Bio201 In Chapter 6 Lesson 3 Skeletal System Notes

Front 1

Lines the articulating surface of bones

Back 1

Cartilage

Front 2

Connect muscles to bone

Are comprised of dense regular connective tissue.
Are strong in one direction

Back 2

Tendons

Front 3

Connect bones to bone at joints.
Are comprised of dense regular connective tissue
Ligaments are usually more flattened than tendons
Both ligaments and tendons have a poor blood supply and are slow to heal

Back 3

Ligaments

Front 4

Functions of the Skeletal System: (6)

Back 4

Support- Bones are cartilage provide structural support for the entire body.
Protection- Vital organs are protected by bone
Leverage- Bones are the levers that move when muscles connected to them contract
Mineral Storage- Calcium and phosphate are stored in bones
Fat Storage- Lipids are stored in the cavities of bone. Fat is stored energy
Blood Cell Production- Blood cells are produced in the red bone marrow. This is also called hematopoiesis

Front 5

Bones that are longer than they are wide

Back 5

Long Bones
Ex: Phalanges, femur, humerus, radius, ulna, tibia, fibula

Front 6

Bones about as wide as they are long

Back 6

Short Bones
Ex: Carpals and tarsals

Front 7

Thin, flat bones that are usually curved

Back 7

Flat Bones
Ex: Sternum, ribs, scapula

Front 8

Bones that dont fit any of the other catergories

Back 8

Irregular Bones
Ex: Vertebrae, pelvic bones, some skull bones like the sphenoid and ethmoid bones

Front 9

Generally small and seed shaped bones. Also develop in tendons near joints in hands and feet

Back 9

Sesmoid Bones

Front 10

Small bones between the flat bones of the skull

Back 10

Sutural Bones

Front 11

The shaft of a long bone. It is comprised of compact bone

Back 11

Diaphysis

Front 12

Ends of a long bone. Contains the red bone marrow.
Are comprised of cancellous bone (spongy bone) and blood cell formation takes place in some adult long bones

Back 12

Epiphyses

Front 13

This is the growth plate where the bone grows in length

Back 13

Epiphyseal plate

Front 14

When the Epiphyseal plate closes a line remains observable on x-ray. When the plate closes, no more bone growth occurs

Back 14

Epiphysial Line

Front 15

The inner cavity of a long bone. Stores fat. Lightens the bone

Back 15

Medullary Cavity

Front 16

Connective tissue lining the marrow cavity.
Contains osteoblasts and osteoclasts.

Back 16

Endosteum

Front 17

Connective tissue lining the outside of bone. Contains nerves and blood vessels, osteoblasts and osteoclasts

Back 17

Periosteum

Front 18

Cartilage that covers the articular surfaces of bone. Is comprised of hyaline carilate

Back 18

Articular cartilage

Front 19

A spongy bone sandwich where layers of compace bone cover a core of spongy bone. Have no diaphyses or epiphyses

Back 19

Flat Bone Structures

Front 20

% of the weight of bone is comprised of hydroxapatite which is calcium phosphate crystals

Back 20

66

Front 21

% of bone mass that is comprised of collagen

Back 21

33

Front 22

% of bone mass that is comprised of living bone cells

Back 22

2

Front 23

_______ fibers provide a framework on which hydroxyappatite crystals can form

Back 23

Collagen

Front 24

The hydroxyappatite crystals are hard but ______

Back 24

Inflexible

Front 25

Collagen fibers are strong and ______

Back 25

Flexible

Front 26

Living bone cells embedded in the mineralized matrix.
Maintain the density and composition of bone

Back 26

Osteocytes

Front 27

Build bone by producing mineralized matrix.
Are derived from osteoprogenitor cells in the periosteum and endosteum. When they become surrounded by bone they become osteocytes

Back 27

Osteoblasts

Front 28

Break down the mineralized matrix of bone.
Their activity releases the stored minerals into the blood
Are giant cells derived from monocytes (white blood cells)

Back 28

Osteoclasts

Front 29

Are the basic functional untis of compact bone.
Are also called Haversian Systems

Back 29

Osteons

Front 30

The small cavities within bone where the osteocytes are located.

Back 30

Lucunae (plural)
Lacuna (singular)

Front 31

The small canals that like the lacunae to blood vessels. Are the means by which nutrients get to all of the osteocytes.

Back 31

Canaliculi

Front 32

Located at the center of each osteon

Back 32

Central Canal or Haversian Canal

Front 33

Canals that run perpendicular to the central canals
They contain blood vessels

Back 33

Perforating canals

Front 34

The rings of mineralized matrix around the central canal

Back 34

Lamellae

Front 35

Comprise the rings of the osteon

Back 35

Concentric Lamellae

Front 36

Fill in the spaces between osteons

Back 36

Interstitial Lamellae

Front 37

Surface layer of bone.
Covered by the periosteum and endosteum.
In spnogy bone they are NOT arranged into osteons

Back 37

Circumferntial Lamellae

Front 38

Interconnecting plates of bone with spaces between them.
Trabeculae are oriented along stress lines

Back 38

Trabeculae

Front 39

_______bones are able to withstand stresses applied from many direcrtion

Back 39

Spongy

Front 40

No blood vessels penetrate the _______. Nutrients reach the osteocytes by canaliculae that open onto the surfaces of the ______

Back 40

trabeculae

Front 41

The spaces between the trabeculae contains red bone marrow. This is where ______ takes place

Back 41

Hematopoiesis

Front 42

Is the process of the formation of bone. The bone is created by osteoblasts.

Back 42

Ossification

Front 43

Formation of bones begins in the embryo _ weeks after fertilization

Back 43

6

Front 44

Some bones of the skeleton do not stop growing until about the age of:

Back 44

25

Front 45

In intramembranous ossification bone is formed out of fibrous _____ tissue

Back 45

connective

Front 46

* Flat skull bones, the mandible and clavicle are formed in this manner (6 steps)

Back 46

1. An ossification center develops where mesenchymal cells aggergate.
2. Mesenchymal cells differentiate into osteoblasts which create bone matrix
3. Spicultes extend into the surrounding tissue.
4. Spicules interconnect and trap blood vessels
5. Spongy bone develops first.
6. Spongy bone can be remodeled into compact bone.

Front 47

Soft spots in the baby's skull where the membrane has not yet been ossified.

Back 47

Fontanels

Front 48

Bones are formed from a hyaline cartilage model

Back 48

Endochondral ossification

Front 49

Most of the bones in the body are formed in this manner (10 steps)

Back 49

1. Cartilage enlarges, chondrocytes enlarge and die and leave cavities.
2. Blood vessels grow around the edges of cartilage.
3. Perichodrium cells convert to osteoblasts.
4. Cartilage becomes ensheathed in superficial layer of bone.
5. Blood vessels penetrate the cartilage, fibroblasts migrate to interior.
6. Fibroblasts differentiate into osteoblasts and produce spongy bone at primary ossification center.
7. Bone formation spreads toward both ends.
8. Remodeling occurs as growth continues.
9. Capillaries and osteoblasts migrate into the epiphyses creating secondary ossification centers.
10. Epiphyseal cartilage remains separating the epiphysis from the diaphysis.

Front 50

Growth of long bones at the epiphyseal plates is called:

Back 50

Endochondral growth

Front 51

The ______ plate separates the epiphysis from the diaphysis. These plates contain actively growing hyaline cartilage that is constantly being converted to bone

Back 51

Epiphyseal

Front 52

______ on the epiphysis side are creating cartilage

Back 52

Chondrocytes

Front 53

Chondrocytes on the epiphysis side are creating cartilage. _______ on the diaphysis side are converting that cartilage to bone. Growth here results in an increase in the length of the bone

Back 53

Osteocytes

Front 54

Bone growth in diameter is called:

Back 54

Appositional growth

Front 55

Cells of the inner layer of the periosteum differentiate into ______

Back 55

Osteoblasts

Front 56

The osteoblasts create bone matrix in the form of circumferential lamellae. When they are surrounded by mineralized matrix they become _______

Back 56

Osteocytes

Front 57

Bone is called _____ tissue because it is constantly remodeling its components

Back 57

Dynamic

Front 58

Bone remodeling is involved in: (6 listed)

Back 58

1. Creating mature bone
2. Bone growth
3. Changes in bone shape
4. Adjustment of bone to stress
5. Bone repair
6. Calcium homeostasis

Front 59

______ is constantly breking down or building up in response to mechanical stress and hormones

Back 59

Bone

Front 60

The _______ are constantly creating new bone and the _____ are constantly breaking bone down (2)

Back 60

osteoblasts
osteoclasts

Front 61

When osteoblastic activty is greater than osteoclastic activity bone mass is _______

Back 61

Increasing

Front 62

When osteoblastic activity is greater than osteoblastic activity bone mass is ______

Back 62

Decreasing

Front 63

In young adults ____ of the entire skeleton is recycled and replaced each year

Back 63

1/5

Front 64

More bone is laid down on _____ lines

Back 64

Stress

Front 65

______ stress (Exercise) causes more bone creation

Back 65

Mechanical

Front 66

When bones are mechanically stressed the mineral crystals generate minute electrical fields. _________ are attracted to these fields to produce bone

Back 66

Osteoblasts

Front 67

Muscles pull on bones at tendons. Where the tendon attaches to the bone is a bump. The harder you pull on the bump the _______ it gets

Back 67

Bigger

Front 68

Heavily stressed bones become thicker and ________

Back 68

Stronger

Front 69

Bone degeneration occurs with physical

Back 69

Inactivity

Front 70

Trigger bone cration or destruction

Back 70

Hormones

Front 71

Hormones are secreted to maintain a constant blood _____level

Back 71

Calcium

Front 72

Is released in response to low blood calcium. Stimulates osteoclasts to break bone down hence raising blood calcium levels.

Back 72

Parathyroid hormone

Front 73

Causes the kidney to reabsorb more clacium and the intestines to absorb more calcium from ingested foods.

Back 73

Parathyroid hormone

Front 74

Is released in response to high blood calcium and is secreted from the thyroid gland.

Back 74

Calcitonin

Front 75

Decreases osteoclastic activity thereby lowering blood calcium. Also increases the rate of calcium excretion at the kidneys

Back 75

Calcitonin

Front 76

Formed from Vitamin D in the skin. Is synthesized in the kidneys.

Back 76

Calcitriol

Front 77

Is necessary for calcium absorption in the digestive tract and calcium reabsorption in the kidneys

Back 77

Calcitriol

Front 78

Stimulates bone growth. Is secreted from the pituitary gland

Back 78

Growth hormone

Front 79

This condition results from too little growth hormone secreted as a child.

Back 79

Dwarfism

Front 80

This condition results from too much growth hormone secreted as a child.

Back 80

Gigantism

Front 81

This condition results from too much growth hormone secreted as an adult. Skull bones and hand bones are inlarged

Back 81

Acromegally

Front 82

From the thyroid gland stimulates bone growth

Back 82

Thyroxine

Front 83

____ hormones. Both estrogen and testosterone stimulate bone growth

Back 83

Sex

Front 84

Males are generally taller than females because estrogen causes the ______ plates to close earlier

Back 84

Epiphyseal

Front 85

Vitamin __ is necessary for calcium absorption in the digestive tract and calcium reabsorption from the kidneys

Back 85

D

Front 86

Vitamin _ is necessary for normal collagen synthesis

Back 86

C

Front 87

Bone, tendons, cartilage, and ligaments contain large amounts of ______

Back 87

Collagen

Front 88

Lack of vitamin _ can result in a loss of bone mass.

Back 88

C

Front 89

Vitamin _ stimulates osteoblastic activity

Back 89

A

Front 90

Vitamins _ and B_ are necessary for protein synthesis in bones (2)

Back 90

K;B12

Front 91

Calcium and _______ main components of bone are supplied in the diet..

Back 91

Phosphates

Front 92

Magnesium,______,_______, and manganese are also required for normal bone growth and maintenance (2)

Back 92

flouride; iron

Front 93

Calcium _____; Bones act as a mineral reserve for your body

Back 93

Bank

Front 94

_____ is the most abundant mineral in the human body

Back 94

Calcium

Front 95

Your nervous system and muscular system are both dependent on _______

Back 95

Calcium

Front 96

Muscles cannot contract without ______. Nerve impulses cannot be sent without _______. Deficient _____ can cause spasms and convulsions.

Back 96

Calcium

Front 97

Excessive ______ causes nerves and muscles to become unresponsive.

Back 97

Calcium

Front 98

When calcium is needed in the body more bone_____ is broken down

Back 98

Matrix

Front 99

Bone tissue is good at repairing itself because of the rich ____ supply

Back 99

Blood