Axial Skeleton Flashcards
what is the axial skeleton made up of
- the skull
- vertebral column (spine or spinal column)
- bony thorax (rib cage and sternum)
what type of bones makes up the skull
flat bones
what two bones forms the skull
- cranial bones (form the cranium)
2. facial bones (form the face)
can the skull bones move
no they are immovable apart from the mandible (the lower jaw)
LABEL THE HUMAN SKULL
page 47
how is the cranium made up
- it is made up of 8 flat bones
- the bones have immovable fibrous joints connecting them called sutures
- self bracing (which allows the bones to be thin and strong so they can protect the brain)
explain the difference in babies craniums
at birth membrane filled spaces called fontanelles exist between the bones of the cranium
these fontanelles allow the:
1. baby’s head to be slightly compressed during childbirth
2. size of the brain to grow rapidly during infancy
what are the functions of the cranium
- protects the fragile brain
- protects the sense organs of smell, sight and hearing
- provides attachment for the muscles of the head
what connects the skull and spine
At the base of the skull is a large opening, the foramen magnum, through which the medulla oblongata (lowest part of the brain) connects with the spinal cord
what is on either side of the foramen magnum
two bumps called occipital condyles
what do the occipital condyles do
they articulate with the first vertebra (the atlas of the vertebral column) in such a way that nodding is possible
how many bones make up the facial bones
14 bones
what are the functions of the facial bones
- form the structure of the face
- protect the sense organs of smell, sight and taste
- provide openings for the passage of food and air
- provide attachment for the facial muscles which give rise to various expressions
- secure the teeth
what is the role of the teeth snd jaws
the masticate and chew food
what is the teeth formula
2123
incisors
canines
pre molars
molars
describe the vertebral column
a strong flexible chain of 33 small bones, the vertebrae, that runs down the middle of the body from the skull to the coccyx
how the vertebrae held in place
by ligaments, which allow some movement but prevent dislocation
what does the vertebral column protect
the spinal cord, which is made up of nervous tissue
what does the spinal cord connect to
the brain and the rest of the body
LABEL A TYPICAL VERTEBRA
PAGE 50
what is found between vertebrae and why
intervertebral discs which have a jelly like centre covered by fibrous cartilage, they act as shock absorbers when we walk, jump or run and they allow the spine to flex and extend as well as to bend sideways
what are the functions of the vertebral column
- support the head
- enclose and protect the spinal cord
- serve as a point of attachment for the ribs
- allows spinal nerves to pass through openings between the vertebrae
- serves as a point of attachment for the muscles
- S-shape absorbs jolts and aids in balance
why is the S-shape of the backbone important
- strengthens the backbone
- balance the body
- absorb jolts during movement
name and explain the different types of vertebrae
- cervical vertebrae (7)
- Atlas
- Axis - thoracic (12)
- Lumbar (5)
- sacral (5)
- coccygeal (5)
DIFFERENTIATE BETWEEN VERTEBRAE
PAGE 52
what is slipped disc
it is when the backbone is out under a lot of pressure, resulting in the outer cartilage of the disc rupturing and the soft inner centre is forced through the surrounding cartilage
this bulge is called a slipped disc
if the bulge presses on the spinal cord or on a spinal nerve it can be very painful and numbness in the limbs may occur
what causes paralysis
when vertebrae are crushed or dislocated this can damage the spinal cord and cause it to break
this in turn will damage nerves leading to muscles and other organs of the body which results in paralysis (if muscles are not stimulated by nerve impulses, they cannot function)
if the cervical region is damaged what happens and if the lumbar region is damaged what happens
cervical - quadriplegic
lumbar - paraplegic
what is the bony thorax
it is a framework formed by the:
- sternum in the front (anteriorly)
- the ribs and the rib cartilage on the sides (laterally)
- the thoracic vertebrae at the back (posteriorly)
how many ribs do we have and where do they go from to where
12 pairs of ribs
they are flat, curved bones which extend from the thoracic vertebrae at the back to the sternum in the front
explain the different ribs
- upper 7 pairs (true ribs) are attached to the sternum by flexible strips of cartilage
- next 3 pairs (false ribs) are connected to the rib above the cartilage
- lowest 2 pairs (floating ribs) are only attached to the vertebral column
how does inhalation and exhalation occur
internal and external intercostal muscles occur between the ribs. on contraction of the external intercostal muscles, the ribcage moves upwards and outwards which results in inhalation
exhalation takes place when the muscles relax
what do the internal intercostal muscles do
they contract to force air out of the lungs, eg. when coughing or sneezing
LABEL THE BONY THORAX
PAGE 54
what are the functions of the bony thorax
- protects the vital organs of the thoracic cavity (lungs, heart, major blood vessels)
- supports the shoulder girdles and upper limbs
- provides attachment points for the muscles of the back, chest and shoulders
- aids in breathing
