Unit II

Question 1

Integumentary System

Answer 1

1. Skin
2. Hair
3. Nails
4. Mammary Glands

Question 2

The 2 layers of skin are:

Answer 2

1. Epidermis

2. Dermis

Question 3

Epidermis is derived from

Answer 3

ectoderm

Question 4

Dermis is derived from

Answer 4

Mesoderm

Question 5

How does embryonic skin begin?

Answer 5

A single layer of surface ectoderm cells

Question 6

What 2 layers does surface ectoderm create?

Answer 6

Periderm and the basal layer

Question 7

Periderm:

Answer 7

Keratinized Layer

Question 8

Basal layer

Answer 8

produces new cells

Question 9

Vernix Caseosa

Answer 9

Whitish, greasy substance formed by secretions of sebaceous glands and exfoliated cells (periderm). It covers the skin of the fetus

Question 10

Vernix Caseosa Functions

Answer 10

1. Protects fetal skin from amniotic fluid (urea and uric acid are in the fluid)
2. Lubricates the fetus to facilitate parturition

Question 11

What replaces the periderm?

Answer 11

The stratum corneum

Question 12

Sweat glands

Answer 12

down-growths of the epidermis into the dermis

Question 13

Epidermal ridges

Answer 13

finger prints (dermatoglyphics)

Question 14

Fingerprints of children with chromosomal abnormalities

Answer 14

Have a pattern

Question 15

Melanocytes

Answer 15

Derived from neural crest cells and produce skin pigmentation

Question 16

Albinism

Answer 16

An autosomal recessive genetic trait where a person lacks pigmentation in the skin, hair, and retina. They have the normal number of melanocytes but lack the enzyme tyrosinase (produces melanin)

Question 17

Problems associated with skin cancer and the retina

Answer 17

Pigmentation is necessary to protect the skin and eyes from UV Radiation

Question 18

Dermal Papillae

Answer 18

project up into the epidermis. Contain blood vessels and nerves

Question 19

Hair buds

Answer 19

down-growths of the epidermis into the dermis

Question 20

Dermal root sheath

Answer 20

mesenchyme surrounding the hair bulb

Question 21

Arrector muscles of hairs

Answer 21

elevate the hair shafts and are responsible for “goosebumps”

Question 22

Sebaceous gland

Answer 22

a small bud grows from the wall of the developing hair follicle

Question 23

Lanugo

Answer 23

The first hairs to develop. Help hold the vernix cases in place

Question 24

Fingernails reach the tips of the digits by week:

Answer 24

32

Question 25

Toenails reach the tips of the digits by week:

Answer 25

36

Question 26

Mammary crest (ridge)

Answer 26

A band-like thickening of the epidermis where mammary glands develop

Question 27

Mammary buds

Answer 27

down-growths of the epidermis into the underlying mesenchyme which develops into lactiferous ducts

Question 28

Polythelia

Answer 28

An extra nipple. More common in females. Always occurs along the mammary crest

Question 29

Polymastia

Answer 29

An extra breast. Usually develops inferior to the normal breast but can occur anywhere along the mammary crest

Question 30

Inverted Nipple

Answer 30

Can cause problems with baby's latching. 1. The nipple is everted and then inverts in adult hood is a sign of breast cancer 2. A nipple that is always inverted is not a sign of breast cancer

Question 31

Somites differentiate into:

Answer 31

1. Sclerotome | 2. Dermomyotome

Question 32

Sclerotome

Answer 32

Gives rise to the vertebrae and ribs and is located ventromedially

Question 33

Dermomyotome:

Answer 33

Gives rise to muscle and dermis of the trunk. Located dorsolaterally

Question 34

Mesenchyme

Answer 34

Connective tissue made up of loosely woven sclerotomes

Question 35

Mesenchyme differentiates into:

Answer 35

1. Fibroblasts 2. Chondroblasts 3. Osteoblasts

Question 36

Intramembranous Ossification

Answer 36

Bone develops from mesenchyme directly within membranous sheaths Ex: Flat bones of the skull

Question 37

Endochondral Ossification

Answer 37

Mesenchyme differentiates first into hyaline cartilage models and then ossifies Ex: Limb and most other bones

Question 38

Neurocranium

Answer 38

encloses the brain

Question 39

Viscerocranium

Answer 39

forms the face

Question 40

Neurocranium subdivides into:

Answer 40

1. Membranous Neurocranium | 2. Cartilaginous Neurocranium

Question 41

Membranous Neurocranium

Answer 41

forms the skull vault

Question 42

Cartilaginous Neurocranium:

Answer 42

forms the base of the skull

Question 43

Membranous neurocranium ossification

Answer 43

intramembranous

Question 44

What seperates flat bones at birth?

Answer 44

Fibrous tissue joints called sutures

Question 45

Fontanelles

Answer 45

sheet-like fibrous areas where more than 2 bones meet

Question 46

How many fontanelles are there?

Answer 46

6

Question 47

Name the 6 fontanelles

Answer 47

1. Anterior fontanelle 2. Posterior Fontanelle 3. Anterolateral fontanelle (paired) 4. Posterolateral Fontanelles (paired)

Question 48

Anterior Fontanelle

Answer 48

Largest, closes about 1.5 years after birth

Question 49

Posterior Fontanelle

Answer 49

closes about 3 months after birth

Question 50

Cartilaginous Neurocranium ossification

Answer 50

endochondral

Question 51

Craniosynthosis

Answer 51

Prenantal fusion of cranial sutures

Question 52

Scaphocephaly

Answer 52

premature fusion of the sagittal suture. Skull becomes long, narrow and wedge shaped (MOST COMMON)

Question 53

Brachycephaly

Answer 53

premature fusion of the coronal suture. Produces high, tower-like skull

Question 54

Acrania

Answer 54

Complete or partial absence of the neurocranium. Associated with major defects of the vertebral column and partial absence of the brain. Usually incompatible with life

Question 55

Viscerocranium

Answer 55

bones of the face formed from neural crest cells of the first 2 pharyngeal arches

Question 56

Sclerotomes differentiate into:

Answer 56

1. Cranial part: loosely packed cells | 2. Caudal part: densely packed cells

Question 57

Anulus Fibrosus

Answer 57

formed of the uppermost cells of the caudal part