Bio 004 Lecture Exam 2: Bone Tissue and Microanatomy Study Guide

an organ is defined as ____ tissues working together for one function

multiple

bone is composed of multiple tissues, therefore, bone can be classified as an______

organ

bone contains different types of tissues

bone (osseous) tissue
dense CT
epithelium (tissue that lines the surface)
adipose tissue (type of tissue that stores fat)
nervous tissue (type of tissue that involved in signaling)

bones

hardened structures to which muscles attach

cartilage

flexible but firm structures that reduce friction at surfaces and provide some structure stability

ligaments

attach two bones or cartilages or hold together a joint

tendons

attach muscles to bones or other structures like an eyeball

osteology

the study of bone structure and the treatment of bone disorders

bone function 1

support: provides the structural framework of the body, supporting soft tissue and points of attachment for tendons

bone function 2

protection: protects internal organs such as the pelvis, ribs, spin and skull

bone function 3

assistance in movement provides a surface for muscular attachment, allowing muscles to pull on bones to produce movement

bone function 4

mineral homeostasis: involves the storage of minerals like calcium and phosphorus

bone function 5

red blood cell production: occurs in the red marrow through the process of hematopoiesis

bone function 6

triglyceride storage: stored in the yellow marrow which mainly consists of adipose cells

diaphysis

the shaft or main portion of a long bone

epiphysis

the proximal and distal ends of the long bone

metaphysis

the region between the epiphysis and the diaphysis; includes the epiphyseal plate

articular cartilage

a thin layer of hyaline cartilage covering the epiphysis where the bone forms a joint

periosteum

a tough CT sheath that covers the bone surface everywhere except where the is articular cartilage

medullary cavity

the hollow space within the diaphysis that contains yellow bone marrow

endosteum

a thin membrane that lines the medullary cavity containing bone forming cells

epiphysis region

the PROXIMAL and DISTAL ends of long bones

metaphysis region

the region between the epiphyses and the diaphysis; involved in bone growth

diaphysis

the shaft or body of the bone; main portion

articular cartilage

functions: reduce friction and shock absorption; this type of cartilage lacks perichondrium and blood vessel supply; damage will have limited repair

layers of periosteum

fibrous layer (outer layer): made of dense irregular ct
osteogenic layer (inner layer): contains cells

periosteum function 1

contains cells for bone growth in thickness; not length

periosteum function 2

protects the bone

periosteum function 3

assists in bone tissue nourishment

periosteum function 4

provides fracture repair of the bone

periosteum function 5

attachment point for ligaments and tendons

What are Sharpey's fibers?

thick bundles of collagen that connect the periosteum to the bone

medullary cavity

contains: fat, marrow and blood vessels
functions: minimizes the weight of the bone by reducing dense bony material where it is least needed, providing maximum strength with minimum weight

what are the 2 types of bone marrow?

red bone marrow for hematopoiesis; yellow bone marrow for fat

what are the components of the endosteum

single layer of bone forming cells
a small amount of CT

Bone tissue

the extracellular matrix (ECM) is an abundant matrix that surrounds widely separated cells

components of ECM

water-15%
collagen fibers-30%
crystallized mineral salts (calcium phosphate + calcium hydroxide)- 55%

calcification

the hardening of bone

step 1 in calcification

calcium hydroxide combines with calcium phosphate to form hydroxyapatite crystals

step 2 in calcification

crystals combine with other mineral slats like calcium carbonate and ions such as magnesium, fluoride, potassium and sulfate

step 3 in calcification

these salts deposit within the farmwork by collagen fibers of the ECM, leading to the hardening of the tissue

the combination of______ fibers and crystalized salts gives bones its characteristics of hardness and flexibility

collagen

hardness of bone

Depends on the crystallized inorganic mineral salts.

flexibility of bone

depends on collagen fibers and other organic molecules. providing tensile strength. the most abundant types are type 1,3 and 5 collagen fibers

osteogenic cells

stem cells that give rise to most other bone cell types, located in the endosteum and inner layer of the periosteum. They continually divide with some becoming osteoblasts

osteoblasts

bone forming cells involved in osteogenesis, found in rows at the endosteum and inner layer of periosteum. they secrete osteocalcin which has endocrine functions like stimulating insulin secretion

osteocytes

former osteoblasts that are trapped in the ECM they deposited. Located in lacunae connected by canaliculi, they function as strain and help in bone remodeling

osteoclasts

bone dissolving cells involved in osteolysis, derived from blood stem cells like monocytes. found in pits called resorption bays, they have a ruffled border that faces the bone

compact bone has few_____ and is the strongest form of bone

spaces

compact bone

location: beneath the periosteum; makes up bulk of diaphysis in long bones
functions: supports and protects; resists stress produced by weight and movement

osteon haversian system

the basic unit of compact bone consists of repeated structural units aligned in the same direction parallel to the length of the diaphysis

concentric lamellae

circular plates of mineralized ECM resembling the growth rings of a tree, surrounding a network of blood vessels and nerves located in the central canal

central canal (haversian canal)

tubelike parallel cylinders that run parallel to the long axis of the bone, carrying blood vessels

lacunae

small spaces found between the concentric lamellae containing osteocytes

canaliculi

canals that radiate in all directions from the lacunae filled with extracellular fluid, containing slender cytoplasmic extensions of osteocytes

spongy bone characteristics

does not contain osteons
always covered by compact bones for protection
contains marrow
structured to resist stress without breaking

spongy bone locations

found in bones where stress is not applied in many directions such as epiphysis of long bones, vertebrae and flat bones.
always located in the interior of a bone covered and protected by compact bone

Trabeculae

little beams which are lamellae arranged in irregular patterns of thin columns
contains: concentric lamellae; osteocytes in lacunae; canaliculi radiating from lacunae

macroscopic spaces

the spaces between the trabeculae fill with bone marrow

spongy bone vs compact bone

spongy bone is light while compact is heavy which reduces the overall weight of the bone, allowing it to move more readily

spongy bone vs compact bone 2

only sites where spongy bone is found containing red marrow for hematopoiesis: hip bones, vertebrae, proximal ends of long bones

bones have rich blood particularly abundant in locations with ______. blood vessels can pass from bone into the_______.

red marrow; periosteum

arteries and veins

supply blood toward bone tissue; veins drain blood carrying blood away

different types of arteries

periosteal arteries; nutrient arteries; metaphyseal arteries; epiphyseal arteries

periosteal artery

supply the periosteum and outer 1/3 compact bone of the diaphysis

nutrient artery

supply compact bone tissue of the inner 2/3 of the diaphysis and spongy tissue as far as the epiphyseal plates, entering through the nutrient foramen in the diaphysis

metaphyseal artery

supply the metaphysis and red bone marrow

epiphyseal

supply red marrow and bone tissue of the epiphysis

different types of veins

nutrient veins, epiphyseal and metaphyseal veins, periosteal veins

nutrient veins

one or two accompany the artery exiting the diaphysis

epiphyseal and metaphyseal veins

both accompany the respective arteries

periosteal veins

accompany periosteal arteries exiting the periosteum

nerves

accompany blood vessels that supply bones. the periosteum is rich in sensory nerves, some of which carry the sensation of pain due to tearing, tension, fracture or tumor

bone biopsy

involves inserting a needle into the middle of the bone to withdraw a sample of red bone marrow for examination of conditions such as lymphoma, Hodgkin's disease and aplastic anemia

locations of bone marrow biopsy

iliac crest of the sacrum; femur

bone formation is the process of what?

osteogenesis

what is another term for bone formation?

ossification

what is the term for the breakdown of bone

bone resorption

bone remodeling

involves the breaking down of bone by osteoclasts and the rebuilding by osteoblasts

situations bone formation occurs pt1:
initial formation of bones in an _____ or fetus

embryo

situations bone formation occurs pt2:
growth of bones during infancy, _____ and adolescence until adult sizes are reached

childhood

situations bone formation occurs pt3:
remodeling of bone replacement of old bone by new bone through_____

life

repair of fractures: breaks in bone throughout____

life

bone formation in embryo pt1:
the embryonic skeleton is composed of_____ found in the general shape of bones

mesenchyme

bone formation in embryo pt2:
it is the site where_____ formation and ossification occur during the_____ week of embryonic development

cartilage; 6th

bone formation in embryo pt3:
intramembranous ossification

bone forms directly within mesenchyme arranged in sheet like layers

bone formation in embryo pt4:
endochondral ossification

bone forms within hyaline cartilage that develops from mesenchyme

intramembranous ossification and endochondral ossification:
characteristic difference

intramembranous ossification involves more flat bones, while endochondral ossification involves most long, short and irregular bones
the embryonic model for intramembranous ossification involves the replacement of dense fibrous CT with hyaline CT

intramembranous ossification and endochondral ossification:
stem cells involved fibroblasts______ in intramembranous ossification, and fibroblasts, chondroblasts, and osteoblasts in______ ossification

osteoblasts; endochondral ossification

intramembranous ossification and endochondral ossification:
the progression of developing tissue types in intramembranous ossification involves dense fibrous CT while endochondral ossification, it involves dense fibrous CT tissue to hyaline and then to ______

bone

intramembranous ossification and endochondral ossification:
marrow space in adult bone is unlikely in intramembranous ossification but is _____ in endochondral ossification

likely

the ______ plate is growth plate in children while _____ line is the bony structure left after these plates have faded in adults

epiphyseal; epiphyseal

epiphyseal plate zones

zone of resting cartilage
zone of proliferating cartilage
zone of hypertrophic cartilage
zone of calcified cartilage

activity of the epiphyseal plate pt1:
as bone grows, chondrocytes proliferate on the ____ side of the plate

epiphyseal

activity of the epiphyseal plate pt2:
new chondrocytes proliferate on the_____ side of the plate

epiphyseal

activity of the epiphyseal plate pt3:
new chondrocytes replace older ones which are destroyed______

calcification

activity of the epiphyseal plate pt4:
cartilage is replace by bone on the ____ side of the plate

diaphyseal

damage to cartilage which is ____ accelerates the closure of the epiphyseal plate sue to cessation of cartilage cell division

avascular

occurs at the end of adolescence at ages____ in women and ____ in men due to estrogen and testosterone

18;21

can be caused by fracture or injury where there is a cessation in _____

cell division