chapter 17 terms

Question 1

derived primarily from surface ectoderm

Answer 1

epidermis

Question 2

surface layer of non-keratinized squamous cells

Answer 2

periderm

Question 3

waxy coating of fetal skin

Answer 3

vernix caseosa

Question 4

created by proliferation of cells of stratum basale&raquo_space; genetically determined and give rise to “prints”

Answer 4

dermal ridges

Question 5

general term for a group of hyper-keratinization disorders&raquo_space; dry, fish-like scaling of skin

Answer 5

ichthyosis

Question 6

genetic recessive trait where skin and hairs lack pigment

Answer 6

albinism

Question 7

genetic dominant trait resulting in patches of albinism

Answer 7

piebaldism

Question 8

formed from lateral somatic mesoderm and from dermatomes of somites

Answer 8

dermis

Question 9

benign skin tumors resulting from the overgrowth of small blood vessels &raquo_space; typically enlarge for a few months after birth and then shrink and disappear by 5-10 years

Answer 9

infantile angiomas

Question 10

dermal root sheath and hair papilla

Answer 10

mesenchymal additions

Question 11

migrate into hair bulbs and differentiate into melanocytes&raquo_space; transfer melanin into hair forming cells

Answer 11

melanoblasts

Question 12

develop as buds off the sides developing epidermal root sheaths &raquo_space; branch to form lobes

Answer 12

sebaceous glands

Question 13

develop as epidermal down-growths into underlying mesenchyme

Answer 13

eccrine sweat glands

Question 14

develop similar to eccrine glands except initiate from hair buds

Answer 14

apocrine sweat glands

Question 15

develop as modified/specialized sweat glands&raquo_space; evaginations of epidermis at 6 weeks

Answer 15

mammary glands

Question 16

thickened strips of ectoderm from which mammary glands develop&raquo_space; appear in week 4 and normally persist only in pectoral region

Answer 16

mammary crests

Question 17

excessive development of mammary glands in males

Answer 17

gynomastia

Question 18

supernumerary breasts

Answer 18

polymastia

Question 19

supernumerary nipples

Answer 19

polythelia

Question 20

develop from oral ectoderm and neural crest derived mesenchyme

Answer 20

deciduous and permanent teeth

Question 21

initiated by neural crest mesenchyme

Answer 21

odontogenesis

Question 22

each tooth bud invaded by mesenchyme

Answer 22

cap stage

Question 23

junction on inner and outer enamel epithelia&raquo_space; induces odontoblasts to form root of tooth

results in narrowing of pulp cavity + formation of root canal to allow passage of nerves and vessels

Answer 23

epithelial root sheath

Question 24

condensation of mesenchyme surrounding developing tooth

Answer 24

dental sac

Question 25

present at birth&raquo_space; painful nursing, lacerate tongue or can fall out and be aspirated

Answer 25

natal teeth

Question 26

results in pits and/or fissures in teeth

underlying causes = rickets, tetracycline, infectious diseases and idiopathic

Answer 26

enamel hypoplasia

Question 27

spherical masses of enamel formed by aberrant masses of ameloblasts

Answer 27

enamel pearls

Question 28

supernumerary teeth that develop in area of maxillary incisors&raquo_space; may disrupt eruption or position of normal teeth

Answer 28

mesiodens

Question 29

one or more teeth absent&raquo_space; familial trait

Answer 29

partial anodontia

Question 30

rare condition resulting from congenital ectodermal dysplasia

Answer 30

complete anodontia

Question 31

fusion of two adjacent teeth (most common) or partial splitting of a single tooth during development

Answer 31

macrodontia

Question 32

yellowish/brown teeth resulting from hypocalcification of enamel&raquo_space; dominant inheritance

Answer 32

ameliogenesis imperfecta

Question 33

brown or bluish gray teeth resulting from hypocalcification of dentin

Answer 33

dentiogenesis imperfecta

Question 34

foreign materials incorporated into forming enamel

Answer 34

discolored teeth

Question 35

blue/black teeth due to incorporation of hemoglobin

Answer 35

hemolytic disease of newborns

Question 36

results in greenish teeth

Answer 36

hyper bilirubinemia

Question 37

maternal use can result in brown/yellow coloring of teeth

Answer 37

tetracyclines