Unit 2 Chapter 6 (Bone Tissue and the Skeletal System) Flashcards
What components make up the axial skeleton
skull (cranial and facial), auditory ossicles (ears), hyoid (tongue and neck attachment), vertebral column (sacrum, cervical/lumbar/thoracic vertebrae), bony thorax (ribs, sternum)
What components make up the appendicular skeleton
pectoral girdle (clavicle and scapula), upper extremities (humerus, radius, ulna, carpals), pelvic girdle (coxal bones; ilium, ischium, pubic), lower extremities (femur, patella, tibia, fibula, tarsals)
What are the 3 classes of bone markings
articulations, projections, holes
What is an articulation
where two bone surfaces come together and conform to each other to facilitate functions (joints)
What is a projection
Area on the surface of the bone that servers as the attachment points for tendons and ligaments. Size and Shape is an indication of the forces exerted through the attachment to the bone.
What is a hole
An opening or groove in the bone that allows blood vessels and nerves to enter the bone. Size and Shape reflect the size of the vessels and nerves that penetrate the bone at these points.
What are the functions of the skeletal system
-Supports soft tissues and provides attachment points for tendons of skeletal muscles
-Protects the most important internal organs
-Assists in movement by acting as levers for skeletal muscles
-Osseous tissue stores and releases minerals, particularly calcium and phosphorus
What is the function of red bone marrow
produces blood cells (hematopoiesis)
What is the function of yellow bone marrow
stores fat
What are the 5 classifications of bone
-long bones
-short bones
-flat bones
-irregular bones
-sesamoid bones
How are long bones described and what is an/are example(s)
greater length than width
tibia, fibula, femur, humerus, radius
How are short bones described and what is an/are example(s)
nearly equal in length and width
carpal bones, tarsal bones
How are flat bones described and what is an/are example(s)
thin
skull, ribs, pubis
How are irregular bones described and what is an/are example(s)
complex in shape
vertebrae, sacrum, hyoid
How are sesamoid bones described and what is an/are example(s)
shaped like a sesame seed
patella, cyamella, fabella
What is the function of articular cartilage
Reduces friction and acts as a shock absorber.
What is the function of periosteum
Contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments also attach to bones here. Also covers the entire outer surface except where the epiphyses meet other bones to form joints.
What is the function of the medullary cavity
Holds yellow bone marrow inside the diaphysis
What is the function of the endosteum
Where bone growth, repair, and remodeling occur
Where is yellow bone marrow located in a long bone
Medullary cavity; hollow region of the diaphysis
Give a description of the extracellular matrix of osseous tissue
ground substance (osteoid)(organic), collagen fibers (gives tensile strength and flexibility)(inorganic), Hydroxyapatites (calcium phosphate salt crystals)
What are hydroxyapatites
Salt crystals that form when calcium phosphate and calcium carbonate combine.
What is the function of hydroxyapatites
Gives bones their hardness and strength
What is the function of osteoblasts
Bone cell responsible for forming new bone and is found in the growing portions of bone
What is the function of osteocytes
Maintain the mineral concentration of the matrix via the secretion of enzymes
What is the function of osteoclasts
Bone resorption or breakdown
What is the difference between spongy and compact bone tissue in terms of bone type
-Compact bone forms external layer of all bones and comprises most of the diaphysis of long bones.
-Spongy bone forms interior of short, flat, irregular, and sesamoid bones, most of epiphysis of long bones, and narrow rim around medullary cavity of long bones
What is the difference between spongy and compact bone tissue in terms of bone function
Compact bone provides support and protection
Spongy bone provides strength and flexibility
What is the difference between spongy and compact bone tissue in terms of bone histology
Compact bone is composed of osteons and forms the external layer of all bones.
Spongy bone is composed of trabeculae and forms the inner part of all bones.
What is the sequence of passageways in compact bone tissue a nutrient encounters from the time it flows from the periosteum until it reaches an osteocyte within an osteon.
Starts at the blood supply of the medullary cavity through perforating (Volkmann’s) canals that meet up with a central canal for each osteon. From a central canal, canaliculi connect with osteocytes.
What are the locations of red bone marrow
medullary cavity of flat bones, spongy bone found at the proximal and distal epiphysis
What tissue does intramembranous ossification occur in
Conversion of mesenchymal tissue into bone. Primarily occurs in the bones of the skull
What tissue does endochondral ossification occur in
Mesenchymal tissue transforming into a hyaline cartilage template, which is later replaced by bone. Forms axial skeleton and long bones
Describe the overall process of intramembranous ossification
-Mesenchyme cells cluster and differentiate into osteogenic cells, then osteoblasts which appear in an ossification center.
-Then calcification occurs (osteoblasts secrete extracellular matrix (osteoid) which hardens into crystals).
-Then, the formation of trabeculae occurs, which fuses into lattice, with blood vessels growing into spaces.
-Finally, the development of the periosteum begins (Mesenchyme cells at periphery of trabeculae form periosteum and osteoblasts)
What are the fontanels and what are 2 functions of them
soft spots on the top of the infant’s head during utero and after birth
-allow for the skull to flex and pass through the birth canal
-allow for growth of brain and skull during first year of life
Are flat or long bones made from intramembranous ossification
flat bones in the skull
Are flat or long bones made from endochondral ossification
long bones
Describe the overall process of endochondral ossification
-Mesenchymal cells differentiate into chondrocytes (cartilage cells) that form the cartilaginous skeletal precursor of the bones Soon after, the perichondrium forms
-Matrix is produced, chondrocytes in the center of the cartilaginous model grow in size, matrix calcifies and then nutrients can no longer reach the chondrocytes, resulting in their death and the disintegration of the surrounding cartilage. Blood vessels then begin to take over that space
-Penetration of capillaries initiates the transformation of the perichondrium into the
bone-producing periosteum
-Osteoblasts form a periosteal collar of compact bone around the cartilage of the
diaphysis, leading to the creation of a primary ossification center
-Chondrocytes and cartilage continue to grow at the ends of the bone, which increases the bone’s length at the same time bone is replacing cartilage
-Fetal skeleton fully forms
-(matrix mineralization, death of chondrocytes, invasion of blood vessels from the periosteum, and seeding with osteogenic cells that become osteoblasts)
How do bones grow longer (interstitial bone growth)
epiphyseal side = cartilage is formed.
diaphyseal side = cartilage is ossified
What happens to the epiphyseal plate when growth stops
Chondrocytes in the epiphyseal plate cease their proliferation and bone replaces the cartilage, leaving behind the epiphyseal line
How do bones grow wider (appositional bone growth)
Osteoclasts resorb old bone that lines the medullary cavity, while osteoblasts, via intramembranous ossification, produce new bone tissue beneath the periosteum.
What is the role of osteoblasts during appositional bone growth
Produce new bone tissue beneath the periosteum
What is the role of osteoclasts during appositional bone growth
Resorb old bone that lines the medullary cavity
Where are osteoblasts during appositional bone growth
periosteum
Where are osteoclasts during appositional bone growth
medullary cavity
Give a description of bone remodeling
Caused from injury, exercise, and other activities. Resorption of old or damaged bone takes place on the same surface where osteoblasts lay new bone to replace that which is resorbed.
What is Wolff’s Law of Bone Remodeling
Bones will remodel and adapt based on the demands placed upon them
What is osteoporosis
A disease characterized by a decrease in bone mass that occurs when the rate of bone resorption exceeds the rate of bone formation
What are some common causes of osteoporosis
age, gender (decrease in estrogen production) , ethnicity, genetics, lack of vitamin D and calcium
What are bones that suffer from osteoporosis like
weak and brittle, common injuries are in the hip, wrist, and spine
How can you delay/prevent the onset of osteoporosis
-Get enough calcium, vitamin D
-Be physically active
-Consider medications that either slow done bone loss or help rebuild bone
What is scoliosis
Lateral curvatures of the spine, creating a hump
What is kyphosis
Spinal curvatures from vertebrae fracture/compressing more anteriorly, gives hunchback appearance and results in thoracic compression
What is lordosis
A posture assumed by some females, in which the back is arched downward.
