What are some components of the skeletal system?
- Connective tissues
What are two types of bones?
What is Compact bone also called?
Dense or cortical bone
What kind of tissue is primarily found in Compact bone?
Dense Connective tissue
What is 80% of bone mass?
What is spongy bone also called?
cancellous or trabecular bone
What is 20% of bone mass?
Two types of cartilage?
- Hyaline Cartilage
- Fibro Cartilage
What kind of cartilage attaches ribs to the sternum?
What is the model for formation of most bones?
What cartilage with stands compression?
What cartilage forms intervertebral discs, pubic symphysis, and cartilage pages of the knees?
What anchor bone to bone?
What anchor muscle to bone?
Bones are _______, _________, and are also a _______ for the body.
Bones serve as attachment sites for
- skeletal muscles
- soft tissues
- some organs
What is Hemopoiesis?
process of blood cell production
Where does Hemopoiesis occur in?
Red bone marrow connective tissue
Red bone marrow connective tissues contain _____ cells that form blood cells and platelets.
What is calcium needed for?
- muscle contraction
- blood clotting
- nerve impulse transmission
Calcium and phosphate
The phosphate stored in bones are used for….
- ATP utilization
- Plasma membrane
Where in the bones are lipids stored?
yellow bone marrow
What are the four classes of bone?
- long bone
- short bone
- flat bone
- irregular bone
Flat bones form…
- the roof of the skull
What is the medullary cavity?
Hallow, cylindrical space within the diaphysis
What does the Medullary Cavity contain?
red bone marrow in children
what is the tough sheath covering the outer surface of bone?
Periosteum if attached to bone by what?
perforating fibers (numerous collagen fibers)
Where do artery and vein exit from?
what is bone marrow?
soft connective tissue of bone
bone marrow has what 2 parts?
red and yellow
red bone marrow is also known as...
red bone marrow is hemp-______ which means?
- blood cell forming
what 3 things do red bone marrow contain?
- reticular connective tissue
- immature blood cells
where can you find red bone marrow in children and in adults?
- in children in the spongy bone and medullary cavity of long bone
- in adults its in the axial skeleton, proximal epiphyses of humerus and femur
what produces yellow bone marrow?
red bone marrow degeneration
what is yellow bone marrow?
may yellow bone marrow convert back to red bone marrow?
what is the primary component of bone?
bone connective tissue
another word for bone connective tissue is...
osseous connective tissue
what is bone connective tissue composed of?
cells and extracellular matrix
what four cells of bone are found in bone connective tissue?
- osteoprogenitor cells
what are osteoprogenitor cells?
stem cells derived from mesenchyme
what do osteoprogenitor cells do?
produce cells that mature into osteoblasts
where can you find osteoprogenitor cells?
periosteum and endosteum
what do osteoblast secrete?
what are osteocytes?
mature bone cells derived from osteoblasts
what detects mechanical stress on bone?
whats involved in breaking down bone?
what is derived from fused bone marrow?
osteoclasts are _____-cytic cells
what is a collagen protein found in the bone matrix and produced by osteoblast?
ground substance of bone?
what are the some components of the bone matrix?
- calcium phosphate
what is compact bone composed of?
what are osteons?
small cylindrical structure basic unit of mature compact bone
what lies central of the osteon and allows blood vessels and nerves to travel through it?
what are concentric lamellae?
rings of bone connective tissue surrounding the central canal
osteocytes are found in small spaces between _____ _______ and hel maintain the ______ _______.
- concentric lamellae (lacunae)
- bone matrix
what are canaliculi?
tiny interconnecting channels within bone connective tissue
what is something important canaliculi take part of?
allowing the travel of nutrients, minerals, gases, and wastes between blood vessels and osteocytes
what are perforating canals?
canal containing blood vessels and nerves perpendicular to the central canal
what is the difference between external circumferential lamellae and internal circumferential lamellae?
external runs immediatelt internal to bone periosteum where as the internal one runs internal to the endosteum
what is interstitial lamellae?
lamellae found between osteons
what are some components of spongy bone?
- parallel lamellae
what are trabeculae?
open lattice of narrow rods and plates of bones bone marrow filling space between
what are parallel lamellae?
lamellae parallel where osteocytes rest between lamellae
what do osteoclast do?
break down bone
what do osteoblasts do?
secrete osteoid and build bone
hyaline cartilage contains no...
bone or nerves
what are the 3 structures of hyaline cartilage?
what are chondroblasts?
produce cartilage matrix
what are chondrocytes?
chondroblasts that have been encased within the matrix occupy spall spaces called lacunae
what is perichondrium?
- dense irregular connective tissue
- covers cartilage and helps maintain its shape
where does appositional growth occur in cartilage?
on the outside edge out
where does interstial growth occur?
within the internal regions of cartilage
the formation and development of bone connective tissue is called?
when does ossification occur?
intramembranous ossification produces....(4)
- flat bone of skull
- central parts of clavival
- some of the facial bones
when does intramembranous ossification occur?
when mesynchyme becomes thickenes with capillaries
steps of intramembranous ossification.... (4)
- 1. ossification centers form within thickened regions of mesychme
- 2.osteoid undergoes calcification
- 3. periosteum forms
- 4. lamellar bone replaces woven bone
what is produced by endochondral ossification?
- bones of the upper and lower limbs
- ends of the clavicle
whats the steps of long bone development in a limb?
- 1. the fetal hyaline model develops
- -chondroblasts begin to secrete cartilage matrix
- 2. cartilage calcifies, periosteal bone collar forms around diaphysis
- -matrix begins to calcify and chondrocytes die
- -osteoblasts develop and begin secreting osteoid
- -form a layer of osteoid around calcified cartilage shaft termed periosteal bone collar
- 3.primary ossification center forms in the diaphysis.
- 4. secondary ossification center form in epiphyses.
- -hyaline cartilage calcifies and egenerates
- -blood vessels and osteoprogenitor cells enter
- 5. bone replaces cartilage, except articular cartilage and epiphyseal plates.
- 6. epiphyseal plates ossify and form epiphyseal lines
growth in long bone continues until _____ ______ is converted to the ______ ______
- epiphyseal plates
- epiphyseal line
when does bone growth and remodeling occur?
during embryologic development
bone growth in length is termed...
bone growth in diameter is termed...
interstitial growth is dependent upon cartilage growth where?
what are the 5 continuous zones of epiphyseal plate?
- resting cartilage
- proliferation cartilage
- hypertrophic cartilage
- calcified cartilage
- ossification zone
where does appositional growth occur?
appositional growth happens because of...
the external circumferential lamellae increases in number
what increases bone mass?
what decreases bone mass?
reduced collagen formation unstressed bones
what are hormones?
molecules released from one cell into the blood
______ can affect bone composition and growth patterns.
4 hormones that influence bone growth?
- sex hormones
- thyroid hormones
- growth hormones
what is calcium required for?
- initiation of muscle contraction
- exocytosis of molecules from cells
- stimulation of the heart by pacemaker cells
- blood clotting
what two primary hormones regulate blood calcium?
- parathyroid hormone
3 steps of vitamin d activated to calcitriol
- 1. uv light coverts precursor molecule in blood to vitamin d
- 2. vit-D circulates through the body
- -converted to calcidiol by liver enzymes
- -addition of -OH group
- 3. calcidiol circulates in blood
- - converted to calcitriol by kidneys
- -OH added again
- -more calcitriol is formed if PTH is present
_______ stimulates absorption of ____ ions from the ______ ______ into the _____
- small intestine
when is PTH released?
in responce to reduced blood calcium levels
actions of parathyroid hormone and calcitriol are....
- elevate blood calcium
- return calcium levels within homeostatic range
calcitriol alone increasing absorption of ______ from where?
calcitonin is released in response to....
high blood calcium levels
calcitonin inhibits what in bone connective tissue?
calcitonin stimulates what to increase what kind of loose?
stimulates the kidneys to increase the loss of calcium through urine
two ways aging affects bone?
- decreased tensile strength of bone
- - reduced rate of protein synthesis by osteoblasts
- bone loss of calcium and other minerals
- -thinner and weaker
- -insufficient ossification, termes osteopenia
what is osteopenia?
decline of osteoblast activity
what is osteoporosis?
reduced bone mass
with age can reduced hormones be a thing?
what is the term for a break in bone?
what are some types of fractures? 4
what is pathalogic fractures?
weaking in bone by disease
what is simple fracture?
broken bone not penetrating the skin
what is a compound fracture?
piercing overlying skin
what is the healing time for simple fractures?
four steps of bone fracture repair?
- fracture hematoma
- -blood vessels torn within periosteum
- fibrocartilaginous callus
- -regenerated blood capilaries infiltrating hematoma
- -fibroblasts producing collagen fibers
- -chondroblasts forming dense connective tissue
- hard callus
- -osteoblasts adjacent to callus producing trabeculae
- -callus replaced by this bone
- -forms a hard (bony) callus
- -continues to grow and thicken
- bone is remolded
- -osteoclasts removing excess bony material