Lecture 5 Flashcards
Where does connective tissue come from?
mesenchyme cells
What are mesenchyme cells?
stem cells
What is connective tissue?
spares cells surrounded by an extracellular matrix
What are the characteristics of cartilage?
semirigid, flexible but resilient, avascular
What are the functions of cartilage?
support soft tissues, articular surfaces for joints, provide a model for endochondral bone formation
What are chondroblasts?
cells that produce cartilage matrix
What are chondrocytes?
mature cartilage cells
Where are chondrocytes found?
lacunae
What is the extracellular matrix in cartilage?
protein fibers embedded in a gel-like ground substance
What is perichondrium?
dense irregular connective tissue
What are the kinds of cartilage?
hyaline, fibrocartilage, elastic
Where is hyaline cartilage found?
costal cartilage, nose, articular cartilage, epiphyseal plate, fetal skeleton, respiratory system
What is hyaline cartilage?
flexible but resilient
What is fibrocartilage?
shock absorber, contains thick collagen fibers
Where is fibrocartilage found?
intervertebral discs, pubic symphysis, menisci of knee, articular discs of jaw
What is elastic cartilage?
provides flexibility, contains elastic fibers
Where is elastic cartilage found?
epiglottis and external ear
What is the epiglottis?
closes the lungs when we swallow
What is bone?
Osseous connective tissue
What are the bone cells?
osteocytes
What is the organic component of the bone matrix called?
osteoid
What is the organic component of the bone matrix made of?
collagen and other proteins
What is the inorganic component of the bone matrix called?
hydroxyapatite
What is the inorganic component of the bone matrix made of?
calcium phosphate and calcium hydroxide
What are the functions of bone?
support the body, protect vital organs, facilitate movement
What is hematopoiesis?
red bone marrow
What kind of tissue is yellow bone marrow?
adipose tissue
What are the long bones?
humerus, radius, ulna, metacarpals, phalanges, femur, tibia, fibula, metatarsals
What are the short bones?
carpals, tarsals
What are the flat bones?
skull, scapulae, sternum, ribs
What are the irregular bones?
vertebrae, sacrum, coccyx, os coxae, ethmoid, sphenoid
What are the sesamoid bones?
patella, small bones found in the tendons associated with feet and hands
What is the periosteum?
connective tissue that connects to the bone
What type of tissue is the periosteum?
dense irregular connective tissue
What is compact bone?
lined by periosteum; composed of osteons
What is spongy bone?
lined by endosteum; often contains red bone marrow
What is spongy bone composed of?
trabeculae
What is another name for spongy bone?
cancellous bone
What is another name for compact bone?
cortical bone
What is the diaphysis?
the shaft of the bone
What is the epiphysis?
the end of the bone
What is the metaphysis?
between the end of the bone and the shaft of the bone
What is the epiphyseal plate or line?
growth plate
What is the apophysis?
bony outgrowth that serves as an attachment site for ligaments or tendons
What is the articular cartilage?
helps with movement; end of the bone where it attaches to another
What is the medullary cavity?
very inside of the bone; contains yellow marrow in adults and red marrow in children
What is the endosteum?
layer of cells lining the spongy bone and medullary cavity
How do bones grow?
from the inside out
What do osteoblasts do?
form bone matrix
What is an osteogenic cell?
stem cell
What is an osteoclast?
resorbs bone; eats up old bone
What is an osteon?
circular unit in compact bone
Where are osteons found?
compact bone
What are lamellae?
a single circle in an osteon
What is the central canal?
goes up through the middle of an osteon
What is the perforating canal?
goes sideways through bone and connects to a central canal
What are osteocytes?
have legs that come off of it and are found around the lacunae
What are canaliculi in compact bone?
small canals that connect osteocytes
What are trabeculae in spongy bone?
crisscrossing beams and plates
What are canaliculi in spongy bone?
in-between the lamellae where vessels can go through
Where are osteoblasts in spongy bone?
outside the whole circular unit
What is responsible for trabecular remodeling?
osteoclasts and osteoblasts
What is ossification?
formation of bones
What are the types of ossification?
intramembranous and endochondral
What is intramembranous ossification?
bone growth within a membrane
What does intramembranous ossification form?
flat bones of the skull, some facial bones, mandible, clavicle
What is endochondral ossification?
bone growth within cartilage
What does endochondral ossification form?
most bones
What does endochondral ossification do?
turns fetal framework of hyaline cartilage into bone
Where does primary ossification occur?
center of cartilage which becomes the diaphysis
Where does secondary ossification form?
in the epiphyses
What is the end result of endochondral ossification?
bone replaces cartilage, except the articular cartilage and epiphyseal plates
What cartilage doesn’t get replaced by bone?
articular cartilage and epiphyseal plates
What is interstitial growth?
bone gets longer
Where does interstitial growth happen?
epiphyseal plates
What is appositional growth?
bone gets wider
Where does appositional growth happen?
periosteum and endosteum
What is osteomalacia?
low bone density caused by vitamin D or calcium deficiency; soft and weak bones, bowed legs