Bones and Skeletal Tissue
Which type of cartilage is most plentiful in the adult body?
Which two body structures contain flexible elastic cartilage?
The epiglottis and external ear cartilage
Cartilage grows by intestinal growth. What does that mean?
Intestinal growth is growth from within
What is the functional relationship between skeletal muscles and bones?
Skeletal muscles use the bones as levers to cause movement in the body and its parts
List two types of substances stored in bone and state where is each is stored?
Bone matrix stores minerals (calcium and phosphate). Bone marrow cavities serve as sites for triglyceride (fat) storage.
What are the components of the axial skeleton?
The components of the axial skeleton are the skull, the vertebral column, and the rib cage
Contrast the general function of the axial skeleton to that of the appendicular skeleton.
The major function of the axial skeleton is to establish the long axis of the body and to protect structures that is encloses. The general function of the appendicular skeleton is to allow us mobility for propulsion and manipulation of our environment.
What bone class do the ribs and skull bones fall into?
The ribs and skull bones are flat bones.
In the figure, name the parts of the bone
What would happen to a bone if you removed all the inorganic components (for example, by soaking it in vinegar for several days)? Would it be able to resist compression? Tension?
Because acidic vinegar soaks away a bone's mineral salts, the bone becomes flexible and bends too easily to support weight, so it would not be good at resisting compression. However, its organic components, particularly collagen, would allow it to resist tension.
Label the medullary cavity and indicate the type of marrow found in the cavity. Label the compact bone. Label the periosteum and endosteum
Which cell has a ruffled border and acts to break down bone matrix? Which organelle would be the likely source of the enzyme that can digest bone matrix?
The osteoclast fits this description. The lysosomes would contain the matrix-digesting enzymes.
Bones don't begin with bone tissue. What do they begin with?
Bones begin as fibrous membranes or hyaline cartilages
When describing endochondral ossification, some say "bone chases cartilage". What does that mean?
The cartilage model grows, then breaks down and is replaced by bone.
Where is the primary ossification center located in a long bone? Where is (are) the secondary ossification center(s) located?
The primary ossification center is in a long bone is in the center of the shaft. The secondary ossification centers are in the epiphyses (bone ends)
As long as bone grows in length, what is happening in the hypertrophic zone of the epiphseal plate?
The chondrocytes are enlarging and their lacunae are breaking down and leaving holes in the cartilage matrix.
Which stimulus -PTH (a hormone) or mechanical forces acting on the skeleton - is more important in maintaining homeostatic blood calcium levels?
Parathyroid hormone maintains blood calcium levels.
How do bone growth and bone remodeling differ?
Bone growth increases bone mass, as during childhood or when exceptional stress is placed on the bones. Bone remodeling follows bone growth to maintain the proper proportions of the bone considering stresses placed upon it.
If osteoclasts in a long bone are more active than osteoblasts, how will bone mass change?
If bone-destroying cells (osteoclasts) are more active than bone-forming cells (osteoblasts), bone mass will decrease.
Despite daily exercise, the bones of astronauts in the International Space Station get thinner and weaker during their time in space. Why does this occur?
The bones of astronauts get thinner and weaker because they are deprived of the normal loading stresses that are p;laced on bones by gravity. Exercise that puts more stress on bones during space flight helps to some extent but cannot substitute for gravity.
How does an open fracture differ from a closed fracture?
In a open fracture, the bone ends are exposed to the external environment. In a closed fracture, the bone ends do not penetrate the external boundary of the skin.
Which bone disorder is characterized by excessive deposit of weak, poorly mineralized bone?
Paget's disease is characterized by excessive deposits of weak, poorly maintained bone.
What are three measures that may help to maintain healthy bone density?
Sufficient vitamin D, calcium, and wight bearing exercise all help to maintain healthy bone density.
What name is given to "adult rickets"?
Adult rickets is called osteomalacia
What is a function of the skeletal system?
support, hematopoietic site, storage, providing levers for muscle activity
Sites of hematopiesis include?
red marrow of spongy bone, the heads of femur and humerus in adults, medullary cavities in bones of infants
The organic portion of matrix is important in providing?
tensile strength, ability to resist stretch, flexibility
Bone remodeling in adults is regulated and directed mainly by?
mechanical stress and PTH
Where within the epiphyseal plate are the dividing cartilage cells located?
between the resting zone and the hypertrophic zone
Wolff's law is concerned with?
the shape of a bone being determined by mechanical stresses being put on it
Formation of the bony callus in fracture repair is followed by?
The fracture type in which the bone ends are incompletely separated is?
The disorder in which bones are porous and thin but bone composition is normal
Describe the proper sequence the events of endochondral ossification in a large bone.
The steps to the endochodral ossification in a long bone are
1. a bone collar forms around the diaphysis of the hyaline cartilage model
2. cartilage in the center of the diaphysis calcifies and then develops cavities
3. the periosteal bud invades the internal cavities and spongy bone forms
4. the diaphysis elongates and a medullary cavity forms, secondary ossification centers appear in the epiphyses
5. the epiphyses ossify
A bone with approximately the same width, length and height is most likely?
a short bone
Which is a function of the skeletal system?
support, hematopoietic site, storage, providing levers for muscle activity
The shaft of a bone is properly called the
an osteon has
a central canal carrying blood vessels, concentric lamellae, osteocytes in lacunae, canaliculi that connect lacunae to the central canal
the flat bones of the skull develop from
fibrous connective tissue
the remodeling of bone is a function of which cells
osteoblasts and osteoclasts
bone remodeling in adults is regulated and directed maily by
mechanical stress, PTH
What bones are the keystone bones of the facial skeleton?
What bone forms the bulk of the orbit floor, and what sense organ is found in the orbit of the living person?
The maxillae form the bulk of the orbit floor. The eye is housed in the orbit.
Sutures of the skull
Bones of the skull
Nathan was vigorously exercising the only joints in the skull that are freely movable. What would you guess he was doing?
Eating or talking, because the only freely movable joints in the skull are the temporomandibular joints of the jaw.
Suppose you work in the coroner's office. The skeleton of a potential murder victim has arrived. It has a fractured hyoid bone. What is the likely cause of death?
The hyoid bone is in the neck. so a fractured hyoid bone suggest death by strangulation.
You have learned about two different processes of bone formation in the embryo. Name the process that leads to formation of most of the skull bones. Name the embryonic connective tissue that is converted to bone during this process.
Most of the skull bones are formed by intramembraneous ossicication in which bone is formed from embryonic tissue called mesenchyme, which contains mesenchymal cells.
Besides the spinal curvatures, which skeletal elements help to make the vertebral column flexible?
Fibrocartilage discs contribute to the flexibility of the vertebral column.
How can you distinguish a lumbar vertebra from a thoracic vertebra?
A lumbar vertebra is heavier and its massive body is kidney shaped. It's spinous processes are short and project directly back. A thoracic vertebral body is generally heart shaped, it's spinous process is long, sharp, and points downward and its transverse processes have facts for articulationg with the ribs.
Vertebral column 5 regions
How does a true rib differ from a false rib?
A true rib connects to the sternum by it's own costal cartilage. A false rib connects to the sternum via costal cartilages of other ribs or not at all
What does the tubercle of a rib articulate with?
The tubercle of a rib articulates with the costal facet of the transverse process of the thoracic vertebra that has the same number as the rib
Besides the ribs and sternum, there is a third group of bones making up the thoracic cage, what is it?
What two bones construct each pectoral girdle?
Scapula and Clavicle
Where is the single point of attachment of the pectoral girdle to the axial skeleton?
The pectoral girdle attaches tot he sternal manubrium of the axial skeleton via the medial end of its clavicle.
What is the major shortcomings of the flexibility allowed by the shoulder joint?
A consequence of its flexibility is that it is easily dislocated.
5 joints of the shoulder
Which bones play the major role in forming the elbow joint?
Ulna and the humerus form the elbow joint.
Which bones of the upper limb have a styloid process?
Ulna and radius each have a styloid process distally.
Where are the carpals found and how would you classify them based on their shape?
Carpals are found in the proximal region of the palm. They are classified as short bones.
The ilium and pubis help to form the hip bone. What other bone is involved in forming the hip bone?
The pelvic girdle is a heavy, strong girdle. How does its structure reflect its function?
The pelvic girdle receives the weight of the upper body and transmits that weight to the lower limbs.
3 regions of the hip bone and the bone that articulates with this socket?
What lower limb bone is the 2nd largest bone in the body?
Bones of the leg
Which of the following sites is a site of muscle attachment?
Greater trochanter, lesser trochanter, fluteal tuberosity
Besides supporting weight, what is the major functions of the arches of the foot?
Save energy during locomotion
What are the two largest tarsal bones in each foot, and which one forms the heel of the foot?
Talus and the calcaneus
Calcaneus forms the heel
Connected by the coronal suture
keystone bone of cranium
keystone bone of the face
form the hard palate
allows the spinal cord to pass
forms the chin
contain paranasal sinuses
contains mastoid sinuses
bone of the axial skeleton to which the pectoral girdle attaches
markings include glenoid cavity and acromion
features include the ala, crest, and greater sciatic notch
doubly curved; acts as a shoulder strut
hip bone that articulates with the axial skeleton
the "sit-down" bone
anteriormost bone of the pelvic girdle
part of the vertebral column
articulates with the acetabulum and the tibia
forms the lateral aspect of the ankle
bone that "carries" the hand
the wrist bones
end shaped like a monkey wrench
articulates with the capitulum of the humerus
largest bone of this "group" is the calcaneus
Which vertebral curvatures are primary and which are secondary curvatures? Why are they called primary and secondary?
Thoracic and Sacral curvatures are called primary because they are present at birth
Cervical and lumbar curvatures are called secondary because they develop after birth.
What is the function of the intervertebral discs?
Act as shock absorbers and provide flexibility to the spine allowing it to flex and extend.
Which ribs are floating ribs and why are they called that?
Rib pairs 11 and 12 are floating ribs because they are not attached to the sternum anteriorly
List 3 important differences between the male and female pelvis
1. the female pelvic inlet and outlet are wider
2. the female pelvis is wider, shallower, and lighter
3. the female ischial spines are farther apart
Frontal Bone : Coronal suture
Parietal Bones: Sagittal suture, Squamous suture
Temporal Bones: External Auditory Meatus; Mastoid Process; Styloid Process; Zygomatic Process
Occipital Bone: Foreman Magnum; Lambdoid suture;
Ethmoid Bone: Perpendicular plate; Crista galli; superior and middle nasal concha; Cribiform plate
Sphenoid Bone: Sella turcica
External Auditory Meatus
superior and middle nasal concha
Inferior Nasal Concha
Cervical Vertebra (1-7)
Transverse Process with Transverse foramen; Spinous process (bifid); Body (except 1 &2 shallow, small, oval); superior articulation facets face superior, while inferior articulation facets face inferior
No Body; No spinous process
Dens (instead of Body)
Thoracic vertebra (1-12)
Transverse Processes (1-10 with facet to articulate rib); Spinous process angles inferiorly; Body is heart shaped (demifacets on body articulate with rib head); superior articulation facets face ventral, while posterior articulation facets face dorsal
Lumbar Vertebra (1-5)
Thick, oval Body; Spinous process is hatchet shaped; inferior/superior articulation facets face laterally (like clapping hands)
Sacral Vertebra (1-5)
fuse between 15-25 yrs. Old; 4 pair pelvic foramina; dorsal spinous processes fused into ‘median sacral crest’; sacral side part of sacroiliac joint
4-5 fuse at 20-30 yrs. Old; can be fractured
Sternum: Manubrium; Body; Xiphoid process; Sternal angle
Scapula: Glenoid (Glenohumoral joint) fossa; Spine; Acromion; Coracoid process
Humerus: Head; Greater Tubercle; Lesser Tubercle; Deltoid tuberosity; Surgical Neck; Trochlea; Capitulum; Olecranon fossa
Radius: Head; Neck
Ulna: Olecranon process
Wrist / Hand
Carpals: Triquetrum; Lunate; Scaphoid; Trapezoid; Trapezium; Capitate; Hamate; Pisiform
Metacarpals: Numbered with Roman Numerals I through V [ I (1); II (2); III (3); IV (4); and V (5)] starting at the Thumb
Phalanges: Proximal Numbered with Roman Numerals I through V; Middle numbered Roman Numerals II through V (because the Thumb does not have a middle phalynx); Distal is numbered Roman Numerals I through V.
Pelvic Gridle: Acetabulum
Ilium: Iliac crest; Sacroiliac joint
Ischium: Ischial tuberosity
Pubis: Pubic symphysis
Femur: Head; Neck; Greater Trochanter; Lesser Trochanter; fovea
Tibia: Tibial tuberosity; Medial malleolus
Fibula: Lateral malleolus
Tarsals: Calcaneus; Talus; Navicular
Metatarsals: Numbered with Roman Numerals I through V [ I (1); II (2); III (3); IV (4); and V (5)] starting at the Big Toe
Phalanges: Proximal Numbered with Roman Numerals I through V; Middle numbered Roman Numerals II through V (because the Big Toe does not have a middle phalynx); Distal is numbered Roman Numerals I through V.
2 Inferior nasal conchae
7 Cervical vertebrae
12 Thoracic vertebrae
5 Lumbar vertebae
2 Hip bone
20 Proximal phalanges
16 Intermediate phalanges
20 Distal phalanges
2 Medial cuneiform
2 Intermediate cuneiform
2 Lateral cuneiform