CH6 Bone Tissue and the Skeletal System
Endochondral ossification follows five steps.
(a) Mesenchymal cells differentiate into chondrocytes. (b) The cartilage model of the future bony skeleton and the perichondrium form. (c) Capillaries penetrate cartilage. Perichondrium transforms into periosteum. Periosteal collar develops. Primary ossification center develops. (d) Cartilage and chondrocytes continue to grow at ends of the bone. (e) Secondary ossification centers develop. (f) Cartilage remains at epiphyseal (growth) plate and at joint surface as articular cartilage.
Where two bones meet Bone Markings Examples
Articulations Knee joint
Long Bone: Features Function(s) Examples
Cylinder-like shape, longer than it is wide Leverage Femur, tibia, fibula, metatarsals, humerus, ulna, radius, metacarpals, phalanges
Inhibits osteoclast activity and stimulates calcium uptake by bones
Calcitonin
Stimulates absorption of calcium and phosphate from digestive tract
Calcitriol
form the hydroxyapatite crystals that give bone its hardness
Calcium
Passage in bone Bone Markings Examples
Canal Auditory canal
Types of Fractures: A fracture in which the skin remains intact
Closed (or simple)
Types of Fractures: Several breaks result in many small pieces between two large segments
Comminuted
Irregular Bone: Features Function(s) Examples
Complex shape Protect internal organs Vertebrae, facial bones
Rounded surface Bone Markings Examples
Condyle Occipital condyles
Ridge Bone Markings Examples
Crest Iliac crest
Short Bone: Features Function(s) Examples
Cube-like shape, approximately equal in length, width, and thickness Provide stability, support, while allowing for some motion Carpals, tarsals
Flat surface Bone Markings Examples
Facet Vertebrae
Slit through bone Bone Markings Examples
Fissure Auricular fissure
Structural component of bone
Fluoride
Hole through bone Bone Markings Examples
Foramen Foramen magnum in the occipital bone
Elongated basin Bone Markings Examples
Fossa Mandibular fossa
Small pit Bone Markings Examples
Fovea Fovea capitis on the head of the femur
Types of Fractures: A partial fracture in which only one side of the bone is broken
Greenstick
Prominent rounded surface Bone Markings Examples
Head Head of femur
Holes and depressions Bone Markings Examples
Holes Foramen (holes through which blood vessels can pass through)
a condition characterized by abnormally low levels of calcium, can have an adverse effect on a number of different body systems including circulation, muscles, nerves, and bone.
Hypocalcemia
Types of Fractures: One fragment is driven into the other, usually as a result of compression
Impacted
Slight, elongated ridge Bone Markings Examples
Line Temporal lines of the parietal bones
Structural component of bone
Magnesium
Opening into canal Bone Markings Examples
Meatus External auditory meatus
Types of Fractures: Occurs at an angle that is not 90 degrees
Oblique
Reduces inflammation that may interfere with osteoblast function
Omega-3 fatty acids
Types of Fractures: A fracture in which at least one end of the broken bone tears through the skin; carries a high risk of infection
Open (or compound)
Stimulates osteoclast proliferation and resorption of bone by osteoclasts; promotes reabsorption of calcium by kidney tubules; indirectly increases calcium absorption by small intestine
Parathyroid hormone
Prominence feature Bone Markings Examples
Process Transverse process of vertebra
Raised markings Bone Markings Examples
Projections Spinous process of the vertebrae
Protruding Bone Markings Examples
Protuberance Chin
____ fills the spaces in the spongy bone.
Red marrow
is where hematopoiesis—the production of blood cells—takes place. Red blood cells, white blood cells, and platelets are all produced
Red marrow
resorption of old or damaged bone takes place on the same surface where osteoblasts lay new bone to replace that which is resorbed. & Injury, exercise, and other activities
Remodeling
These bones form in tendons (the sheaths of tissue that connect bones to muscles) where a great deal of pressure is generated in a joint.
Sesamoid bone
Promote osteoblastic activity and production of bone matrix; responsible for adolescent growth spurt; promote conversion of epiphyseal plate to epiphyseal line
Sex hormones
Air-filled space in bone Bone Markings Examples
Sinus Nasal sinus
Sesamoid Bone: Features Function(s) Examples
Small and round; embedded in tendons Protect tendons from compressive forces Patellae
Sharp process Bone Markings Examples
Spine Ischial spine
Types of Fractures: Bone segments are pulled apart as a result of a twisting motion
Spiral
Groove Bone Markings Examples
Sulcus Sigmoid sulcus of the temporal bones
Flat Bone: Features Function(s) Examples
Thin and curved Points of attachment for muscles; protectors of internal organs Sternum, ribs, scapulae, cranial bones
Stimulates bone growth and promotes synthesis of bone matrix
Thyroxine
Types of Fractures: Occurs straight across the long axis of the bone
Transverse
Small, rounded process Bone Markings Examples
Tubercle Tubercle of humerus
Rough surface Bone Markings Examples
Tuberosity Deltoid tuberosity
Needed for calcium absorption
Vitamin D
Supports bone mineralization; may have synergistic effect with vitamin D
Vitamin K
contains adipose tissue; the triglycerides stored in the adipocytes of the tissue can serve as a source of energy
Yellow marrow
a thin layer of cartilage that reduces friction and acts as a shock absorber.
articular cartilage
is where two bone surfaces come together
articulation
The nerves sense pain, and it appears the nerves also play roles in regulating ___ (2), hence their concentrations in metabolically active sites of the bone.
blood supplies and in bone growth
The periosteum contains ____(3) that nourish compact bone. ____ (2) also attach to bones at the periosteum.
blood vessels, nerves, and lymphatic vessels Tendons and ligaments
The process in which matrix is resorbed on one surface of a bone and deposited on another is known as ____.
bone modeling
channels within the bone matrix.
canaliculi
The only short bones in the human skeleton are in the ____ and the ____.
carpals of the wrists tarsals of the ankles
The walls of the diaphysis are composed of dense and hard ____.
compact bone
The two layers of ____ (2) work together to protect the internal organs
compact bone and the interior spongy bone
is the tubular shaft that runs between the proximal and distal ends of the bone.
diaphysis
Flat bones, like those of the cranium, consist of a layer of ____ (spongy bone), lined on either side by a layer of compact bone
diploë
In ____ ossification, bone develops by replacing hyaline cartilage.
endochondral
The medullary cavity has a delicate membranous lining called the ____ , where bone growth, repair, and remodeling occur.
endosteum
The periosteum covers the entire outer surface except where the ____ meet other bones to form joints. In this region, the epiphyses are covered with ____
epiphyses articular cartilage
The wider section at each end of the bone is called the ____, which is filled with ____.
epiphysis spongy bone
Bone also serves as a site for ____ and ____.
fat storage blood cell production
Increases length of long bones, enhances mineralization, and improves bone density
growth hormone
is an opening or groove in the bone that allows blood vessels and nerves to enter the bone
hole
The ____ crystals give bones their hardness and strength, while the collagen fibers give them ____ so that they are not brittle.
hydroxyapatite flexibility
a condition characterized by abnormally high levels of calcium, the nervous system is underactive, which results in lethargy, sluggish reflexes, constipation and loss of appetite, confusion, and in severe cases, coma.
hypercalcemia
The flat bones of the face, most of the cranial bones, and the clavicles (collarbones) are formed via ____
intramembranous ossification.
Each osteocyte is located in a space called a ____ and is surrounded by bone tissue.
lacuna
found at the borders of adjacent lamellae.
lacunae
Each osteon is composed of concentric rings of calcified matrix called ____
lamellae
The hollow region in the diaphysis is called the _____, which is filled with yellow marrow.
medullary cavity
Each epiphysis meets the diaphysis at the____
metaphysis
the narrow area that contains the epiphyseal plate (growth plate), a layer of hyaline (transparent) cartilage in a growing bone.
metaphysis
The arteries enter through the ____, small openings in the diaphysis
nutrient foramen
When the bone stops growing in early adulthood (approximately 18-21 years), the cartilage is replaced by ____ tissue and the epiphyseal plate becomes an ____.
osseous epiphyseal line
early osteoblasts appear in a cluster called an ____.
ossification center
is the bone cell responsible for forming new bone and is found in the growing portions of bone, including the periosteum and endosteum.
osteoblast
Four types of cells are found within bone tissue:
osteoblasts, osteocytes, osteogenic cells, and osteoclasts
The cell responsible for bone resorption, or breakdown
osteoclast
the primary cell of mature bone and the most common type of bone cell
osteocyte
These osteogenic cells are undifferentiated with high mitotic activity and they are the only bone cells that divide.
osteogenic cell.
uncalcified matrix, which calcifies (hardens) within a few days as mineral salts are deposited on it, thereby entrapping the osteoblasts within.
osteoid
The microscopic structural unit of compact bone
osteon
also known as Volkmann's canals
perforating canal
The outer surface of the bone is covered with a fibrous membrane called the ____
periosteum
By the second or third month of fetal life, bone cell development and ossification ramps up and creates the ____, a region deep in the periosteal collar where ossification begins
primary ossification center
is an area of a bone that projects above the surface of the bone
projection
is the next layer toward the diaphysis and contains stacks of slightly larger chondrocytes.
proliferative zone
The longitudinal growth of bone is a result of cellular division in the ___ and the maturation of cells in the ____.
proliferative zone zone of maturation and hypertrophy
is the region closest to the epiphyseal end of the plate and contains small chondrocytes within the matrix.
reserve zone
After birth, this same sequence of events (matrix mineralization, death of chondrocytes, invasion of blood vessels from the periosteum, and seeding with osteogenic cells that become osteoblasts) occurs in the epiphyseal regions, and each of these centers of activity is referred to as a ____.
secondary ossification center
the lacunae and osteocytes are found in a lattice-like network of matrix spikes called ____.
trabeculae
Intramembranous ossification begins in ____ during fetal development and continues on into adolescence.
utero
the zone closest to the diaphysis, are dead because the matrix around them has calcified.
zone of calcified matrix
are older and larger than those in the proliferative zone.
zone of maturation and hypertrophy