EXAM 3 Flashcards
Functions of the Skeleton
Support—limb bones and vertebrae support body; jaw bones support teeth; some bones support viscera
Protection—of brain, spinal cord, heart, lungs, and more
Movement—limb movements, breathing, and other movements depend on bone
Electrolyte balance—calcium and phosphate levels
Acid–base balance—buffers blood against large pH changes by altering phosphate and carbonate salt levels
Blood formation—red bone marrow is the chief producer of blood cells (rbc, wbc, platelets)
Sound Amplification – small bones of the middle ear (ossicles – malleus, incus, stapes)
Bone (osseous tissue)
connective tissue with the matrix hardened by calcium phosphate and other minerals
General Features of Bones
Flat Bone-Thin, curved plates protect soft organs Wider than long
Long Bone- Longer Than Wide
Short Bone- equal length
Irregular Bone- Shapes that do not fit in a categories .
The four principal types of cells in bone tissue include:
- Osteogenic (osteoprogenitor) cells
- osteoblasts
- osteocytes
- osteoclasts
- Spongy Bone
o lighter in density than compact bone
o has an irregular, honeycomb-like appearance
o present during bone development and can be found in the marrow cavities of long bones
o form networks of trabeculae which allow for nutrient diffusion without the use of blood vessels.
- Cartilage
o Hyaline cartilage acts as the articular cartilage in our joints, coverings at the ends of long bones, and support for the tip of the nose and much of the respiratory system.
o Elastic cartilage is present in the external ear and epiglottis, and is similar to hyaline cartilage, but with more elastic fibers in the matrix.
o Fibrocartilage is located in body regions that require strong support and the ability to withstand pressure (specifically in the knee, pubic synthesis, and spine). This type of cartilage obtains its more rigid characteristics from rows of chondrocytes alternating with thick collagen fibers in the matrix.
- Dense Regular Connective Tissue
o Tendons – attach muscle to bone allowing for the muscle to pull on the bone and create movement
o Ligaments – attach bone to bone and prevent excessive movement at a join
o Tendons
attach muscle to bone allowing for the muscle to pull on the bone and create movement
o Ligaments
attach bone to bone and prevent excessive movement at a joint
- Sutural bone
as the bones of the skull begin to grow, they join up together into a joint known as a suture. As these sutures begin to close, there can be an additional bone(s) that can grow in the suture
o Epiphysis
(proximal and distal) this is the ends of the long bone. They are typically enlarged to accommodate the attachment of ligaments and tendons. The end closest to the attachment of the limb is referred to as the proximal end and the one furthest away is known as the distal end. This portion of the bone is mainly made up of spongy bone.
o Articular Cartilage
is found on the epiphysis. It is typically made up of hyaline cartilage and forms the joints of the bone.
o Metaphysis
Sits between the epiphysis and diaphysis. This area contains the epiphyseal GROWTH PLATE, where long bones grow longitudinally. This happens when the hyaline cartilage of the growth plate converts into bone. When bone growth longitudinally ceases, the
growth plates will be replaced with the epiphyseal line.
o Medullary Cavity
this is the empty cavity within the diaphysis of a long bone. In early childhood, it is filled with red bone marrow. The red bone marrow is replaced with yellow bone marrow in adulthood.
o Endosteum
a thin layer of connective tissue lining the medullary cavity.
o Periosteum
dense fibrous connective tissue lining the outside of the diaphysis. The inner layer of the periosteum is the osteogenic layer lined with osteoblasts and allows for bone remodeling and growth. The periosteum is also highly innervated and thus causes pain if damaged.
- Structure of Skin
o Epidermis
o Dermis
o Subcutaneous layer (hypodermis
Accessory Structures
o Sweat glands
o Oil (sebaceous) glands
o Hair
o Nails
Functions of Skin
- Protection- against dehydration and infection (includes acid mantle, keratin, antimicrobial peptides)
- Synthesis of Vitamin D- contributes to bones
- Sensation – skin is largest sense organ: tactile, thermal, pain
- Thermoregulation -regulating body temp in cold and hot environment, sweat and evaporation
- Nonverbal communication- expressive faces, general appearance of skin/hair
Epidermis- comprised of 5 cell types
- Stratified squamous epithelium
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
Papillary Layer
most superficial layer of dermis
Made of areolar tissue
Rich in blood supply
Reticular Layer
Dense irregular tissue, collagen & elastic fibers
Hair follicles, hair roots, nerve endings, cutaneous glands
Produces stretch marks (striae) due to collagen fibers tearing
o Cutaneous Membrane
dermis + epidermis
- Subcutaneous Layer (Hypodermis)
o Consists of loose connective tissue (adipose, areolar)
o Well-vascularized
o Connects skin to fascia beneath it
o Provides insulation, stores fat
o Keratinocytes
90% of epidermal cells
Produce keratin- toughens and protects skin
Produces granules for water- proofing, prevents entry of pathoge
Melanocytes
Produce melanin pigment
Stratum basale
Long slender projections connect with keratinocytes, melanin shuttled there
Form protective shield over nucleus to protect DNA from UV damage once inside keratinocyte.
o Langerhans Cells
AKA dendritic cells or intraepidermal macrophages
Migrate from bone marrow
Stratum spinosum and granulosum
Mount immune response to microbes, easily damaged by UV light
o Merkel (tactile) Cells
Receptors for touch and are connected to a dermal nerve fiber.
Stratum basale
Attached w/ nerve to a “tactile disc”
o Papillary layer
supplies nutrients to epidermis, helps regulate temperature