Skelatal System Flashcards
skeletal system is made up of
bone tissue, cartilage, blood, dense connective tissue, and nervous tissue
Bone functions
attach to muscles, protect softer tissues, contain cells that produce blood, store salts, and form blood vessels and nerve passageways
work with muscles to
maintain body position and control precise movements
Flat bones
ribs, shoulder bones, certain skull bones
Irregular bones
many facial bones, spinal and pelvic vertebrae
Sesamoid (round) bones
inside tendons near joints in the knees, hands, and feet
Short bones
wrist and ankle bones
Long bones
arm, forearm, thigh, leg, palms, soles, fingers, toes
longer bone shafts with expanded ends
Long bones
At each end of long bones which articulate and connect with other bones
epiphysis
articular cartilage
What the articulating portion of long bone is coated in
epiphysis consists primarily of
spongy or cancellous bone
diaphysis
is connected to each epiphysis, and has walls consisting of a layer of compact or dense bone
relatively solid, contains a central space called the marrow cavity
Compact bone
A cellular layer lining the marrow cavity
endosteum
diaphysis portion forms a tube that contains
hollow medullary cavity
all bones are covered by
superficial periosteum layer
processes
create sites where ligaments and tendons can attach
osteocytes
occupy small chambers (lacunae)
create concentric circles around central (Haversian) canals in bones
(lacunae)
canaliculi
microscopic canals
Compact bones have a central canal that helps to make up cylinder-shaped osteons
Haversian systems
Hemopoiesis
the process of blood cell production that begins in the yolk sac of the developing embryo
occurs in the red bone marrow, which is located in some spongy bone
Red bone marrow contains
stem cells that form all of the blood cell types
hemoglobin
oxygen-carrying pigment of the red blood cells
yellow bone marrow
red bone marrow degenerates into a fatty tissue
Adults also have red bone marrow in
proximal epiphyses of the femur and humerus
certain portions of the axial skeleton
bones act as
levers
bones store
more than 90% of the minerals calcium and phosphorus
bone tissue is broken down so that they can be released into the bloodstream
When minerals are needed
Calcium is essential for
muscle contraction, blood clotting, and nerve impulse transmission
Phosphate
is required for ATP utilization
Bones begin to form during
the first six weeks after fertilization
Intramembranous bones
originate between layers of connective tissues that are “sheet-like” in appearance
Bone-forming cells develop, depositing bony matrix around them to become osteocytes
osteoblasts
Endochondral bones
begin as cartilaginous masses that are eventually replaced by bone tissue
develop from hyaline cartilage that is shaped similarly to the bones they will become
When a spongy bone begins to replace the original cartilage,
primary ossification center is created
will appear in the epiphyses, forming more spongy bone
secondary ossification centers
ossification
The process of replacing other tissues with bone
involves the deposition of calcium salts
Osteogenesis
formation of bone
Long bones are first formed of
hyaline cartilage, replaced by bony tissue that becomes compact bone
Osteogenesis begins with
Diaphysis and ends with epiphyses (endochondral ossification)
Flat bones are not formed via
intramembranous ossification
intramembranous ossification
bones develop from connective tissue membranes that are replaced by spongy bone, and then compact bone
exists where the diaphyses meet the epiphyses
It is made of:
–Reserve cartilage
–Proliferating (hyperplastic) cartilage
–Hypertrophic cartilage
–Calcified matrix
Epiphyseal Plate
the long bones can no longer grow
Once the epiphyseal plate experiences “closure”
cells that produce bone matrix – they are related to osteoprogenitor cells and osteocytes
Osteoblasts
mature osteoblasts that have become embedded in the bone matrix
Osteocytes
large, multinucleated bone cells – also known as osteophages
Osteoclasts/osteophages
Axial skeleton
supports and protects the head, neck, and trunk; includes the skull, hyoid bone, vertebral column, and thoracic cage
Appendicular skeleton
contains the upper and lower limb bones, as well as the bones anchoring the limbs to the axial skeleton; includes the pectoral girdle, upper limbs, pelvic girdle, and lower limbs
human skull is made up of
22 firmly interlocked bones
Skull bones divided into
Facial and cranium
lines where the bones of the skull lock together
sutures
mandible
is attached to the cranium by ligaments
Air-filled spaces inside the cranial bones
help the voice to resonate and also reduce the weight of the skull
paranasal sinuses
facial skeleton(14)
Maxillae – form the upper jaw, anterior roof of the mouth, floors of the eye orbits, and the nasal cavity sides and floor
–Zygomatic bones – form the cheek prominences below the eyes as well as the lateral walls and floors of the eye orbits
–Nasal bones – form the bridge of the nose
–Vomer bone – forms the nasal septum
–Inferior nasal conchae – support the mucous membranes of the cavity
Cervical vertebrae
7 structures that comprise the neck – the atlas (1st vertebrae) supports the head with two kidney-shaped facets; the axis (2nd vertebrae) has a process (dens) that it pivots around
Thoracic vertebrae
12 structures that increase in size, moving down the spine, which articulate with the ribs
Lumbar vertebrae
five structures in the lower back that are larger than the thoracic vertebrae, to support more body weight
triangular structure containing five fused vertebrae that form the vertebral column’s base
Sacrum
(tailbone) – the lowest part of the vertebral column, composed of four fused vertebrae
Coccyx
thorax
comprised of the thoracic cage, which includes 12 pairs of ribs, the sternum (breastbone), and costal cartilages attaching the ribs to the sternum anteriorly
true ribs
first seven
false ribs
The last five
floating
Final two ribs
pectoral girdle
made up of a clavicle (collarbone) and a scapula (shoulder blade) on each side
clavicles
collarbones) are shaped like rods with an elongated “S” shape
They are located at the base of the neck, bracing the scapulae to hold the shoulders in place
The scapulae
(shoulder blades) are somewhat triangular bones on either side of the upper back
Hand
wrist, palm, and fingers
metacarpals articulate with
carpals and phalanges (finger bones)
pelvic girdle
Two hipbones
which articulate with each other and the sacrum
attaches the lower limbs to the axial skeleton
sacrum, coccyx, and pelvic girdle form the pelvis
the largest portion of the hipbone, and forms the prominence of the hip
ilium
is the L-shaped, lowest portion of the hipbone – it supports the weight of the body when sitting
ischium
the anterior portion of the hipbone, and forms an angle known as the pubic arch
pubis
lower limbs
femur (thighbone)
kneecap (patella)
tibia (shinbone
fibula
made up of seven tarsal bones that are arranged so that the talus bone moves freely where it joins the leg bones
ankle (tarsus)
largest tarsal bone
calcaneus (heel bone)
is made up of five metatarsal bones
instep (metatarsus)
articulations
junctions between bones, and vary widely in structure and function
They are classified by how they move and according to the types of tissue that binds bones together at the joint
Joints
Joints are classified as:
Synarthrotic (immovable)
–Amphiarthrotic (slightly movable)
–Diarthrotic (freely movable)
–Fibrous
–Cartilaginous
–Synovial
total of 230 joints in the human body
Fibrous joints
lying between bones that closely contact each other – they are joined by thin, dense connective tissue
Cartilaginous joints
connected by hyaline cartilage (fibrocartilage), these joints include those that separate the vertebrae
those that allow free movement, are more complex, and have an inner lining that secretes synovial fluid, which lubricates the joint
Synovial joints
Some synovial joints have shock-absorbing fibrocartilage pads
menisci and/or fluid-filled sacs (bursae)
Ball and socket
Shoulders and hips
Condyloid(ellipsodial)
Between metacarpals and phalanges
Gliding plane
In wrists and ankles
Hinge
In elbows and phalanges
Pivot
Between proximal ends of radius and ulna
Saddle
Between carpal and metacarpal bones
Flexion
bending at a joint so that parts come closer together (opposite of extension)
Dorsiflexion
moving the ankle so that the foot comes closer to the shin (opposite of plantar flexion)
Hyperextension
extending parts at a joint beyond normal range of motion
Abduction
moving a part away from the body’s midline (opposite of adduction)
Rotation
moving a part around an axis
Circumduction
moving a part so that its end follows a circular path
turning the hand so that the palm is downward, facing posteriorly (opposite of supination)
Pronation
Turning the foot so the plantar surface faces laterally (opposite of inversion)
Eversion
moving a part backward (opposite of protraction)
Retraction
raising a part (opposite of depression)
Elevation
