Ch5.ppt

Ch. 5

Overview - pg 134

The skeletal system, the bones and cartilage, is the framework of the

body…it gives the body structure and protects all the organs. Each bone in the skeleton is an organ.

Divisions

1. Axial skeleton (white) – made up of the

bones of the skull,

vertebral column, and thorax.

2. Appendicular skeleton

(yellow) – made up of the bones of the

Function -

1. Support – Provides framework and supports soft tissue of the body.

2. Protection – Protects internal organs.

3. Movement – Work with the muscles to move the body.

4. Storage of minerals and homeostasis – Store Ca and P among other minerals.

Homeostasis – add and remove minerals as needed.

Types of bones – 4 general

shapes; one special example

1.

Long bones

– the bone’s length is greater

than its width

• Structure – 1. long cylindrical shaft

2. two heads/ends of the

bone

Types of Bones,cont.

2.

Short bones

– cubed shaped, nearly

equal in length and width.

• Structure – superficially they contain thin

plates of compact bone that encase

Types of Bones,cont.

3. Flat bones

– Flattened bones made of

thin plates.

• Structure – 2 plates of compact bone

that encase spongy bone.

•

Example: Scapula and Sternum

4. Irregular bones

– Bones that don’t fit into

the last 3 categories

One additional type of bone -

1. Sesamoid bones – a special type of short bone…

These are small bones within a tendon.

Parts of the Long (general) Bone

1. Diaphysis – shaft portion of the bone

2. Epiphysis – head/end of the bone

3. Metaphysis – (*orange notes only) where the diaphysis

and meet, in developing bone the growth plate is here. The plate is made of cartilage and makes new bone as the human grows.

4. Articular Cartilage – hyaline cartilage that covers the

epiphysis

5. Peristeum – a connective tissue that covers the surface

of the bone.

Histology of the Bone

Remember that bone is a type of

connective tissue. A big difference is that

the matrix of the bone is filled with mineral salts, mainly calcium, and is hardened.

There are some spaces in the bones that serve as passageways for blood vessels

Types of Cells in

Bone Tissue -

1. Osteoprogenitor

– precursor to an

osteoblast.

2. Osteoblast

– cells that build bone tissue

by calcifying cartilage.

Bone Tissues

1. Compact Bone – pg 137-140 • External layer of bone

• Function: Protection, support, and resist stress from weight

• Structure: the structural unit of bone tissue is called an osteon, and contains the following structures:

-Volkmann’s canal- hollow canal where blood vessels and nerves penetrate the bone superficially and

continue to the deep

-Central canal- center of osteon. These canals run along the length (top to bottom) of the bones.

Compact Bone, cont.

-Concentric lamellae- the calcified matrix of the bone that surrounds the central canal and form concentric circles

- Lacunae- hollow spaces in the lamellae that house osteocytes (mature bone cells).

Bone Tissues

2. Spongy bone – Is not composed of a true

osteon. This type of tissue makes up

short flat irregular bone and ends of long

bones. (see pg. 141 figure 5.4a)

Structure-

Spongy Bone Structure, cont.

•Trabeculae continued – Some of the spaces of the spongy bone is filled with red bone marrow.

• Blood Vessels from the periosteum

Ossification of bone – 2 types

1. Intramembranous – Formation of bone

directly on or within fibrous connective

tissue (flat bones)

2. Endochondral – Formation of bone within

a hyaline cartilage model (most bones).

Homeostasis-pg 140

1. Bone growth and

maintenance-• Bone is continuously growing throughout life • Remodeling – replacement of old bone

tissue with new tissue

• Compact bone is formed by the

transformation of spongy into compact

• Growth is from the inside of spongy bone to the outside making compact bone

• Bone is the body’s storage bed for Ca+

Homeostatic example

Bone and minerals – pg. 140

• Bone stores more calcium and phosphorus (used to make RNA and DNA) than any other organ.

a. Stimulus – stress causes decrease in blood calcium level

b. Controlled Condition – normal blood Ca+ level

c. Receptors – parathyroid gland

d. Control Center – Parathyroid hormone (PTH) gene turned on

e. Effectors – osteoclasts increase reabsorbtion of bone and kidneys retain Ca in blood

Homeostasis, cont.

3. Exercise and bones

•

When stress is put on the bone, the bone

will remodel itself. As the bone remodels

itself, it becomes stronger

Homeostasis, cont.

4. Aging and bones

• As your age increases the amount of calcium in bones decreases

• Females – after age 30 bones begin to lose calcium

Fractures and Bone Repair

• A fracture is defined as any break or crack in a bone. There are many

Types of Fractures

A. Incomplete-the

break doesn’t

make it across the

entire bone. A

greenstick fracture

is a type of

incomplete

Incomplete Fractures

1. Green stick – many little cracks in the bone.

Incomplete Fractures

3. Depressed – bone is pressed inward, typical in skull

Complete Fractures

• The break goes through the entire bone (OUCH!)

1. Simple – clean break that does not penetrate the

Complete Fractures

2. Compound – broken ends of the bone

Complete Fractures

3. Spiral – the breaks are jagged due to twisting forces.

Bone Repair-pg 143

A. Hematoma Formation

• Hematoma, a mass of clotted blood, form at the fracture site.

• Shortly after the

break, bone cells die and the tissue

B. Fibrocartilage callus forms

(occurs over 3-4 weeks)

• Formation of a soft callus occurs

• Macrophages clean up damaged tissue

• Fibroblasts produce collagen fibers to hold

the broken ends together

• New capillaries deliver oxygen to the area

• Osteoblasts begin to make new bone

Bone Repair

C. Bony callus formation (occurs after 3-4 weeks and continues for 2-3 months)

Bone Repair

D. Remodeling (continues several months

after bony callus formation)

The Axial Skeleton

Frontal

Parietal

Nasal

Ethmoid

Lacrimal

Sphenoid

Occipital

Temporal

Vertebral Column and Thorax

(pg 150)

I.

Vertebral Column (spine)

a. Protects the spinal cord

b. Supports the head (skull)

c. Serves as point of attachment for the

muscles of back and the ribs

d. 33 vertebrae prior (evolution) to the

Vertebral Column, cont.

e. 26 vertebrae after the fusion of the sacral

and coccygeal vertebrae

1. 7 cervical vertebrae (most superficial &

superior)

Vertebral Column, cont.

f. The vertebral column has a natural S curve.

II. Structure of a typical

vertebrae (pg 155)

a. Body

1. thick, disc shaped front portion

2. Weight bearing part

b. Vertebral arch is formed by

c. Processes

1. Transverse – a. two

projections to the sides

b. site for rib attachment

2. Spinous

a. large

projection on the back.

Typical Vertebrae, cont.

d. Openings

1. Intervertebral

foramen (orange notes only

Typical Vertebrae, cont.

e. Connection points (articulations)

1. superior articular facet (or facet on superior articular process)

Typical Vertebrae, cont.

2. Inferior articular facet -Point of attachment where each vertebrae articulates. On the

bottom of the vertebrae.

III. Differences between the vertebrae pg. 155-156

a. Cervical (C1-C7) 1. C1 – atlas

a. lacks a body and spinous process

b. connects skull and vertebral column

2. C2 – axis

a. projection called dens

3. C3-C6

a. spinous process is bifid (cleft)

4. C7 vertebral prominens

a. large spinous process

b. Thoracic (T1-T12)

1. Spinous process hooks downward 2. Two facets on the

c. Lumbar (L1-L5)

1. Largest body

2. Hatch-like spinous process

d. Sacrum – 5 fused vertebrae

1. sacral body –

Regional

Thorax pg. 157-158

IV. Sternum – flat bone formed by the union of three bones. Serves as an attachment

point to the first seven pairs of ribs.

V. Ribs – 12 pairs that form the

thoracic cage

a. True ribs

1. First 7 pairs

2. Connect with vertebral

column and the sternum by costal cartilage.

b. False ribs

1. Next 5 pairs

2. Connect with vertebral column and indirectly

attached to sternum or not at all

Appendicular Skeleton

• The appendicular

skeleton is composed of 126 bones that

• I. The shoulder girdle is made up of a clavicle and scapula

– A. Clavicle (collarbone)

• 1. Slender bone that has a double curve.

• 2. Medial end articulates with sternum (manubrium)

• B. Scapula (shoulder blades)

1. Large, triangular, flat bones

2. Spine – sharp ridge on posterior side.

3. Acromion process – articulates with clavicle.

4. Coracoid process – muscle attachment

5. Glenoid cavity – articulates with the

II. Bones of upper limbs are made

up of 30 different bones in each

arm

• A. Humerus (upper arm)

1. Head – rounded projection that

articulates with the scapula (glenoid

cavity)

2. Tubercles – sites for muscle

attachment

3. Body – lone shaft of the bone

a. Deltoid

4. Distal end (closest to the elbow)

a. Capitulum – rounded head that articulates with radius

b. Radial fossa – depression that receives the radial head when forearm is flexed

c. Trochlea – surface that articulates with ulna (underside of olecranon process)

d. Coronoid fossa – depression that receives head of the ulna when forearm is flexed

e. Olecranon fossa – depression that receives the olecranon process when are is straight

III. Ulna – bone in lower arm on little finger

side (medial)

A. Olecranon process – forms the elbow

B. Trochlear notch – receives the

trochlea of humerus

C. Radial notch – depression for radial

head

IV. Radius – sits on the thumb side of the

forearm

A. Radial tuberosity – point of

attachment of tendon

B. head – articulates with the radial

notch on humerus

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V. Carpals – bone of the wrist

A. Scaphoid B. Lunate

VI. Metacarpals – bones of the

hand

A. Numbered 1-5

V. Phalanges – bones of the fingers

A. Thumb made up of two bones

1. Proximal 2. Distal

B. Rest of the fingers are made up of three bones

Pelvic Girdle and Lower Limbs

• The pelvic girdle

supports the vertebral column and protects some organs

I. Coxal– formed by the fusion of 3

bones (ilium, ischium, pubis)

A. Ilium – large, flaring bone that makes

up most of the pelvis

1. Great sciatic notch – located on

the posterior side, inferior to the crest

allows sciatic nerve to pass

B. Ischium – small bone that is located inferior to the ilium and posterior to the pubis

C. Pubis – anterior portion of the coxal bones. D. Areas of Importance

1. Acetabulum – area where all 3 bones meet. Forms the joint where the femur articulates with the pelvis

• The angle (pubic arch) formed by the fusion of the pubis bones is

different if males and females.

• The pubic arch of a

female skeleton forms an angle that is greater than 90°

II.

Lower Limbs – the lower limbs are

formed by the femur, patella, tibia, fibula,

tarsal, metatarsal, and phalanges

a. Femur – Thighbone; longest and heaviest bone in the body.

1. head – portion that articulates with the hip 2. body – long shaft portion

3. greater trochanter – structure for muscle attachment

5. condyles – surfaces articulate with the

tibia; located on distal end of bone

a. medial – on medial

side

b. lateral – on lateral

side

III. Patella (knee cap)

IV. Tibia (shinbone) – larger,

medial, weight bearing bone of

the lower leg

A. Condyles – articulate with the femur

(proximal)

1. medial – on the medial side

2. lateral – on the later side (duh!)

B. Tibial Tuberosity – posterior attachment

for the patellar ligament

V. Fibula – smaller, lateral bone of

the lower leg

A. Head – proximal end that articulates with the tibia.

B. Lateral Malleolus – aritculates with the

VI. Tarsals, metatarsals, and

phalanges

A. Tarsal (tarsus) – collection of the seven bones that make up the ankle.

1. Talus – articulates with the tibia and fibula

2. Calcaneus (heel) – large bone on posterior part of foot

3. Cuboid – cube shaped bone on the lateral side of the foot

a. First (medial) b. Second

(Intermediate) c. Third (lateral)

Joints (brief)

• Diarthrosis – freely moving joint

– Gliding Joint – bone

surfaces flat, move back and forth and side to side. Ex. Carpals and tarsals – Hinge Joint – convex

portion of one bone fits into the concave portion of another. Ex.

Joints

- Pivot Joint –

rounded or pointed surface on one bone fit in a ring formed partly by one bone and partly by a

ligament. Ex.

Joints

• Condyloid joint – the oval shaped surface of one bone

articulates with a depression on

Joints

• Saddle Joint –

articulating surface of one bone looks like a saddle and the

Joints

• Ball and Socket –

consist of a bone with a ball like projection and another bone with a compression. Ex. Between the