the skeletal system - yolamscoxholyname.yolasite.com/resources/ch6sketletalsystem.pdf ·...

Essentials of Human Anatomy & Physiology

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Seventh EditionElaine N. Marieb

Chapter 6The Skeletal System

The Skeletal System

Slide 5.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Made up of 4 types of connective tissue:

1. bones (compact and spongy)

2. marrow (red and yellow)

3. cartilage

4. ligaments

(bone to bone) and

tendons

(bone to muscle)

6 Functions of Bones


1. Support of the body

2. Protection of soft organs

3. Movement due to attached skeletal muscles

4. Storage of minerals

5. Storage of fats (energy)

6. Blood cell formation

Bones of the Human Body

Slide 5.3

The skeleton

has 206 bones.

You are required to

name only 22 of them.

Figure 5.2b

Bones of the Human Body


Two basic types of bone tissue:

1. Compact bone∙composed of osteons

2. Spongy bone∙Small needle-like

pieces of bone

∙Many open spaces

Figure 5.2b

Classification of Bones by Shape

Slide 5.4aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

4 Types of bones:

1. Long

2. Short

3. Flat

4. Irregular

Classification of Bones on the Basis of Shape

Slide 5.4cCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 5.1

Classification of Bones: Long


Long bones

-Typically longer than wide

-Have a shaft with heads at both ends

-Contain mostly compact bone

Examples: femur, humerus

Classification of Bones: Short

Slide 5.4bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Short bones

-Generally cube-shape- short and wide!

-Contain mostly spongy bone

Examples: carpals,

tarsals

Classification of Bones: Flat


Flat bones

-Thin and flattened

-Usually curved

-Thin layers of compact bone around a layer of spongy bone

Examples: skull, ribs,

sternum

Classification of Bones: Flat


Classification of Bones: Irregular


Irregular bones

-Irregular shape

-Do not fit into other bone classification categories

Example: vertebrae

and hip

Gross Anatomy of a Long Bone

Slide 5.6

Epiphysis

-Ends of the bone

-Composed mostly of spongy bone

Diaphysis

-Shaft- length of bone

-Composed of compact bone

Figure 5.2a

Gross Anatomy of a Long Bone

Slide 5.6

Diaphysis

Figure 5.2a

Structures of a Long Bone


1. Periosteum-Outside covering of the diaphysis

-Fibrous connective tissue membrane

2. Nutrient arteries-Supply bone cells with nutrients, via diffusion

Figure 5.2c



3. Articular cartilage

-Covers the external surface of the epiphyses

-Decreases friction at joint surfaces

Figure 5.2a



4. Medullary cavity

-Cavity of the shaft

-Contains yellow marrow (mostly fat - energy storage) in adults

-In infants, contains red marrow for blood cell formation

Figure 5.2a



∙In adults, red marrow is found mostly in spongy bone or the epiphysis of a few long bones.

Figure 5.2a

Microscopic Anatomy of Bone

Slide 5.10b


Figure 5.3


Slide 5.10a

Osteon (Haversian System):

A cylindrical unit of bone

Osteocyte: a mature bone cell; found within tiny cavities of compact bone

Central canal (parallel to shaft of diaphysis):

Opening in the center of an osteon

Carries blood vessels and nerves lengthwise


Slide 5.10b


Figure 5.3


Slide 5.10a

Central canal


Slide 5.10b


Figure 5.3

4 Types of Bone Cells


osteocytes: Mature bone cells

osteoblasts: Bone-forming cells

Think “b” is for “build”

osteoclasts: Bone-destroying cells

Think “c” is for “corrode”

osteogenic cells: Stem cell with mitotic potential and the ability to differentiate into an osteoblast

4 Types of Bone Cells


osteocytes

osteoblasts

osteoclasts

osteogenic cells

Bone Growth

Slide 5.13b


Osteoblasts add bone to external periosteum.

Osteoclasts remove bone from the endosteum.

After vertical growth is stopped,

bones in adults grow only in

diameter (width) and thickness (strength).

Bone Remodeling

Slide 5.13b


The ongoing forming and break down of bone

tissue (by osteoblasts and osteoclasts,

respectively).

Bone Remodeling is signaled by many factors. It is necessary to maintain proper bone mass and to transport nutrients into the body.

Ex. negative feedback system of blood-calcium levels

Negative Feedback Mechanism

Slide 5.13b


4 Factors That Affect Bone Growth

Slide 5.13b


Individual’s choices affect width/strength of bone:

-diet: amount of minerals (especially calcium)

-diet: amount of vitamins (especially vitamin D)

-negative feedback mechanisms: production of hormones (PTH or calcitonin) that signal the functions of osteoclasts or osteoblasts

-exercise: amount of strain on bone (weight by gravity or the pulling of muscles)

99% in the body: keeps bones

and teeth strong

Facilitates muscle movement, by concentration gradient

Activates enzymes and active transport mechanisms

As an electrolyte, helps maintain regular heartbeat

Importance of Calcium

Bone Fractures


Fracture = a break in a bone

∙ Types of bone fractures

1. Closed (simple) fracture – break that does not penetrate the skin

2. Open (compound) fracture – broken bone penetrates through the skin

∙ Bone fractures are treated by reduction and immobilization∙Realignment of the bone

Stages in the Healing of a Bone Fracture


Figure 5.5

Skull Fractures

The Axial Skeleton

Slide 5.20a


Axial: Forms the longitudinal part of the body

∙ Divided into three parts

1. Skull

2. Vertebral column

3. Bony thorax

The Axial Skeleton

Slide 5.20b


Figure 5.6

21b


Figure 5.7

The Vertebral Column


∙ Vertebrae separated by intervertebral discs made of fibrocartilage.

∙ Each vertebrae is given a name according to its location and number.

Figure 5.14

∙ Mnemonic to remember:

∙ Cervical = breakfast time 7 am or 7 bones.

∙ Thoracic = lunch time 12pm or 12 bones.

∙ Lumbar/Sacral= supper at 5 pm or 5 bones.

∙ I

Disc Deterioration

∙ Disc can deteriorate over time due to chronic use and injury.

∙ Surgical intervention is often common to alleviate pain and nerve damage.

Abnormal Curvature

∙ Abnormal curvatures can result from:

1.Poor posture

2.Poor nutrition

3.Genetics/disease

Three types:

Scoliosis, Kyphosis, Lordosis

The Thoracic Cage or Bony Thorax

Slide 5.31a


∙ Protects heart, lungs and major blood vessel.

∙ Composed of three parts:

1.Sternum

2.Ribs

3.Thoracic Vertebrae Figure 5.19a

Bony Thorax: Sternum

Slide 5.31a


∙ Commonly known as breastbone.

∙ Flat bone made from the fusion of three bones:

1.Manubrium

2.Body

3.Xiphoid Process Figure 5.19a

An Evolutionary Perspective…….

Gender Differences of the Pelvis


Figure 5.23c

The Pectoral (Shoulder) Girdle


∙ Composed of two bones:

1. Clavicle – collarbone, keeps “arm in place” and prevents should dislocation.

2. Scapula – shoulder blade or “wings”

a. Acromioclavicular joint:

∙ These bones allow the upper limb to have exceptionally free movement

Bones of the Shoulder Girdle

Slide 5.34a


Figure 5.20a, b

Bones of the Upper Limb

Slide 5.35a

Upper Arm is formed by a typical long bone:

1. Humerous (upper arm)

a. Greater/lesser tubercles: site of muscle attachment.

b. Surgical neck: often needs surgery

c. Deltoid tuberosity: deltoid attaches

d. Radial groove: radial nerve on.


Slide 5.35a

Upper Arm is formed by a typical long bone:

e.Trochlea and capitulum: attaches with lower arm

f. Medial and lateral epicondyle: all free movement of bent arm.

Bones: Upper Limb

Slide 5.35b


• The forearm (lower) has two bones

1. Ulna (“pinky”)

2. Radius (“thumb”)

Figure 5.21c



∙ The hand: three main sections of bones.

1.Carpals : wrist (8)

2. Metacarpals :palm (5)

3. Phalanges: fingers (5, thumb = #1)

Figure 5.22

Upper Limb: Phalanges


∙ The hand: three main sections of bones.

1.Carpals : wrist (8 bones)

2. Metacarpals :palm

3. Phalanges: fingers

Figure 5.22

Bones of the Lower Limbs

Slide 5.40a


∙ The thigh has one bone

∙Femur – thigh bone

∙Trochanters = muscle attacment

∙Condyles = articulate with tibula

∙Patellar surfaceFigure 5.35a,

b


Slide 5.40b


∙ The leg has two bones:

1.Tibia: (“shin”) larger, medial

∙Articulate with femur and patellar.

2.Fibula: thin, distal

∙Doesn’t form knee joint.

∙Lateral malleolus forms outer part of ankle.

Figure 5.35c

Bones of the Lower Limbs: Knee

Slide 5.40b


∙ Patella:

∙ Articulates with the femur

Figure 5.35c


Slide 5.41Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummins

∙ The foot

∙Tarsus – “ankle”

∙7 tarsal bones, calcaneus (heel) and talus bear most weight.

∙Metatarsals – sole (5)

∙Phalanges – toes (14)

Figure 5.25

The Skull

Slide 5.21a


∙ Two sets of bones

1. Cranium: encloses brain

2. Facial bones

∙ Bones are joined by sutures: immoveable joints.

∙ Only the mandible is attached by a freely movable joint (you can move your jaw right??? ☺)

21b


Figure 5.7

Paranasal Sinuses

Slide 5.25a


∙ Hollow portions of bones surrounding the nasal cavity

Figure 5.10

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