Exam 2 A&P pgs. 1-3

what do keratinocytes produce?

keratin

what do melanocytes produce?

melanin

what is the purpose of keratin?

to give the skin protective properties

what is the purpose of melanin?

pigment and UV protection

what are the 4 layers of the epidermis? (excluding lucidum)

• corneum

• granulosum

• spinosum

• basale

what cells are found in the basale?

a single row of stem cells

what kind of cells are in the spinosum?

• spikey keratinocytes called “prickle cells”

• dendritic cells are scattered amoung the keratinocytes

what kind of cells are in the granulosum?

• keratinocytes; appearances constantly change

• cells are flat, nuclei disintegrates

what kinds of cells are in the corneum?

dead keratinized cells

are cells in the basale dead or alive?

alive

are cells in the spinosum dead or alive?

alive

are cells in the granulosum dead or alive?

alive

are cells in the corneum dead or alive?

dead

how many daughter cells does mitosis produce in the basale?

2

how do the cells in the basale move?

one daughter cells stays at the basale, one moves to the epidermal surface

how long does it take for a cell to move towards the surface?

25-45 days

true or false: cells die as they move towards the surface

true

what are prickle cells composed of?

intermediate filaments that contain pre-keratin

what is the function of prickle cells?

to resist tension

where are keratinohyaline granules and lamellar granules located?

the granulosum

what do keratinohyaline granules secrete?

a “glue” that prickle cells bind with to make keratin

what do lamellar granules secrete?

a water-resistant glycolipid into the extracellular space

what is the purpose of the granulosum?

external water resistance

how is the granulosum made water resistant?

keratin and the glycolipids

what layer of the epidermis ONLY has dead cells?

corneum

what is the purpose of dead cells in the corneum?

to protect the body from abrasion and penetration

what is the alternate name for the basale?

stratum germinativum

what is the spinosum often referred to as?

the prickly layer

what is the granulosum often referred to as?

the granular layer

what is the corneum often referred to as?

the horny layer

how thick is the basale?

a single row

how thick is the spinosum?

several cell layers thick

how thick is the granulosum?

1 to 5 cells thick

how thick is the corneum?

20-30 rows of flat, anucleated keratinized dead cells

how many types of glands are found in the body?

2

what 2 types of glands are found on the body?

• sweat glands

• sebaceous glands

what are the 2 types of sweat glands called?

eccrine and apocrine

what is the difference between eccrine and apocrine sweat glands?

eccrine is found all over the body; apocrine is limited to axillary and anogenital regions

what sweat gland is most abundant in the body?

eccrine glands

what do eccrine glands function to do?

aid with thermoregulation

what is the difference between the secretions of eccrine and apocrine glands?

• eccrine: sweat only

• apocrine: sweat with added fatty substances and proteins

what characteristics do apocrine scretions contain?

• appears milky or yellowish in color

• odorous

what fluid do sebaceous glands secrete?

sebum

how would you describe sebum?

oily holocrine secretion

what funtions does sebum have?

• kills bacteria

• softens hair and skin

are sebaceous glands active all throughout life?

no, typically inactive until puberty

what does cyanosis indicate?

low oxygenation of hemoglobin in red blood cells

what does pallor indicate?

• anemia

• low blood pressure

• fear

what does erythema indicate?

• fever

• hypertension

• inflammation

• allergy

what does jaundice indicate?

liver disorder

what do bruises indicate?

blood clots beneath the skin

what does a brown or black “necklace” indicate?

insulin resistance and elevated blood glucose level

what is hair made of?

flexible strands of dead, keratinized cells

where on the body does hair not grow?

palms, soles of feet, lips, nipples, portions of external genitalia

how does hair grow?

hair is produced by hair follicles

what are the 3 regions of hair?

• medulla

• cortex

• cuticle

what factors influence hair growth?

nutrition and hormones

what are the main types of hair found on the body?

• vellus hair- fine hair

• terminal hair- coarse, long hair

where is terminal hair found?

scalp and eyebrows

what dictates hair color?

melanocytes

what are nails made of?

modifications of the epidermis that contain hard keratin

how does blood supply affect nails?

underlying capillaries give nails their normal pink color

where is the hypoychium located?

under the free edge

what is the nail matrix?

the portion of the nail bed responsible for nail growth

lunule

thickened nail matrix, appears white, under the cuticle

what are the metabolic functions of skin?

• synthesis of vitamin D

• neutralize carcinogens

• activate hormones

• makes collagenase

what are the 3 types of skin cancer?

• basal cell carcinoma

• squamous cell carcinoma

• melanoma

what skin cancer is the least dangerous?

basal cell carcinoma

what skin cancer is the most dangerous?

melanoma

what skin cancer is the most common?

basal cell carcinoma

how does basale cell carcinoma affect the body?

cancerous cells proliferate and invade the dermis and hypodermis

does basale cell carcinoma have a high level of metastasis?

no, it is slow growing and rarely metastasizes

how is basal cell carcinoma treated?

surgery

what is the second most common skin cancer?

squamous cell carcinoma

can squamous cell carcinoma metasize?

yes

what does squamous cell carcinoma involve?

keratinocytes in the stratum spinosum

what is the appearance of squamous cell carcinoma?

scaly, reddened papule on the scalp, ears, lower lip, or hands

how is squamous cell carcinoma treated?

radiation therapy or surgery

what is the most dangerous type of skin cancer?

melanoma

does melanoma metasize?

melanoma metasizes at a high rate

what treatment is melanoma resistant to?

chemotherapy

how is melanoma treated?

surgery with immunotherapy

what is the major key to surviving melanoma?

early detection

what is the immediate concern with burns?

dehydration and electrolyte imbalance

what does dehydration from burns lead to?

kidney failure

what is the Rule of Nines?

an evaluation system used to assess the severity of burns

using the Rule of Nines, how many sections is the body broken into?

11

what does the Rule of Nines estimate?

the volume of fluid loss

what 3 types of burns are there?

• first degree

• second degree

• third degree

how would you describe a first degree burn?

redness and swelling

how would you describe a second degree burn?

blistering

how would you describe a third degree burn?

skin is gray-white, cherry red, or blackened

what is appositional growth?

cartilage forming cells in the perichondrium that secrete matrix against the external face of existing cartilage

what is intersitial growth?

chondrocytes within the lacunae divide and secrete new matrix

what is the effect of interstitial growth?

expands cartilage from within

what are the 5 general structures of a typical long bone?

• shaft

• bone ends

• epiphyseal line

• epiphyseal plate

• membrane

what are the 2 components of a bone membrane?

1. periosteum

   • contains a fibrous layer

   • contains a osteogenic layer

2. endosteum

   • connective tissue covering internal bone surface

what does the central (haversian) canal run through?

the core of each osteon

what is the perforating (volkmann’s) canal?

canal lined with endosteum that occur at right angles to central canal

what does the perforating canal connect?

blood vessels and nerves of periosteum, medullary cavity, and central canal