Quiz 1 Flashcards
Bone is both
Tissue and an organ
A specific type of biological tissue with its own unique chemical and molecular structure
Bone
5 Types of stimuli that bone responds to
- Bio-mechanical
- Nutritional
- Degeneration
- Disease
- Trauma
4 Descriptive types of bone (organ)
- Tubular
- Flat
- Irregular
- Sesamoid
Description of tubular bones
-Provides structural support
-Weight bearing
-Muscles attachment sites
Examples of Tubular bones
Arms, legs, clavicle (long bones)
Hand, feet (short bones)
Description of flat bones
Cover and protect vital organs, muscle attachment sites
Examples of flat bones
-Most bones of the skull
-Illium (pelvic blade)
-Sternum
-Ribs
-Scapula
Examples of irregular bones
-Tarsal (ankle)
-Carpal (wrist)
-Vertebrae
-Ear ossicles
-Pubis and ischium
Sesamoid bones are
Embedded in tendons
Examples of sesamoid bones
-Patella
-Pisiform
n
n
In individuals, bone(s) exhibit _____, _____, _____, _____ variation
- Sexual
- Orthogenetic (growth)
- Idiosyncratic (individual)
- Population
Bones provide _____ support for soft tissues
structural
Vital organs that are protected by bones
-Brain
-Spinal chord
-Heart/lungs
-Reproductive organs
Physiological roles of bone (2)
-Red blood cell production
-Storage of fat reserves
Number of individual bones at birth
270
Number of individual bones as an adult
206
Last bone to fuse
Clavicle at 25 yrs of age
The earliest bone to fully form
Ear ossicles
The bone that is fully formed and adult size at birth
Ear ossicles
The skeleton can be divided into two parts
- Skull
- Post-cranial skeleton
Skull bones includes
hyoid and mandible
Axial skeleton is
the trunk
Bones in the axial skeleton
Ribs, sternum, vertebrae, pelvis
The appendicular skeleton is
limbs
Bones in the appendicular skeleton
Clavicle, scapula, upper and lower limbs
Description of anatomical position
-Standing
-Looking forward
-Feet together and pointing forward
-Arms alongside
-Palms facing forward
-Thumbs facing away
Lateral surface of the ____ teeth is in contact with adjacent teeth but faces the cheek in posterior teeth
anterior
Internal surface of the anterior teeth faces _____ but _____ in posterior teeth
posteriorly, medially
Closest plane that shows how the cranium is set during everyday life, approximately parallel to the ground surface when walking
Frankfort horizontal
Accomplished by muscles acting directly or via tendons on bones, movement generally occurs at joints between bones
Motions of the body
Bending movement that decreases the angle between body parts
Flexion
A straightening movement that increases the angle between body parts
Extenstion
Flexion of the anterior part of the foot
Dorsiflexion
Flexing of anterior part of the foot interiorly
Plantarflexion
Movement away from the sagittal plane
Abduction
Movement usually of a limb toward the sagittal plane
Adduction
A combination of abduction and adduction as well as flexion and extension, that results in an appendage being moved in a cone-shaped path
Circumduction
Rotary movement of the forearm that turns the palm form anteriorly facing (thumb lateral) to posteriorly facing (thumb medial)
Pronation
Rotary motion of the forearm that returns the palm to a position in which the thumb is lateral
Supination
Bone is a unique combination of
Organic and inorganic components
Two levels of study of bone biology are
- Macroscopic
- Microscopic
Macroscopic is
gross morphological features
Microscopic is
Histology, study of tissues
Two levels of histology
- Cellular
- Molecular
All bone in the adult skeleton is found in two basic configurations is
Compact (cortical) bone and Cancellous (trabecular) bone
Very dense, seemingly solid bone, found on the outer surface of all bones
Compact (cortical) bone
Where is compact bone concentrated on long and short bones?
On the walls of shafts
Variant of compact bone, found at joints, covered in cartilage during life; lacks osteon and Haversian system
Subchondral bone
Spongy bone that is more porous, honeycomb-like structure
Cancellous (trabecular) bones
Formed by bony columns (trabeculae) separated by large spaces
Cancellous (trabecular) bone
Under joint surfaces, at ends of tubular bones, inside flat bones (skull), inside vertebral bodies, at insertion sites for large tendons
Cancellous (trabecular) bone
The only difference between cancellous and compact bone
Porosity and distribution
Tubular bones are described according to
their centers of ossification
Components of tubular bones:
- Diaphysis
- Epiphysis
- Metaphysis
Main portion of tubular bone, primary ossification center of the bone, shaft
Diaphysis
Ends, form joint surfaces, secondary ossification center of the bone
Epiphysis
Expanded, flared ends of the shafts, site of growth plates and fusion of diaphysis and epiphysis; forces acting on surface of tubular bones
Metaphysis
Hollow tube with thick walls, good as a solid cylinder for resistance and weight bearing, thicker cortical walls and stronger cylinder
Diaphysis
Joint surfaces, forces applied over a broad surface and in variable directions, larger joint surfaces = transmission of greater forces through joints
Epiphysis
More economical in transmitting and resisting stress, a force acting upon internal aspect of tubular bones
Trabeculae
Law of bone formation that is dynamic, highly vascularized living tissue, capable of changing shape during lifetime (remodeling)
Wolff’s Law
Production of red blood cells
Hematopoiesis
At birth all marrow is
red (hematopoietic) marrow
During growth some red marrow is
replaced with yellow (fatty) marrow
In adults, hemopoetic marrow remains in
Flat bones and epiphyses of tubular bones
Connections between bony elements are
joints
__________ is a series of bony levers operated by muscles
Musculoskeletal system
Where do bones articulate with each other?
At the joints
Bones are connected to each other with
cartilage and ligaments
Movement at joints is limited by
Shape of the articular surfaces and strength of attachment ligaments
Three main categories of joints:
- Synovial
- Cartilaginous
- Fibrous
Freely moving joints, joined by hyaline cartilage, most joints in the body are made of these
Synovial joints
Area between adjacent bones (joint cavity) of synovial joints is lined by
A membrane that secretes a lubricant (synovial fluids)
_______ nourishes cartilage and is surrounded by a fibrous joint capsule made of connective tissue
Synovial fluid
Joint with very little movement possible aka synchondroses, no joint capsule, joined entirely by cartilage, found at epiphyseal growth plate in tubular bones
Cartilaginous joints
Some cartilaginous joints persist into adulthood like
those between the ribs and sternum
Cartilaginous joints are found in
the pelvis; at the pubic symphysis (anterior) and the sacro-illiac joint (posterior
Intervertebral discs in the spine are comprised of
Cartilaginous joints
Joints with no movement possible aka syndesmoses
Fibrous joints
Fibrous joints have
no joint capsule and no cartilage
Fibrous joints are joined by
tough, dense fibrous bands of tissue in the form of membranes or ligaments
Where are fibrous joints found
-Distal fibula/tibia
-Interosseous membrane between radius and ulna
-Cranial sutures: Interlocking joints with very thin layer of fibrous tissue
Most important tissue
Bone
A dense, flexible connective tissue, very similar to bone
Cartilage
______ is mainly made up of collagen but a higher percentage of other proteins and water, an organic matrix, not mineralized
Cartilage
Surface layer of cartilage
Vascularized perichondrium
The way cartilage is different from bone: (3)
-More flexible
-Less rigid and stiff
-Fewer blood vessels (less vascularized)
3 Main types of Cartilage
- Hyaline
- Fibrous
- Elastic
Articular cartilage in joints, costal cartilage associated with ribs, structure of the larynx and trachea. Found mainly in synovial (more mobile) and some cartilaginous (less mobile) joints
Hyaline cartilage
Used to stabilize joints in vertebral column and pelvis, found in cartilaginous (less mobile) joints
Fibrous cartilage
Very flexible, not associated with joints, found in nasal septum, external ear, Eustachian tubes, epiglottis (soft palate)
Elastic cartilage
-Movement mainly occurs at synovial joints
-Muscles contract across joints between bones
-Pull bone surfaces in certain directions
-Most muscles attached to two bones (but some attach to more than two)
-Muscles are connected to the bones via tendons
Description of Tendons: (5)
Why are ligaments and tendons similar
-Structurally similar
-Both consist of bands of tough collagen fibers
Attach bone to bone and form part of the joint
Ligaments
Attach muscles to bones and do not form part of the joint
Tendons
Outer surface of bones (except articular surfaces) covered by a tough, vascularized (lots of blood vessels) membrane; surrounding bone
Periosteum
Some periosteal fibers penetrate bone layers (Sharpey’s) to adhere
the periosteum to the bone surface
Periosteum also intertwines with ______ and ______ to anchor muscles to bones or bones to each other
tendons and ligaments
Thinner, less defined membrane of the inner bone surface
Endosteum
Endosteum is the
connective tissue between medullary canal and internal bone surface
Osteoid is an
organic (unmineralized) matrix
90% of the organic matrix is made of
collagen
________ molecules intertwine to form flexible, slightly elastic fibers
collagen
The mineral matrix is called
Hydroxyapatite
Hydroxyapatite crystals impregnate collagen fibers which
provides stiffness and strength
Organic and inorganic matrices cemented together by protein-sugar compounds (protein polysaccharides)
Bone matrix (bone tissue)
Description of bones
- Stiff
- Rigid
- Elastic
Bone is stiff and a
large force needed to permanently distort it
Bone is rigid and is
equally resistant to both compressive and tensile forces
Bone is elastic and
Gives then slowly reverts back to original shape
Bone is stronger than
oak and granite
The two histological types of mammalian bone
- immature (woven) bone
- Mature (lamellar) bone
-The first kind of bone to develop in utero
-Replaced with mature bone
-Characterizes fetal skeleton, sites of injury (fracture repair), sites of bone tumors
-Forms rapidly, higher proportion of osteocytes
-Collagen fibers arrange in a non-oriented random pattern
Immature (woven) bone
Impregnated collagen fibers are arranged in concentric layers
Mature (lamellar) bone
Thin layer near bone surface below periosteum
Circumferential lamellar bone
Organized structure of ________ produced by the repeated addition of uniform lamellae to bone surfaces during appositional growth
lamellar bone
Cross-section of tubular bone (e.g. tibia) reveals the structure of
compact bone (Haversian)
The cross section of the Haversian system/structure of compact bone looks like
An end-view of a pile of tree trunks, each trunk is a Haversian system
_________ is a cross-section of each trunk shows 4-8 concentric layers (like the tree rings)
Haversian lamellae
Compact bone is comprised of
tightly bound lamellar Haversian systems
_____ canal in the center, contains blood vessels and nerves and provides blood flow to bone as it remodels and thickens
Haversian
________ run obliquely between Haversian systems that bring blood supply from bone surface
Volkmann’s canals
Microscopic cavities within the Haversian system
Lacunae
Lacunae contain living bone cells
Osteocytes
Lacunae are interconnected by minute, fluid filled channels
Canaliculi
Canaliculi ultimately connect to Haversian canal and allow for flow of nutrients and minerals between ____________
osteocytes within the Haversian system
Compact bone is dense bone that cannot be nourished by
diffusion from surface blood vessels
Compact bone requires
a Haversian system for sustenance
_____ bone is more porous and receives blood supply from blood vessels in surrounding marrow spaced, lacks Haversian system
Trabecular
Types of bone (3)
- Cancellous (ends of tubular bones)
- Cortical (shafts of tubular bones)
- Subchondral (joint surfaces)
Bone growth
Osteogenesis
All bone growth occurs through a process of
bone deposition on a pre-existing surface
Bone always develops by replacement of a
pre-existing connective tissue
Growth process of bone (3)
-Skeleton increases dramatically
-Osteocytes (bone cells) do not divide unlike other cells in the body
-Bone matrix calcifies (hardens) soon after it is produced, so bone tissue cannot expand from within
Two main patterns of ossification in the skeleton
- Endochondral ossification
- Intramembranous ossification
Type of ossification that is layed down in membranes, no cartilage involved, occurs in most skull bones (except cranial base) and clavicle
Intramembranous ossification
Woven bone is laid down via
intramembranous ossification
Osteogenesis is the mechanism used in both
Endochondral and intramembranous bone
The blood vessel penetrates the bone at the
nutrient foramen
Growth radiates from the site on initial penetration which is
nutrient foramen
Most of the osteoprogenitor cells are
osteoblasts
Single nucleus cells that synthesize the remaining parts of pre-bone matrix osteoid
Osteoblasts
Osteoblasts synthesize
protein polysaccharides and an enzyme called pyrophosphatase
Pyrophosphatase “eats” pyrophosphate which is the inhibitor that holds
calcium in suspension in bodily fluids, especially blood
Calcium now falls out of solution and joins with collagen which is
already present in cartilage
Calcification (ossification) of bone occurs as crystals of
hydroxyapatite (inorganic component) are deposited into the pre-bone matrix (osteoid)
As ossification proceeds the ______ becomes trapped in the (now bony) matrix
Osteoblast
______ (bone cells) that live in the lacunae (spaces) within the Haversian lamellae
Osteocytes
Osteocytes are supplied by blood vessel in Haversian cancal via
canaliculi
Osteocytes are responsible for
maintaining bone tissue
removing bone
osteoclasts
making new bone
osteoblasts
Allows shaft diameters to enlarge during development
appositional growth
Living bone cells, former osteoblasts
osteocytes
_____ and ______ occurs through coordinated action of osteoclasts and osteoblasts
Bone growth and remodeling
Located between the metaphysis (primary center of ossification) and the epiphysis (secondary center of ossification)
Cartilaginous epiphyseal growth plate
Cartilage is replaced by bone on the
diaphysial side of the growth plate
First bone to ossify
Clavicle followed by the mandible and cranial vault
Deposition on the periosteal (ectocranial) surface and at sutures, resorbtion on endosteal (endocranial) surface
Cranial growth
Six areas of membrane between ossification centers, “soft spots”
Fontanelles
All fontanelles close
around birth (except for the bregmatic fontanelle (which fuses at 3-4 yrs old)
Can get a pretty good idea of age when someone is under 30 due to
Epiphyseal fusion
___________ regulates calcium and other concentrations in the body
mineral physiology of the bones
Cells (esp. nerve and muscle) function properly only if bathed in the proper concentration of _______
Calcium (9-11 mg per 100 cm3)
Low mineral density
Osteopenia
Osteopenia can lead to
osteoporosis
Osteoporosis is most common in
Post-menopausal people and people over the age of 60
Osteoporosis is common in what 3 bones (and what part of them)?
Proximal Femur
Distal radius
Vertebrae
