Lecture: Chapter 06 Flashcards
SKELETAL SYSTEM
Bones & Skeletal Tissues
SKELETAL CARTILAGES
contains no nerves or blood vessels; is surrounded by perichondrium - dense, irregular connective tissue that is vascularized. Nutrients diffuse into cartilage. 3 kinds: Hyaline, Elastic, & Fibrocartilage
HYALINE CARTILAGE
most abundant; Includes… articular cartilage; costal cartilage (connects ribs to sternum); respiratory cartilages in the larynx; and nasal cartilage in nose.
*3 Functions: Protection, Support, Resilience
ELASTIC CARTILAGE
found in external ear and epiglottis (flap that covers opening of larynx when swallowing)
*Function: (great) flexibility
FIBROCARTILAGE
located between vertebrae, menisci of knees, and pubic symphysis
*Function: Shock absorption (very strong)
CLASSIFICATION OF BONES
Axial and Appendicular
AXIAL SKELETON
skull, vertebral column, & ribs
APPENDICULAR SKELETON
arms, legs, shoulder girdles (scapula & clavicle), and hip girdles (ilium, ischium, & pubic bone); appendages
SKELETAL FUNCTIONS
1) Support - provides framework
2) Protection - e.g. skull protects brain, vertebra protects spinal cord, ribs protect thoracic organs.
3) Movement - bones used as levers for motion
4) Mineral Storage - bone stores Calcium and Phosphate (inorganic) in intracellular matrix
5) Blood Cell Formation: hematopoiesis occurs in marrow (red)
* Collagen=organic fiber in bone
-GROSS ANATOMY-
see following cards
BONE MARKINGS
sites of attachment to muscles, ligaments, or tendons; also holes in bones where different blood vessels and nerves pass through
COMPACT BONE
outer layer; very dense, smooth, more organized, stronger.
SPONGY BONE
a.k.a. “Cancellous” bone; inner part; usually filled with red or yellow bone marrow; spiky, porous, less organized, contains lots of open space
DIAPHYSIS
shaft of bone; main function in adult bone is muscle attachment; primary ossification center; lots of compact bone; (medullary cavity is the hollow space in the shaft)
EPIPHYSIS
ends of bone; covered with layer of articular (hyaline) cartilage; secondary ossification center; lots of spongy bone.
EPIPHYSEAL LINE
between diaphysis and epiphysis in adults; remnant of epiphyseal plate; bone lengthens from here in children; growth region in length of the long bone
PERIOSTEUM
double layer membrane around long bones, outer layer is fibrous layer, inner layer is osteogenic layer which has osteoblasts (make bone) and osteoclasts (destroy bone); contain lots of blood vessels, lymph vessels, and nerve fibers.
FUNCTIONS OF
THE PERIOSTEUM
1) Provides nutrients via blood vessels
2) Innervation
3) Attachment to tendons
ENDOSTEUM
thin connective tissue membrane that lies in the medullary cavity
YELLOW MARROW
substance contained in medullary cavities in adult bones.
RED MARROW
the hemopoietic tissue in the adult is only located in the heads of the humerus and femurs, inside flat bones, and hip bones. In infants, hematopoietic tissue is located in all spongy bone.
-MICROSCOPIC ANATOMY-
see following cards
OSTEON
a.k.a. “Haversian System;” structural unit of compact bone; is parallel with the long axis of bone
HAVERSIAN CANAL
a.k.a. “Central Canal;” is in middle of osteon blood vessels; nerve fibers run through it.
VOLKMANN’S CANALS
a.k.a. “Penetrating Canals;” perpindicular to Haversian canals; connect to the blood & nerve supply of the periosteum.
LAMELLA
layers of bone; like rings of a tree; surround Haversian canals.
OSTEOCYTES
(mature) bone cells that occupy little lakes called “lacunae”(cavities where bone cells live) in between the lamella layers
TRABECULAE
tiny plates of bone material found in spongy bone.
-BONE DEVELOPMENT-
see following cards
OSSIFICATION
a.k.a. “Osteogenesis;” bone formation
INTRAMEMBRANOUS OSSIFICATION
Bone forms from a fibrous membrane; this gives rise to bones of SKULL and the CLAVICLES(usually medial 2/3 or lateral 1/3 fracture); replaces connective tissue membrane with bony tissue.
ENCHONDRAL OSSIFICATION
bone forms by replacing hyaline cartilage with bony tissue; this gives rise to ALL OTHER BONES. Bone growth is controlled by growth hormone in infancy and childhood.
-BONE REMODELING-
Bone is dynamic; bone is constantly being deposited and regenerated. Processes essentially equal in young adults.
(see following cards)
BONE DEPOSIT
if a bone is injured or under high stress, more bone is laid down by osteoblasts.
BONE RESORPTION
osteoclasts move along bone surface digging little trenches
BONE REMODELING
CONTROL MECHANISMS
1) Negative feedback loop
2) Gravitational forces/mechanical stress
(1) NEGATIVE FEEDBACK LOOP
hormonally controlled; as calcium in blood rises, hormone calcitonin is released which puts calcium into bone. If blood calcium levels fall, parathyroid hormone takes calcium out of bone.
CALCITONIN
hormone formed by thyroid gland; decreases blood calcium levels.
PARATHYROID
(PTH; from parathyroid gland) increases blood calcium levels
(2) MECHANICAL STRESS
“Wolff’s Law:” bone grows in response to stress placed on it. Bones are stressed by muscles pulling against them or by gravitational forces. One side of the bone is compressed; the other side is stretched with an off-center force. The forces cancel each other out in the middle, so the center of bones are much less dense, almost hollow.
-BONE FRACTURES-
see following cards
NON-DISPLACED Fracture
ends are in alignment
DISPLACED Fracture
ends are NOT in alignment
COMPLETE Fracture
bone is broken through
INCOMPLETE Fracture
bone is NOT broken through
LINEAR Fracture
fracture along LONG axis of bone
TRANSVERSE Fracture
fracture across the bone (perpendicular to long axis)
OPEN/COMPOUND Fracture
bone breaks through skin
CLOSED/SIMPLE Fracture
bone does NOT break through skin
SPIRAL Fracture
common in sports; results from twisting force
COMMINUTED Fracture
bone fragments into 3 or more pieces
COMPRESSION Fracture
bone is crushed
GREEN STICK FRACTURE
one side breaks, the other side bends
-BONE REPAIR-
Fracture repaired by:
1) OPEN Reduction - surgical fix w/ pins & screws
2) CLOSED Reduction - realignment of bones by hand; (bony callus is evidence of previous fracture)
OSTEOMALACIA / RICKETS
Similar condition; name changes depending on age. CHILDREN get RICKETS, and ADULTS get OSTEOMALACIA; both caused by INADEQUATE amounts of CALCIUM in diet or LACK of Vitamin D. (Rickets often results in bowed legs.)
OSTEOPOROSIS
Bone resorption outpaces bone deposit. Bones become fragile and break with incidental incident. Most common breaks are compression fracture of vertebrae or neck of femur - broken hip. Contributing factors: not enough Calcium or Vit. D, petitie body frame, little/decreased exercise, smoking (reduces estrogen levels), and some hormonal conditions (like Hyperthyroidism & Diabetes Mellitus). Affects entire skeleton, but spongy bone in more vulnerable. Can delay by: getting enough Calcium; drinking flouridated water; weight-bearing exercises(walking, jogging, tennis).
PAGET’S DISEASE
(rarely occurs before age 40) Usually incidental findings; more spongy bone than compact bone and demineralization. Most common bones involved: spine, skull, pelvis, and femur. It may affect any part of the skeleton but is usually a LOCALIZED CONDITION.
OSTEOPENIA
a condition that occurs with aging that causes a gradual reduction in bone mass.
STAGES OF BONE HEALING
1) Hematoma formation
2) Fibrocartilagenous callus
3) Bony callus formation
4) Remodeling
