Flashcards in Musculoskeletal System: Vertebrae, Ribs and Body Segments Deck (49):
what does the axial skeleton consist of?
vertebrae, ribs, sternum and skull
what does the appendicular skeleton consist of?
limbs and girdle
what is the role of the axial skeleton?
to protect CNS (spinal cord and brain) and viscera (thoracic and abdominal), breathing movement, support and movement.
in how many places do the vertebrae articulate with each other?
2 places - between the bodies (via intervertabral discs) and between the arches
what protects the spinal cord?
small spaces between the articulating vertebrae allow the exit of what from the spinal cord?
how many cervical (neck) vertebrae are there?
what are some characteristics of cervical vertebrae?
small, no free ribs, low weight bearing, the first 2 cervicals (atlas and axis) are specialised to allow head movement.
what are the first two cervicals called?
atlas and axis
how many thoracic vertebrae are there?
what are some characteristics of thoracic verterbrae?
medium sized, rib bearing (12 pairs of ribs)
how many lumbar vertebrae are there?
what are some characteristics of lumbar vertebrae?
large, high weight bearing, no free ribs
how many sacral vertebrae are there?
what are some characteristics of sacral vertebrae?
large, fused into a single mass to support weight of body and pelvis
how many coccygael (tail) vertebrae are there?
what are some characteristics of coccygael vertebrae?
tiny and vistigal
which is the part of the spinal cord that is most often damaged in humans?
where is the lumbar region in a human?
it lies between the thorax and pelvis
what is osteoporosis?
when the lumbar region collapses which crushes the lumbar spinal nerves leading to pain in the back and legs
what is the function of osteoblasts and osteoplasts?
remove and replace bone cells
what are axial muscles?
intercostal muscles, abdominal wall muscles, deep back muscles
where would you find epaxial muscles?
above/dorsal to the ribs
where would you find hypaxial muscles?
below/ventral to the ribs
what do epaxial muscles do?
what do hypaxial muscles do?
does flexion increase or decrease the angle between structures?
does extension increase or decrease the angle between structures?
in early vertebrate ancestors that had no vertebrae, what structure stiffened the body?
the notochord - a flexible mesodermal rod
in early vertebrate ancestors, where did the notochord lie?
immediately below the nerve cord
what does the notochord form in humans?
nucleus pulposus - the core of the vertebral column
what does the paraxial mesoderm form?
what do somites split into?
sclertome and dermomyotome
what happens to sclerotomal cells?
sclerotomal calls break away from the somite and wrap around the notochord and neural tube, forming vertebrae
what happens to dermomoyotome?
breaks into dermatome and myotome
what does dermatome form?
epidermis of skin
what does myotome form?
what provides shock absorption in the spinal cord?
what herniates in a slipped disc?
the nucleus pulposus
what does the myotome split into?
into dorsal (epimere) and ventral (hypomere) parts. forms epaxial and hypaxial muscles respectively. hypomere also forms limb muscles.
what are the three layers of intercostal muscles?
external, internal and innermost
what are the three layers of abdominal muscle?
external, internal and transverse
what forms BLOCKS of muscle and skin?
the dermomyotome of somites
what forms vertebrae (a series of repeating units)?
where is residual segmentation most obvious in adults?
in the thorax: intercostal muscles of chest wall; segmental pattern of blood vessels; segmental nerves to muscles and skin; ribs, vertebrae and sternal elements.
what do vertebrate animals show variation in?
vertebral numbers (no of segments = somites) and vertebral regionalisation (specification of segment identity)
how many cervical vertebrae do mammals have?
mammals developed a rib-less lumbar region. what does this allow?
greater dorsoventral flexion of the spine