two or more kinds of tissues grouped together and performing specialized functions constitute this
What are the functions of the skin?
Slows water loss
Regulates body temperature
Houses sensory receptors
Synthesizes chemicals (including Vit D)
Contains immune cells
Excretes small amounts of waste
What structures are contained in the epidermis?
composed entirely of stratified squamous epithelium; stratum basale-enables the cells to divide and grow;; there are four layers: stratum basale which is the deepest layer; stratum spinosum, stratum granulosum, and the stratum corneum;; stratum lucidum is in the thickened skin of the palms and soles
What structures are contained in the dermis?
composed of connective tissues, smooth muscle tissue (and fibers), nervous tissue, and blood;; contains dermal papillae, irregular dense connective tissue, muscle cells, nerve cell processes, specialized sensory receptors (Pacinian Corpuscles, Meissner's Corpuscles, Free Nerve Endings), blood vessels, hair follicles, and glands
is beneath the dermis and contains masses of areolar and adipose tissues that bind the skin to underlying organs;; also contains major blood vessels that supply the skin
the process in which cells begin to harden ; strands of tough, fibrous, waterproof keratin proteins that are synthesized and stored in the cell
specialized cells in the deeper epidermis where the blood supply is good and they produce the dark pigment melanin
provides skin color and absorbs ultraviolet radiation in sunlight preventing mutations in DNA of skin cells and other damaging effects
one of the specialized sensory receptors on the dermis -stimulated by heavy pressure
Free nerve endings
one of the specialized sensory receptors on the dermis - respond to temperature change or tissue damage that extends into the epidermis
What is the difference between eccrine and apocrine?
eccrine glands respond through life to body temp elevated by environmental heat or physical exercise; they secrete mostly water with small quantities of salts and wastes and are located on the forehead, neck, and back;;; apocrine glands develop a scent as metabolized by skin bacteria that become active at puberty; respond when emotionally upset, frightened, pain, and during sex; location is in the axillary regions, groin, and around the nipples; open into hair follicles
groups of specialized epithelial cells; keep hair soft, pliable, and waterproof; located near or connected to hair follicles, everywhere but on palms and soles
mixture of fatty material and cellular debris; secreted into hair follicles and keeps hair soft, pliable, and waterproof
a needle injects ink into the dermis. The color is permanent because the dermis cells do not shed. To remove a tattoo, a laser shatters the ink molecules and the immune system removes the resulting debris. Earlier procedures= scraped away, frozen off, or cut away (all painful)
What is the function of a hair follicle?
hair follicle extends from the surface into the dermis and contains the hair root, the portion of hair embedded in the skin. A hair grows from the base of a hair follicle when epidermal cells divide and older cells move outward and become keratinized
Function of the nail parts
protective coverings on the ends of fingers and toes; nail plate- overlies nail bed, nail bed- epithelial cells that are continuous with the surface of skin, lunula- whitish, half-moon shaped region at the base of a nail; the growing region---nail appearance mirrors health
Of what importance is the regulation of body temperature?
vital because even a slight shift can disrupt metabolic reactions; if too cold: blood vessels constrict, sweat glands remain inactive, and shivering occurs; if too hot: blood vessels dilate, and sweat glands secrete
What is the difference between hyper-thermia and hypothermia?
hyperthermia- abnormally high body temperature (fatigue, dizziness, headache, muscle cramps, nausea)
hypothermia- abnormally low body temperature (shivering and feeling of coldness progresses to mental confusion, lethargy, loss of reflexes and consciousness, eventually shutting down of major organs)
What are some genetic and environmental factors that affect skin color?
Genetic: Varying amounts of melanin and varying size of melanin granules
Environmental: Sunlight, UV light from sunlamps, X-rays (they darken existing melanin and stimulate melanocytes to produce more pigment and transfer it to epidermal cells
What happens when wounds heal?
Inflammation, blood vessels in the affected area dilate, become permeable, and allow fluid to leak into damaged tissues; the dilated blood vessels then provide the tissues with more nutrients and oxygen; the inflamed skin becomes red, swollen, warm, and painful to touch
What are the three kinds of burns?
1st degree - superficial partial thickness burn; 2nd degree - deep partial thickness burn; 3rd degree - full thickness burn
Explain a 1st degree burn
slightly burned, dermal vessels dilate (skin turns red), and healing occurs within a few days to 2 weeks
Explain a 2nd degree burn
result of exposure to hot objects, liquids, and flames; destroys some epidermis and some dermis, blisters appear, injured region moist, firm, color from dark red to waxy white, skin usually recover without scars unless an infections occurs
Explain a 3rd degree burn
destroys epidermis, dermis, and all accessory structures of the skin; immersion in hot liquids, prolonged exposure to hot objects, flames, corrosive chemicals; injured skin is dry, leathery, and it's color can be from red to black
What is the rule of nines?
subdivides the skin's surface into regions, each accounting for 9% of the total surface area; see page 187
What are the specific shapes of bones?
the shape of individual bones is closely related to their functions; they have processes, grooves and openings, and ends of bones
Ends of bones
are modified to form joints with other bones (depression of one bone articulates with the process of another)
variety of shapes and are usually connected with other bones ex: vertebrae; facial bones
expanded portion at the end of bone which articulates to form a joint with another bone (it is covered with hyaline cartilage called articular cartilage); composed of spongy bone which consists of numerous branching bony plates
What is the microscopic structure of compact bone?
Bone cells are called osteocytes and are in tiny, bony chambers called lacunae, which form concentric circles around central canals. Osteocytes trandport nutrients and wastes to and from nearby cells by means of cellular processes passing through canaliculi. The extracellular matrix of bone tissue is largely collagen and inorganic salts. Collagen gives bone its strength & resilience, and inorganic salts make it hard ad resistant to crushing.
What is the structure of spongy bone?
it is composed of osteocytes and extracellular matrix; has branching bony plates (trabeculae) that are very thin; the bone cells are not arranged around the central canals but instead lie within the trabeculae; spongy bone on ends of bones allows for compression
What are the 2 kinds of bone development?
Intramembranous ossification and Endochondral ossification
bones originate within sheetlike layers of connective tissues, include broad, flat bones (skull bones= ex.)
bones begin as hyaline cartilage, they form modles for future bones, these include most bones of the skeleton
the plate that separates the diaphysis from the epiphysis; the epiphyseal plate forms four layers (see page 198)
Homeostasis of bone tissue:
after intramembranous and endochondral bones form, the actions of osteoclasts and osteoblasts continually remodel them
osteoclasts- resorb bone
osteoblasts- replace bone
What are the factors that affect bone development, growth and repair?
deficiency of Vitamin A, Vitamin D and Vitamin C, insufficient growth hormone, physical stress (exercise), sex hormones, excessive growth hormone
What are the 6 different bone fractures?
greenstick fracture, fissured fracture, comminuted fracture, transverse fracture, oblique fracture, spiral fracture
Bone Fracture Repair
blood escapes from ruptured blood vessels and forms hematoma, spongy bone forms in regions close to developing blood vessels and fibrocartilage form in more distant regions, a bony callus replaces fibrocartilage, osteoclasts remove excess bone tissue, restoring new bone structure much like the original
What is bone function?
bones shape, support, and protect body structures
bones aid body movements
bones house tissues that produce blood cells
bones store various inorganic salts
**see screen shot
large opening in the bast of the occipital bone; passageway for the spinal cord to connect to the brain
Palatine processes of the maxillae
form them anterior portion of the hard palate (roof of the mouth)
forms upper jaw, anterior roof of mouth, floors of orbits, and sides and floor of nasal cavity
Know the fontanels
fontanels- fibrous membranes; soft spot on the skull
frontal suture, frontal bone, anterior fontanel, posterior fontanel, sagittal suture
Know the hyoid bone
located in the neck between the lower jaw and the larynx; does not articulate with any other bones; supports the tongue
What are the different kinds of vertebrae?
Cervical vertebra (7)
Sacrum (1) (5 fused bones)
Coccyx (1) (4 fused bones) -tail bone
Explain the function of intervertebral discs.
they are pads of flexible fibrocartilage, cushion the vertebrae, absorbs shocks, allows for bending of the spinal column
What are the 2 curvatures of the vertebral column?
1. Cervical curvature- appears when the baby begins to raise its head
2. Lumbar curvature- develops when the baby begins to walk
Know about the ribs.
Ribs- 12 pairs of ribs are attached to the thoracic vertebrae; shaft, head- posterior end; articulates with vertebrae; tubercle- articulates with vertebrae; anterior end of ribs- attached to costal cartilage which goes to sternum