BB1701 skeletal system Flashcards
what are bones composed of?
- nerves and blood
- dense compact layer that forms an organised outer shell
- spongy cancellous structure that consists of trabeculae
what is the function of bones?
support
movement
protection
blood cell production
mineral storage
remodelling (continually renews structure and strength)
function of bone cells?
make up bone tissue
osteoclasts break down existing bone
osteoblasts build new bone
role of osteoblasts?
transform immature osteoclasts into mature osteoclasts by emitting a cytokine that stimulates this transformation
how is bone remodelling initiated?
through changing blood calcium levels due to adequate physical stress
process of bone resorption?
- mature osteoclasts use enzymes to remove existing bone tissue
- these osteoclasts then release chemicals that stimulate immature osteoblasts to mature and release osteoprotegerin
- osteoclasts are deactivated
- bone resorption stops
- bone formation occurs
process of bone formation
- mature osteoblasts deposit osteoid, a matrix containing minerals, calcium and phosphorus, and collagen
- calcium and phosphorus mineralise the osteoid and transform it into hydroxyapatite crystals
what influences bone remodeling
- estrogen
- it suppresses osteoclasts which inhibits resorption
- maintains bone strength
how does estrogen levels effect resorption
when estrogen levels fall, osteoclasts are unchecked
there is increased resorption which leads to bone loss
what is osteoporosis?
- rate of bone resorption exceeds the formation
- trabeculae in cancellous bone become fewer and further apart
- compact bone thin
- bones become weak and prone to fracture
how can osteoporosis be treated?
- vitamin d and calcium supplements maintain blood calcium levels
- antiresorptive medication
- anabolic medications
- exercise
how does antiresorptive medication treat osteoporosis?
promotes bone strength and prevents osteoclast activation and excessive resorption
how does anabolic medication treat osteoporosis?
increases osteoblast activity and promote bone formation
how does exercise treat osteoporosis
weight-bearing activities
add stress to bone
promote remodelling
what does the skeletal system consist of?
tendons
ligaments
cartilage associated with joints
axial and appendicular skeleton
what are the different classifications of bones?
long
short
flat
irregular
features of long bones
longitudinal axes
expanded ends - epiphysis
example of long bone
forearm
thigh bones
major parts of long bone
epiphysis
diaphysis
epiphyseal plate
epiphyseal line
periosteum
endosteum
medullary cavity
feature of epiphysis
- expanding ends
- forms joint with another bone
- nearest attachment to the proximal epiphysis
- furthest from trunk of body is distal epiphysos
- coated with a layer of articular cartilage
what is diaphysis
shaft of bone between epiphysis
what is epiphyseal plate
located between the epiphyses and diaphysis
region of cartilage where bone grows
what is epiphyseal line
site of former growth plate when bone no longer grows
what is the periosteum
outer covering
tough covering of dense connective tissue
encloses bone except articular cartilage on ends
helps form and repair bone tissue
what is the endosteum
line internal surfaces of bone
lines medullary cavity and spaces within spongy bone
marrow fills spaces
what is the medullary cavity
found deep in the diaphyses of long bones and are filled with yellow marrow in the adult
what is the macroscopic structure of long bone
- periosteum
- periosteal fibers (continuous with connecting ligaments and tendons)
- medullary cavity
- endosteum
what is the articular cartilage
material that protects the ends of bones in joints
where does growth in length occur?
epiphyseal plate
what is the medullary cavity
cavity within the shaft of a bone
what is the proximal epiphysis
enlarged end nearest the trunk
what is the diaphysis?
shaft of the bone
what is the distal epiphysis
enlarged end farthest the trunk
what is the distal metaphysis
located in the lower (distal) part of the tibia (shin bone)
what is the proximal metaphysis
the insertion point of the confluence of tendons of the sartorius, gracilis, and semitendinosus
what is the spongy bone?
type of bone formed by networks of trabeculae
what is compact bone?
bone composed of osteons
what is yellow marrow?
tissue containing fat
what is the space containing marrow?
holes in the bone
what is trabeculae
small struts of bone
what is the central canal?
- tunnel located in the middle of osteons
- contain the arterial, venous, and nervous supply for the compact bone
what is the perforating canal
tunnel in compact bone that is perpendicular to the osteon
what is an osteocyte
bone cell
osteoblasts encased in matrix
what is canaliculus?
small tunnel in bone for an osteocyte process
what is bone matrix?
contains calcium and collagen fibers
what does confluence mean?
from anterior to posterior and superficial to deep
how do osteocytes maintain contact with neighbouring osteocytes?
cellular processes contained within canaliculi
where are lacunae found?
between layers of concentric circles
what are lacunae occupies by?
osteocytes
what is a sesamoid bone?
a small bone commonly found embedded within a muscle or tendon near joint surfaces
function of sesamoid bones?
focal areas of ossification and functioning as a pulley to relieve tension within muscles and tendons
what is an irregular bone
bones that vary in shape and structure and therefore do not fit into any other category
what is a short bone
- cube shaped
- contain mostly spongy bone
- thin layer of compact bone on outer surface
what is a flat bone
- made up of a layer of spongy bone between two thin layers of compact bone
- have a flat shape
- have marrow
- no bone marrow cavity.
what is a long bone
- has a shaft and 2 ends
- longer than it is wide
- thick outside layer of compact bone
- inner medullary cavity containing bone marrow
- ends of a long bone contain spongy bone and an epiphyseal line.
function of irregular bone?
- fairly complex shape helps protect internal organs/nervous tissue
- multiple anchor points for skeletal muscle attachment
- maintaining pharynx and trachea support
- tongue attachment
function of long bone?
- provide movement and structure to the upper and lower extremities.
- interact with tendons and muscles to allow limb movement
- act as levers to provide the most effective use of their muscles (lifting objects and fast movement)
function of flat bone?
- protect internal organs such as the brain, heart, and pelvic organs
- provide large areas of attachment for muscles
function of short bone?
provide strength, stability, and support with little movement
examples of irregular bone?
vertebra, coccyx, sacrum, temporal, ethmoid, sphenoid, zygomatic, mandible, maxilla, inferior nasal concha, palatine, and hyoid
examples of short bone?
carpal and tarsal bones
examples of long bone?
humerus, clavicle, femur, tibia, fibula, radius, ulna, metacarpals, metatarsals, and phalanges of the hands and feet.
examples of flat bone?
scapula, occipital, parietal, frontal, nasal, lacrimal, vomer, sternum, ribs
examples of sesamoid bone?
patella, hallucis, pollicis sesamoids
What kind of connective tissue forms the outer layer in the diaphysis of a long bone?
compact bone
whats the first step in the repair of a fracture?
blood escapes from the broken blood vessels and forms a hematoma
what’s the second step in repair of a fracture?
spongy bone forms in regions close to developing blood vessels
whats the third step in repair of a fracture?
a bony callus replaces fibrocartilage
whats the last step in repair of a fracture?
osteoclasts remove excess bony tissue, restoring a new bone structure
what happens when stimulus detects decrease in blood calcium levels?
- cells in the parathyroid gland sense the decrease in blood calcium
- parathyroid glands release parathyroid hormone
- osteoclasts break down bone to release calcium
- blood calcium level is returned to normal
what happens when stimulus detects increase in blood calcium levels?
- cells in the thyroid gland sense the increase in blood calcium
- thyroid gland releases calcitonin
- osteoblasts deposit calcium in bones
- blood calcium levels returned to normal
What is a function of bone that results from its relationship with skeletal muscle?
Movement of limbs
What is the role or function of yellow marrow in the bone tissue?
Yellow bone marrow is a site for storage of fat
What organ is protected by bones of the axial skeleton?
heart
What are some functions of the skeletal system?
- protection of soft tissue
- attachment for muscles
- storage of inorganic salts
- site of blood producing cells
Which bones are part of the axial skeleton?
frontal bone
skull (cranial and facial bones)
ears
neck
back (vertebrae, sacrum and tailbone)
ribcage (sternum and ribs)
which bones are part of the appendicular skeleton?
femur, radius, clavicle, metatarsals, ilium, hands, feet, upper extremity, lower extremity, shoulder girdle, pelvic bones
function of the axial skeleton?
consists of structures that support and protect the organs of the head, neck, and trunk
function of the appendicular skeleton?
consists of bones that provide attachment points for muscles in the upper and lower limbs and bones that anchor the limbs to the trunk
what are the cranial bones?
frontal
occipital
temporal
sphenoid
ethmoid
what is the posterior process of bone in the vertebra
spinous process
what is the lateral process of bone in the vertebra
transverse process
what is the hole that contains the spinal cord in the vertebra
vertebral foramen
what is the central mass of bone in the vertebra
the body
what is the little foot of the vertebral arch
pedicle
what is the surface for articulation with the vertebra above
superior articular facet
what is the portion of vertebral arch between spinous and transverse processes
lamina
order of vertebral column
cervical vertebrae
thoracic vertebrae
lumbar vertebrae
sacral vertebrae
coccygeal vertebrae
how many vertebrae in cervical region
7
how many vertebrae in the thoracic region
12
how many vertebrae in the lumbar region
5
how many vertebrae in the sacral region
5 - fuses to 1
how many vertebrae in the coccygeal region
4 - fuses to 1
which skeleton has a prominent mastoid process on skull
male
which skeleton has a wider pubic arch
female
which skeleton has a Sacral curvature that bends sharply posteriorly
female
which skeleton has a Larger acetabulum
male
which part of bone tissue is responsible for resorbing bone matrix
osteoclasts
which part of bone tissue is responsible for replacing bone matrix
osteoblasts
What vitamin is necessary for proper absorption of calcium in the small intestines?
Vitamin D
what is the true rib?
the ribs that directly articulate with the sternum with their costal cartilages
what is the false rib?
the ribs that indirectly articulate with the sternum
What are the concentric rings of compact bone called?
lamellae
what is the extracellular matrix of bone tissue composed of?
Collagen and inorganic salts
What living tissues make up a bone?
bone tissue
carilage
dense connective tissue
blood
nervous tissue
What classifies a rib as a floating rib?
A floating rib has no sternal attachments.
