Exam 4 - chapter 6 Flashcards
Functional properties of hyaline cartilage
Provides support, flexibility, and resilience for articular, costal, respiratory, and nasal region.
Functional properties of elastic cartilage
Provides elasticity in external ear and epiglottis
Functional properties of fibrocartilage
thick collagen fibers provide tensile strength for the menisci of the knee and the vertebral discs. (also in pubic symphosis)
Cartilage growth: appositional
cells secrete matrix against external face of existing cartilage
Cartilage growth: interstitial
chondrocytes divide and secrete new matrix, expanding cartilage from within.
2 major groups of the skeleton
axial: skull, vertebrae, rib cage
appendicular: limbs, girdles (shoulder, pelvic)
4 bone classes
long bones: longer than they are wide. ex, limbs.
short bones: cube-shaped bones. ex, wrist & ankle
flat bones: thin, flat, and slightly curved. ex, sternum, scapula, ribs, most skull bones.
irregular bones: anything else. ex, vertebrae, coxal bones.
7 important functions of bones
- support - for body & soft organs
- protection - brain, spine, vital organs
- movement - levers for muscle action
- mineral & growth factor storage - Ca + phosphorus, growth factors reservoir
- blood cell formation - blood cell formation in red marrow cavities in certain bones (hematopoiesis)
- triglyceride (fat) storage - fuel / energy
- hormone production - osteocalcin - regulates bone formation, protects from obesity, glucose intolerance, diabetes.
gross anatomy of long bones
composed of spongy (trabeculae, honeycomb) and compact bone (dense outer layer, smooth & solid)
has 2 epiphyses (ends) and the middle piece is the diaphysis. between the epiphyses and the diaphysis is the epiphyseal line (plate in younger people).
bone is lined with periosteum, and inner medullary cavity is lined with endosteum. inside is yellow bone marrow.
Joints are covered by articular cartilage
gross anatomy of flat bone
thin plates of spongy bone covered by compact bone. plates are sandwiched between connective tissue membranes (periosteum, endostum).
no shaft or epiphyses, bone marrow throughout spongy bone, but no marrow cavity.
hyaline cartilage covers articular surfaces.
microscopic anatomy of compact bone
5 types of cells:
osteogenic, osteoblasts, osteocytes, bone lineing cells (periosteal / endosteal), and osteoclasts
osteogenic
mitotically active stem cells in periosteum and endosteum. when they are stimulated, they differentiate into osteoblasts (bone forming) or revert back to more osteogenic cells
osteoblasts
bone forming cells, secrete unmineralized bone matrix (osteoid) - includes collagen and Ca-binding proteins. actively mitotic.
osteocytes
mature bone cells in lacunae. they monitor and maintain bone matrix. respond to strain and stress and communicate with osteoblasts and osteoclasts for bone remodeling.
bone-lining cells
periosteal/endosteal: flat cells on bone surfaces which maintain matrix.
osteoclasts
break down bone - hematopoietic stem cells that become macrophages. rest in resorption bay and have a ruffled border to increase surface area for enzyme degradation of bone and seals off area from surrounding matrix.
microscopic anatomy of compact bone
osteon: structural unit of compact bone - cylinder parallel to the long axis of the bone.
elongated cylinder parallel to the long axis of bone
lamellae - hollow tubes of bone matrix; collagen fibers in the same ring run in the same direction, but adjacent rings run in different directions to withstand stress and resist twisting
central canal runs through core of osteon which contains blood vessels and nerve fibers.
volkmann’s canals run perpendicular to canal, and connect blood vessels and nervs of periosteum, medullary cavity, and central canal.
lacunae - small cavities that contain osteocytes.
canalculi = hairline canals that connect lacunae to each other and central canal.
microscopic anatomy of spongy bone
appears poorly organized, with trabeculae
contain irregularly arranged lamellae and ostoecytes interconnected by canalculi. capillaries in endosteum supply nutrients.