The Skeletal System Flashcards
5 types of connective tissue that make up the skeletal system
- Bone
- Cartilage
- Dense Regular Connective Tissue
- Dense Irregular Connective Tissue
- Marrow
Secretion takes place primarily by what in the gut?
mucosa
segmentation takes place in what part of the digestive system?
small intestine
What is bone?
a tissue and organ
What do bones do for muscles?
They are points of attachment and leverage for muscles
4 functions of bones
- Support
- Protection
- Blood cell formation
- Mineral homeostasis
what is bone composed of?
connective tissue composed of osteocytes and ground substance (matrix)
cells associated with bone, living within and maintaining ground substance
osteocytes
osteocytes arise from…
osteoblasts
cells associated with bone matric, function to break it down
osteoclasts
What does collagen do?
forms fibres in connective tissue
what is the ground substance in bone?
collagen, mineralized by calcium phosphate
two types of cone
compact and spongy
What is compact bone organized into?
osteons
what does the central canal of bone contain?
blood vessels and nerves
what is spongy bone organized into?
trabeculae
trabecular forms a network with…
red and yellow marrow
what does spongy bone do?
transmits stress
bones are wrapped within fibrous connective tissue called…
periosteum
what does the inner layer of periosteum do?
supports osteoblasts
2 main inner and outer components of bones
cortical layer and medullary cavity
what is the medullary cavity?
the inner empty space of bone
what is the shell of the bone called?
cortical layer
what is another word of the diaphysis of the long bone?
shaft
what are epiphyses
parts of joins that prevent bones from grinding against eachother
what is cartilage made of?
collagen matrix with chondroplasts
Why is caritlage considered avascular?
contains little or no blood vessels
the skeletal elements made of cartilage are referred to as…
cartilages
types of cartilage
- Hyaline
- Fibrocartilage
- Elastic
smooth cartilage with thin fibred
hyaline
what type of cartilage forms good surface for bones to move over one another?
hyaline
what type of cartilage forms intervertebral discs?
fibrocartilage
what type of tissue are ligaments made of?
dense regular connective tissue
what do ligaments do?
connects bones
term for dense regular connective tissue that connects skeletal muscles to cones
tendons
what is ossification
when a tissue becomes a bone
what is calcification?
a pathological process where tissue is replaced by crystalline calcium phosphate
what is endochondrial process?
process by which long bones are produces
a cone first forms embryonically as a…
hyaline cartilage model
in the formation of bones, perichondrium changes to…
periosteum
what lays down bone around the model in bone formation in the fetus?
osteoblasts
the invasions of blood vessels on fetal bone model does what?
lays down ground material to be mineralized
what does secondary ossification in fetal bone development do?
establishedes connection between bones at the epiphsysis
What is intramembranous ossification?
the process by which flat bones are produced
what does intramembranous ossification begin with?
a sheet of embryonic connective tissue
what stage is skipped in intramembranous ossification?
the cartilage model stage
at what point do long bones grow?
cartilage growth plates at epiphyses
the growth of cartilage plates is in what pattern?
appositional
at sexual maturity, rate of cartilage production…
slows
what happens when the epiphyseal plate ossifies?
the bone cannot grow any longer in length
long bones increase in diameter by…
osteoblast activity under the periosteum
how do flat bones grown?
by adding new bone around edges - appositional growth
how is bone considered a dynamic tissue?
it is constantly being broken down and built up in response to compressive stresses
osteoclasts break bone down in response to which hormone?
the parathyroid hormone
the parathyroid hormones is secreted in response to
low levels of calcium
osteoblasts deposit bone in response to
calcitonin
when is calcitonin secreted?
in response to high levels of calcium
what type of “bank” are bones?
a bank of calcium and phosphate
what is calcium necessary for?
muscle contraction, neutransmitter secretion and blood clotting
what is phosphate necessary for ?
ATP
osteoblasts and osteoclasts reabsorb and deposit bone in response to…
piezoelectric currents
what are piezoelectric currents cause by?
compressive stress
what type of bone remodelling involves breaking down and reconstituded in alignment with direction of compressive stress
compact bone
what is broken down in the bone remodelling of spongy bone?
trabeculae
how many bones are in the body?
206
what are the two divisions of skeletal system?
axial skeleton, appendicular skeleton
3 organs of skeletal system
bones, ligaments, joint capsules
what does the acial skeleton do?
supports the trunk and encloses central nervous system
4 components of the axial skeleton
skull, spinal column, ribs and sternum
what does the appendicular skeleton do?
provides insertions for organs and origins for limb muscles
the appendicular skeleton includes…
limbs and girdles
term for any area of contact or near-contact between adjacent bones
joints
bone is joined to bone by…
ligaments
what are cartilaginous joints?
cartilage between bones, low mobility
what are cartilaginous joints missing?
capsules
dense irregular tissue that fills gap between adjacent bones and holds them immobile relative to one another
fibrous joint
what are the fibrous joints called that are found in the skull?
sutures
what are synovial joints?
freely-moving adjascent bones
What are synovial joints separated by?
cavity
what is the synovial cavity enclosed by?
the synovial capsule
what does the synovial capsule secrete?
synovial fluid
another word for synovial joints
hinge joints
what does synovial fluid do?
lubricates joints
