Skeletal System (PP5) Flashcards
Function of skeletal system
Support
movement
protection
mineral storage
hematopoiesis
What is hematopoiesis and where does it occur?
The production of RBC
Occurs in red bone marrow
What controls hematopoiesis?
EPO- erythropoietin hormone
produced by the kidneys
When is EPO released?
decrease of O2
Where is red bone marrow found?
Kids: every single damn bone
Adults: skull, ribs, femur head, sternum, vertebrae
Osteoprogenitor cell
stem cells that make osteoblasts
Osteoblasts
immature cells that produce the matrix, new bone in childhood, remodeling, and repair broken bone
Osteocytes
Mature cell in the lacunae that performs daily tasks
Osteoclasts
Breaks down bone in remodeling
Reabsorbs matrix to release minerals
What is remodeling?
Starting at age 30, all bone in your body is broken down and rebuilt over the course of 10 years, and the process repeats once completed
Sesamoid bone
round (patella)
Long bone
includes shaft (diaphysis) and 2 knobby ends (epiphyses)
Irregular bone
vertebrae
need I say more?
Short bone
lil square things
carpals and tarsals
Flat bone
skull bones
Compact bone
dense and smooth
outer surface of bone
Spongy
Looks like a dry sponge
In middle
Osteon
weight baring pillars running parallel to the axis of the long bone
Lamella
rings of the osteon
Haversian Canal
conduit for small BV and nerves for osteon cells
center of osteon
Volkmann’s Canal
connects vascular and nerves of haversian canals
Lacunae
cavities between lamella
Canaliculi
connect lacunae
tie all osteocytes in an osteon together.
nutrient and waste transport
Trabiculae
Irregularly organized lamella and osteocytes interconnected by canaliculi
no osteons
arranged for max stress resistance
What cartilage is in epiphyses?
hyaline cartilage
What does the endosteum cover
trabeculae
When does ossification occur
Starts at week 6/7 in utero and continues into puberty
Remodeling in 30s
Where is intramembranous ossification?
bone formed within fibrous CT membrane
What bones are made from intramembranous ossification
skull, mandibles, scapula (flat bones)
What are the steps of intramembranous ossificaiton?
Mesenchymal cells collect
Change to osteoprogenitor cells
Change to osteoblasts, which help create the matrix
The matrix hardens, forming trabeculae
Internal space turns into red bone marrow
Mesenchyme outside turns into periosteum
What bones are made from endochondral ossification?
All bones below the head excluding the clavicle
Where is endochondral ossification performed?
formed within the cartilage model