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Unformatted text preview: nses to pain, pressure, heat etc.
– Skin secretes sebum nd antimicrobial substances
to protect against microbial invasion.
– Skin contains melanocytes which provide
protection against excessive UV light.
– Skin absorbs UV light and produces a vitamin D
precursor (needed for calcium absorption).
Note missing word: In opening graphic, the label
skeletal system should read: " Skin absorbs
sunlight ad produces a vitamin D precursor. " 2. A tattoo inserts ink into the upper layer of the dermis
where it becomes trapped within fibroblasts (as part
of the body sealing off the foreign material). While
it is trapped here, it remains a relatively inert and (a) Stratum basale: Epidermis (innermost). The
regenerative layer of cells, which produces new
cells and also contains the mealnocytes, which
give skin its protective dark pigment.
(b) Stratum corneum: Epidermis (outermost).
Provides protection against wear and therefore
protects the deeper layers of cells.
(c) Sweat glands: Dermis (reticular layer):
Produce sweat, which cools by evaporation
(d) Collagen fibers: Lower dermis. Provide strength to
the dermis, making it resilient. Bone (page 50)
1. Bones grow in length by continuous growth of new
cartilage in the epiphyseal plate, which is then
covered in a bone matrix and calcified to form new
bone. Appositional growth, in contrast, involves
addition of new bone to the outside of the diaphysis
and resorption of bone from the inner diaphysis
surface. 2. (a) Support: Provides a frame to keep the body
(b) Protection: Bones can serve to protect internal
organs, such as the skull protecting the brain or
the ribs protecting the heart and lungs.
(c) Movement: Bones, skeletal muscles, tendons,
ligaments, and joints function together to
generate and transfer forces so that body parts or
the whole body can be moved.
(d) Blood cell production: The marrow, located within
the medullary cavity of long bones and interstices
of cancellous bone, produces blood cells in a
process called haematopoiesis.
(e) Mineral storage: Bones act as reserves of
minerals important for...
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This document was uploaded on 01/28/2014.
- Winter '13