Anatomy Exam 2

What are the components of the skeletal system?

• Bone

• Cartilage

• Tendons and ligaments

What is the other name for “bony” tissue?

osseous tissue

what are the 5 functions of the skeletal system?

1. support and protection

2. body function

3. fat storage

4. blood cell formation

5. inorganic salt storage

what is found in yellow marrow?

adipose tissue and fat storage

what type of cartilage is articular cartilage?

hyaline cartilage

what is the function of articular cartilage?

• Reduces friction between bones

• Absorbs shock during movement

• Distributes load across the joint

• Protects underlying bone from wear

what is the location of the periosteum?

outer surface of bones

what is the tissue type of periosteum?

dense irregular CT

what is the function of periosteum?

aids in growth/repair

Where is red bone marrow found in a long bone?

epiphyses of long bones

which type of bones have the most red marrow?

flat bones

what is the function of red bone marrow?

development of Myeloid cells and Lymphocytic cells

at what age does the Epiphyseal plate fuse to become the line?

18–25 years old

how does Epiphyseal enable bone to grow?

producing new Epiphyseal cartilage allows it to grow

Why is damage to epiphysial plates in children a concern?

Because the growth plate controls bone lengthening, injury can disrupt normal growth and cause permanent deformity

What percent of bone matrix is due to inorganic salts?

67%

what are the 2 salts in the composition of bone?

calcium and phosphate

hydroxyapatite

inorganic material that makes up 85% of inorganic matter in bone.

what is found in the organic portion of bone composition?

collagen fibers and ground substance

calcification

calcium deposition

what is the function of the osteoid (collagen)?

gives bone its flexibility and tensile strength rather than fragility

what is the function of calcium phosphate salts?

give bone its hard strength

Osteoprogenitor

Mesenchymal precursors of osteoblasts

Osteoblasts

mesenchymal-derived; secrete matrix of bone

Osteocytes

trapped in lacunae and maintain bone

Osteoclasts

monocyte-derived; break down (‘eat’) bone

which two bone cells must be kept balanced to maintain bone mass?

Osteoblasts and Osteoclasts

Spongy (cancellous) bone

network of struts and plates; found within the inner parts of bone and epiphyses; made of trabeculae

compact bone

solid; found on outer parts of bone & Diaphysis; made of osteons

Haversian canal

central canal containing blood vessels and nerves

Haversian system

cylindrical unit of compact bone made of layers round a central canal.

lamellae

layers around central canal of compact bone

lacunae

pockets within bone matrix

Canaliculi

Microscopic tunnels running through the bone matrix

trabeculae

little beams

In a long bone, which part has more compact bone epiphysis or diaphysis?

diaphysis

ossification

replacement of other tissues with bone

osteogenesis

creation of new bone

intramembranous ossification

• bones originate within sheetlike layers of fibrous or mesenchymal connective tissues

• broad, flat bones

• skull bones, clavicle (collarbone), mandible

• forms the intramembranous bones

endochondral ossification

• bones begin as hyaline cartilage

• most bones of the skeleton (humerus, femur, radius)

• forms the endochondral bones

what is the starting material for intramembranous ossification?

mesenchymal tissue

what is the starting material for endochondral ossification?

hyaline cartilage

what are the major bones in the body generated by intramembranous ossification?

• skull

• mandible

• clavicles

what are the major bones in the body generated by endochondral ossification?

• Femur

• Tibia

• Fibula

• Humerus

• Radius

• Ulna

• carpals

• tarsals

bone remodeling

a process that continues throughout life, and is accomplished by resorption and deposition

bone resorption

action of osteoclasts and parathyroid hormone

bone deposition

action of osteoblasts and calcitonin

what are the factors that influence bone remodeling, growth, and repair?

nutrition and hormones

what specific dietary factors affect bone development/growth/strength?

• Mineral salts, especially Calcium and Phosphorus

• Vitamins C, and D

what is the function of calcium?

provides hardness and strength in bones

what is the function of phosphate?

form hydroxyapatite crystals giving bone hardness

what is the function of vitamin C?

gives bone a hard structure

what is the function of vitamin D?

Vitamin D increases calcium and phosphate absorption so bones can mineralize properly and not be soft

how does stress help bone?

stimulates bone growth

growth hormone

makes bones grow longer and thicker

estrogen

matures the skeleton

testosterone

stimulates bone growth, increases bone density, and helps maintain strong bone remodeling

thyroxine

accelerates bone growth and bone turnover by increasing osteoblast activity, osteoclast activity, and overall metabolic rate

how does bone function as a reservoir of calcium?

It stores calcium in mineral form and releases it into the blood when levels drop

why is calcium significant?

it keeps your nerves firing, your muscles contracting, your blood clotting, and your bones strong

Parathyroid hormone

raises blood calcium when it drops too low

what gland produces the parathyroid hormone?

parathyroid glands

What is the stimulus for the release of PTH and its effect when released?

low blood calcium levels

effect: raises blood calcium on bone kidneys, etc.

calcitonin

lowers blood calcium when too high

which gland produces calcitonin?

thyroid gland

What is the stimulus for the release of calcitonin and its effect when released?

high blood calcium levels

effect: lowers it by inhibiting osteoclasts

how does the release of vitamin D effect?

raises blood calcium and phosphate by increasing their absorption in the intestine, helping the kidneys retain them, and supporting proper bone mineralization

hematopoiesis

process of making all blood cells

where does hematopoiesis take place in the body?

red bone marrow

what are the two major blood cell lineages produced by hematopoiesis?

Myeloid cells

Lymphocytic cells

lymphocytic cells

They recognize specific pathogens, remember them, and destroy them

myeloid cells

They handle phagocytosis, inflammation, clotting, and oxygen transport

fracture

a break in the continuity of a bone

comminuted fracture

bone fragments into three/more places

compression fracture

bone is crushed

spiral fracture

ragged break occurs when excessive twisting forces are applied to the bone

epiphyseal fracture

• epiphysis is disconnected from the diaphysis along the epiphyseal plate

• occurs when the cartilage cells are dying and matrix calcification

depressed fracture

• broken bone portion is pressed inward

• skull fracture usually

greenstick fracture

• bone breaks incompletely

• only one side of the shaft breaks while other side bends

what are the steps in the healing of a fracture?

1. hematoma forms

2. fibrocartilaginous callus forms

3. bony callus forms

4. bone remodeling occurs

spina bifida

• posterior portion of vertebra fails to form.

• Thought to be due to a combination of genetic, environmental and nutritional (low folate) factors

osteoporosis

bone density levels become critical and frequent fractures are likely to happen

osteomalacia

• Bones are poorly mineralized

• Osteoid is produced, but calcium salts not adequately deposited

• Results in soft, weak bones

• Pain upon bearing weight

rickets

• Results in bowed legs and other bone deformities because bones ends are enlarged and abnormally long

• Cause: vitamin D deficiency or insufficient dietary calcium

what are factors that reduce the risk of osteoporosis?

• exercises that stimulate osteoblasts

• increased vitamin D

• good calcium intake

• normal estrogen levels

• no smoking

Why is osteoporosis more common in postmenopausal women?

anabolic hormone levels (like estrogen) decrease rapidly

joint

• joins two bones or, parts of bones, together, regardless of ability of the bones to move around the joint

• Bind parts of skeletal system together

• Make bone growth possible

• Permit parts of the skeleton to change shape during childbirth

• Enable body to move in response to skeletal muscle contraction

How are joints classified?

• fibrous

• cartilaginous

• synovial

fibrous

• dense connective tissues connect bones

• between bones in close contact

• examples: Gomphosis (Synarthrosis), suture (Synarthrosis), syndesmosis (Amphiarthrosis)

cartilaginous

• hyaline cartilage or fibrocartilage connect bones

• examples: Synchondrosis (Synarthrosis), symphysis (Amphiarthrosis)

synovial

• most complex

• allow free movement

• have a cavity

• examples: gliding (nonaxial), hinge (monaxial), pivot (monaxial), condyloid (biaxial), saddle (biaxial), ball/socket (polyaxial)

synarthroses examples

• Gomphosis

• suture

• Synchondrosis

amphiarthroses examples

• Syndesmosis

• Symphysis

diarthroses examples

synovial joints

arthros

joint

syn

together (immovable)

dia

through, apart (freely moveable)

amphi

on both sides (slightly moveable)