Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
78 Cards in this Set
- Front
- Back
|
How many bones does a human baby have? A human adult? Why the difference?
|
Baby - 270
Adult - 206 Bones fuse together as a person ages. |
|
|
What are "sutures" in terms of bone?
|
Places where bones "sew" or fuse together.
|
|
|
Fontanalis
|
Used to be cartilage, the place on the skull that is soft on a baby, later fuses together (sutures). It visibly moves up and down with blood pressure on a baby, so the Italians (Latin) named it after a fountain.
|
|
|
Axial Skeleton
|
The part of the skeleton that includes the skull, vertebrae, backbone and ribs. So named because it forms an "axis".
|
|
|
Appendicular Skeleton
|
Name for the part of the skeleton that attaches to the axis of the body, includes the arms, legs, hip bones. Anything that is NOT the Axial skeleton.
|
|
|
Functions of Bone
Support |
Bone creates a framework for the body.
|
|
|
Functions of Bone
Blood Cell Production |
Bone is a blood factory, creating WBCs (white blood cells and RBCs (erethrocytes, red blood cells).
|
|
|
Functions of Bone
Protection |
Bone protects organs (Ribs protect heart, skull protects brain, vertebrae protect spinal cord. Where there's no bone, body triples up on muscle and protects with reflex to cover (i.e. bend over when poked in abdomen, arms rush to cover it).
|
|
|
Functions of Bone
Leverage |
Provides a mechanical advantage. The longer the lever, the more power (i.e. taller person has more power on bicycle).
|
|
|
Structure of Bone - What is composed of?
|
Osseous Tissue (supporting connective tissue) specialized cells, ground substance, fibers.
|
|
|
What is bone matrix made of?
|
Calcium salts
|
|
|
Osteocytes
Lacunae |
Bone Cells have lacunae (tiny "lagoons") organized around blood vessels.
|
|
|
Osteocytes
Canaliculi |
Narrow passageways between lacunae and vessels. Tiny "canals".
|
|
|
Periosteum
|
Dense membrane of fibrous connective tissue that closely wraps (invests) all bone, except that of the articulating surfaces in joints which are covered by a synovial membrane. "Peri-" meaning "around or about" and "-osteum" from "osteon" meaning "bone", = "around the bone."
|
|
|
Where on the bone would you NOT find periosteum?
|
You wouldn't find it at the joints.
|
|
|
Osteoprogenitor cell
or Osteogenitor cell |
"before bone begins"; type of stem cell precursor of osteoblast. Looks a bit like squamous epithelia. Lives outside of bone and inside hollow part of bone, squished in those locations in case needed.
|
|
|
Osteoblasts
|
"Blast = Bone Builder" Cells that secrete/form bone tissue. They build "cement wall" around themselves then trapped (like 3 stooges painting themselves into corner). Cuboidal in shape.
|
|
|
Osteocytes
|
Maintains bone tissue. Develops cytoplasmic extensions that reach out and touch neighbors. Can go back to being an osteoblast in the case of a broken bone.
|
|
|
Osteoclasts
|
Clasts = "CL" for "CLear out); these cells are the demolition crew that clears out/destroys/hollows bone for "renovation". Up to 50 nuclei containing DNA that codes for new protein. Functions in resorption/destruction of bone matrix.
|
|
|
How many nuclei can be in Osteoclasts, and where do those nuclei come from?
|
There can be up to 50 nuclei in a single osteoclast. The nuclei in Osteoclasts used to be white blood cells. They escaped from the bloodstream to gather together and form osteoclasts. Each nuclei was a white blood cell.
|
|
|
Osteoclasts
Catalytic Enzymes |
The proteins coded for in the many copies of DNA carried by osteoclasts are catalytic enzymes that help break up bone.
|
|
|
What else besides catalytic enzymes do osteoclasts contain to help break up bone?
|
There are chambers in the osteoclasts that contain acids that help break up bone.
|
|
|
What is the significance of osteoblasts and osteoclasts in terms of Osteoporisis?
|
Porous bone is caused when the bone building cells (osteoblasts) stop working and the demolition crews (osteoclasts) continue working.
|
|
|
Osteoporosis
|
Thinning of bones with reduced bone mass due to depletion of calcium and bone protein. Osteoporosis predisposes a person to fractures and crumbling, which heal poorly and slowly. More common in older adults, particularly post-menopausal women; in patients on steroids; and in those who take steroidal drugs. Unchecked osteoporosis can lead to changes in posture, physical abnormality (particularly the form of hunched back known colloquially as "dowager's hump"), and decreased mobility. Hip, Writs, Spine affected. Weight bearing exercise good for prevention.
|
|
|
Minerals in Bone
|
Calcium Carbonate, calcium phosphate, hydroxyapatite.
|
|
|
Bone Matrix
Hydroxyapatite or hydroxylapatite |
A mineral comprised of two molecules (calcium phosphate + Ca(OH)2 = Ca10(PO4)6(OH)2. Makes up 70% of bone.
|
|
|
Are thinner or fatter post-menopausal women more likely to develop osteoporosis?
|
Thinner women are more at risk for this bone disease.
|
|
|
Why does weight bearing exercise help prevent osteoporosis?
|
This type of exercise causes bone to compress and increases electrical activity which calls more osteoblasts in to build bone.
|
|
|
Cancellous Bone
|
The "spongy" end part of the bone where red marrow is, looks like an ice pick "cancelled" it out by making holes. Dogs like to chew on this end part of bones.
|
|
|
Compact or dense bone
|
Found in the shaft part of the bone,and in a thin layer even around the bone end. It contains yellow marrow (fat). An animal bone of this sort would be used to give flavor to soup.
|
|
|
Articular cartilage
|
Made of hyaline cartilage, creates a soft cushion found in places where bone meets other bone.
|
|
|
Articulation
|
Where bones join other bones (articular cartilage present), whether actual movement happens at that location or not.
|
|
|
What is a danger with fat from a broken bone?
|
This type of fat from the yellow marrow can dislodge when a bone breaks and enter the bloodstream, may cause problems with heart or lungs (blocked vessels).
|
|
|
Medullary Cavity
|
Marrow cavity - central cavity in diaphysis (main shaft) of bone where yellow marrow (adipose tisue) stored. Has walls composed of compact bone and lined with thin, vascular membrane (endosteum). In an infant, it would have red marrow since RBCs are forming.
|
|
|
Diaphysis
|
Main shaft of bone. Dia (through) + physis (fused) = "fused through the middle". The yellow marrow is found in the middle of this part.
|
|
|
Endosteum
|
Thin vascular membrane that lines the inside of medullary cavity of bone shaft.
|
|
|
What would the medullary cavity in an anemic adult contain?
|
The medullary cavity in an anemic adult, as in that of an infant, might contain red marrow, since blood needs to be formed.
|
|
|
Sharpeys fibers
|
These strong collagenous fibers hold the periosteum (fibrous connective tissue around bone) in place. they extend to the outer circumferential and interstitial lamellae (layers).
|
|
|
Periosteum
|
Thin layer of dense, irregular connective tissue membrane covering outer surface of bone except at joints. has nociceptive nerve endings, making it sensitive to manipulation. Provides nourishment by providing blood suply. Connected to bone by strong collagenous fibers called Sharpey's fibers.
|
|
|
Nutrient Foramen
|
Natural opening through bone in order to let nutrient arteries and veins through
|
|
|
Formaen Magnum
|
The large hole at the base of the skull which allows passage of the spinal cord. This is the largest bone foramen in the body.
|
|
|
epiphysis
|
The name for a rounded end of a long bone. The epiphysis is filled with red marrow, which produces erythrocytes, or red blood cells. Located in the epiphysis is the epiphysial plate, also known as the growth plate. Epi (top) + physis (fused) = fused on top.
|
|
|
proximal epiphysis
|
The rounded end of a long bone that is closest to the point of attachment. Epi (top) + physis (fused) = fused on top.
|
|
|
distal epiphysis
|
The rounded end of a long bone that is far from the point of attachment. Epi (top) + physis (fused) = fused on top.
|
|
|
metaphysis
|
Part of a long bone between the epiphyses and diaphysis. "Growth plate", "physis", or "epiphyseal plate", although it precedes the development of the ossified metaphysis, may also be referred to as the metaphysis. This is the part bone growing during childhood; as it grows, it ossifies near the diaphysis and the epiphyses. Metaphysis stops growing altogether at 18-25 years and completely ossifies into solid bone. Epiphyseal plates ("growth plates") are located in the metaphysis and are responsible for growth in the length of the bone. Meta (beyond, next, or change) + physis (fused) = fused next (beyond the epiphysis).
|
|
|
Supraorbital foramen
|
The two small notches or holes above the orbits for the supraorbital nerve, arteries, and veins.
|
|
|
Orbit
|
The bony cavity containing the eyeball and its associated muscles, vessels and nerves.
|
|
|
Describe the foramen using a house-building metaphor.
|
When building a house, work crews will put in one big hole/conduit to run many wires, ducts,and pipes of a number of systems for the house, rather than weakening walls by poking lots of little holes. Arteries (blood in) Veins (blood out).
|
|
|
Skull formation
|
Like a spongy bone sandwich bread = inner and outer table of compact bone. Inside made of inner spongy, cancellous bone (with diploe/trabeculae). Like a car, it's designed to "crinkle up" in the case of impact, but protect the passenger (brain).
|
|
|
Diploe
|
The soft spongy material between the inside table and outside table (the interior and exterior bony plates) of the skull. The diploe contains bone marrow.
|
|
|
Trabeculae
|
A partition which divides or partly divides a cavity. One of a number of small interconnecting rods of bone making up a mass of spongy bone as, for example, the trabeculae within the skull. From latin "trabes" meaning little beam or plank of wood. These function like "struts".
|
|
|
Makeup of the Periosteum
|
An outer fibrous layer and an inner osteogenic layer of osteoprogenitor cells and fibroblasts.
|
|
|
Trace a drop of blood from the outside of the bone all the way to where the cells live.
|
Periosteal vessels -> perforating (Volkmann)vessels -> central (Haversian) vessels -> canaliculi -> lacuna -> osteocyte.
|
|
|
Is it harder to break bones by up and down compression or by vertical fracture?
|
Bones are much stronger in an up and down direction (like a tall building) than in a sideways direction (wrecking ball coming in from the side).
|
|
|
Periosteal Vessels
|
These vessels "punch holes" through the bone (through nutrient foramina on surface) and open into the narrow perforating (Volkmann) canals/vessels.
|
|
|
Perforating or Volkmann Vessels/Canals
|
These cross the matrix (at right angles to the bone) horizontally and feed into the central canals.
|
|
|
Central or Haversian Canals/Vessels
|
These vessels originate from the Volkmann/Perforating Vessels/Canals but turn a right angle and run up and down the length of bone (vertically). They bleed out through the canaliculi.
|
|
|
Canaliculi
|
Tiny canals that run between the central canals into the lacaunae.
|
|
|
Lacuna/lacunae
|
Tiny "lagoons" that bring the nutrients from the canaliculi to the osteocytes (mature bone cells).
|
|
|
How much blood does the skeleton receive per minute?
|
A half a liter of blood per minute.
|
|
|
Do the cytoplasmic processes of the osteocytes maintain a one-way or two-way flow between the central canal and the outermost cells of the osteon?
|
Two-way flow of nutrients/wastes.
|
|
|
In what order are bone cells built?
|
Osteoprogenitor Cells -> osteoblasts -> osteocyte; also, backward from osteocyte -> osteoblast if need be (in the case of a broken bone).
|
|
|
Hormonal Nutritional Effects on Bone
Hypercalcemia/Hypocalcemia |
too little calcium in blood causes tetany/spasms. Too much calcium in blood causes depressed nervous system, cardiac arrest. Ca can only vary by 1/3 either up or down.
|
|
|
Hormonal Nutritional Effects on Bone
Minerals Needed |
Calcium - Ca; Phosphorus - P; Manganese - Mn; Magnesium - Mg; Fluoride - F.
|
|
|
Hormonal Nutritional Effects on Bone
Calcitriol (Vitamin D) |
A hormone made in the kidneys that needs precursor steroid cholecalciferol. Takes calcium out of bone and raises it in blood. Stimulates osteoclasts.
|
|
|
Hormonal Nutritional Effects on Bone
Vitamin C |
Needed for synthesis of collagen. If too low, scurvy occurs. Decrease of mass and strength of bones.
|
|
|
Hormonal Nutritional Effects on Bone
Vitamin A |
Stimulates osteoblast activity (bone building).
|
|
|
Hormonal Nutritional Effects on Bone
Vitamin K and B 12 |
Needed for protein synthesis, and blood protein levels.
|
|
|
Hormonal Nutritional Effects on Bone
Growth Hormone |
From pituitary gland, needed for protein synthesis.
|
|
|
Hormonal Nutritional Effects on Bone
Thyroxine |
From thyroid, necessary for metabolism of bone.
|
|
|
Hormonal Nutritional Effects on Bone
Sex hormones |
Androgens/estrogen - epiphyseal plate closes. Toes by age 11, wrists by age 25.
|
|
|
Hormonal Nutritional Effects on Bone
Calcitonin |
Think Calcit"on"in = NO
Opposite of calcitriol, calcitonin originates in thyroid, lowers blood Ca2+ concentration, may prevent bone loss in pregnant/lactating women |
|
|
Hormonal Nutritional Effects on Bone
Parathyroid Hormone |
Originates in parathyroid, indirectly activates osteoclasts. Tells kidney to release calcitriol (Vitamin D) and raise calcium level of blood.
|
|
|
Compact Bone
Concentric Lamellae |
Onion-like layers of matrix (bullesyes) concentrically arranged around a central (haversian or osteonic) canal and connected with each other by canaliculi.
|
|
|
Compact Bone Structure
Interstitial Lamellae |
Between osteons, we find these irregular regions, which are the remains of old osteons that broke down as the bone grew and remodel itself. You can't fill a circle with circles, so these fill it out.
|
|
|
Osteon
|
A central canal and its lamallae constitute an osteon (haversian system), the basic structural unit of compact bone. Cylinder of tissue surrounding central canal. Bullseyes.
|
|
|
Compact Bone Structure
Circumferential Lamellae |
The inner and outer boundaries of dense bone are arranged in these circles within circles, that run parallel to the bone surface. The osteons are inside these, they surround the osteons (bullseyes).
|
|
|
Lamellae
|
Layer/lamination of bone.
|
