Lecture 5 Content

Skeletal System

tendon

tissue that connects muscle to bone

ligament

bone to bone

cartilage

gel like padding between bones

body movement

position of joints and placement of muscle attachments, allow bones to act as levers

protection

critical organs surrounded by bones

support

organs, membranes, and other supporting structures may be attached allowing for suspension in place

hematopoiesis

process of forming red blood cells

Storage

calcium and phosphorus

calcium

muscle contraction, nerve impulse transmission, blood clotting, heart function

phosphorus

energy production, DNA, RNA, cell membranes

5 functions of the skeletal system

body movement, protection,,support, hematopoiesis, storage

3 types of cartilage

fibro, elastic, hyaline

fibrocartilage

weight bearing, shock absorption, resists compression

fibrocartilage examples

intervertebral discs, knee meniscus, pubic symphysis

elastic cartilage

flexible, repeated bending, shape retention

elastic cartilage examples

external ear, epiglottis, eustachian tubes

hyaline cartilage

smooth, low-friction surfaces for joint movement

hyaline cartilage examples

nose, trachea, costal cartilage

axial skeleton

skull, vertebral column, ribs, sternum

appendicular skeleton

upper and lower limbs, scapula, clavicle, pelvic girdle

spongy bones

lightweight, porous, ends of long bones, shock absorber, houses red blood marrow, trabecular

compact bones

dense, heavy, outer layer of all bones, bears weight, resists stress, protects organs, osteons

lamellae

players of compact bones

circumferential lamella

form the inner and outer regions of compact bone

concentric lamella

find like layers that surround each osteon

interstitial lamella

incomplete layers between osteons

osteon

bone unit

central (Haversian) canal

hollow channel at center of osteon, contains blood vessels and nerves that supply bone tissue

concentric lamellae

rings of calcified bone matrix surrounding central canal, provide strength and support

lacunae

small spaces between lamellae, houses osteocytes

canaliculi

tiny channels connecting lacunae to each other and to central canal, allow tissue fluid to transport nutrients and wastes between osteocytes and blood vessels

perforating (volkmans) canals

channels running perpendicular to osteons, connect blood vessels of periosteum to central canals

bone shapes

long, short, irregular, sesamoid, flat

long bones

length is much greater than width

long bone example

radius, ulna, femur

short bone

length and width about equal, short and boxy

short bone examples

carpals and tarsals

flat bone

thing, plate like, thin layer of compact bone with spongy between

flat bone examples

cranial, ribs, sternum

irregular bones

bones that do not fall into any other category, short, notched, flat, or ridged

irregular bone examples

facial, vertebrae, coxal

sesamoid bone

type of irregular bone imbedded in tendon, small flat sesame seed shaped

sesamoid bone example

patella

diaphysis

shaft, mostly compact bone, provides strength and support, contains medullary cavity with yellow marrow, fat and energy storage

metaphysis

meeting points, region between diaphysis & epiphysis, site of bone growth and ossification, epiphyseal line, no marrow

epiphysis

ends, mostly spongy bone covered by a thin layer of compact bone, helps form joints and distributes forces, spongy bone spaces contain red marrow ( some yellow marrow)

yellow bone marrow

medullary cavity, storehouse for fat cells, gradually changes to yellow with age

red bone marrow

site of hematopoiesis, primarliy found in epiphysis and flat bones, all marrow red at birth

periosteum

double outer surface, fibrous layer, osteogenic layer

periosteum function

protection, nourishment, attachment, growth, and repair

endosteum

inner surfaces of medullary cavity, central canals, covers trabeculae, thin cellular membrane, bone forming and remodeling cells

endosteum function

bone growth and remodeling

osteocytes

maintains bone tissue, mature bone tissue, responsible for monitoring bony matrix

osteoblasts

builds new bone matrix

osteoclasts

breaks down bone matrix, removes old/damaged osteocytes

bone remodeling

bone deposit (osteoblasts), bone respiration (osteoclasts)