A&P TEST II

What are the functions of skeleton system?

Provide structural support and point of attachment for tendons and ligaments

Protect internal organs

Assist body movements

Store and release salts and calcium and phosphorus

Participate in blood cell production

Store triglycerides in adipose cells of yellow marrow

Is bone vascularized?

Yes, highly. With a hard extracellular matrix.

What are the two types of bone?

Compact and spongey

What are the tissues of the skeletal system?

Bone and cartilage, which are associated with ligaments, tendons, and joints.

Is bone dynamic?

Yes. It is always remodeling (building up and breaking down).

What is compact bone good for?

Providing protection and support.

Strongest.

It makes up the diaphysis of the long bones,

Makes up external layer of all bones.

What is the spongey bone good for?

Lightweight and provides tissue support

Also called trabecular or cancellous bone

Forms epiphysis and medullary cavity

What are the bone cells?

Osteoprogenitor cells: stem cells which differentiate into other types

Osteoblasts: bone building, synthesize and secrete collagen

Osteocytes: mature osteoblasts (maintenance)

Osteoclasts: remodel bones and cause them to release calcium; bone resorption

What other tissues does the skeletal system consist of?

Endothelium form capillary walls

nerves

red marrow (hematopoiesis)

yellow marrow (fat storage)

What is the chemical constituent of bone?

25% water, 25% organic proteins, 50% mineral salts (hydroxyapatite crystals).

Organic constitutions include collagen fibers which provide flexibility, tensile, and strength

Inorganic hydroxyapatite crystals are calcium phosphate, calcium carbonate, and other trace elements of magnesium, fluoride, and sulfate

What is the structure of the long bone?

Diaphysis (shaft)

2 epiphysis (both ends)

2 metaphases/growth plates (between diaphysis and epiphysis)

Articular/hyaline cartilage covering epiphyses

Periosteum (connective tissue surrounding diaphysis)

Medullary cavity (hollow space within diaphysis)

Endosteum (thin membrane lining medullary cavity)

What is the medullary cavity of the bone?

Space within the diaphysis which contains fatty yellow bone marrow in adults.

The endosteum lines the medullary cavity and is composed of dense irregular connective tissue and contains osteoclasts and osteoblasts

What is the articular cartilage of the bone?

Thin layer of hyaline cartilage covering the epiphysis of long bones.

Found where bone forms an articular (joint) surface - one bone moves against another

What is the growth called for bone thickness?

Appositional growth

What is the perichondrium?

Dense irregular CT that surrounds cartilage.

Chondrocytes are cells that form cartilage.

What is the periosteum?

Tough sheath of dense irregular CT.

Contains osteoblasts

Assists with fracture repair and serves as an attachment point for tendons and ligaments

What is the epiphyseal line/growth plate?

Growth plate is hyaline cartilage which actively divides and causes bone to elongate.

Growth plate turns into epiphyseal line in adulthood (calcified)

What is the histology of compact bone?

Units of osteons or Haversian systems forming concentric lamellae.

Interstitial lamellae are between osteons which are leftover fragments of old osteons

Outer circumferential lamellae encircle bone beneath periosteum

Inner circumferential lamellae encircle medullary cavity

Lacunae are small spaces between lamellae which house osteocytes

Canaliculi are small channels filled with extracellular fluid counting lacunae

Blood and lymphatic vessels are found in central canal/haversian

Volkmann’s canal allow transit of vessels to outer cortex of bone

What does spongy bone have instead of osteons?

Trabecular.

Offer support and protect red bone marrow and oriented along lines of stress (resist breaking)

Lacunae are located in each trabecular which contain the osteocytes to nourish mature bone tissue

What is the interior of long bones primarily made up of?

Spongy bone

What makes up blood supply of bone?

Periosteal arteries enter diaphysis through Volkmann’s canal and are accompanied by periosteal veins

Nutrient arteries enter the center of diaphysis through nutrient foramen. Exist via same canal

Nerves accompany blood vessels (periosteum is rich in nerves)

What is formation of bone tissue?

Ossification or osteogenesis.

When does ossification occur?

Formation of bone in embryo

Growth of bones until adulthood

Remodeling of bone

Repair of fractures

What are the two methods of ossification?

Intra-membraneous ossification produces spongy bone. It may be remodeled to form compact bone

Endochondral ossification is process whereby cartilage is replaced by bone. Forms both compact and spongey.

What bones use intra-membraneous ossification?

All bones of skull and clavicle

Which is the primary method of ossification?

Endochondral ossification

What are the zones/layers of the epiphyseal growth plate?

1. Zone of resting cartilage which are scattered chondrocytes that do not function for bone growth

2. Zone of proliferating cartilage are larger chondrocytes which undergo interstitial growth as they divide and secrete extracellular matrix

3. Zone of hypertrophic cartilage which is chondrocytes in columns

4. Zone of calcified cartilage is lysis of chondrocytes and osteoblasts lay down matrix. This zone becomes new diaphysis.

Does the epiphysis ever increase in length?

No

What is growth in length?

Interstitial

Define bone deposition

Addition of minerals and collagen fibers to bone by osteoblasts

What is bone resorption

Removal of minerals and collagen fibers from bone by osteoclasts.

What causes Acromegaly?

New tissue formed due to excessive growth hormone after growth plate is closed

What causes Gigantism?

New tissue rapidly formed before closing of the growth plate due to excessive growth hormone

What hormone is responsible for growth of growth plate?

Growth hormone

What is osteomalacia?

Vitamin D deficiency causes soft bones.

Its called rickets in children.

Vitamin factors of bone growth

Vitamin A: stimulates osteoblasts

Vitamin C: synthesis of collagen

Vitamin D: promotes abosprtion of calcium

Vitamins K and B12 are needed for synthesis of bone proteins

Hormones affecting bone growth:

Human Growth Hormone (hGH): Secreted by the anterior lobe of the pituitary gland; promotes general growth of all body tissues, including bone by stimulating insulin growth factors

Insulin Growth Factors (IGFs): Secreted by liver, bones, and other tissues on the stimulation by growth hormone; promotes normal bone growth by stimulating osteoblasts and by increasing the synthesis of proteins needed to build new bone

Thyroid hormones: Secreted by thyroid gland; promote normal bone growth by stimulating osteoblasts

Insulin secreted by pancreas; promotes normal bone growth b increasing synthesis of bone proteins

Parathyroid Hormone (PTH): secreted by parathyroid glands and promotes resorption of osteoclasts and enhances recovery of calcium ions from urine. Promotes formation of Vitamin D.

Calcitonin (Thyrocalcitonin): Secreted by thyroid gland and inhibits bone resorption of osteoclasts.

Sex hormones of bone growth:

Estrogen secreted by women and testosterone by men

Stimulates osteoblasts and promote growth spurt in teenage years

Shown down growth when 18-21

Contribute to bone remodeling during adulthood

What contributes to calcium homeostasis?

PTH stimulates osteoclastic and raises calcium level

Calcitonin and hGH (lesser extent) stimulate osteoblastic activity and lower serum calcium level

Vitamin D is needed for absorption of Ca and PO4 ions from small intestine and reabsorption of those same ions in kidneys

What is the bone’s role in calcium homeostasis?

Bone stores 99% of calcium. PTH is secreted when calcium levels drop, which stimulates osteoclasts to increase bone resorption and calcium is released. PTH also stimulates calcitriol production in kidneys to increase calcium absorption.

What is a complete fracture?

Fracture all the way through bone

What is closed fracture?

Simple

What is open fracture?

Fracture punctures skin

What is green stick fracture?

Small linear break in bone cortex

What is impacted fracture?

One part is shoved up into another

What is comminuted fracture?

Multiple fragments due to crash injury

What is the healing process of fractures?

Reactive phase is early inflammatory phase

Reparative phase includes formation of fibrocartilaginous callus first and a bony callus second

Bone remodeling phase is last step as the bony callus is remodeled

What is the axial skeleton?

Skull, auditory ossicles, hyoid bone, ribs, sternum, bones of vertebral column

What is the appendicular skeleton?

The bones of the upper and lower limbs and bones forming pectoral and pelvic girdles that connect the limbs to the axial skeleton

What is long bone?

Long bones

What is short bone?

Short and cube shaped (wrist and ankle)

What is flat bone?

Thin layers of parallel plates (skull/sternum/scapulae)

What is irregular bone?

Complex shapes (vertebra)

What is sesamoid bone?

Sesame seed shaped (patella)

What are sutural bones?

Also known as Wormian. They are the cranial bones.

What do depressions and openings in bone do?

Form joints and allow passage of blood vessels and nerves

What is condyle process and example?

Projections or outgrowths that form joints and serve as attachment points for ligaments and tendons

Ex. Lateral condyle of femur

What is a fissure and an example?

Narrow slit between adjacent parts of bones where blood vessels or nerves pass.

An example is superior orbital fissure of sphenoid bone

What is a foramen and example?

Opening for blood vessels, nerves, or ligaments.

Ex. Optic canal of sphenoid bone

What is fossa and example?

Shallow depression.

Ex. Coronoid fossa of humerus

What is sulcus and example?

Furrow along bone surface that accommodates blood vessel, nerve, or tendon?

Ex. inter tubercular sulcus of humerus

What is meatus and example?

Tubelike opening.

Ex. External acoustic meatus of temporal bone

What is facet process and example?

Smooth, flat slightly concave or convex articular surface.

Ex. Superior articular facet of vertebra

What is head process and example?

Rounded articular projection supported on neck of bone

Ex. head of femur

What is crest process and example?

Ridge or elongated projection.

Ex. Iliac rest of hip bone

Epicondyle process and example?

Roughened projection above condyle.

Ex. Medial epicondyle of femur

Line process and example?

Long narrow ridge or border

Ex. Linea aspera of femur

Spinous process and example?

Sharp, slender projection

Ex. spinous process of vertebra

Trochanter process and example?

Large projection

Ex. Greater trochanter of femur

Tubercle process and example?

Greater tubercle of humerus

Tuberosity process and example?

Variably sized projection with rough, bumpy surface

Ex. Ischial tuberosity of hip bone

How many bones are in axial skeleton?

80

Two categories of skull bones?

Cranial (8) and facial bones (14)

What is a suture in the skull?

A “seam” or immovable joint between bones of the skull

What are fontanels?

They are found in babies and are unossified mesenchyme filled spaces between cranial bones.

They ossify between 19-24 months and become sutural joints

Allow expansion of brain after birth and easy birth of baby

What are paranasal sinuses?

Prominent features of frontal, ethmoid, sphenoid, and maxillary bones

Lined with mucuous membrane that humidify and warm air

Reduce weight of skull

Help resonate sound of our voice

What is temporomandibular joint dysfunction

Dull pain around ear, tender jaw muscles, clicking noise with mouth

Caused by improperly aligned teeth, grinding of teeth, trauma to the head, arthritis

Treatment includes moist heat or ice, soft foods and pain relievers

Function of hyoid bone

Supports tongue and provides attachment for muscles of neck and pharynx

Does not articulate with any other bone

How many bones and regions in the vertebral column?

26 vertebrae and 5 regions

Are the cervical and lumbar curves convex or concave?

Convex

Are the thoracic and sacral curves convex or concave?

Concave

What cartilage makes up intervertebral disc

Fibrocartilage

What does spinal cord travel through

Vertebral foramen?

Characteristics of cervical vertebrae?

C1 is atlas and holds up head

C2 is Axis because it allows head to pivot

Characteristics of thoracic vertebra

12 vertebrae form thoracic cage

Characteristics of lumbar vertebra

Largest and strongest

No special structures

Anatomy of vertebrae

Consist of a body (weight bearing) and vertebral arch (pedicle and laminate).

Several processes (attachments for muscle)

Function of thoracic cage

Enclose and protect organs in the thoracic and abdominal cavities

Play a role in breathing and supports bones of upper limbs

Markings of Thorax

True ribs (upper 7 - attach to sternum)

False ribs (bottom 5 8th to 12)

Floating ribs (11th and 12th pairs - do not attach)

What are costal cartilages?

Hyaline cartilage connecting sternum to the ribs

What is scoliosis

Increased lateral curve

What is kyphosis

Increased thoracic curve

What is lordosis

Increased lumbar curve

What is spina bifida

Laminae of vertebral column did not develop normally

Where do fractures of vertebral column most often occur?

C1, C2, C4-T, and T12-L2.

What are bones held together by dense collagen?

Fibrous

What are bones held together by cartilage

Cartilaginous

What are joints held together by ligaments?

Synovial

What is an immovable joint?

Synarthrosis

What is a SLIGHTLY moveable joint?

Amiphiarthrosis