Anatomy Exam 2 - Mizzou (Hill)

What is the function of cartilage?

1. support soft tissues

2. model for formation of bone

3. gliding surface at articulations

What is the function of bone?

support, protection, movement, hemopoiesis (blood cell production), energy and mineral reserves

Hyaline Cartilage

-Most common type

-Has tiny nearly invisible collagen fivers called fibrils

Found: Ends of long bones, costal cartilages, respiratory structures, fetal skeleton

Elastic Cartilage

- VERY similar to hyaline but los of elastic fibers

- Very resilient/flexible, tolerates bending

Found: in pinna (outer ear) and epiglottis

Fibrocartilage

- Has little ground substance and the matrix has thick, dense collagen fibers

- Resists strong compression

Found: in intervertebral disks, knee joint, public symphysis

Irregular bone

- Elaborate/complex shapes

- Compact bone covers internal spongy bone

- Vertebrae, ossa coxae (hip bones), and several bones in the skull (ethmoid and sphenoid bones)

Long bone

- Greater length than width

- Most common bone shape

- Upper/lower limbs

Short bone

- length nearly equal to their width

- covered by compact bone, interior is spongy bone

- carpals (wrist bones) and tarsals (bones in the foot). Sesamoid bones, which are tiny, seed-shaped bones along the tendons of some muscles, are also classified as short bones. The patella (kneecap) is the largest sesamoid bone

Flat bone

- flat, thin surfaces

- roughly parallel surfaces of compact bone with a layer of internally placed spongy bone

- provide extensive surfaces for muscle attachment and protect underlying soft tissues

- form the roof of the skull, the scapulae (shoulder blades), the sternum (breastbone), and the ribs

Parts of a long bone

Cross-section of bone

Intramembranous ossification

-bone growth within a membrane

-produces the flat bones of the skull, some of the facial bones (zygomatic bone, maxilla), the mandible (lower jaw), and the central part of the clavicle (collarbone)

Endochondral ossification

-begins with a hyaline cartilage model and produces most of the other bones of the skeleton, including those of the upper and lower limbs, the pelvis, the vertebrae, and the ends of the clavicle

Foramen

A hole in the bone (typically for nerves/blood vessels)

Fossa

A depression in a bone ex: mandibular fossa, lacrimal fossa

Process

projection from bone, narrow or wide, protrudes from surrounding bone ex:styloid or mastoid process

Meatus

a hole or tube-like structure ex:auditory meatus

Canal

A groove or tube-like structure ex:optic canal

Osteoblast

Build new bone

Osteoclast

Break down (consume) bone

Osteocytes

Mature bone cells

Which has more cartilage, an adult or a juvenile?

Adult

Osteogenesis

New bone formation

What happens when epiphyseal plates have closed?

Becomes an epiphyseal line

What are the cells involved in producing new bone tissue?

Osteoblasts

What is the periosteum? Where is it located? How is this different from endosteum?

- outer layer (covers compact bone)

- endosteum is the inner layer and lines the medullary cavity

What is an osteon? What are the concentric tubes that make up an osteon?

- a structural unit of compact bone

- made of lamellae

Components of the axial skeleton

Skull, vertebral column, and thoracic cage

Skull bones

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Coronal suture

between the anterior frontal bone and the more posterior parietal bones

Sagittal suture

in the midline of the cranium (along the midsagittal plane) and is the articulation between the right and left parietal bones

Squamous suture

articulates the temporal bone and the parietal bone of that side

What forms the bones of the neck?

Seven cervical vertebrae C1-C7

What bones form the superior region of the back?

Twelve thoracic vertebrae T1-T12

What bones form the inferior concave region ("small") of the back?

Lumbar vertebrae L1-L5

Sacrum

formed from five sacral vertebrae (S1-S5), which fuse into a single bony structure by the mid to late 20s

Coccyx

commonly called the "tailbone," is formed from four coccygeal vertebrae (Co1-Co4) that start to unite during puberty

Cervical vertebrae

Thoracic vertebrae

Lumbar vertebrae

Spinal curvatures

These spinal curvatures better support the weight of the body when standing than a straight spine could.

Thoracic Cage

acts as a protective framework around vital organs, including the heart, lungs, trachea, and esophagus. It also provides attachment points for many muscles supporting the pectoral girdles

What is the function of the axial skeleton?

To form a framework that supports and protects the organs. The axial skeleton also houses special sense organs (the organs for hearing, balance, taste, smell, and vision) and provides areas for the attachment of skeletal muscles

Are most of the bones of the skull formed by endochondral or intramembranous ossification?

Intramembranous

What is the term for joints in the skull?

Sutures

What is a fontanelle? Why are these present in the fetus and infant?

A fibrous membrane remnants that are not yet ossified. To ease the babies passage.

What are the functions of the cranial bones?

Surround and enclose the brain

What are the functions of the facial bones?

protect the entrances to the digestive and respiratory systems as well as providing attachment sites for facial muscles

What does the external acoustic meatus protect/surround?