Chapter 7: Skeletal System

Skeleton means?

dried framework

Bones have many functions including?

support, movement, mineral storage, and blood cell production

How are bones grouped?

according to shape which are long, short, flat, irregular

At the each end of the long bone with articular cartilage and other bones is what?

epiphyses

The shaft of the long bone is called what?

diaphysis

The region between the epiphysis and diaphysis is the what in the long bone?

metaphysis

In the long bone except for the articular cartilage a bone is covered by a?

periosteum

Compact bone is?

dense bone tissue in which cells are organized in osteons without spaces

Compact bone in a long bone has a continuous extracellular matrix with?

no gap

Spongy bone is?

bone that consists of bars and plates separated by irregular spaces; cancellous bone

Spongy bone in a long bone has irregular interconnecting spaces between?

bony plates called trabeculae

What is trabeculae?

branching a bony plate that seperates irregular spaces within spongy bone

Both compact and bony are?

strong and resist bending

The diaphysis contains a medullary cavity filled with?

marrow

Medullary cavity is?

cavity containing red or yellow marrow within the diaphysis of a long bone

Osteocytes are in bony chambers called?

Lacunae

Compact bone contains?

osteons held together by bone matrix

Central canals in compact bone contain blood vessels that?

nourish the cells of osteons

Perforating canals in compact bone connect?

central canals transversely and communicate with the bones surface and the medullary cavity

Diffusion from the surface of thin body plates nourishes cells of?

spongy bones

Bone functions are?

support, movement and protection

At different stages in life where does hematopoiesis occur?

yolk sac, the liver, spleen, and red bone marrow

Hematopoiesis is?

production of blood cells from dividing stem and progenitor cells

Red bone marrow houses?

developing red blood cells, white blood cells, and platelets

Inorganic salt storage: the extracellular matrix of bone tissue contains?

abundant calcium phosphate in the form of hydroxapitite

Inorganic salt storage: when blood calcium ion concentration is low osteoclasts resorb bone that releases

calcium salts

When blood calcium ion concentration is high, osteoblasts are?

stimulated to form bone tissue and store calcium salts

Bone stores small amounts of?

sodium, magnesium, potassium, and carbonate ions

Bone tissues may accumulate?

lead, radium, or strontium

Intramembranous bones are?

flat bones of the skull, clavicles, sternum, and some facial bones

Intramembranous bones develop?

sheetlike layers of embryonic connective tissue

Osteoblasts in intramembranous bones within the membranous layer form?

bone tissue

Osteoblasts surrounded by extracellular matrix are called?

osteocytes

Messenchyme outside the developing bone gives?

rise to the periosteum

Most of the bones of the skeleton are?

endochondral

Endochondral bones develop as hyaline cartilage?

bone tissue later replaces

The primary ossification center appears in the?

diaphysis

Secondary ossification centers appear in the?

epiphyses

An epiphyseal plate remains between the?

primary and secondary ossification center

An epiphyseal plate consists of layers of cells:

zone of resting cartilage

proliferating

hypertrophic

calcified cartilage

What ar ethe epiphyseal plates responsible for?

bone lengthening

Long bones continue to lengthen until?

the epiphyseal plates are ossified

Growth in bone thickness is due to what?

ossification beneath the periosteum

The action of osteoclasts form what?

medullary cavity

Homeostasis of bone tissue: osteoclasts and osteoblasts continually do what?

remodel bone

Homestasis of bone tissue: the total mass of bone?

remains nearly constant

factors that affect bone development, growth, and repair consist of?

defieciencies of vitamin A, C, or d result in adnormal bone development

Insufficient secretion of pituitary growth hormones may result in?

dwarfism

Thyroxin stimulates replacement of cartilage in the?

epiphyseal plates with bone

Male and female sex hormones promote bone formation and also?

stimulate ossification of the epiphyseal plates

True or false: physical stress stimulates bone growth?

true

Usually an adult human skeleton has but it may vary?

206 bones

Extra bones include?

sutural and sesamoid bones

The skeleton can be divided into what portions?

axial and appendicular

The axial skeleton consists of?

skull, hyoid bone, vertebral column, and throacic cage

The appendicular skeleton consist of?

pectoral girdle, upper limbs, pelvic girdle, and lower limbs

The skull consist of how many bones?

20 includes 8 cranial 14 facial

Cranium encloses and protects the?

brain and provides attachments for muscles

Some cranial bones contain air filled parnasal sinuses that help?

reduce the weight of the skull

Cranial bones include the?

frontal bone, parietal, occipital, temporal, sphenoid, ethmoid

Facial bones form?

basic shape of the face and provide attachments for muscles

Facial bones include the?

maxillae, palatine, zygomatic, lacrimal, nasal, vomer, inferior nasal conchae, and mandible

Infantile skull incomplete?

developed bones connected by fontanels

Infantile skull bones are thin and somewhat?

flexible and less easily fractured

The vertebral column extends from the?

skull to the pelvis and protects the spinal cord

The vertebrae is seperated by?

intervertebral discs

The vertebral column has four curvatures?

cervical, thoracic, lumbar, and sacral

A typical vertebra consists of a?

body, pedicles, laminae, spinous process, transverse process, superior and inferior articular process

Notches on the upper and lower surfaces of the pedicles on adjacent vertebrae forms?

intervertebral formanina through which spinal nerves pass

Cervical vertebrae comprise the?

bones of the neck

Transverse processess have?

transverse foramina

The atlas (first vertebra) supports?

head

The dens of the axis (second vertebra) provides a pivot for the?

atlas- allows the head to turn from side to side

Thoracic vertebrae are larger than?

cervical vertebrae

Thoracic vertebrae their transverse process project?

posteriorly at sharp angles

Thoracic vertebrae their long spinous process slope?

downward and facets on the side of the vertebral bodies articulate with the head of the ribs

Vertebral bodies of lumbar vertebrae are?

long and strong

Lumbar vertebrae their processess project?

laterally and their spinous processess project posteriorly nearly horizontally

The sacrum formed of?

5 fused vertebrae it is a triangular structure that has rows of dorsal sacral foramina

The sacrum is united wit the?

hip bones at the sacroiliac joint

The sacral promontory provides a guide?

determines the size of the pelvis

The coccyx is composed of?

4 fused vertebrae and forms the lower part of the vertebral column

Coccyx acts as a shock absorber when a person sits and it is also?

an attachments for muscles of the pelvic floor

The thoracic cage includes the?

ribs, throracic vertebrae, sternum, and costal cartilages that attach to the ribs to the sternum

The throacic cage supports the?

pectoral girdle and upper limbs, protects viscera, and function in breathing

How many pairs of ribs are attached to the twelve thoracic vertebrae?

12

Costal cartilages of the true ribs join the?

sternum directly and false ribs join indirectly or not at all

A typical rib has a?

shaft, head, and tubercles that articulate with the thoracic vertebrae

The sternum consists of?

manubrium, body, and xiphoid process

What articulates with costal cartilages of the ribs and the clavicles?

the sternum

The pectoral girdle is composed of?

2 clavicles and 2 scapulae

Pectoral girdle forms an incomplete ring that supports?

upper limbs and provides attachments for muscles that move the upper limbs

Each clavicle is a rodlike bone that?

runs horizontally betwn the sternum and shoulder

Each scapula is broad, triangular bone with a?

body, spine, acromion process, coracoid process, glenoid cavity, supraspinous and infraspinous fossa, superior border, axillary border, and vertebral border

The scapula each articulates with the?

humerus of each upper limb and provides attachments for muscle of the upper limb and chest

Bones of the upper limb provide?

the framework for the limb and provide the attachments for muscles that move the limb

the humerus extents from?

scapula to the elbow

What consists of the humerus?

head, greater tubercle, lesser tubercle, intetubecular sulcus, anatomical neck, surgical neck, deltoid tuberosity, capitulum, trochlea, epicondyles, coronoid fossa, and olecranon fossa

The radius is on the?

thumb side of the forarm between te elbow and wrist

The radius consist of?

head, radial turberosity, styloid process, and ulnar notch