THE SKELETAL SYSTEM

CH. 6INTRODUCTION TO CHAPTER

ROOTS:

arthr/o = joint cervic/o = neck chondr/i, chondr/o, chondr/io = cartilage cost/o = rib myel/o= bone marrow occipit/o = back of head oss/eo, oss/i, ost/e, ost/eo = bone sacr/o = sacrum spondyl/o = vertebra stern/o = sternum

WHY DO WE NEED A SKELETON?

It provides a framework for the body and gives it ___________.

It supports organs and ____________ them from injury.

It provides a place for muscles, ligaments, and tendons of the body to ____________ to.

It helps to make ________________ possible.

It stores ______________.

It provides a place for __________________.

WHAT IS BONE AND WHAT IS IT MADE OF?

Bone is one of the types of ______________ tissue in the body.

It is also called _____________ tissue.

It is made up of water and mineral salts.

________________ is the formation of or conversion into bone or a bony substance (calcification is the deposition of calcium in a tissue).

WHAT IS BONE MADE OF?

The outer surface is called _____________ BONE and is very dense. It is the thickest in the midshaft of a long bone to provide

strength and prevent bending of the bone

The inner layer is called ________________ BONE and is spongy and latticelike and is less dense than compact bone

WHAT IS BONE MADE OF?

The SHAFT (____________) of the bone contains the _____________ CAVITY

It is filled with YELLOW MARROW (fat storage) and RED MARROW (hematopoietic tissue)

Yellow marrow replaces red marrow as an animal ages.

WHAT IS BONE MADE OF?

________________ covers the surface of bone and is a tough, vascular membrane. It is where tendons, ligaments, and muscles attach to the body. It has a nerve and blood supply.

The inner layer of the periosteum contains ___________________ which are cells responsible for bone growth and repair.

WHAT IS BONE MADE OF ?

The medullary cavity of bone has arteries and veins that enter and exit the cavity via the ___________ ____________ which are openings in the bone

HOW DO BONES GROW?

They grow in LENGTH at the junction of the EPIPHYSIS and the DIAPHYSIS at the _____________ _________ (growth plate). It is also called the ___________.

They grow in THICKNESS in the layers of the periosteum.

HOW DO BONES GROW?

Bones are stimulated to grow via ___________ HORMONE (GH) which is produced by the ____________ gland.

There is a teamwork between ______________ producing bony tissue and _______________ eating away bony tissue to prevent the bone from becoming too thick. This process slows as an animal ages.

SHAPES OF BONE

________ (femur, humerus)

________ (carpal bones)

________ (sternum, scapula)

____________ (vertebrae)

AXIAL & APPENDICULAR SKELETON

AXIAL SKELETON: SKULL, HYOID BONE,VERTEBRAL COLUMN, RIBS, STERNUM

APPENDICULAR SKELETON: BONES OF THE LIMBS

SKULL

2 major segments: Bones of the Cranium and Facial Bones

PURPOSE: protects the brain and the sensory organs.

The ONLY mobile bone is the ______________________ (lower jaw)

The skull bones unite at the ____________.

• SINUSES are located within the skull and are _______- filled cavities

• Sinuses are usually named for the skull bone that contains the sinus

The nares open into 2 major air passages that end in the pharynx. The nasal passages are filled with very fine scrolls of bone called ___________________.

These are covered in pink mucosa. Air is warmed, moistened, and filtered as it passes through the turbinates in the nose on the way to the lungs. 

CRANIAL BONES

FRONTAL BONES – form the forehead Horns are an extension of the frontal bone

PARIETAL BONES – form upper part of each side of the skull

TEMPORAL BONES – form the lower part of the sides of the skull.

OCCIPITAL BONE – forms the back of the skull foramen magnum– opening at the base of the occipital

bone that allows the spinal cord to pass from the skull to the spine

FACIAL BONES

MAXILLA – bone that forms the upper jaw

MANDIBLE – forms the lower jaw. Only movable bone in the skull

maxilla

mandible

HYOID APPARATUS – U shaped structure made up of both bone and cartilage. Suspends the tongue, larynx, and floor of the mouth

VERTEBRAL COLUMN (backbone)

There are 5 types of vertebrae: ____________(C), ____________ (T), ______________ (L), ____________ (S), _______________ (Cy)

Each vertebrae has a body Each vertebrae has a body and an arch. and an arch. – BodyBody – bears the weight – bears the weight– ArchArch – forms the canal that – forms the canal that

houses the spinal cordhouses the spinal cord

• Intervertebral discsIntervertebral discs are are between the bodiesbetween the bodies• -Made of cartilage and -Made of cartilage and

serve as shock serve as shock absorbersabsorbers

CERVICAL VERTEBRAE

1st vertebrae: _______: supports the skull

2nd vertebrae: _____:

what the atlas rotates on

THORACIC VERTEBRAE

Attach to ribs Thoracic Cage: composed

of the thoracic vertebrae, ribs, costal cartilages, and sternum

protects the vital organs of the chest and allows the lungs to expand and contract during respiration

RIBS

PURPOSE: form the thoracic wall and protect the heart and lungs

Flat, curved Each rib has bony and

cartilagenous components The cartilagenous

component is located ventrally

They unite at the ___________________ junction

STERNUM

BREASTBONE Located on ventral midline of chest Flat bones called STERNEBRAE

that connect to each other via cartilage

Most cranial bone is the __________________

Most caudal bone is the __________________

LUMBAR VERTEBRAE

Support the abdomen

One bone that results from the fusion of 3-5 vertebrae Attaches to pelvisSACRAL VERTEBRAE

COCCYGEAL VERTEBRAE

Also called caudal or tail vertebrae

Can be docked- spinal cord ends near the lumbosacral junction

AXIAL & APPENDICULAR SKELETON

AXIAL SKELETON: SKULL, HYOID BONE,VERTEBRAL COLUMN, RIBS, STERNUM

APPENDICULAR SKELETON: BONES OF THE LIMBS

SCAPULA (shoulder blade) Large triangular bone on the side

of the thorax

HUMERUS (upper arm)

ULNA and RADIUS (forearm) Ulna forms the elbow

CARPUS (wrist) Numerous short/irregular

bones arranged in 2 rows

METACARPALS (palm) Vary in number between species (Ex: dog – 5, horse – 3) Numbered from medial to lateral

DIGITS (toes) Numbered from medial to lateral PHALANGES are located within the digits Usually 3 phalanges in one digit (P1, P2, P3)

PELVIS (hip)

3 pairs of bones that fuse to become one IIium – the largest bone

Flares out to the side Ischium – strongest, most caudal Pubis – Most ventral

FEMUR (thigh) Longest bone in the body Forms part of the STIFLE (knee)

PATELLA (kneecap)

TIBIA (shin) AND FIBULA Tibia is larger than fibula, and

bears more weight

TARSUS (ankle) Called HOCK in animals Composed of numerous irregularly

shaped bones arranged in rows

METATARSALS (foot) Very similar to metacarpals Vary in number between species Numbered medial to lateral

DIGITS (toes) Same as forelimb

JOINTS-an articulation between bones and cartilage that is held in place by ligaments

SYNARTHROSES (Fibrous joints) no movement Ex: Skull

AMPHIARTHROSES (Cartilaginous joints)

slight movement Ex: Pelvis at pubic symphysis, vertebral column

DIARTHROSES (Synovial joints) freely movable Most numerous in the body Ex: Hip joint, shoulder joint