Skeletal System Flashcards
- internal framework which gives your body support
- gives your body its shape, allows movement, makes blood cells, provides protection for you organs and stores minerals
skeletal system
Types of Skeletal System
- Hydrostatic Skeletal System
- Exoskeleton
- Endoskeleton
skeleton formed by a fluid-filled compartment within the body, called the coelom
hydrostatic skeleton
external skeleton that consists of a hard encasement on the surface of an organism
exoskeleton
skeleton that consists of hard, mineralized structures located within the soft tissue of organisms
endoskeleton
Significance of the Skeletal System in the human body
- provides support and shape
- protection
- allows movement and locomotion
- blood cell production
- mineral reservoir
- endocrine regulation
- detoxification
- growth and development
Major Components of the Skeletal System
- bones
- ligaments
- carilage
- joints
types of bones
- long bones
- short bones
- flat bones
- irregular bones
- longer than they are wide
- facilitates movement due to their length
- most of the upper and lower limb
long bones
what are the long bones
upper
1. humerus
2. radius
3. ulna
4. metacarpal
lower
5. femur
6. tibia
7. fibula
8. metatarsal
both
9. phalanges
parts of long bones
- diaphysis
- epiphysis
- metaphysis
- medullary cavity
- periosteum
- endosteum
- articular cartilage
- epiphyseal plate
long central shaft
diaphysis
ends of the bone
epiphysis
region where the diaphysis meets the epiphysis
metaphysis
hollow space within the diaphysis
medullary cavity
inside the medullary cavity
- yellow marrow
- red marrow
consists mostly of adipose tissue
yellow marrow
blood forming cells
red marrow
dense layer of vascular connective tissue enveloping the bones
periosteum
thin connective tissue membrane lining the inner cavities of the bone
endosteum
covers the ends of the epiphysis where the bone articulates (joints) with other bones
articular cartilage
separates the epiphysis from the diaphysis
epiphyseal plate
- approximately as wide as they are long
- help transfer force between long bones
short bones
what are the short bones
- carpals
- tarsals
- are thin and often slightly curved, serving protective functions
- protect soft organs
flat bones
what are the flat bones
- cranial bones
- ribs
- scapulae
- sternum
- have complex shapes that don’t fit into the other categories
- provide protection and flexibility in regions like the spine
irregular bones
what are the irregular bones
- vertebrae
- sacrum
Bone Composition
- organic components
- inorganic components
organic components of bones
- collagen
- proteoglycan
inorganic components of bones
- calcium
- phosphate
classified according to the amount of the bone matrix to bone space
bone tissue
Two types of bone tissue
- compact bone (cortical)
- cancellous bone (spongy)
it is dense and has a solid outer layer
compact bone (cortical)
parts of compact bone
- osteons
- blood vessels
- canaliculi
consist of connective rings of lamellae surrounding central canal
osteons
- run parallel to the long axis of the bone
- located in the central canals/ haversian canals
blood vessels
where are the blood vessels of the compact bone found
Haversian canal/ central canal
- give osteon the appearance of having tiny cracks within the lamella
- where nutrients are passed
canaliculi
- very porous and is located in the epiphysis of long bones and lines the medullary cavity of long bones
- less bone matrix
cancellous bone (spongy)
delicate interconnecting rods of plates of bones
trabeculae
what does the trabeculae add
strength to a bone without the added weight
spaces between the trabeculae are filled with __
marrow
Two main parts of the major bones of the human body
- axial skeleton
- appendicular skeleton
protects vital organs like the brain and spinal cord
axial skeleton
facilitates movement and interaction with the environment
appendicular skeleton
- connect bone to other bones
- made of a fibrous connective tissue
ligaments
function of ligaments
hold structures together and keep them stable
strong, flexible connective tissue that protects your joints and bones.
cartilage
Three types of Cartilage
- hyaline cartilage
- fibrocartilage
- elastic cartilage
- most common type of cartilage
- lines the joints and caps the ends of bones
- slippery and smooth
- precursor for bones
hyaline cartilage
different types of hyaline cartilage based on where they are found
- Bronchial
- Laryngeal
- Articular
- Nasal
- Costal
- Epiphyseal Growth Plates
- Tracheal
- rings in bronchial tree
- helps keep airways open
- prevents bronchi from collapsing, especially during expiration
bronchial cartilage
- framework of larynx
- provides protective covering for vocal cords
laryngeal cartilage
- covers ends of bones
- provides smooth surface for articulation and reduce friction during movement
- absorbs shock
articular cartilage
- shapes nose
- provide support for nasal passage, allowing proper airflow
nasal cartilage
- connects ribs to sternum
- allows for chest expansion
costal cartilage
enables bone growth
epiphyseal growth plates
- rings the trachea
- provide structural support
- helps keep airway open
- acts as protective barrier
tracheal cartilage
- tough cartilage made of thick fibers
- strongest and least flexible
- tough enough to hold parts of your body and absorb impact
fibrocartilage
example of fibrocartilage
- intervertebral disc
- meniscus
- most flexible cartilage
- supports parts of the body that need to bend and move to function
- can bounce back to its original shape, even after a strong force
elastic cartilage
example of elastic cartilage
- ear
- eustachian tube
- epiglottis & corniculate cartilage (larynx)
connection between two bones in the skeletal muscle
joints
classification of joints by type of tissue
- fibrous joints
- cartilaginous joints
- synovial joints
- bones are formed by fibrous connective tissue
- require strength and stability over range of movement
fibrous joints
three types of fibrous joints
- sutures
- gomphoses
- syndesmoses
- immobile joints (synarthrosis) found only in the cranium
- at birth, it allows bones in the skull to move
sutures
where are sutures found
skull
immobile joints
synarthrosis
- immobile joints found only between the teeth and their sockets in the madible and maxillae
- periodontal ligament is the fibrous tissue connecting the tooth to the socket
gomphoses
where are gomphoses found
between teeth and socket in the mandible and maxillae
fibous tissue connecting the tooth to the socket
periodontal ligament
- slightly movable (amphiarthroses)
- held together by interosseous membrane
- found in middle of radioulnar joint and tibiofibular joint
syndesmoses
slighlty movable joints
amphiarthroses
where are syndesmoses found
- middle of radioulnar joint
- middle of tibiofibular joint
joints united by fibrocartilage or hyaline cartilage
cartilaginous joints
two main types of cartilaginous joints
- synchondroses (primary cartilaginous)
- symphyses (secondary cartilaginous)
- bones are connected by hyaline cartilage
- immovable (synarthrosis)
- cartilage are ossified after a period of growth
synchondroses (primary cartilaginous)
where are synchondroses found
joint between diaphysis and epiphysis of growing long bone
- bones are united by a layer of fibrocartilage
- slightly movable
- usually permanent
- all are present in the midline of the body
symphyses (secondary cartilaginous)
example of symphyses
- pubic symphysis
- joints between vertebral bodies
- joint is enclosed in a fibrous capsule lined by synovial membrane that secretes synovial fluid
- freely movable (diarthrosis)
- most common joint within the human body
synovial joints
freely movable
diarthrosis
six types of synovial joints
- hinge
- pivot
- ball and socket
- condyloid
- saddle
- gliding/plane joint
different types of movement in joints
- flexion and extension
- adduction and abduction
- circumdiction
- internal and external rotation
decreases the angle between the bones (bending of the joint)
flexion
increases the angle and straightens the joint
extension
refers to moving a limb away from the midline of your body.
Abduction
refers to moving a limb toward the midline of your body.
Adduction
the movement of the limb, hand, or fingers in a circular pattern, using the sequential combination of flexion, adduction, extension, and abduction motions
circumdiction
refers to a shoulder or hip motion that causes the associated limb to rotate internally or toward the body.
Internal rotation
shoulder or hip motion that causes the limb to rotate externally or away from the body
External rotation
- uniaxial
- for flexion and extension
- elbow, knee
hinge joint
- uniaxial
- rotation of one bone around another
- top of the neck (atlas, axis)
pivot joint
- multiaxial
- flexion and extension, adduction and abduction, internal and external rotation
- shoulder, hip
ball and socket
- biaxial joints
- flexion and extension, adduction and abduction, circumduction
- radiocarpal (wrist) joints, metacarpophalangeal (knuckle) joints
condyloid joint
- biaxial
- resemble condyloid joints but allow greater freedom of movement
- flexion and extension, adduction and abduction, circumduction
- carpometacarpal (CMC) joint at the base of the thumb
saddle joint
- multiaxial but restricted by surrounding ligaments
- gliding
- intercarpal joints in the hands, intertarsal joints in foot
gliding/pivot joint
Functions of the skeletal system
- support and shape
- protection of vital organs
- movement facilitation
- storage
- blood cell production
Support and Shape
- skeleton support body against pull of gravity
- keeps body upright
Protection of Vital Organs
- forms bony covering around vital organs
- prevent physical injury
Movement Facilitation
- serve as points of attachment for muscles
- act as levers
Two types of Storage in Skeletal System
- mineral storage
- triglyceride storage
mineral storage
- stores calcium, phosphorus, and magnesium which facilitate growth and body repair
- helps in regulation of nutrients such as vitamin D
triglyceride storage
- yellow bone marrow
- energy reservoir of the body
Blood Cell Production
- aka hematopoiesis
- occurs in bone marrow
where does hematopoiesis start with
hematopoietic stem cells (HSCs)
what are hematopoietic stem cells (HSCs)
- proliferative and mulitpotent
- can become any type of blood cell
hematopoietic stem cell (HSCs) differentiates into what?
- myeloid progenitor cell
- lymphoid progenitor cell
undergo further differentiation and give rise to a variety of cell types involved in immune function, blood clotting, and oxygen transport
Myeloid progenitor cell
cell types the myeloid progenitor cell differentiate into
for
- immune function
- blood clotting
- oxygen transport
undergo further differentiateion and give rise to lymphocytes which are essential for adaptive immunity
lymphoid progenitor cell
Different bone cells
- osteoblast
- osteocyte
- osteoclast
- bone lining cells (BLC)
bone-forming cells that create new bone and help heal and grow existing bones
osteoblast
mature bone cells that sense mechanical stimuli and translate them into biochemical signals
osteocyte
cells that break down old or damaged bone tissue, creating space for enw bone growth
osteoclast
form a protective barrier on the surface of bones, preventing direct contact with osteoclasts
bone lining cells
refers to the process by which bone tissue is formed
ossification
Two types of ossification
- intramembranous ossification
- endochondral ossification
- occurs mainly in the flat bones of the skull, mandible, and clavicles
- bone forms directly from mesenchymal tissue (connective tissue)
- simpler and faster type of ossification
intramembranous ossification
where does intramembranous ossification mainly occur
- flat bones of skull
- mandible
- clavicle
where does bone directly form from in intramembranous ossification
mesenchymal tissue (connective tissue)
- occurs in majority of bones, especially long bones
- involves the replacement of a cartilage model with bone tissue
- cartilage first forms the framework, and over time, this framework is replaced by bone as the body grows
endochondral ossification
where does endochondral ossification occur
majority of bones, especially long bones
endochondral ossification involves the replacement of what?
cartilage model with bone tissue
process of endochondral ossification
- cartilage first forms framework
- overtime, this framework is replaced by bone as the body grows
what happens to osteoblasts once embedded in bone matrix
differentiate into osteocytes
small spaces where osteocytes reside
lacunae
how do osteocytes communicate with each other
through canaliculi (tiny channels)
what role do osteocytes play
detecting mechanical stress and signaling
what do osteoclasts release into the bloodstream
calcium and phosphate
Process of Bone Remodeling
- activation
- resorption
- reversal
- formation
- quiescence
osteoclast precursors are recruited to the remodeling site where they differentiate into mature osteoclasts
activation
mature osteoclasts attach to the bone surface and create an acidic environment to dissolve the mineralized bone matrix
resorption
digests collagen and minerals
cathepsin K
macrophages help clean up the resorbed area by removing debris, preparing for new bone formation
reversal
pre-osteoblasts differentate into osteoblasts and begin producing new bone matrix, called osteoid, which is mainly composed of collagen
formation
new bone matrix
osteoid
osteoid is mainly composed of what
collagen
surface is covered by lining cells (flattened osteoblasts), and the area returns to a resting phase until next remodeling cycle
quiescence
- continuous process by which old or damaged bone tissue is replaced with new bone
- process is essential for maintaining bone strength, repairing micro-damage, and regulating calcium levels in the body
bone remodeling
bone remodeling stages (image)
- resting state
- resorption
- reversal
- formation
- mineralization
- resting state
factors affecting bone growth
- genetics
- nutrition
- hormones
- physical activity
determines bone size, shape, and density
genetics
intake of calciu, phosphorus, and vitamin D is essential for bone mineralization
nutrition
vitamin that is necessary for collagen synthesis
vitamin C
vitamin that plays a role in bone metabolism
vitamin K
stimulate bone growth
hormones
what are the hormones that stimulate bone growth
- growth hormone
- thyroid hormone
- sex hormones (estrogen and testosterone)
mechanical stress and weight-bearing exercises stimulate bone remodeling and increase bone density
physical activity
states that bone in a healthy individual will adapt to the loads under which it is placed
Julius Wolff
Hormone Regulation
- parathyroid hormone
- calcitonin
- vitamin D
- secreted by parathyroid glands in response to low blood calcium levels
- stimulates osteoclasts to resorb bone and release calcium into the bloodstream
- also promotes the conversion of vitamin D into its active form (calcitriol), which enhances calcium absorption in the intestine and reabsorption in the kidneys
parathyroid hormone (PTH)
gland that secrete parathyroid hormone (PTH)
parathyroid glands
what do parathyroid hormone (PTH) promote
conversion of vitamin D into active form
active form of vitamin D
calcitriol
- produced by thyroid gland, acts to lower blood calcium levels when they are too high
- inhibits osteoclast activity, reducing bone resorption, and promotes calcium deposition into bone
calcitonin
gland that produce calcitonin
thyroid gland
- essential for proper calcium and phosphorus metabolism
- promotes bone mineralization by aiding in the availability of calcium and phosphate for bone formation
vitamin D
bone healing process
- hematoma formation
- fibrocartilaginous callus formation
- bony callus formation
- bone remodeling
- blood vessels in the bone and surrounding tissue are damaged
- clot serves as scaffold for the subsequent stages of healing and brings inflamattory cells to the site to clean up debris
hematoma formation
- fibroblasts and chondroblasts invade the fracture site and produce a soft callus of collagen and cartilage
- soft callus bridges the gap between the broken bone ends, providing initial stability
fibrocartilaginous callus formation
invade the fracture site and produce a soft callus of collagen and cartilage
fibroblasts and chondroblasts
bridges the gap between the broken bone ends, providing initial stability
soft callus bridges
soft callus is gradually replaced by a bone (hard) callus as osteoblast begin to deposit bone tissue
bony callus formation
what happens in bony callus formation
soft callus is gradually replaced by bony (hard) callus
- osteoclasts remove excess bone tissue from the fracture site, while osteoblasts refine the bone structure to restore its original shape and strength
- bone undergo this for a long period
bone remodeling
Different Skeletal Disorders
- osteoporosis
- scoliosis
- rickets
- bone fracture
- arthritis
- health condition that weakens bones
- this is due to aging, lack of pysical activity, hormonal changes, and nutritional deficiencies
osteoporosis
symptoms of osteoporosis
none
sideways curvature of spine that most often is diagnosed in adolescents
scoliosis
types of scoliosis
- idiopathic scoliosis
- congenital scoliosis
- neuromuscular scoliosis
- most common type of scoliosis
- cause is unknowen
idiopathic scoliosis
- rare spine abnormality that may be detected at birth
- vertebrae does not form during embryonic development
congenital scoliosis
- neurological (nerve) or muscular conditions like and injury
- due to abnormalities in the muscle and nerves
neuromuscular scoliosis
- condition that affects bone development in children
- causes bone pain, poor growth and soft, weak bones that can lead to bone deformities
- lack of vitamin D and calcium
rickets
- partial or complete break in the bone
- classified as open and close
bone fracture
classification of bone fracture
open and close fracture
types of bone fracture
- greenstick
- transverse
- spiral
- oblique
- compression
- comminuted
- segmental
- avulsion
- incomplete break
- commonly occurs due to injuries after a fall on an outstretched arm, and sports injuries
greenstick
- break is in a straight line across the bone
- cause by traumas like falls or car accidents
transverse
- break spirals across the bone
- caused by traumas like sport injuries when your bones are twisted with great force
spiral
- break is diagonal across the bone
- usually caused by landing on your bone at an angle after a fall
oblique
- break in a vertebra, it then collapses
- may be due to trauma or due to weakening of the vertebra
- most commono cause is osteoporosis
compression
- bone has broken into 3 or more places
- cause by fall from a great height
comminuted
- same bone is broken in 2 places
- caused by accidents that has a great impact to the bones
segmental
- bone is broken near a tendon or ligament
- overuse injuries that develop over time through repetitive stress on the bone, such as running
avulsion
- redness and swelling (inflammation) of a joint
- due to joint injuries, overuse, aging, and muscle weakness
arthritis
