Skeletal tissue Flashcards
The human skeleton has __#__ bones.
206
The largest human bone is the _____.
femur
The smallest human bone is the ___.
stapes
The skeleton accounts for about ____% of total body weight.
15-18%
The 5 functions of bones are:
- Support
- Protection
- Movement
- Mineral storage
- Hematopiesis
bone function: framework of the body
support
bone function: provide protection to the delicate structures they enclose
protection
bone function: muscles attach to bone; as muscles contract, they produce ___ at joints
movement
bone function: involves calcium, phosphorus, etc.
mineral storage
bone function: blood cell formation
hematopiesis
type of bone with extended longitudinal axes
long bones
type of bone that is cube or box-shaped
short bones
type of bone that is broad and thin with a flattened surface
flat bones
type of bone that varies in size and shape
irregular bones
type of bone that usually develops in the tendons close to the joints
sesamoid bones (ie. patella)
main shaft of long bone that is hollow, cylindrical shape with thick compact bone surrounding a central cavity
diaphysis
function of diaphysis
provide strong support without cumbersome weight
both ends of the long bone, made up of cancellous bone filled with marrow.
it is a bulbous shape
epiphysis
function of epiphysis
provide attachments for muscles and give stability to joints
meta
between
regions between the diaphysis and the epiphysis
metaphysis
function of metaphysis
in growing bone, contains epiphyseal plate - a thin layer of hyaline cartilage that allows bone to grow in length
layer of hyaline cartilage that covers the articular surface of epiphyses
articular cartilage
function of articular cartilage
provide some cushioning between bones, reduce friction
articular cartilage is hyaline cartilage but an exception to the rule, it lacks ______ .
perichondrium
In _____ _____ repair is very limited.
articular cartilage
dense, white, fibrous membrane that covers bones, and attaches tendons firmly to bones
periosteum
the 2 layers of periosteum are:
- outer fibrous layer
- inner osteogenic layer
contains cells that form and destroy bone
inner osteogenic layer
functions of periosteum
- attaches tendons to bones
- contains blood vessels important in growth and repair
- contains osteoblasts and osteoclasts, essential for bone formation
tube-like hollow space in diaphysis that is filled with blood vessels and yellow marrow in adults
medullary cavity
thin epitheal membrane that lines medullary cavity of long bones.
made up of single layer of bone-forming cells and a small amount of connective tissue
endosteum
instead of yellow marrow, red marrow fills the spaces of cancellous bone inside many ____ bones.
flat bones
bone tissue is also called
osseous tissue
bone tissue ECM is made up of ____ ____ (2/3) and ____ ____ (1/3).
Inorganic salts (2/3) organic matrix (1/3)
Bone tissue contains these 4 types of cells:
- osteoprogenitor
- osteoblasts
- osteoclasts
- osteocytes
stem cells of the bone. only bone cells that undergo cell division
osteoprogenitor cells
bone building cells
osteoblasts
bone break-down cells
osteoclasts
rocklike crystals of calcium and phosphate
hydroxyapatite crystals (inorganic salts)
process of forming the hydroxyapatite crystals within the softer tissue
calcification
____ ____ make up 85% of the total inorganic matrix
hydroxyapatite crystals
about 10% of bone tissue’s inorganic matrix contains (5):
- calcium carbonate
- magnesium
- sodium
- sulfate
- fluoride
bone tissue’s organic matrix contains (4):
- collagenous fibers
- ground substance (proteins and polysaccharides)
- chondroitin sulfate
- glucosamine
strongest form of bone tissue
compact bone
constitutes about 80% of the total bone mass and contains many cylinder-shaped structural units called osteons, or haversian systems
compact bone
_____ surround canals that run lengthwise through bone and are connected by transverse Volkmann’s canals
osteons
living bone cells are located in these units, which constitute the structural framework of compact bone
osteons
function of osteons
permit delivery of nutrients and removal of waste products
concentric, cylinder-shaped layers of calcified matrix (tree rings) about 8-15 layers thick. Each layer is oriented in the opposite direction
lamellae
small spaces containing tissue fluid in which bone cells are located between hard layers of the lamella
lacunae
very small canals radiating in all directions from the lacunae and connecting them to each other and to the Haversian canal
canaliculi
extends lengthwise through the center of each osteon and contains blood vessels and lymphatic vessels
Haversian canal
cancellous bone does not contain _____.
osteons
irregularly formed lamellae that lie between 2 layers of compact bone or near the ends of long bones
trabeculae
in cancellous bone, nutrients are delivered and waste products are removed by diffusion through ______.
tiny canaliculi
____ bone decreases overall bone weight
cancellous
orientation of _____ along lines of stress, enhancing the bone’s strength.
trabeculae
____ produce bone matrix and promote deposition of calcium
osteoblasts
____ contain lysosomes which secrete enzymes and acids that “lyse” proteins/minerals of the matrix
osteoclasts
mature, non-dividing osteoblast that lies within lacunae and is surrounded by matrix. Can change back into osteoblast or osteoclast when needed
osteocytes
specialized type of soft, diffuse connective tissue and is the site for the production of blood cells
bone marrow (myeloid tissue)
___ ____ is found in medullary cavities of long bones and in the spaces of spongy bone.
bone marrow
the 2 types of bone marrow:
- red marrow
- yellow marrow
marrow that gradually reduces over time and functions to produce red blood cells
red marrow
marrow that replaces red marrow in long bones. Marrow cells become saturated with fat and are no longer active in blood cell production
yellow marrow
the 4 main bone structures in an adult that still contain red marrow are:
- ribs
- pelvis
- vertebral bodies
- epiphyses of the humerus and femur
____ ____ can change to ___ ____ during times of decreased blood supply, such as with anemia, exposure to radiation, and certain diseases.
yellow marrow, red marrow
____ ____ has one or more arteries that supply bone marrow and areas of cancellous bone.
medullary cavity
in ____ bone arteries covered in the periosteum and incorporated into the bone itself (transverse canals)
compact bone
stem cells for transplants are typically harvested from the ____.
pelvis
bones serve as a storage site for about __% of the body calcium reserves
98%
It is the balance between deposition of bone by ____ and breakdown and resorption of bone by ____ that helps to regulate blood calcium levels.
osteoblasts, osteoclasts
the process by which osteoblasts and osteoclasts work together to transform cartilage into bone
osteogenesis or ossification
skull, facial bones, and clavicles develop through this process which starts with a fibrous membrane instead of a cartilage model
Intramembranous ossification
most bones are formed from cartilage models in this process
endochondral ossification
clusters of osteoblasts
ossification centers
______ _____ occurs within a connective tissue membrane where groups of osteogenic stem cells with the membrane differentiate into osteoblasts
intramembranous ossification
Bone begins as a cartilage model —> formation of periosteum around cartilage —> osteoprogenitor cells differentiate and osteoblasts are formed —> bone tissue forms (spongy) —> more trabeculae are formed and fuse into lamellae —> bone formation spreads from the center to the ends —> development of cavities for marrow
Endochondral ossification cycle
bone grows in length as osteoblasts form bone in middle and chondroblasts are adding new cartilage to ends of bone. Bone grows in width by addition of periosteal bone
endochondral ossification
after birth secondary ossification centers develop in the ends of long bones to allow for continued growth until end of puberty
epiphyseal plate
until bone growth is complete, a layer of cartilage remains between each epiphysis and diaphysis
epiphyseal plate
____ ____ fractures can cause a slowing or cessation of growth in the bone
epiphyseal plate
___% of bone mass is remodled at any given time
5
Spongy bone replaced at rate of __% per year; compact bone replaced at rate of __% per year
20,
4
the balance between osteoblast and osteoclast activity
bone remodeling
Factors that affect bone remodeling (4):
vitamins D, C, and A,
and inorganic matrix (Ca2+, Mg, P)
Vitamin necessary for absorption of CA2+
D
Vitamin used for collagen synthesis
C
Vitamin used to balance osteoclast and osteoblast activity
A
inorganic matrix that is necessary for hardness of bone
Ca2+, Mg, P
gravitational forces exerted to support the weight of the body,
functional forces exerted on bones by contracting muscles
stress
bone grows or remodels in response to the forces or demands placed on it
Wolff’s Law
Condition where bone breakdown is greater than bone formation.
composition of bone is normal - decreased bone mass occurs
Osteoporosis
Factors contributing to the cause of Osteoporosis (3):
- decreased circulating sex hormones
- insufficient WBing exercise
- poor nutritional intake of necessary supplements
a break in the continuity of a bone that tears and destroys blood vessels that carry nutrients to osteocytes
fracture
process that results in bone repair
fracture healing
formation of fracture hematoma –> soft procallus formation –> bony callus
Stages of fracture healing
Stage of fracture healing where vascular damage initiates repair sequence; early inflammatory phase, blood clot forms 6-8 hrs after injury, nearby cells die (oseoclasts and phagocytes remove debris)
formation of fracture hematoma
fibrocartilaginous callus forms as hematoma is reabsorbed, to bridge broken bones. Fibroblasts produce collagen and chondroblasts produce fibrocartilage; forms in 3 weeks.
Bony callus forms from osteoblasts; replaces soft callus and forms spongy bone - lasts 3-4 months
Soft procallus formation
stage in fracture healing where osteoclasts continued to absorb dead portions of broken bone. Compact bone replaces spongy bone around periphery of fracture
bony callus formation
Factors that influence bone growth:
- stresses
- nutrition
- hormones (growth, sex)
____ cells lie in lacunae; there are no canals or blood vessels in matrix.
cartilage
In ____, nutrients reach cells through diffusion (through perichondrium or synovial fluid)
cartilage
The 3 types of cartilage:
- hyaline
- elastic
- fibrocartilage
cartilage that covers articular surfaces of bones, forms costal cartilages, forms rings in trachea, found in bronchi of lungs and tip of the nose
hyaline cartilage
cartilage that contains elastic fibers and collagenous fibers and has firm elasticity. Forms exernal ear, epiglottis, eustachian tube
elastic cartilage
cartilage that has most numerous amount of collagen fibers and greatest tensile strength. is strong and rigid and found near points of attachment of some large tendons to bone
fibrocartilage
4 functions of cartilage:
- sustain great weight
- shock absorption
- strong pliable support structure that resists deformation or collapse
- permits growth in length of bones
