Skin and Appendages

Question 1

What is the integumentary system?

What does it consist of?

Answer 1

Integument is the skin (organ: made up of different tissues)

Consists of the skin and appendages

Question 2

What are seven functions of the skin?

Answer 2

1. Protects
2. Synthesis of vitamin D and UV
3. Regulates body temperature
4. Prevents unnecessary water loss
5. Sensory reception
6. Excretion
7. Blood reservoir

Question 3

What are the two types of skin?

What is its classification dependent on?

Answer 3

1. Thin skin
2. Thick skin

Dependent on thickness of the epidermis

Question 4

What are the two main layers of the skin?

Answer 4

1. Epidermis

2. Dermis

Question 5

What are the five layers of the dermis, from deepest (1st layer) to superficial (5th layer)?

Answer 5

1st stratum basale (germinativium)
2nd stratum spinosum
3rd stratum granulosum
4th stratum lucidum
5th stratum corneum

Question 6

What are the different types of cells contained in the dermis?

Answer 6

1. stratified squamous keratinized epithelium
2. melanocytes
3. keratinocytes
4. merkel
5. langerhans

Question 7

Describe layer 1 of the epidermis.

Name? Cells contained? Function?

Answer 7

Stratum basale (germinativium)

single layer of cubodial or columar keratinocytes on basement membrane

melanocytes- brown pigment melanin, found on superficial layer of keratinocytes

merkel cells- sensory nerve endings

Question 8

Describe layer 2 of epidermis.

Name? Cells contained? Function?

Answer 8

Stratum spinosum

8-10 layers of polyhedral cells, cells contain protein cytokeratin

separated by narrow translucent clefts

spine like cytoplasmic extensions connect from one cell to next by desmosomes

contain Langerhans cells- act as macrophages

Question 9

Describe layer 3 of epidermis.

Name? Cells contained? Function?

Answer 9

Stratum granulosum

cells become flat 3-5 cells

contain basophilic keratohyaline granules

cellular organs begin to disintegrate

Question 10

Describe layer 4 of epidermis.

Name? Cells contained? Function

Answer 10

Stratum lucidum

several layers of clear flat dead cells

faint nuclear outline in some cells

protein eleidin intermediate keratin

only found in thick skin

Question 11

Describe layer 5 of epidermis.

Name? Cells contained? function?

Answer 11

Stratum corneum

30 cells thick , 3/4 of epidermis

cells shed regularly, looser appearance

individual cells difficult to observe

Question 12

What is the dermis? Cells contained? Fibers contained?

Answer 12

strong, flexible connective tissue layer

cells: macrophages, mast cells, white blood cells, fibroblasts
fibres: collage, elastic, recticular

Question 13

What are the two layers of the dermis?

Answer 13

1. Papillary

2. Recticular

Question 14

What is the Papillary layer of dermis?

Answer 14

Extends into epidermis

1/5 of dermis

highly vascular

forms dermal papillae: fingerprints

Question 15

What is the Reticular layer of the dermis?

Answer 15

irregular dense connective tissue

contains: 
hair follicles
arrector pili muscles
sebaceous glands
sweat glands
Meissner's corpuscle
Pacinian corpuscle

Question 16

What is the hypodermis?

Answer 16

superficial fascia

fatty tissue that stores fat and oils

areolar and adipose tissue

Question 17

What are skin appendages? Examples?

Answer 17

derived from epidermis but extend to dermis

include: hair/hair follicle
sebaceous oil glands
sweat glands
nails

Question 18

What is hair pili?

Answer 18

Composed of dead columns of keratinized cells
Two parts: shaft & root
consists of medulla, cortex(keratin and pigments), outer cuticle

Question 19

Hair?

Answer 19

Root hair in epidermal tube (root follicle) extending into dermis

Hair bulb: dilation at base

dermal papilla: invigilates into bulb, contains blood capillaries

arrector pili muscle extends from deep part of hair follicle to papillary layer, supplied by sympathetic nerves= contraction

Question 20

Sebaceous oil glands?

Answer 20

dermis of thin skin
opens into upper portion of hair follicle
produces sebum by holocrine secretion
oils and lubricates

Question 21

Sweat glands?

Answer 21

aka sudoriferous

prevents overheating, produced in response to heat or stress

has acinus lined by columnar cells

found in entire skin surface

Question 22

What are the three types of sweat glands?

Answer 22

1. Eccrine or merocrine
2. Apocrine
3. Modified apocrine glands

Question 23

What are eccrine or merocrine glands?

Answer 23

most numerous, open through pores

Question 24

What are apocrine glands?

Answer 24

ducts open into hair follicles

organic molecules decompose with time = odor

Question 25

What are modified apocrine glands?

Answer 25

ceruminous- secrete ear wax

mammary- secrete milk