Skeletal System Flashcards
the skeletal system is divided into 2 divisions
what are they?
axial skeleton
- skull, ribs, vertebra
appendicular skeleton
- pelvis, extremities
what are the functions of the bone?
- support of body
- protection of soft organs
- movement due to attached muscles
- storage of minerals + fats
- blood cell formation
what are 2 basic types of bone tissue?
compact bone
- homogenous
spongey bone
- small needle like pieces of bone
- many open spaces
classification of bones
- long bones
- short bones
- flat bones
- irregular bones
long bones
contain mostly compact bone
e.g. femur, humerus
short bones
generally cube shaped
contain mostly spongy bones
e.g. carpals, tarsals
flat bones
- thin + flat
- thin layers of compact bone around layer of spongy bone
e.g. skull, ribs, sternum
irregular bones
don’t fit into other bone classification categories
e.g. vertebrae + hip
diaphysis
shaft
composed of compact bone
epiphysis
ends of bone
composed of spongy bone
structure of long bone
periosteum
- outside covering of diaphysis
- fibrous connective tissue membrane
structure of long bone
sharpeys fibres
secure periosteum to underlying bone
structure of long bone
arteries
supply bone cells with nutrients
structure of long bone
articular cartilage
covers external surface of epiphyses
made of hyaline cartilage
dec friction of joint surfaces
structure of long bone
medullary cavity
- cavity of shaft
- contains yellow marrow (mostly fat) in adults
- contains red marrow (for blood cell formation) in infants
where do projections and processes grow out from?
bone surface
where do depressions / cavities arise from?
indentations
what are bone markings passages for?
nerves and blood vessels
what is the osteon?
unit of bone
what does the central canal do?
carried blood vessels and nerves
what does the perforating canal do?
carries blood vessels and nerves
in embryos, the skeleton is …
primarily hyaline cartilage
where does the cartilage remain isolated?
- bridge of nose
- parts of ribs
- joints
… plates allow for growth of long bone during childhood
epiphyseal
bones grow in …
width
what are osteocytes?
mature bone cells
what are osteoblasts?
bone forming cells
what are osteoclasts?
bone destroying cells
break down bone matrix for remodelling + release of calcium
bone remodelling is a process by both …
osteoblasts + osteoclasts
bone resorption
action of osteoclasts + parathyroid hormone (PTH)
bone deposition
action of osteoblasts + calcitonin
homeostasis in bones occurs by …
direction of thyroid + parathyroid glands
what does a deficiency of vitamin A cause
retards bone development
what does a deficiency of vitamin C cause
results in fragile bones
what does a deficiency in vitamin D cause
rickets, osteomalacia
what do glucocorticoids do?
activate osteoclasts + resorption of bone
the skull
2 sets of bones
- cranium
- facial bones
only mandible attached by freely movable joint
what is the paranasal sinuses?
hollow portions of bones surrounding nasal cavity
function of the paranasal sinuses?
- lightens skull
- gives resonance + amplification to voice
the hyoid bone
serves as moveable base for tongue
the foetal skull is …. compared to the infants total body
large
what are fontanelles and what do they do?
fibrous membranes connecting cranial bones
- allows brain to grow
- convert to bone within 24 months after birth
the vertebral column
- vertebrae separated by intervertebral discs
- spine has normal curvature
how can abnormal spinal curvatures arise?
- diseases
- paralysis of trunk muscles
- poor posture
- pregnancy
- congenital defect
what is scoliosis
abnormal lateral curvature
what is kyphosis (hunchback)
exaggerated thoracic curvature
usually from osteoporosis
or weight lifting at young age
what is lordosis (swayback)
exaggerated lumbar curvature
from pregnancy/ obesity
the bony thorax forms…
a cage to protect major organs
what is the bony thorax made of?
- sternum
- ribs
- thoracic vertebrae
what does the appendicular skeleton involve?
- limbs
- pectoral girdle
- pelvic girdle
the pectoral (shoulder) girdle is composed of 2 bones
what are they?
- clavicle - collarbone
- scapula - shoulder blade
allow upper limb to have free movement
the arm is formed by a single bond which is the …
humerus
what 2 bones does the forearm have?
- ulna
- radius
bones of the hand
- carpals - wrist
- metacarpals - palm
- phalanges - fingers
what 3 fused bones are hip bones composed of?
- ilium
- ischium
- pubic bone
what do the bones of the pelvic girdle protect?
- reproductive organs
- urinary bladder
- part of the large intestine
features of the female pelvis?
- Iliac bones more flared
- broader hips
- pubic arch = greater
- lighter bones
- sacral curvature = shorter + flatter
- more distance between ischial spines and ischial tuberosities
the thigh has one bone, which is…
femur - thigh bone
what 2 bones does the leg have?
- tibia
- fibula
bones of the foot
- tarsus
- metatarsals - sole
- phalanges - toes
bones of the foot are arranges to form 3 strong arches, what are they?
- medial longitudinal arch
- transverse arch
- lateral longitudinal arch
