Skeleton Axial - Anatomy and Physiology LAB - Lecture Slides, Slides of Physiology

Download Skeleton Axial - Anatomy and Physiology LAB - Lecture Slides and more Slides Physiology in PDF only on Docsity!

Skeleton:

Axial

Classification of Bones

Human body consists in 206 bones. They aredivided in two groups:

• Axial skeleton (form the long axis of the

body) includes – bones of the skull, vertebralcolumn, and rib cage. Functions: protecting,supporting or carry other body parts.

• Appendicular skeleton – bones of the upper

and lower limbs, shoulder, and hip. Function:locomotion and manipulation of ourenviroment

Classification of Bones: By Shape

Figure 6.2b

• Short bones
  • Cube-shaped bones of

the wrist and ankle

• Sesamoid bones

“shaped like a sesameseed” that form withintendons (e.g., patella).They vary in size andnumber in differentindividual. Somesesamoid bones act toatter the direction of pullof a tendon

Classification of Bones: By Shape• Flat bones –

thin, flattened,and a bitcurved (e.g.,sternum, andmost skullbones)

Figure 6.2c

Function of Bones

• Support – form the framework that supports

the body and cradles soft organs. Ex: Lowerlimb

• Protection – provide a protective case for:

the brain (bones of skull), spinal cord(vertebrae), and vital organs (rib cage)

• Movement – provide levers for muscles• Mineral storage – bone is a reservoir for

minerals, especially calcium and phosphorus

• Blood cell formation – hematopoiesis occurs

within the marrow cavities of bones

Bone Markings: Projections –Sites of Muscle and Ligament Attachment• Tuberosity – rounded projection• Crest – narrow, prominent ridge of bone• Trochanter – large, blunt, irregular surface• Line – narrow ridge of bone

Chemical Composition of Bone: Organic

• Bone has both organic and inorganic

components. Organic components:1.-Cells:• Osteoblasts – bone-forming cells• Osteocytes – mature bone cells• Osteoclasts – large cells that resorb or break

down bone matrix 2.- Osteoid – unmineralized bone matrix

composed of proteoglycans, glycoproteins,and collagen

The Skeleton

• The skeleton (“dried up body” or mummy)• It is strong, yet light, and almost perfectly

adapted for the protective, locomotor andmanipulative functions it perform

• Composed of bones, cartilages, joints and

ligaments, accounts for about 20% of bodymass.

• The skeleton is divided into Axial and

Appendicular

The Skull

• The skull, the body’s most complex bony

structure, is formed by the cranium andfacial bones

• Cranium – protects the brain and is the site

of attachment for head and neck muscles

• Facial bones

Supply the framework of the face, the senseorgans, and the teeth

Provide openings for the passage of air andfood

Anchor the facial muscles of expression

Anatomy of the Cranium

• The cranium can be divided in :

1.- cranial vault (calvaria)2.- cranial base (floor)

• Eight cranial bones – two parietal, two

temporal, frontal, occipital, sphenoid, andethmoid

• Cranial bones are thin and remarkably

strong for their weight

Skull: Anterior View

Figure 7.2a

Skull: Posterior View

Figure 7.2b

Occipital Bone and Its Major Markings

-^

It articulates anteriorlywith the paired parietaland temporal bones viathe lambdoid andoccipitomastoid sutures.

-^

It also joins with thesphenoid bone in thecranial floor via a platecalled the pharingealtubercule.

-^

Forms most of skull’sposterior wall and base

-^

Major markings includethe posterior cranial fossa,foramen magnum,occipital condyles, and thehypoglossal canal

Figure 7.2b

Temporal Bones

Figure 7.

-^

Between the styloid and mastoid processes exist thestylomastoid foramen thatallow cranial nerve VII toleave the skull.• The mastoid region of thetemporal bone exhibits theconspicuous mastoidprocess, an anchoring sitefor some neck muscles