Overview of Basic Concepts Flashcards
skin is also called… and consists of….
cutaneous membrane; epidermis and dermis
epidermis
- outermost layer of skin
- consists of keratinized stratified squamous epithelial tissue
- no blood vessels here but relies on connective tissue underneath it for blood supply
- consists of 4 or 5 layers with extra layer being present in areas receiving a lot of wear & tear
- Stratum Corneum, Statum Lucidum, Statum Granulosum, Stratum Spinosum, Statum Basale (think…Come Let’s Get Sun Burned)
dermis
- largest part of skin
- connective tissue that contains blood vessels, nerves, glands and hair follicles
- consists of 2 layers: papillary and reticular layers
- Papillary Layer: connective tissue with collagen, elastic fibers and blood vessels; dermal papillae (superficial peglike projections)
- Reticular Layer: majority (~80%) of dermal thickness; dense fibrous connective tissue with elastic fibers (stretch-recoil properties) and collagen fibers (strength and resiliency)
papillary layer of dermis
connective tissue with collagen, elastic fibers and blood vessels; dermal papillae (superficial peglike projections)
reticular layer of dermis
- majority (~80%) of dermal thickness
- dense fibrous connective tissue with elastic fibers (stretch-recoil properties) and collagen fibers (strength and resiliency)
flexure lines
dermal folds at or near joints
- dermis tightly secured to deeper structures
- skin cannot slide easily for joint movement, causing deep creases
- visible on hands, wrists, fingers, toes, soles
cleavage/tension/langer’s lines
- lines of human body parallel to orientation of collagen fibers in and along muscle fibers
- ideal for skin incisions for minimal tension across the wound
osteogensis/ossification
process of bone formation
- at 6 wks, embryo is made from fibrous membrane and hyaline cartilage
- after 6 wks, bone begins to develop and eventually replacing most of existing fibrous or cartilage structures
intramembranous ossification
process of bone developing from fibrous membrane
endochondral ossification
process of bone formation that occurs by replacing hyaline cartilage
remodeling
bone absorption and deposition in response to stress and repair of bone
bone perform several important functions:
- support
- protection
- movement
- mineral storage
- blood cell formation
two types of bone tissue:
- Spongy/Trabecular/Cancellous Bone: found at end of long bones and in middle of other bones; always surrounded by compact bone
- Compact Bone: dense and solid; found at shaft of long bones and surrounding the spongy bone; contains medullary (marrow) cavity; provides strength for weight-bearing
Medullary Cavity
where bone marrow sits snd where blood cells and platelets are formed
bones are classified according to their shape:
- long bones = tubular structures; longer length than width
- short bones = cuboidal; found only in ankle and wrist
- flat bones = usually serve protective functions; ex - cranium, sternum, ribs
- irregular bones = various shapes other than long, short or flat; ex - facial bones, vertebrae
- sesamoid bones = protect tendons from excessive wear; ex - patella
osteoporosis
abnormal reduction in quantity of bone or atrophy of skeletal tissue
- decrease in organic and inorganic components of bone
- bones become brittle, lose their elasticity and fracture easily
Diaphysis
- long & tubular; shaft of the bone
- collar of compact bone surrounds a central medullary or marrow cavity
- in adults, cavity contains fat
- adults = more yellow bone marrow; children = more red bone marrow for blood cell formation
Epiphysis
- ends of the bone
- joint surface is covered with articular cartilage
- epiphyseal line separate diaphysis and epiphysis
Bone Membranes
- Periosteum: covers outer bone surface; contain nerve fibers, blood and lymph vessels secured by Sharpey’s fibers
- Endosteum: covers internal bone surfaces/lining the medullary cavity
functional classification of joints
- Synarthroses - immovable joints (think…syn→sin→bad→time out→ can’t move)
- Amphiarthroses - slightly movable joints
- Diarthroses - freely movable joints (think…di→die→spirit freely moves around)
structural classification of joints
- Fibrous Joints - united by fibrous tissue; generally immovable (synarthrotic); example - sutures of skull, dento-alveolar syndesmosis (gomphosis), syndesmosis (interosseous membrane)
- Cartilaginous Joints - united by hyaline cartilage or fibrocartilage; immovable or slightly moveable (amphiarthrotic); example - pubis symphysis (child birth), intervertebral discs
- Synovial Joints - most numerous in body; articulating bones are separated by a joint cavity which is filled with synovial fluid for lubrication and nourishment; freely moveable (diarthrotic)
fibrous joints
united by fibrous tissue; generally immovable (synarthrotic); example - sutures of skull, dento-alveolar syndesmosis (gomphosis), syndesmosis (interosseous membrane)
cartilaginous joints
united by hyaline cartilage or fibrocartilage; immovable or slightly moveable (amphiarthrotic); example - pubis symphysis (child birth), intervertebral discs
synovial joints
most numerous in body; articulating bones are separated by a joint cavity which is filled with synovial fluid for lubrication and nourishment; freely moveable (diarthrotic)
- – Plane Joint (Gliding Joints) - carpals
- – Hinge Joint - elbow, jaw, knee
- – Pivot Joint - neck
- – Condyloid Joint - knuckles
- – Saddle Joint - thumb
- – Ball-and-Socket Joint - shoulders, hips
types of muscle fibers
- Skeletal Striated Muscle - moves bones and other structures
- Cardiac Striated Muscle - forms most of the walls of heart and adjacent part of great vessels
- Smooth Muscle - forms part of the walls of most vessels and hollow organs, moves substances through viscera such as intestine, controls movement through blood vessels
skeletal muscle type
- location = skeleton
- function = movement, heat, posture
- appearance = striated, multi-nucleated (eccentric), fibers parallel
- control = voluntary