Uark Human Anatomy Becker Exam 2

Parts of the Skeletal System

Skeleton, Cartilage, Ligaments

Axial Skeleton

Skull, spine, thoracic cage

Appendicular Skeleton

Limbs, pectoral girdle, pelvic girdle

Functions of the Skeletal System

1. Support

2. Movement/Locomotion

3. Storage of Ca and P04

4. Blood Cell Production

5. Protection

What Makes Up Osseous Tissue?

-Matrix of Bone

-Collagen fibers

-Bone Cells

Matrix of Bone consists of:

- hydroxyapatite crystals (Calcium Phosphate and Calcium Hydroxide)

- Enables bone to resists compression

- 2/3 of bone mass

Collagen Fibers:

- makes up 1/3 of bone mass

- gives bone tensile strength

Bone Cells (Osteocytes and other cells)

account for 2% of bone mass

Osteocyte

mature bone cell that maintains the bone matrix

Osteoprogenitor cell

Stem cell that divides to produce osteoblasts

Osteoblast

Immature bone cell that secretes osteoid, the organic bone matrix

Osteoclast

multinucleate cell that secretes acid and enzymes to dissolve bone matrix

Osseous Tissue Types

compact bone and spongy bone

Compact bone

-dense and solid

-forms walls of bone

-resists parallel compression

Spongy bone

-surrounds medullary cavity

-resist multi directional or light strain

-open network of struts and plates

Epiphysis

ends of long bones

Diaphysis

shaft of long bones

Metaphysis

transition between epiphysis and diaphysis

Periosteum

superficial layer of compact bone, everywhere besides within a joint, multi cell layer

Functions of Periosteum

- Isolates and protects bone from surrounding

- Attachment for circulatory and nervous supply

- Bone growth and repair

- Attachment site for tendons and ligaments

Endosteum

inside bone, lines the medullary cavity, perforating canal, and central canal

Both the Endosteum and Periosteum have:

- Osteoblast: produces matrix

- Osteoprogenitor cells: produce osteoblasts

- Osteoclast: breakdown matrix

Appositional growth

- Osteoblasts in periosteum add bone to matrix to surface.

- Forming circumferential lamellae on out surface

- Osteons are formed

- Osteoclasts break down layer below endosteum to enlarge medullary cavity

Why do bones change shape?

Bones change shape in response to strain

Factors regulating bone growth

- Minerals

- Vitamins

Minerals affecting bone growth

calcium, phosphate, magnesium, citrate, carbonate, sodium

Vitamins affecting bone growth

A: stimulates osteoblasts

C: collagen formation and osteoblast differentiation

D: used for increase in Ca and PO4 absorption in kidneys

What do hormones do?

work to regulate plasma Ca 2+ levels

Thyroxine and Growth hormone

- influence basal metabolic rate of bone cells

- maintain activity in epiphyseal region for growth

estrogen and testosterone

-stimulate osteoblast activity causing growth spurts during puberty

-maintain bone density in adults

Parathyroid Hormones

- stimulate osteoclast

Calcitonin (produced by thyroid gland)

- inhibits osteoclasts

- decreases circulation Ca2+

Osteoporosis

a bone disease that weakens bones and causes them to likely break

Sutural Bone

found in-between flat bones, small, flat, oddly shaped.

Pneumatized

hollow and contain numerous air pockets

ex. ethmoid bone

Short bones

external surface are covered by compact bone

ex. carpal bones

Irregular bones

complex shapes with short, flat, notched, or ridged surfaces

ex. vertebra

Flat bones

thin, roughly parallel surfaces of compact bone

ex. parietal bone

Long bone

long and slender bones

ex. humerus, femur, tibia, radius, ulna

Sesamoid bone

round, small, and flat

ex. patella

intramembranous ossification

process of creating bone from connective tissue, without going through a cartilage stage

Endochondral Ossification

process of bone formation from a pre-existing cartilage model

Steps of intramembranous ossification

1. Mesenchymal cells multiply and condense into a nodule.

2. A membrane surrounds the nodule.

3. Osteoprogenitor cells change into osteoblasts.

4. Osteoblasts line the nodule and secrete an extracellular matrix (ECM).

5. Woven bone forms.

6. Woven bone is remodeled and replaced by mature lamellar bone.

Steps of endochondral ossification

1. Formation of Cartilage model

2. Calcification of Cartilage

3. Formation of Bone Collar

4. Development of Primary Ossification Center

5. Formation of Medullary Cavity

6. Formation of Secondary Ossification Centers

7. Epiphyseal Plate Formation

8. Maturation and Remodeling

Functions of the Axial Skeleton

- Houses Central Nervous System (CNS)

- House senses

- Allows for sound production and communication

- Feeding

- Breathing

- Attachment points for appendicular system

throatic cage

-Ribs

-Sternum

-Thoracic vertebrae

-Costal Cartilage

Suture

dense fibrous connective tissue

Sinuses

- produces mucus

- Resonate sound

- Lighten skull

- Humidifies air

What are joints?

where 2 bones meet made up of fluid, cartilage, or fibrous tissue

Synarthrosis Joints

no movement

types of synarthrosis joints

fibrous, cartilaginous, bony fusion

fibrous synarthrosis

two or more bones are held together by a thin layer of dense, fibrous connective tissue (Sutures - skulls and Periodontal ligaments - tooth)

Cartilaginous synarthrosis

diaphysis and epiphyseal ends are bound together by an epiphyseal cartilage (sternum)

Bony Fusion synarthrosis

joint where boundary between them disappears making a longer bone (frontal bone)

Amphiarthrosis

some movement

fibrous amphiarthrosis

bones connected by collagen fibers

ex. between tibia and fibula, fibula and talus

Cartilaginous amphiarthrosis

bones connected by fibrous cartilage

ex. pubic symphysis and intervertebral discs

Diarthrosis (synovial)

free movement

synovial joints

- are covered by articular cartilages and therefore are not in direct contact with one another.

- help reduce friction within the joint

Synovial Fluid functions

- Lubrication and friction reduction

- Nutrient distribution

- Shock absorption

Ligaments

fibrous bands of tissue that connect bones or organs together. They are made of collagen, elastic fibers, and connective tissue.

Tendons

a fibrous connective tissue connecting bone to muscle allowing for movement by transmitting the force of muscle contraction to the skeletal system

Bursae

small, fluid-filled pockets in connective tissue that reduce friction and act as shock absorbers.

Strength vs Mobility in Joints

the more mobile a joint is then the weaker it is, stronger joints permits less movement

Abduction

is movement away from the longitudinal axis of the body in the frontal plane. (thing moving away from the body)

Adduction

towards the body

Flexion

is movement in the anterior-posterior plane that decreases the angle between the bones of the joint.

Extension

increases the angle between the bones of the joint

hyperextension

any movement in which a limb is extended beyond its normal limits, resulting in joint damage

circumduction

involves moving the arm in a circle, as when drawing a large circle on a chalkboard in one continuous motion

Rotation of head

left rotation or right rotation think shaking head

internal rotation (medial rotation)

anterior surface of the limb rotates inward, toward the anterior surface of the body

external rotation (lateral rotation)

turning outward

pronation

moves the wrist and hand from the palm-facing-front position to the palm-facing-back position.

supination

opposing movement of pronation

Special Movements

Special terms apply to specific joints or unusual types of movement

Eversion

motion of the foot that turns the sole outward

inversion

opposite of eversion

Dorsiflexion

movement of the foot towards the head, pointing foot up

Lateral flexion

the vertebral column bends to the side

Plantar flexion

pointing foot down, standing on tiptoes

Protraction

moving a part of the body anteriorly in the horizontal plane

Retraction

reverse movement of protraction

ex. returning jaw to normal position

Opposition

special movement of the thumb that produces pad-to-pad contact of the thumb with the palm or any other finger

Reposition

opposite movement that returns the thumb and fingers to their normal position

Elevation

structure moving in an inferior direction

Depression

structure moving in an superior direction

What is the orbit made of?

- frontal bone

- maxilla bone

- lacrimal bone

- ethmoid bone

- sphenoid bone

- zygomatic bone

Muscles anchored by hyoid bone

- tongue

- larynx

How many cervical vertebrae are there

7

how many thoracic vertebrae are there

12

how many lumbar vertebrae are there

5

How many sacral vertebrae are there

1

how many coccygeal vertebrae are there

1

lambdoid suture

Sagittal suture

Coronal suture

Squamous suture

Frontonasal suture

Maxilla Bone