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Flashcards in Ch5,6,7,8 Deck (141):
1

Functions of the skeletal system

Support
Storage of minerals and lipids
Blood cell production (yellow or red bone marrow)
Protection
Leverage

2

Outer lining

Periosteum

3

Endosteum

Inner lining

4

Sutural bones

Bones that form within a suture

5

Sesamoid bones

Bones that form in places of stress

6

Bone structure

Two types of bone
1. Compact bone (dense)
2. Spongy bone (cancellous) hard and rigid different structure ``1

7

A typical long bone includes

-Diaphysis
-Epiphyses
-Metaphysis
-Articular cartilage
-Marrow cavity
Filled with red or yellow marrow

8

Epiphyses

Epi= means on top of
Located at the top ends of long bones (both top and bottom)

Epiphyses. X————————————-X Epiphyses

9

Metaphyses

These are located directly under epiphyses on the top and bottom ends of the long bone

Epiphyses (metaphyses) X—————————X Epiphyses (metaphyses)

10

Marrow cavity

Located in the shaft middle area of long bones
Yellow marrow= fats and lipids
Red marrow=RBC

11

Articular

Joint

12

Articular cartilage

Thin cartilage found on the Epiphyses of bones
Prevents rubbing of bones

13

Osseous Tissue

Supporting tissue with a solid matrix
-Crystals of hydroxyapatite (calcium salt)
Minerals deposited in lamellae (layers of matrix)
-covered by periosteum (thin membranous sheet cove

14

Matrix of bones (ground substance and fibers/ what cells are suspended in)

Calcium (extremely brittle)
Collagen (very elastic and rubbery)
Combination very strong compared to concrete

15

Central canal

Area in bone where artery and vein are that are going to nourish the bone

16

Osteocyte

-mature bone cell
Accounts for the majority of bone cells
DO NOT DIVIDE
-maintain the protein and mineral content of the matrix (KEEPS bone strong firm and rigid )
Lives in a house lacuna

17

Lacunae

Means little house
Pocket in the bone matrix where osteocytes reside

18

Canaliculi

Canals or highways that lead from one osteocyte to another
Cytoplasmic extension of osteocytes (like tentacles) that attach them to each other and to the central canal

19

Lamellae

Osteocytes form ring like patterns in the matrix
These rings are called lamellae (layers of matrix)

20

Osteon

Unit of compact bone that includes
Osteocyte
Lacunae
Canaliculi
Lamellae
Central canal
Matrix

21

Compact bone

Made up of osteons (basic unit)
-osteocytes are arranged around a central canal (where central artery and vein located)
-perforating canals extend between adjacent osteons
-compact bone located where stresses are limited in direction (on the outside, really great at handling weight)

22

Osteocytes

Mature bone cells in lacunae
Connected by canaliculi

23

Osteoblasts






Synthesize new matrix
-Osteogensis (process of creating new bone or matrix) or heal fracture
-immature bone cell

24

Osteoclasts

Dissolve bone matrix
-osteolysis
This is very important

25

Osteoprogenitor cells

Differentiate into osteoblasts
Important in bone repair

26

Spongy bone

On interior of bone
-spongy bone located where stresses are weaker or multidirectional (really tough, can take weight and stress) so porous makes bone light ( so we dont have to carry a ton of weight around)
-Contains trabeculae ( looks like coral reef or branches of tree or sponge)

27

Bones are

Covered by periosteum (thin membranous sheet)
-lined by enosteum (incomplete lining inside the marrow cavity)

28

Ossification

Converting other tissues into bone
Two types
1.intra-membranous (inter-utero fetal development, dermal bones, bones of skull)
2.endochondral ossification

29

Calcification

Depositing calcium salts within the tissues

30

Endochondral ossification

-cartilage model gradually replaced by bone at metaphysis (right under ephysis end of bone so its the middle)
-increasing bone length
-timing of epiphyseal closure differs
-appositional growth increases bone diameter
Production of the rest of the skeleton
Starts with hyline cartilage

31

Epiphyseal cartilage

GROWTH PLATE
Timing of closure or completely ossifies growth ends

32

Bone is continually changing

-remodeling
-exercise (increases bone mass)
-hormone levels (also increase bone mass)
Growth hormone and thyroxine bone mass
-calcitonin (lowers blood Calcium) and PTH (parathyroid calcium increases calcium) control blood calcium levels

33

The skeleton in a calcium reserve

-99%of the bodys calcium is in the skeleton
-Calcium ion concentration maintained by the bones, GI tract, and kidneys (if too low gi tract will absorb more instead of letting it go, kidneys will hold on instead of urinating it out, bones will disolve releasing it into the blood.) if too high the bones with store excess.
-Calcitonin and PTH regulate blood calcium levels
-PTH increases blood calcium levels

34

Bone fracture repair 3 step process

1. Fracture hematoma = (extensive bleeding occurs, large blood clot forms and fracture hematoma develops)
2. Internal callus : an internal callus forms as a network of spongy bone unites the inner surfaces, and an external callus of cartilage and bone stabilizes the outer edges.
3. External callus: the cartilage of the external callus has been replaced by bone, and struts of spongy bone now unite the broken ends. Fragments of dead bine and the areas closest to the break have been removed and replaced.
4. Remodeling occurs

35

Bone markings

Are characteristics for each bone and each individual
Markings include
-elevations
-projections
-depressions (valleys)
-grooves and tunnels

36

Osteopenia

Is inadequate ossefaction or reduction in bone mass because osteoblasts activity declines

37

Osteoporosis

Loss of spongy bone mass
Over the age of 49, 25% of women will be diagnosed

38

Axial skeleton (axis =center or core)

SKULL
Auditory ossicles and hyoid bone
Vertebral column
Thoracic cage (rib cage)

39

Appendicular skeleton (appendages)

Pectoral and pelvic girdles
Upper and lower limbs

40

Skull

Frontal paritial occipital temporal ethmoid nasal lacrimal zygomatic maxillary vomer

41

Vertebral column

Vertebrae, sacrum, coccyx
-7cervical vertebrae
-12 thoracic vertebrae
-5 lumbar vertebrae
-sacrum and coccyx are fused vertebrae

42

Four spinal curves

Primary (accommodation) curves= thoracic and sacral ; late in fetal development
Secondary (compensation) curves= lumbar and cervical ;appear several months after birth

43

Kyphosis

Hunch back
Abnormal curvature at the top of the thoracic spine
Normally in elderly osteoporosis loss of spongy bone mass , sometimes in children

44

Lordosis

Abnormal curvature of lower (lumbar) spine.
Caused in differences in thickness of intervertebral disc spacing, pregnancy, excessive weight gain

45

Scoliosis

Sway back like an S in the spine, exaggerated lateral curvature. Higher rates in women.

46

Sacrum

Protects reproductive, digestive and urinary organs
Articulates with pelvic girdle and fused elements of coccyx

47

Appendicular skeleton

-upper and lower limbs
-pectoral and pelvic girdle

48

Pectoral girdle (shoulder girdle)

-articulates (joins where two bones join) the upper limbs with the trunk
-consists of clavicle and scapula

49

Clavicle and scapula

-position shoulder joint
-help move upper limb
-provide a base for muscle attachment (back of scapula is flat and allows for attachment)

50

Humerous

-articulates with the radius and ulna
Forms elbow joint

51

Carpal bones and hand

-carpus forms wrist
-two rows of short bones
-distal row articulates with metacarpals
-pollex (thumb) has two
#ed from 1-5, 1 will always be the thumb and 5 will always be the pinky

52

Pelvic girdle and lower limbs

- more massive than the pectoral girdle
-consists of two os coxae
-fusion of ilium, ischium, and pubis

53

Ilium

Largest hip bone
-within acetabulum, fused to the ischium (posteriorly) and the pubis (anteriorly)
-pubic symphysis limits left to right

54

The lower limbs

-femur longest bone in the body
-articulates with tibia at the knee
Patella is a large sesamoid bone
-fibula parallels tibia laterally

55

TARSUS (FOOT)

-7 tarsal bones
-pattern of metatarsal bones and phalanges parallels that of the hand
-all toes have three phalanges except the hallux (two phalanges)

56

Ankle and arches

-when standing, most of the weight of the body is transferred from the talus to the calcaneous
-rest os passed onto the metatarsals
-weight transfer occurs along longitudinal arch
-transverse arch

57

Articulations

Where two bones interconnect

58

Immovable joints

Synothroses or bony

59

Slightly movable joints

Amphiarthroses, or fibrous/cartilagenous

60

Keratinocytes

Produce tough protein called kerotin

61

The epidermis

Stratum basale (activly divide and are pushed up)
Deepest layer
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum
-most superficial layer

62

Stratum basale

Location of melanocytes
Cells in this area are undergoing active reproduction mitosis

63

Stratum spinosum

Keratinocytes are bound together by desmosomes

64

Stratum granulosum

Keratinocytes produce a lot of keratin

65

Statum corneum (cornous like a horn hard structure)

Superficial layer
Consist of interlocking dehydrated dead cells
Far away from nutrition and die
Flat filled with keratin and smashed

66

Epidermal ridges

Stratum germinativum forms epidermal ridges
Ridges (dermal papillae) extend into the dermis
-increase friction when grabbing objects
-creates ridges called finger prints

67

Reticular layer

High amount of collagen fibers
Dense irregular connective

68

Wavy boarder

- epidermal ridge and
-dermal papilla
1. Increases surface area
More surface area to exchange oxygen and glucose
2.prevent slippage side to side
Prevents tissue from coming apart by side to side forces

69

Areolar connective tissue

On dermis
Filled with fluid and blood vessels

70

Skin color

Due to
-dermal blood supply (hemoglobin)
-thickness of stratum corneum
Various concentrations of carotene and melanin

71

Dermal blood supply

Increased blood flow results in flushing
Reduction in blood flow results in pale color
Sustained reduction in blood flow results in cyanosis

72

Carotene

-derived from carrots corn squash
Can convert to vitamin A
Vit a is needed for synthesis of visual pigments in the photoreceptors of eye

73

Melanin

-90% of skin color
Produced in melanocytes
Creates natural skin color AND TAN
PROTects skin against UV radiation

74

Melanocyte activity

Exposure to UV light
Increases the rate of melanin formation
Tanning begins
Repeated exposure to UV light
Can result in collagen and elastic epidermal and dermal damage
Results in abnormal connective tissue damage

75

The vitamin D formation

UV converts cholesterol related precursor
Converts vit D
Vit d1 undergoes kidney and liver
Vit d1 converts to active form calcitrol

76

Dermis two layers

Papillary layer
Reticular layer

77

Papillary layer

Superficial dermis

78

Reticular layer

Deep dermis

79

Papillary layer

-areolar connective tissue loose connectibe

80

Reticular layer

Glands hair follicles

81

Wrinkles

The interwoven collagen fibers provide tensile strength
The elastic fibers allow the skin to stretch and recoil
Skin wrinkles are due to
Age
Change in hormone levels
UV

82

Stretch marks

Extensive stretching during preg excessive weight gain can cause reticular fibers to break
The skin does not recoil
The skin wrinkles and creases resulting in stretch marks

83

Lines of cleavage

Collagen and elastic fibers have a tendency to organize themselves in a parrallel pattern
In certain areas of body Lines of Cleavage
Collagen and elastic fibers have a tendency to organize themselves in a parallel pattern
In certain areas of the body, there is a pattern of cleavage lines due to stress or a specific type of movement
To reduce scar formation (extensive damage to the fibers), surgeons try to cut parallel to the lines of cleavage

84

The dermis

Contains a Network of:
Blood vessels
Lymph vessels( tubes that drain away excess fluid prevent swelling)
Nerve fibers

85

The dermis

Blood Supply to the Skin
Arteries and veins form the cutaneous plexus
Smaller blood vessels form the subpapillary plexus
Function
Thermoregulation
Blood flow to the skin is regulated to help maintain constant flow to other tissues of the body

86

The dermis nerve supply

Nerve Supply to the Skin
Function
Controls blood flow to the skin
Adjusts gland secretion rates
Monitors sensory receptors
Examples
Tactile corpuscles (light touch receptors) less tissue
Ruffini corpuscles (stretch receptors)
Lamellated corpuscles (deep pressure and vibration receptors) more tissue above

87

The subcutaneous layer

The subcutaneous layer is deep to the dermis
Also called the hypodermis layer (technically not part of the skin mostly adipose with areolar tissue women have more estrogen controlled)
Also referred to as the superficial fascia
Not technically considered a part of the integument
Helps stabilize the integument

88

The subcutaneous

Consists of:
Adipose tissue
Major blood vessels
Due to the location of the vessels, we have 
terms such as:
Hypodermic needles
Subcutaneous injections

89

Accessory structures

Includes:
Hair follicles
Sebaceous glands
Sweat glands
Nails

90

Hair

Hair Follicles and Hair
Found everywhere except:
Palms
Soles of feet
Sides of the fingers and toes
Lips
Portions of genitalia
Glans penis
Clitoris
Labia minora
Inner surface of labia majora

91

Hair follicles

Hair Follicles and Hair
Hair follicles (sheath of epithelial and connective tissue that surrounds and supports growing hair)
Hair papilla where hair grows from
Hair bulb where hair gets big
Hair Structure
Medulla
Cortex
Cuticle

92

Hair follicles and hair

Hair Follicles and Hair
Functions of hair
Protection from UV light
Insulation
Guards entrance to nose and ears
Movement of the hair sends impulses via nerves to the brain (presence of root hair plexus)
Such as when a bug is crawling on your arm
Contraction of the arrector pili muscles
Results in goose bumps

93

Vellus hair

Covers most of the body

94

Intermediate hair

Arms and legs
Not as thick but still can be pigmented

95

Terminal hair

Head
Pigmented
Eye brows
Eye lashes

96

Erector pili

Smooth muscle
Involuntary

97

Glands in skin


Sebaceous glands
Sweat glands
Apocrine glands
Ceruminous glands (a type of apocrine gland)
Mammary glands (a type of apocrine gland)
Merocrine glands
Gland function
Lubricates the epidermis, excretes waste, assists in thermoregulation

98

Sebaceous Glands


Secrete sebum to collect dirt; lubricate the skin
Holocrine secretions (oily)
Found all over the body except for the palms and soles
Found in high concentrations on the forehead, face, and upper back
If the ducts become blocked, acne may occur

99

Apocrine glands

Sweat Glands
Apocrine sweat glands
High concentration in the axillary, anal, genital regions
Produce an odorous secretion (musky odor; “BO”)
Secretions may contain pheromones
Post-puberty males/females have these secretions (may function in mate selection)
Mechanism of secretion is merocrine

100

Sweat glands

Sweat Glands
Eccrine sweat glands
Found all over the body
Found in high concentrations on the palms and soles
Produce “true” sweat for cooling purposes

101

Mammary glands


Mammary glands
A special type of apocrine gland
Produce milk under the control of hormones from the pituitary gland

102

Ceruminous glands

Ceruminous glands
A special type of apocrine gland
Found only in the ear canal
Produce cerumen (earwax)
Provide minimal protection associated with the ear

103

Sweat glands

2 types
Apocrine
Merocrine ECCRINE

104

Sebaceous glands

Secrete sebum
Holocrine secretions oily
Found all over body not palms and soles
Found in high concentrations face,upper back, forehead
If ducts blocked acne may occure

105

Apocrine

High concentration axillary, anal, genital
Odorous secretion
Secretions contain pheromones

106

Eccrine

Highest concentration
Found all over
Palms and soles of feet
Produce true sweat for cooling

107

Lunula

Moon shaped

108

The Histological Organization of Mature Bone


The matrix of bone
Calcium phosphate eventually converts to 
hydroxyapatite crystals
Calcium phosphate makes up ~65% of the bone mass
Hydroxyapatite crystals resist compression

108

Collagen fibers


Make up ~35% of the bone matrix
Contribute to the tensile strength of bones
Collagen and hydroxyapatite make bone tissue extremely strong
Bone cells
Contribute only 2 percent of the bone mass

109

Osteocytes

Osteocytes
Mature bone cells
Maintain the protein and mineral content of the matrix
Sit in depressions called lacunae
Matrix layer associated with osteocytes is lamellae
Small channels extending from the osteocytes to the bone capillaries are called canaliculi

110

Osteoblasts

Immature bone cells
Found on the inner and outer surfaces of bones
Osteoblasts are involved in making new bone. This is a process called osteogenesis

111

Osteoprogenitor cells

These are bone stem cells
Found on the innermost layer of the periosteum and the inner lining of the endosteum
Differentiate to form new osteoblasts
Heavily involved in the repair of bones after a break

112

Osteoclasts

Multinucleated cells
Secrete acids, which dissolve the bones thereby causing the release of stored calcium ions and phosphate ions into the blood
This process is called osteolysis

113

Compact bone (dense bone)

Compact bone (dense bone)
Compact bones are dense and solid
Forms the walls of bone

114

Spongy bone (trabecular, or cancellous, bone)

Open network of plates
Surrounds the medullary cavity
Medullary cavity consists of bone marrow

115

Spongy Bone (details)
Spongy bone


Arranged in parallel struts
Forms branching plates called trabeculae
Trabeculae form an open network
Creates the lightweight nature of bones

116

Epiphysis (ends of the long bones)

Consists of red marrow

117

Diaphysis (shaft of the long bones)


The medullary cavity of the diaphysis consists of yellow marrow

118

Periosteum


Outer surface of the bone
Isolates and protects the bone from surrounding tissue
Provides a route and a place for attachment for circulatory and nervous supply
Actively participates in bone growth and repair

119

Endosteum


Inner surface of bone
Lines the medullary cavity
Consists of osteoprogenitor cells
Actively involved in repair and growth

120

Ossification

Before six weeks of development, the skeleton is hyaline cartilage
Cartilage cells will be replaced by bone cells
This is called

121

Osteogenesis


Bone formation

122

Calcification


The deposition of calcium ions into the bone tissue

123

Intramembranous ossification



Involved in the development of clavicle, mandible, 
skull, and face

124

Endochondral ossification


Involved in the development of limbs, vertebrae, and hips

125

Intramembranous Ossification


Stem cells differentiate to form osteoblasts
Osteoblasts begin secreting a matrix
Osteoblasts become trapped in the matrix
Osteoblasts differentiate and form osteocytes
More osteoblasts are produced, thus move outward
Blood vessels are trapped by the formation of spicules

126

Blood vessel entrapment 3

Bone growth is an active process,
and osteoblasts require oxygen 
and a reliable supply of nutrients. 
As blood vessels branch within
the region and grow between the
spicules, the rate of bone growth
accelerates. As spicules interconnect, 
they trap blood vessels within 
the bone.

127

Formation of spongy bone 4

Continued deposition of bone
by osteoblasts creates a bony
plate that is perforated by blood
vessels. As adjacent plates
fuse together, the bone
structure becomes increasingly
complex.

128

Endochondral Ossification


Cartilage cells die and are replaced by osteoblasts
Osteoblasts begin to form spongy bone
This is the primary ossification center
An increase in bone length and diameter begins

129

Phase 1 bone remodeling

As the cartilage enlarges,
chondrocytes near the
center of the shaft
increase greatly in size,
and the surrounding
matrix begins to calcify.
Deprived of nutrients,
these chondrocytes die
and disintegrate, leaving
cavities within the 
cartilage.

130

Endochondral Ossification


Osteoblasts begin to migrate into the epiphysis region
This is the secondary ossification center
Osteoblasts begin to replace cartilage with bone
This results in pushing the epiphysis away from the diaphysis thus resulting in longer bones

131

Increasing the Diameter of a Developing Bone
Appositional growth


Inner layer of the periosteum differentiates to form osteoblasts and adds bone matrix to the surface
This forms circumferential lamellae to the outer surface
Osteons form
Bone continues to enlarge in diameter

132

Epiphyseal Plate


Area of cartilage in the metaphysis
Cartilage near the diaphysis is converted to bone
The width of this zone gets narrower as we age
Marks the former location of the epiphyseal cartilage

133

Factors Regulating Bone Growth


Vitamins A, C, D (calcitriol)
Hormones
Parathyroid gland releases parathyroid hormone
Stimulates osteoclasts
Increases calcium ion absorption from the small intestine to the blood
Reduces the rate of calcium ion loss from the kidneys

134

Thyroid gland

releases calcitonin
Inhibits osteoclasts
Increases rate of calcium ion loss in the urine
Removes calcium ions from blood and adds it to bone

135

Thyroid gland

releases thyroxine
Maintains normal activity in the epiphyseal region
Keeps all of the epiphyseal growth plates growing at the same rate

136

Pituitary gland


releases growth hormone (somatotropin)
Stimulates bone growth
Stimulates growth in the cartilage of the epiphyseal growth plate

137

Estrogen and testosterone


stimulate osteoblast activity
Osteoblast activity produces bone faster than epiphyseal cartilage expansion
Ultimately the epiphyseal cartilage narrows and growth plates close (about age 20-25)

138

Remodeling of Bone


Realignment of teeth can change the shape of tooth sockets
Increased muscular development
Bone changes occur due to stress
Different features develop on the bone
Attachment of ligaments
Attachment of tendons
Stressed bones become thicker and stronger

139

Inactivity of bones

Remodeling of Bone
Inactivity of bones can cause degeneration (bones need stress!)
After a few weeks, unstressed bones can lose about a third of their mass
Astronauts in space = severe 
loss of bone mineral density

140

Injury and Repair
Fractures


Transverse fractures
Break transverse to the long axis
Displaced fractures
Produces new and abnormal bone arrangements
Compression fractures
Bones “jam” together
Spiral fractures
Bones twist along the length of the bone