the skeletal systemlincolnhs.org/ourpages/auto/2013/4/18/55390628/notes_the skeletal system.pdf ·...
TRANSCRIPT
What is the skeleton?
Humans have an endoskeleton that develops from
mesenchyme cells of the mesoderm.
Composed of
Bones
Cartilage
Ligaments: bone-to-bone
Tendons: muscle to bone
The Human Skeleton
Divided into two main regions
Axial skeleton
Spine, rib cage, skull
Appendicular skeleton
Upper Appendages (extremities)
Arms, hands, wrists
Lower Appendages (extremities)
Legs, feet, hips
The Human Skeleton
Articulations: where two bones meet to make a
joint
Surface features: protrusions and edges on the bone
Sites of tendon and ligament attachment
Projections that help form joints
Depressions and openings allowing blood vessels and
nerve fibers to pass
Sites of muscle and ligament
attachment
- Trochanter – large, blunt,
irregularly shaped process
(Only found on the femur)
Spine
- Spine – sharp, slender, often pointed projection
Fossa
- Fossa – shallow basin like depression in bone
Axial Skeleton
Made up of the
Skull
Cranial bones
_______ (skull cap)
Cranial base
Facial Bones
Held together by _____
Vertebral Column
Rib cage
Axial Skeleton: Skull
Skull
Cranial Bones
Calvaria (skull cap)
Cranial base
Facial bones
Held together by sutures
Axial Skeleton: Skull
Cranial Bones: Calvaria (skull cap)
parietal
temporal
occipital
frontal
sphenoid
ethmoid
Coronal suture
squamosal suture
lambdoid suture
Axial Skeleton: Skull
Cranial Bones
Frontal: makes up the forehead and eyebrow ridges
Upper part of the orbits (eye sockets)
Thicker area above the orbits is the supra-orbital ridge
Temporal: has a flat portion, along with…
mastoid process: where neck muscles attach
styloid process: attachment for neck & throat muscles
tympanic region: contain the ear bones
zygomatic process (arch): forms the cheek bone and articulates with the mandible
Parietal: helps protect brain
Axial Skeleton: Skull
Cranial Bones
Occipital: posterior base of the cranium
Formed of several bones that fuse and leave an opening called
the foramen magnum
Occipital condyles attach the head to the vertebral column
Axial Skeleton: Skull
Mandible:
alveolus, body, condyle,
and ramus
Tooth Anatomy:
crown: covered by enamel
(made of calcium)
Axial Skeleton
Vertebral Column
Flexible column that
protects the spinal cord
Two major types of bone
True (movable) vertebrae
Cervical vertebrae:
supports the head and
allows it to rotate
Axial Skeleton
Thoracic Vertebrae
Has two articulation
points with the ribs;
allows the ribs to flex for
breathing
Lumbar Vertebrae
Larger and thicker than
other vertebrae
Supports most of body’s
weight
Axial Skeleton
False (fixed) vertebrae
Fused to one another;
don’t move
Sacrum: fuses with pelvis
Coccyx: tailbone; attachment
point for muscles of the
upper leg
Axial Skeleton
Rib Cage (thorax): protective structure that also aids in breathing
Costal cartilage
Ribs
True ribs: attach to sternum
False ribs: floating
Sternum
Manubrium
Gladiolus
Xiphoid process: attachment for stomach muscles
Appendicular Skeleton
Superior extremities (upper appendages)
Shoulder girdle
Clavicle (collarbone): long bone that runs parallel to first rib
Attachment for muscles of the arms, back, chest, and neck
Scapula (shoulder blade): flat bone, parallel to vertebrae
Attachment for muscles that move the shoulders and arms
Appendicular Skeleton
Arm Bones
Humerus: largest bone of
the upper arm
Radius: shorter forearm
bone; located thumb side
Ulna: longer forearm bone
Olecranon process (elbow)
Trochlear notch:
articulates with the
humerus
Appendicular Skeleton
Hand Bones
Carpals: wrist bones
Metacarpals: form the palm
of the hand
Phalanges: finger bones
Appendicular Skeleton
Inferior Extremities (lower appendages)
Pelvic bone: supports body weight
Acetabulum: forms the point of articulation with the femur
Obturator foramen: passage for major blood vessels and nerves
Appendicular Skeleton
Inferior Extremities
Leg bones
Femur: longest and
strongest bone of the
body
Tibia (shin bone)
Fibula: smaller, lateral
bone of the leg
Patella (knee-cap)
Appendicular Skeleton
Inferior Extremities
Foot bones
Tarsals: forms ankle
Metatarsals: arch of the
foot
Phalanges: toes
Bone
Bone tissue is called osseus
Bone types (shape)
a) Long (femur, phalanges)
b) Short (carpals, tarsals)
c) Flat (skull bones)
d) Irregular (vertebrae)
e) Sesamoid (patella)
Bone Structure
External
Periosteum: connective tissue that surrounds the bone
Important in bone growth, maintenance, and healing
Contains blood vessels and nerves providing the nutrition and
nutrition
Where tendons and ligaments attach
Bone Structure
Diaphysis: shaft
Epiphysis: ends of bone;
contain red marrow
Epiphyseal plate: found
between diaphysis and
epiphysis; long bone growth
Hyaline cartilage: covers the
articular surface of bones
Internal Features
Compact (cortical) bone:
rigid outer shell of the
bone; 20% of structure,
80% of weight
Osteon: structural unit of
compact bone tissue
Haversian canal: internal
structure of osteon; blood
vessels and nerves pass
through here
Internal Features
Osteocytes: cell of bone tissue; secrete bone matrix Bone matrix composed of
collagen fibers and osteocalcin (contain calcium salts)
Lacunae: cavities that store osteocytes
Connect to each other and to blood vessels through canaliculi
Volkmann’s canals: carry blood vessels and nerves of the periosteum to the central Haversian canals
Internal Features
Cancellous
(trabecular/spongy)
bone: forms the ends of
the long bones and the
center of the other
bones; 80% structure;
composed of
honeycomb-like network
bony struts; less dense
and more flexible than
compact
Internal Features
Medullary (marrow) cavity: hollow center of long bones; bordered by spongy bone and lined with a thin layer of connective tissue called endosteum (capable of generating new bone cells); filled with bone marrow
Yellow marrow: consists of fat cells; act as food reserve for bone cells
Red marrow: produces red blood cells
Joints
Joints: some accompanied by a bursa that contains
synovial fluid.
Type of movement depends on
The manner in which the bones fit together
The tightness of fit between the articular surfaces
The tension of the tissues forming the articulation
The position of the ligaments, muscles, and tendons
associated with the joints
Joints
Structural
Cartilaginous: cartilage covers the articulating bone surfaces;
example is the pubic bones
Fibrous: articulated bones are attached by fibrous
connective tissue; example is between the radius and
ulna
Synovial: articulating surfaceis coverd with a fluid-filled,
fibrous, connective-tissue sack called the synovial
capsule; examples are elbows and knees
Joints
Functional
Synarthrosis: permit no movement;
Gomphosis: formed by a conical process; it is held in a socket by a
ligament; teeth
Syndesmosis: formed when two bones are joined by one or more
ligaments; example is the joint that holds together the tibia and
fibula in the ankle region
Synchondrosis (symphysis) joints: two bones join together by a
piece of cartilage
Synostosis (sutures): formed by the fusion of two bones
Amphiarthrosis: slight movement
Joints
Diarthrosis: provide variety of movements; synovial joints
Ball-and-socket: wide array of movements; like the hip and shoulder
Condyloid (ellipsoid): occurs where a ball-like articular surface rests against the curve-shaped end of the another articular surface; examples: knee between radius and carpals
Joints
Gliding: side-to-side
movements; carpals
Hinge: permit angular
motion along one
plane; example: elbow,
knee, ankle joint
Joints
Pivot: allows rotation;
example: invertebral
joints
Saddle: resemble a
saddle in which one
articular surface rocks
back and forth upon
another; joint of thumb
Bone Growth
Bone-forming cells (osteoblasts and osteoclasts)
move into the cartilage pegs helping to sculpt
growing bones
Osteoblasts build bone tissue
Osteoclasts break down bone and cartilage; carve &
sculpt bone
Process
osteoclasts carve out a cavity in the center of the
cartilage pegs
blood vessels begin to grow into bone entering the
cavity, providing nutrients for bone growth and
maintenance
Process
osteoblasts enter and start secreting the bone
tissue to replace the cartilage
compact bone is deposited first, then converted
into spongy bone as the cavity enlarges
Homeostatic Imbalance
Fracture – a break in the bone
Open fracture – bone penetrates through the skin
Closed fracture – bone does not penetrate skin
Fracture treatment
Closed reduction – physician pulls on bone to
realign bone ends
Open reduction – physician surgically inserts
pins or wires to realign bones
Shin Splint
Shin Splint: a painful condition of the anterior
lower leg that develop from overuse of the ankle
joint
NOT the same as
a stress fracture
Bone and Joint Problems
Arthritis: a condition causing swelling and
stiffness in the joints
Osteoarthritis: deterioration of the articular
cartilage covering the ends of bones
Bone and Joint Problems Rheumatoid arthritis: a condition in which the
immune system attacks connective tissues
Bone and Joint Problems Ankylosing spondylitis: arthritis that affects
the spine; causes the fusion of the vertebrae
Organ-System Diseases
Gout: a metabolic disorder that causes oxalic
acid build-up severe inflammation of
connective tissues throughout body
Organ-System Diseases
Systemic Lupus erythematosus: an
autoimmune disease that attacks body’s own
proteins and connective tissues
Organ-System Diseases
Scleroderma: connective tissue disorder that
causes thickening of skin and abnormal growth
of connective tissues; autoimmune disease
Organ-System Diseases
Fibromyalgia: disorder that causes widespread
joint pain; no degeneration of tissues… patients
look normal.
Osteoporosis
Osteoporosis: degenerative bone disorder; can
occur at any age
Causes:
Malnutrition or undernutrition (not enough calcium-
rich foods or vitamin D)
Decreased levels of sex hormones
Smoking
Excessive alcohol consumption
A less severe case is bone density loss.
Tooth Decay Tooth decay: tooth destruction caused by bacteria.
Enzymes created by bacteria remove calcium, and
break down matrix of tooth leading to a cavity
Advanced tooth decay leads to teeth loss and
destruction of underlying jawbone structure
Myeloma
Myeloma: a cancer of red bone marrow;
weakens the immune system
Most common treatment is chemotherapy with
thalidomide
Osteonecrosis Osteonecrosis: a condition caused by osteocyte
death due to the obstruction of blood flowv
The Aging process
Bone is regularly broken down as new bone is
added
Rate of bone production is greater in young
people bones are denser, heavier, and larger
As we grow older, osteoclast activity outpaces
the bone rebuilding activity of the osteoblasts.