joint with another bone

What are perforating canals?

aka Volkmans canal; where blood vessels and artery resides from the periosteum

What other organs can be found accompanied with blood vessels in the bone tissue?

arteries and sensory nerves.

NUTRIENT ARTERY & FUNCTION

artery that passes through hole in compact bone called nutrient foramen & branches out to distal part of bone; it supplies diaphysis and epiphysis

Why would one feel pain during a bone marrow biopsy?

because bones especially in the periosteum are rich in sensory nerves which are sensitive to tearing or tension.

OSTEOBLASTS, LOCATION & FUNCTION

bone-building cells found in e.c. matrix that secrete collagen fibers and organic compounds to build e.c. matrix and initiate calcification. Develops in to osteocytes as they get trapped in the their secretions

What are OSTEONS and describe is structure

cylinder structural unit of compact bone; consists of lamellae surround a central canal which contains a blood vessels & artery; circular layer formation of lamellas are called centric lamellae; site of osteocytes; between the lamellaes are lacunae (spaces) and canaliculi (small channels) that connect lacunae together

COMPACT BONE, LOCATION, & FUNCTION

dense (few spaces); makes up most of diaphysis of long bones; provides protection & support, resist the stresses produced by weight & movement

OSTEOCLASTS, LOCATION, & FUNCTION

derived from many monocytes (type of WBC) that contains 5 nucleus in one cell. Releases lysosomes to break down e.c matrix and digest protein (collagen) and mineral components (mineral salts) as part of normal dev., maintenance, and bone repair

EPIPHYSEAL ARTERY

enters the epiphyses of long bones w/ nutrient artery and supplies red bone marrow & bone tissue of epiphyses.

METAPHYSEAL ARTERY

enters the metaphyses of a long bone w/ nutrient artery and supplies red bone barrow & bone tissue of the metaphases

What are circumferential lamellae?

found on the circumference of bone shaft

What are the types of ossification? (2)

intramembranous ossification and endochondral ossification

OTEOCYTES, LOCATION, & FUNCTION

mature bone cells that maintains bone tissues metabolism (exchange of nutrients and wastes)

Our bones hardness and flexibility depends on what?

mineral salts and collagen fibers

What are interstitial lamellas?

older osteons

What are the four types of cells found in bone tissue?

osteogenic cells, osteoblasts, osteocytes, osteoclasts

What part of the bone tissue would you feel the most pain?

periosteum because it is rich in sensory nerves that are sensitive to tearing or tension.

What is the function of collagen fibers in bone tissues?

provides tensile strength (resistance to be stretched or torn apart)

PERIOSTEAL ARTERIES

small arteries w/ nerves that enter diaphysis to perforating canals and supply periosteum and outer part of compact bone with nutrients and removes waste to keep bone alive.

SPONGY BONE, LOCATION & FUNCTION

spongy-like; interior protected by compact bone, makes up most of epiphysis & metaphysis; support and protection red bone marrow

ENDOSTEUM & FUNCTION

thin membrane that lines medullar cavity that contains a single-layer of bone forming cells and connective tissues.

What does the extracellular matrix of bones tissues consist of?

water (15%), collagen fibers (30%), crystallized minerals; calcium phosphate(55%)

OSTEOGENIC CELLS, LOCATION & FUNCTION

young stem cells that undergo mitosis to develop osteoblasts. Found in inner part of periosteum, endosteum, and canals within bone that contain blood vessels