Muscles and Bones Flashcards
Functions of skeletal system
support leverage protection blood cell production storage- of minerals (calcium, phosphate)
how many bones are you born with?/ as an adult how many do you have?
350+
206- bones fuse together as a child
why might infants have more bones?
have to be able to fit through birthing canal
what are the Macroscopic features of the Bone?
bones- solid network of living cells and protein fibers that are surrounded by deposits of calcium salts
-connective tissue
Periosteum
tough, connective tissue covering
- joins with tendons and ligaments
bone marrow
inside bone cavities
- red: makes blood cells
- yellow: fatty connective tissue
what are the microcsopic features of the bone?
compact bone
compact bone
dense
osteon
basic functional unit
- arranged around canals
- aka Haversian system
Spongy Bone
lattice adds strength w/o mass
- no osteon’s
- calcified matrix forms trabeculae
mass of your bones is made up of
minerals
2% cells
1/3 collagen fibers
2/3 ca_3 (PO_4)_2
osteocytes
mature bone cells
maintain normal bone structure
osteoclasts
secrete acids and enzymes to break down bony matrix and release minerals
-very large and may contain over 50 nuclei
BREAK DOWN
osteoblast
cells that create new bone
-when surrounded by calcified matrix, matures into osteocyte
CREATE
ossification
replacing tissues with bone
intramembranous
bone grows in membranes
endochondrial
bone replaces cartilage
-many long bones have growth plates at either end
ossification by adulthood
cartilage remains where flexibility is needed timing of ossification varies - toes by age 11 -arms and legs 18 (women) 20 (men) -pelvis, wrist by age 25
Remodeling
Osteoclast activity balanced by osteoblast activity
-18% turnover rate for bone
support
- what you don’t use, you lose
Homeostasis and mineral storage
- body usually only allows 10% chance in calcium
Axial Skeleton
-supports the central axis of body and encases viscera (soft organs)
-includes 80 bones
=skull (29)
=Vertebral column (26)
=Rib cage (25)
The skull is divided into…
brain case and facial bones
-8 cranial bones
-14 facial bones
7 associated bones
sutures
held together by immovable joints
- flexible in young children, becomes fixed as you age
Found in the Skull
Hyoid
fuses from 3 bones in early adulthood
function: provides anchor point for muscles of tongue and neck
Cranial Bones
8
Fontanels
Newborn “soft spots”
Foramina
Allow blood vessels and nerves to enter/ leave cranium
Foramen Magnum
where medulla oblongata projects out from skull
Vertebral Column
Vertebrae are irregular bones consisting of several parts
- spinous process: found on the outside
- transverse process
- vertebral foramen
- body: found on the inside
how many vertebrae do humans have?
have 33/ end with 26 7 cervical (neck) 12 thoracic (articulate with ribs) 5 lumbar (lower back/ major weight-bearing) 5 sacral (fused to form the sacrum) 4 coccygeal (fused to form the coccyx)
Intervertebral Discs
Fibrocartilagenous rings that contain a jelly-like fluid
Major role is bearing weight
Thoracic Cage
protects the visceral organs -sternum =manubrium =body =xiphoid process -ribs -12 pairs of ribs, connected posteriorly to vertebrae Anteriorly: - 1 to 7 connect to sternum -8 to 10 connect with cartilage - 11 to 12 are the "floating ribs"
Sternum
=manubrium
=body
=xiphoid process
ribs
-12 pairs of ribs, connected posteriorly to vertebrae Anteriorly: - 1 to 7 connect to sternum -8 to 10 connect with cartilage - 11 to 12 are the "floating ribs"
What is the appendicular skeleton
suspended from axial skeleton
includes: bones of limbs, pelvis and shoulder
Upper Appendicular Skeleton
clavicle scapula humerus radius ulna carpal bones metacarpals phalanges- fingers
Lower Appendicular Skeleton
pelvis -ilium -ischium -pubic bone Femur Patella Tibia- Thicker Fibula- smaller, fib-little white lie Calcaneus Tarsal Bones- ankle Metatarsals- meet the fat part of foot Phalanges- toes
articulations (joints) types
where bones meet one another
- immovable
- slightly movable- little farther apart
- freely moveable
immovable
(close together)
=between bones of skull
=between teeth and jaws
slightly movable
little farther apart
- adjacent vertebrae
- R/L halves of anterior pelvis
freely moveable joints
most familiar joint
types of freely moving joints
- gliding joint- 2 bones come together and glides: clavicle and manubrium
- hinge joint-only operates in 2 directions
- pivot joint
- saddle joint- modified hinge
- ball and socket- ball shape at end of bone and sits in a preformed socket
structure of joints
-ligament- bone to bone
-tendon- bone to muscle
-joint capsule
=synovial fluid: lubricating film
-may have bursae - “shock absorbers”
-bones in a joint may be covered by cartilage
= ex. meniscus in knee
joint disorders
-bursitis- too much fluid fills the bursae and become inflamed
-arthritis: inflammation of the joints (affects 10% of population)
=over 100 types
=osteoarthritis- most common
=Rheumatoin- autoimmune disorder
-hypermobility “double jointed”
appositional growth
occurs as cells of the peritoseum develop into osteoblasts and produce additional bony matrix
how does vitamin D play an important role in normal calcium metabolism?
after it is processed in the liver, kidneys convert it into calcitriol, a hormone that stimulates the absorption of calcium and phosphate ions into the digestive tract
what do reduced amounts of calcium salt cause?
bones to become flexible, bowleggedness is developed
during intramembraneous ossification, what type of tissue is replaced by bone?
fibrous connective tissue
how can x-rays of the femur be used to determined full height
by looking at the epiphyseal cartilage, if it is still present, bone growth is still occurring
how does castration affect height?
removes the source of testosterone, which contributes to a spurt of bone growth. would expect longer (slower) growth period, end up being taller
why are women given calcium suplements and encouraged to drink milk, even though their skeletons are fully formed?
to support bone growth in the developing fetus. Body will take mothers calcium and give it to baby if there is not enough
