BIO203 - Exam 2, Skeletal System

axial vs appendicular skeleton

axial: skull and vertebrae, trunk

appendicular: shoulders, arms, hips, legs

what are sutural bones and sesamoid bones? what can they do?

sutural: sometimes flat bones form abnormalities

sesamoid: sometimes called round bones, form where pressure develops, usually solely in tissues and not connected to other bones. ex: patella

can cause the formation of more than 206 bones

classify the 6 types of bones

1. long bones: longer than they are wide, slightly curved, mostly compact bone

2. short bones: cube-ish in shape, mostly spongy but surrounded by compact. ex: tarsals & carpals

3. flat bones: provide a lot of protection, two layers of compact bone with little spongy between, provides surface for muscle attachment. ex: skull, scapula, sternum, ribs

4. irregular bones: no definite shape, complex. ex: some facial bones, ossicles, vertebrae

5. sesamoid bones

6. sutural bones

what are bone markings? what do they do generally

surface features on bone, they are related to the bones function

name the 8 types of bone markings

1. epiphysis

2. diaphysis

3. process: a bony projection

4. foramen: a hole blood vessels and nerves travel through

5. fossa: a deep depression

6. tuberosity: notch/site on bone where ligaments/tendons connect

7. trochlea: guides a tendon or acts at a surface for a joint

8. condyle: round bump at the end of a bone that forms a joint with another bone

what is a epiphysis

the end of a long bone, mostly spongy bone, filled with red marrow. covered with articular cartilage to reduce friction

what is a diaphysis

a shaft of bone, mostly compact, contains medullary cavity which contains yellow marrow

difference between red marrow and yellow marrow

red bone marrow is where blood cells are made

yellow marrow replaces red marrow as we age, stores fat and stem cells

what is the periosteum

a tough membrane that covers bone, allows muscles to attach

what are osteogenic cells

maintain osteoblasts population, can differentiate into other types of bone cells

what are osteocytes?

mature bone cells that contribute to bone density and blood concentration (salt, calcium, phosphorus)

what are osteoblasts

“blasts = build” they produce bone matrix through ossification

what are osteoclasts

cells that digest bone via secreting acids and enzymes to break down bone to be remodled

what is compact bone? what is spongy bone?

compact bone is often an external wall, a continuous matrix with no gaps; functional unit is an osteon

spongy bone is located inside epiphysis; functional groups are branching bony plates called trabeculae

describe the structure of an osteon

made of concentric lamellae around a central canal with blood vessels and nerves. Lacunae are little deposits of osteocytes, canaliculi are ravines that connect them together

perforating canals are transverse connections of central canals

list the three types of bone growth

• appositional growth: existing bone grows in diameter by adding layers of lamellae, osteogenic cells differentiate into osteoblasts

• endochondral growth: begin as embryo with skeleton of hyaline cartilage, which slowly dies and is replaced by bone, forms a primary ossification center in diaphysis, secondary ossification center at epiphysis, leaves behind epiphyseal line

• intramembranous ossification: starts in fibrous membrane of CT instead of cartilage, mesenchymal cells form osteoblasts, which form a membrane around themselves that turns into bone, forms two layers of compact bone with spongy in-between

explain bone tissue homeostasis

bone is constantly being digested and remodeled. a balance must be maintained of osteoblasts building and osteoclasts breaking down bone

so bone is strengthened where it is needed and eroded where it is not

by how many weeks can almost all bones of the skeleton be identified in a fetus?

when do fontanels seal up?

16 weeks

fontanels: 2 years

list some ways nutrition affects bone growth/development/repair

vitamin D deficiencies can cause rickets in kids and osteomalacia in adults

vitamin C is needed for the integrity of collagen fibers

how do hormones effect bones?

growth hormones

s3x hormones help with bone growth and density

• low calcium in blood trigger parathyroid gland to secrete PTH (below 8mg/dL), which signals to hold onto calcium and break down bone

• high calcium in blood triggers thyroid gland to secrete calcitonin (above 11mg/dL), signals release of calcium and decreases osteoclast activity

what is pituitary growth failure?

what is achondroplasia?

what is marfan syndrome?

PGF: inability to secrete enough growth hormone

achondroplasia: cartilage at epiphyseal plate replaced by bone sooner

marfan: excess cartilage at epiphyseal plates, causes super long bones

explain gigantism and acromegaly

gigantism: overproduction of growth hormone before puberty

acromegaly: increased thickness of bones after epiphyseal plates have closed (puberty)

explain bone fractures

a hematoma forms when bone is broken, next is a callus of spongy bone and cartilage

sometimes a bulge on the outside forms, an external callus

name the 7 types of bone fractures

transverse: simple or compound

spiral: bone is twisted and snaps

displaced: forced completely out of normal alignment

compression: bones are forced together, often in vertebrae

greenstick: cracks on one side, bends on the other, common in kids

comminuted: bone is completely shattered

epiphyseal: break at the growth plate