Skeletal System Flashcards
Many _______ and all _______ possess exoskeletons.
invertebrates, arthropods
An ______ is an external skeleton
exoskeleton
Vertebrates contain an _________ on the inside.
endoskeleton
An endoskeleton can be divided into the _____ skeleton (core bones) and the _________ skeleton (appendages).
axial
appendicular
Types of bones in the endoskeleton
Long bones
Short bones
Flat bones
Sesamoid bones
Irregular bones
What are long bones made of?
Made of cortical bone (compact) and pockets of cancellous bone (spongy).
What important features do long bones have?
EMDME
Epiphysis
Medullary cavity
Diaphysis
Metaphysis
Epiphyseal plate
Epiphysis?
Forms what w/ other bones?
What important marrow does it contain?
END of a long bone
Forms joints with other bones
Contains red bone marrow for hematopoiesis (blood cell synthesis)
Diaphysis?
Located where?
Long hollow shaft in CENTER of bone
Medullary cavity?
Located where?
What important marrow does it contain?
Located within the diaphysis
Contains red AND yellow bone marrow (area of fat storage).
Metaphysis?
Located where?
Similar to epiphysis
Found between the medullary cavity & epiphyseal plates.
Epiphyseal plate?
Located where?
Made out of what?
Lengthens what?
“Growth plate”
Located between epiphysis & metaphysis
Made out of hyaline cartilage
Lengthens diaphysis through growth & ossification
Short bones provide _____
support
Flat bones provide _____
protection
Sesamoid bones are found within _______ to help ______
tendons, muscles
Cortical bone? Function?
Inner or outer layer of bone?
Dense outer layer of bone that supports the weight of our bodies
What microstructures is cortical bone made of?
Osteons
Haversian canals
Lamellae
Lacunae
Canaliculi
Volkmann’s canals
Osteons
Composed of what?
Also known as what?
Cortical bone’s functional unit, Composed of tiny multi-layered cylinders
Known as haversian systems (contain a haversian canal in center)
Haversian canals
Contain what?
‘tubes’ that contain blood vessels for nutrient supply
Lamellae
layers of the osteon
Lacunae
Hold what?
Interconnect through what?
small spaces between lamellae
Hold bone cells
Interconnect through canaliculi
Canaliculi
Connect what?
small channels that connect
lacunae and the haversian canal
Volkmann’s canals
Connect what?
connect Haversian canals to the periosteum
Cancellous bone?
Dense or spongy?
Soaks up what?
Spongy inner layer of bone
Soaks up red bone marrow via a web of trabeculae (connective tissue that supports cancellous bone)
Resorption is bone _____
LOSS
Ossification is bone ______
FORMATION
What cells are involved in bone remodeling?
Osteoprogenitors
Osteoblasts
Osteocytes
Osteoclasts
Osteoprogenitors
Differentiate into what?
immature precursor cells that differentiate into osteoblasts
Osteoblasts
Function?
Mature into what?
BUILD bone by secreting proteins & utilizing blood calcium. Mature into osteocytes
Osteocytes
Live where?
live in lacunae in osteons to maintain bone
Osteoclasts
Function?
Derived from what?
EAT & RESORB bone
Releases calcium & phosphate back into the blood
Derived from monocytes.
mechanisms of bone remodeling
Parathyroid hormone function?
Secreted by what?
Increases blood calcium levels by stimulating osteoclasts & depressing osteoblasts
Secreted by the parathyroid gland.
mechanisms of bone remodeling
Vitamin D function?
Activated by what?
Increases blood calcium levels by raising calcium absorption
Activated by PTH but provides negative feedback on PTH production.
mechanisms of bone remodeling
Calcitonin function?
Secreted by what?
Decreases blood calcium levels by depressing osteoclasts, allowing osteoblasts to build bone without competition
Secreted by parafollicular cells (C cells) of the thyroid gland.
- CalciTONin (tone it down)
______ is the organic component of bone containing many proteins
Osteoid
What gives the bone tensile strength?
Collagen
_______ is the inorganic mineral component of bone that gives the bone density and strength.
Hydroxyapatite
Embryonic ossification
Endochondral ossification
Created indirectly or directly where?
Mainly for what bones?
Explain the process
What is created?
Bone is created indirectly through a cartilage model
Mainly for long bones
The cartilage model calcifies during fetal development
Ossification centers & long bone features are created
Embryonic ossification
Intramembranous ossification
Created indirectly or directly where?
Mainly for what bones?
Explain the process
What bone is created?
Bone is created directly within fibrous membranes
Mainly for flat bones
Osteoblasts start by secreting osteoid, which hardens and houses osteocytes.
Cortical bone is created
What are the two types of embryonic ossification?
- Intramembranous ossification
- Endochondral ossification
Types of connective tissue (there’s 3)
- Fibrous connective tissue
- Cartilage
- Joints
Fibrous connective tissue is maintained and repaired by ________.
fibroblasts
What makes up fibrous conn. tissue?
Tendons
Ligaments
Periosteum
Endosteum
Tendons connect ______ to ________.
muscle to bone
Ligaments connect ______ to ________.
bone to bone
Periosteum
Membrane covers what?
What layers does it have? specify what they have
Covers cortical bone
Outer fibrous layer (vascularized) Inner layer (collagen for attachment to cortical bone)
Endosteum
Membrane located where?
membrane located between cortical & cancellous bone.
Cartilage is ______ and is NOT ________.
avascular, not innervated
What builds cartilage?
Chondroblasts
3 types of cartilage
Hyaline cartilage
Fibrous cartilage
Elastic cartilage
Hyaline cartilage
Flexibility?
Provides what to joints?
slightly flexible
Important in providing support and
stability to joints.
Fibrous cartilage
Flexibility?
Found where?
high rigidity & resists tension
Found in intervertebral discs
Elastic cartilage
Flexibility?
Found where?
highly flexible
Found in ears & epiglottis.
highly flexible and found
in ears and epiglottis.
Chondroblasts build cartilage by secreting ______ and ______.
collagen and elastin
Joints are ______ and _______. They are found ______ bones
vascularized, innervated, between
3 Types of joints
Synarthroses
Amphiarthroses
Diarthroses
Synarthroses
Type of joint?
How do they move?
Dense, fibrous joints
Do NOT move
Amphiarthroses
Type of joint?
How do they move?
Cartilaginous joints
Partially move
Diarthroses
Type of joint?
How do they move?
Contain what kind of cartilage?
Synovial joint
Fully move
Typically contain hyaline cartilage
