Chapter 6&7 - Bones and Skeletal Tissues Flashcards
Skeletal Functions:
Support
Provides the framework and support of the rest of the body
Skeletal Functions:
Protection
Protects soft organs. Includes the skull, vertebrae, rib cage, etc.
Skeletal Functions:
Site of Hematopoesis
The generation of blood cells, RBCs and platelets come from red marrow
Skeletal Functions:
Storage
The major site for calcium deposits, phosphate, minerals, and growth factors.
Skeletal Functions:
Movement
Movable joints permit the muscular system to cause the skeleton and the body to move. Bones are used as levers.
Functions of the Skeletal System
Support, protection, site of hematopoesis, storage, and movement
Long Bones
Longer than wide, bones of the legs, arms, fingers. A shaft plus two ends, mainly compact bone, some spongy.
Short Bones
Cube shaped bones found in the ankle and wrists
Flat Bones
Sheet-like and include the bones of the cranium and ribs. Usually curved, two thin plates of compact bone separated by spongy bone
Irregular Bones
Have no distinct shape. Include the bones of the face, vertebrae, and hip and shoulder girdles.
Sesamoid Bones
Bones that form inside of tendons. Vary in number and placement from person to person. A special type of short bone. Ex: the patella
Wormian (sutural) Bones
Form between suture lines, vary in number and position. Small, flat, and irregular bones found between the flat bones of the cranium.
Skeletal Cartilage
Contain no verves of blood vessels, instead attached to dense connective tissue with blood vessels that delivers nutrients.
Hyaline Cartilage
Provides support, flexibility, and resilience. Most common type.
Elastic Cartilage
Very similar to hyaline, but has elastic fibers. Strong and able to stretch.
Fibrocartilage
Has collagen fibers, which give it tensile strength
Growth of cartilage
Calcification of cartilage only occurs during normal bone growth.
Appositional Growth
Cells secrete a matrix against the external face of existing cartilage (long bones)
Interstitial Growth
Chondrocytes divide secreting a new matrix, expanding the cartilage from within.
External Anatomy of a Long Bone
Has two heads, epiphyses, connected by a shaft, diaphysis. The bone is covered by a membrane, the periosteum.
Periosteum
A double membrane covering the outside of the bones. The outer later is a fibrous later of connective tissue, and the inner has osteoblasts, nerve fibers, and vessels.
Cancellous (Spongy) Bone
Highly porous bone. Made of flat, spiky pieces called trabeculae. The spicules interconnect leaving spaces which are usually filled with red marrow. Reduces bone weight.
Marrow (Medullary) Cavity
Found in the center of the diaphysis. Lined by the endosteum filled with one of two kinds of marrow.
Compact Bone
Very dense bone. Solid, smooth, and homogenous. Composed of tightly packed cylindrical structures called osteons or Haversian systems.
Endosteum
Membrane that covers the inner lining of bones. Contains osteoblasts and osteoclasts
Red Marrow
Fills the medullary cavity during embryology and early life. It generates blood cells.
Yellow Marrow
Consists of fat and fills the marrow cavities in the bones of adults
Epiphyseal Plates
Cartilaginous growth plates that are found in the epiphyses. They allow bones to continue to grow throughout childhood and adolescence. When done they become ossified and growth in the length of the bone ceases.
Epiphyseal Line
Cartliage at the junction of the epiphysis and diaphysis in young bones. The area for bone growth.
Bone Markings
Bumps, ridges, projection, holes which are found on bones. Their function is to allow passage for a blood vessel or nerve and for attachment for a tendon or muscle.
Tuberosity
A rounded projection
Crest
A narrow prominent ridge
Trochanter
A large, blunt, irregular surface (on the femur)
Line
A narrow ridge, less prominent than a crest
Tubercle
A small rounded projection
Spine
A sharp, slender projection
Epicondyle
A raised are above a chondyle
Process
A bony prominence (general word)
Meatus
Canal-like passageway
Sinus
Cavity found within a bone, has a flat articular suface
Fossa
A shallow basin-like depression
Groove
A furrow
Fissure
A narrow, slit-like oplening
Foramen
A round or oval opening
Head
A bony expansion on a narrow neck
Facet
A smooth, nearly flat articular surface
Condyle
A rounded projection
Ramus
An arm-like bar
Osteon or Haversian System
Contain central canals, canaliculi, lacunae, and lamellae.
Central (Haversian) Canal
Located in the center of each osteon. Houses blood vessels, and nerves.
Canaliculi
Narrow passageways that communicate with the lacunae and diffuse nutrients and wastes to and from the blood and nerves.
Matrix
Very dense deposits of calcium, makes up 1/3 of bone and gives it it’s tensile strength.
Lacunae
Pockets found in concentric circles around the central canal that house the osteocytes
Lamellae
Bony concentric layers formed from the bone cells laying down layers of bone to either side.
Osteoprogenitor/ Osteogenic Cell
Bone stem cell, differentiates into an osteoblast.
Osteoclasts
Bone resorbing cells, remove bone matrix.
Osteoblasts
Bone forming cell., Producing a new bone matrix
Osteocytes
A mature bone cell
Ossification
Process of bone formation either intramembrenous or endochondrial.
Intramembrenous Ossification
Only in the skull.
- Two membranes bud off osteoblasts between them.
- Osteoblasts begin to secrete bony tissue around themselves.
- Ossification being in two or three centers and moves from there.
- At birth not all the centers have met leaving soft spots called fontanels.
Fontanels
Soft spots of membrane where ossification has not been completed. Allow for pliability wieh going thorught hte birth cancal and for brain growth in the early years.
Endochondral Ossification
- A cartilage model of the bone is formed
- Chondrocytes secrete an enzyme which results in mineral deposits and hardening of the cartilage. Leads to the death of the chondrocytes which starts the degeneration of the cartilage
- Concurrent with cartilage death, the perichondrium turns into periosteum and begins to bud off osteoblasts.
- A body collar is formed around the diaphysis by the periosteum and starts the cavitation in the hyaline cartilage.
- A clump of osteoblasts breaks through tthe collar into the degenaerating cartilage and starts the primary center of ossification.
- Additional osteogenic buds invade the epi[hyses forming secondary centers of ossification.
- The last cartilage to the replaced are the epiphyseal plates which continue to grow until the end of adolescence
Fractures
Break in the bone
Simple Fracture
The bone breaks but stays within the body
Compound Fracture
The bone breaks and protrudes through the skin.
Greenstick Fracture
Characteristic fracture of children. The bone breaks, but the ends do not come apart.
Impacted Fracture
Broken bone ends are forced into each other. Usually during falls, wrists or hips.
Compressed Fracture
Bone is crushed. More common in porous bones.
Depressed Fracture
Broken bone portion is pressed inwards. Skull fracure
Spiral Fracture
A ragged break. From excessive twisting forces. Very common in sports.
Comminuted Fracture
The bone fragments. Mostly in the aged with brittle bones.
Epiphyseal Fracture
Epiphysis separates from the diaphysis along the epiphyseal plate.
Pott’s Fracture
Ankle fracture
Transverse Fracture
Break occurs across the axis of a shaft
Displaced and nondisplaced
Abnormal or normal arrangement of the bone.
Bone Repair
- Hematoma forms
- The periosteum forms a callus, a mass of fibrocartilage tissue at the break filled with collagen fibers.
- The fibro-callus is gradually converted to bone (bone remodeling)
- The area is reshaped and remodeled with the callus being reabsorbed.
Osteoporosis
Loss of bone mass. Resorption is outpacing deposits. Leaves porous, thin bones.
Osteomalacia
Bones aren’t getting enough minerals, they soften and become weak. Called “rickets” in children. Can be caused by calcium, vitamin D, etc, deprivation.
Paget’s Disease
Excessive or abnormal bone formation
Wolf’s Law
A bone grows or remodels in response to forces or demands placed on it.
2 Major Divisions of the Skeleton
The axial and the appendicular division.
Axial Division
Forms the long axis of the body and consists of the skill, vertebral column, rib cage, and sternum
Skull
Composed of 29 bones. Forms a protective box for the brain and special sense organs. 2 major regions, the cranium and the face.
Nasal Sinuses
Mucus lined cavities inside the facial and cranial bones. Acts as resonance chambers to enhance voice quality.
Cranium
Bony box that surrounds the brain. Bones are joined by immovable joints called sutures.
Orbits
Bony cavities for the eyes cushioned by adipose tissue.
Hyoid Bone
In the neck, connected by ligaments to the styloid process of the temporal bone. Muscles of the tongue, neck, pharynx, and larynx attach there and allow for movement.
Face
Irregular shaped bones which are joined by sutures. Houses the teeth, the nasal cavity, hard palate, and most of the eye orbits.
Vertebral Column
Typically consists of 26 bones and forms a protective enclosure for the spinal cord. The skull is balanced at the top with the ribs and the viscera suspended in front.
5 regions of the Vertebral Column
- Cervical - 7 bones
- Thoracic - 12 bones
- Lumbar - 5 bones
- Sacrum - 5 fused bones
- Coccyx - 4 fused bones
Common Features of Vertebraes
All have a body (a rounded mass), a spine (a dorsal projection), a transverse process (a lateral projection), vertebral foramen (central opening), and are separated by a disc of fibrocartilage.
Curves of the Vertebral Column
3 normal curves that adjust the center of gravity and give the spine resiliency and flexibility.
- Cervical - concave
- Thoracic - convex
- Lumbar - concave
Kyphosis
An exaggerated convexity of the thoracic region (hunchback)
Lordosis
An exaggerated concavity of the lumbar region (swayback)
Scoliosis
A lateral curvature in any place in the colum
Ribs
12 pairs, connected to the thoracic vertebrae
True Ribs
First 7 pairs of ribs. Each has its own costal cartilage which connects directly to the sternum
False Ribs
Next 3 pairs. Each connects the sternum indirectly via the costal cartilage of the seventh pair of ribs
Floating Ribs
The last 2 pairs of ribs. They have no connection to the sternum at all.
Sternum
Breastbone, a dagger shaped bone that forms with the ribs and vertebral column the cage known as the thorax
Appendicular Division
Consists of the appendages and the girdles. A total of 126 bones.
Pectoral Girdle
Left and right. Each consists of two bones, the scapula and the clavicle. The the clavicle and the scapula form a V with the humerus suspended from the glenoid cavity.
Pelvic Girdle
Two bones, the os coxae, which join with the sacrum posteriorly and with each other anteriorly at the pubic symphysis.
Upper Appendage
The humerus articulates distally with the radius and ulna which articulate distally with the carpals. They articulate with the metacarpals, and them with the phalanges.
Lower Appendage
The femur articulates distally with the tibia. The tibia articulates with the fibula, and the tarsals. The tarsals with the metatarsals and the metatarsals with the phalanges.
