Skin- 19

Question 1

functions

Answer 1

1: protect body from injury by external forces
2: prevents excessive loss of body fluids
3: major sense organ- touch, temp, pressure, pain
4: regulation of body temperature

Question 2

epidermis

Answer 2

outer covering
stratified squamous epithelium
composed of KERATINOCYTES
4 major morphologic divisions

Question 3

dermis

Answer 3

fibrous CT
contains hair follicles, sebaceous and sweat glands, blood vessels and sensory nerves

fibrous tissue mixed intermixed with elastin fibers: high collagen provides skin resistance to mechanical force and elastin allows the sin to recoil after mechanical deformation.
elastin fibers are decreased/destroyed with age/disease- skin becomes loose and wrinkled

Question 4

subcutis/ subcutaneous tissue

Answer 4

deep layer of adipose tissues

Question 5

4 divisions of epidermis

Answer 5

1: Basal Layer
2: Spinous layer
3: granular layer
4: Cornified layer

Question 6

basal layer

Answer 6

deepest
single layer of predominantly cuboidal germinative cells that gives rise to all other epidermal cells by mitotic division

Question 7

spinous layer

Answer 7

several layers of keratinocytes undergoing progressive maturation while producing keratin fibrils

Question 8

granular layer

Answer 8

keratinocytes acquire keratohyaline granules and form rows parallel to the skin surface

Question 9

cornified layer

Answer 9

granular layer cells eventually die and shed their nucleus to form this outmost layer
thickness varies in different body segments: pal and fingers very thick, eyelid- think

Question 10

Melanocytes

Answer 10

scattered throughout the basal layer
large, pale cells that may contain brown granules.
produce brown melanin pigments- help protect the skin from sunlight damage and contribute to skin color

Question 11

eccrine glands

Answer 11

present in deep dermis over nearly entire body surface

produces sweat in response to heat stress

Question 12

apocrine glands

Answer 12

produce a sticky proteinaceous and lipid rich fluid in response to hormonal stimuli

axillae, pubis, perineum, nipples, ear, lips

dormant until puberty

Question 13

hair follicles

Answer 13

covers entire body but soles, palms, parts of genitals

Question 14

sebaceous gland

Answer 14

attached to each hair follicle

secretes lipid-rich sebum (waterproofs skin and hair and protects from dehydration)