Exam 2 Study Guide Flashcards
What are the four primary human tissues?
nervous tissue, muscle tissue, epithelial tissue, and connective tissue
Name and describe the various types of epithelia
Squamous: flat and scale like
Cuboidal: cube shaped
Columnar: tall and column shaped
What is the difference between stratified and simple?
Stratified: two or more layers of cells stacked
Simple: single layer of cells
Why is collagen important in connective tissue?
-strongest and most abundant type
-tough; provides high tensile strength
-the more collagen, the stronger it is
What is the major difference between skeletal and cardiac and smooth muscle?
skeletal: attached to the bones of the skeleton; cells are striated
cardiac: only found in the wall of the heart; does not regenerate; cells are striated
smooth muscle: cells have no visible striations; within walls or hollow organs
Indicate the general characteristics of nervous tissue.
main component of nervous system; internal communication; contains neurons and supporting cells
What are neurons?
specialized nerve cells that generate and conduct nerve impulses; respond to stimuli and transmit electrical impulses
What are the three embryonic germ layers?
Ectoderm: nervous tissue
Mesoderm:
Endoderm:
Stratum basale
deepest epidermal layer; one row of actively mitotic stem cells
Stratum spinosum
several layers of keratinocytes unified by desmosomes; cells contain thick bundles of intermediate filaments made of pre keratin
Stratum granulosum
1-5 layers of flattened cells, organelles deteriorating; cytoplasm full of lamellar granules and keratohyaline granules
Stratum corneum
most superficial layer; 20-30 layers of dead cells, essentially flat membranous sacs filled with keratin. l
Basal cell carcinoma
least malignant; most common
-stratum basale cells proliferate and slowly invade dermis and hypodermis
-cured by surgical excision in 99% of cases
Squamous cell carcinoma
second most common type; involves keratinocytes of stratum spinosum; usually scaly reddened papule; does metastasize; good prognosis if treated by radiation therapy or removed surgically
Melanoma
cancer of melanocytes; most dangerous; highly metastatic and resistant to therapy; ABCD rule
Asymmetry: two sides of pigmented area do not match
Border: exhibit indentations
Color: various colors
Diameter: spot is larger than 6mm
What tissue types compose the epidermis and dermis?
The epidermis is composed of epithelial tissue
The dermis is composed mostly of fibrous connective tissue
What are the layers of the epidermis?
Stratum basale
Stratum spinosum
Stratum granulosum
Stratum lucidum
Stratum corneum
What are the layers of the dermis?
papillary and reticular
Is the dermis or epidermis composed largely of dead cells?
epidermis
Why are stem cells important in the epidermis?
aid in the repair of the dermis after injuries
What are the cells of the epidermis?
Keratinocytes
Melanocytes
Dendritic Cells
Tactile Epithelial Cells
Describe keratinocytes
-produce keratin
-most cells of epidermis
-tightly connected by desmosomes
Describe melanocytes
-10-25% of cells in deepest epidermis
-produce pigment melanin(protect keratinocyte nucleus from UV damage)
Describe dendritic(Langerhans) cells
-arise from bone marrow and migrate to epidermis
-macrophages, ingest foreign substances and are key activators of immune system
Describe tactile(Merkel) cells
-present at epidermal/dermal junction
-sensory receptor for touch
Which cells are actively in the cell cycle, versus differentiated?
osteoprogenitor cells differentiate into osteoblasts or bone lining cells
Why are serious burns life threatening?
dehydration and electrolyte imbalance(loss) can lead to renal shutdown and circulatory shock
How do you determine the extent of a burn
rule of nines; method divides the body into 11 areas, each accounting for 9% of total body area plus 1% for genitals on body surface
Describe first degree burns
First: only the epidermis is damaged; localized redness, swelling, and pain; tend to heal in 2-3 days; ex: sunburn; considered partial degree burn
Describe second degree burns
injure the epidermis and the upper region of the dermis; redness, swelling, pain, and blisters; skin regeneration occurs w little to no scarring within 2-3 weeks; considered partial thickness burn
Describe third degree burn
full thickness burn; involving entire thickness of skin; burned area appears grey, white cherry red, or blackened; not painful; skin grafting is advised to prevent fluid loss and infection
When are burns considered critical?
-over 25% of the body has second degree burns
-over 10% of the body has third degree burns
-third degree burns on face(possibly mean burned respiratory passageways), hands, or feet
Bone is a source of what crucial nutrient? Why does the body need it?
calcium; functions in nerve impulse transmission, muscle contraction and blood coagulation
Parathyroid hormone(PTH)
produced by the parathyroid glands; when blood levels of Ca decline, PTH is released, which stimulates osteoclasts to resorb bone, releasing calcium into the blood; removes calcium from bone regardless of bone integrity
Describe the histology of compact bone
also called lamellar bone; has osteons or Haversian system; hollow tubes of bone matrix called lamellae; perforating(volkmann’s) canals; lacunae: small cavities that contain osteocytes; canaliculi: hairlike structures
Describe the histology of spongy bone
mesh of bony spines called trabeculae which: align along lines of stress; no osteons; irregularly arranged lamellae and osteocytes interconnected by canaliculi; capillaries in endosperm supply nutrients
Chemical composition of bone(ORGANIC components)
includes cells and osteoid; osteogenic cells; osteoblasts, osteocytes, bone lining cells, and osteoclasts; osteoid: 1/3 of organic bone matrix secreted by osteoblasts; provides tensile strength and flexibility
Chemical composition of bone(INORGANIC composition)
hydroxyapatites(mineral salts); 65% of bone by mass; mainly of tiny calcium phosphate crystals in and around collagen fibers; responsible for hardness and resistance to compression
What calcium compound is important to bone hardness?
calcium hydroxyapatite`
Osteoblasts
produce matrix
Osteocytes
maintain matrix
Osteoclasts
degrade bone
Explain how hormones regulate bone remodeling
negative feedback hormonal loop for Ca homeostasis; controls blood Ca levels not bone integrity
Explain how physical stress regulates bone remodeling
remodel in response to demands placed on it; ex: tennis player’s arm
Describe the disorder of bone remodeling in osteoporosis.
bone resorption outpaces deposit
