Integumentary System

Question 1

What is the purpose of the Integumentary system?

Answer 1

Covers and protects underlying structures. Forms barrier against external world

Question 2

What are the 6 functions of Integument (skin)?

Answer 2

1. prevent desiccation
2. reduce threat of injury
3. help maintain body temperature
4. excretion of water/salt/organic wastes
5. sensory organ
6. site of vitamin D synthesis and storage

Question 3

Name the 3 organizations of skin

hint: -dermis

Answer 3

1. epidermis
2. dermis (corium)
3. hypodermis

Question 4

Name the functions and describe the epidermis

Answer 4

outermost layer, composed of keratinized stratified squamous epithelium. Is avascular.

Question 5

Define and explain the Corium

Answer 5

dermis, includes blood vessels, glands and hair follicles. Composed of loose connective, smooth muscle, and dense fibroelastic. Dominant layer of skin, basememnt membrane. Dermal papillae

Question 6

Define and describe the hypodermis

Answer 6

subcutaneous layer, mainly composed of adipose tissue. functions to be an insulator and mechanical shock absorber.

Question 7

Name the four cells in the epidermis

Answer 7

1. keratinocytes
2. melanocytes
3. langerhans
4. merkel

Question 8

What is the purpose of keratinocytes?

Answer 8

primary cell found in the epidermis, produces keratin. Constantly dividing on basement membrane and die as pushed up to surface, becoming sheets of keratin.

Question 9

What is the purpose of melanocytes?

Answer 9

found in the basal layer of epidermis, octopus cell shape extension that reach keratinocytes. produced pigment melanin stored in melanosome granules that get released into interstitial space. Are absorbed by keratinocytes superficially from UV light exposure

Question 10

Define Langerhan cells

Answer 10

macrophage specific to epidermis, originates from bone marrow and migrates to skin. Play an important role in stimulating aspects of immune system and phagocytizes microinvaders.

Question 11

Define Merkel cells

Answer 11

located at epidermal-dermal junction. Found in small numbers and associated with sensory nerve endings thought to aid in touch sensation.

Question 12

What are the 5 layers of the Epidermis?

Answer 12

1. Stratum basale
2. Stratum spinosum
3. Stratum granulosum
4. Stratnum lucidum
5. Stratnum corneum

Question 13

Describe the stratum basale

Answer 13

Deepest layer of epidermis. Consists of single row of keratinocytes, which are firmly attached to epithelial basement membrane. Includes small amounts of merkel cells and melanocytes.

Question 14

Describe the stratum spinosum

Answer 14

Spiny layer, consists of many layers of keratinocytes held together by desmosomes. Keratinocytes also called prickles cells. Infrequent cell division. Abundant langerhans form web-like frame around keratinocytes

Question 15

Describe the stratum granulosum

Answer 15

middle layer of skin, composed of 2-4 layers of flattened diamond shaped keratinocytes. Cytoplasm fills with keratohyaline granules.

Question 16

Describe the Stratum lucidum

Answer 16

clear, translucent layer, only found in very thick skin. Composed of a few rows of flattened, dead cells.

Question 17

Describe the stratum corneum

Answer 17

horny, most outer layer, dominates the epidermis. Composed of 20-30 rows of keratinocytes. Keratinocyte remnants are also called horny or cornified cells

Question 18

How many layers of skin does a furred animal have?

Answer 18

usually only 3:
- stratum basale
- stratum spinosum
- stratum corneum

Question 19

Summarize the Dermis

functions, location, qualities

Answer 19

greatest portion of the integument, responsible for the structural strength of skin, highly fibrous, toughest layer in skin

Question 20

What is the dermis composed of?

Answer 20

dense irregular connective: collagen, elastic, and reticular fibers. hair follicles, nerve endings, glands, smooth muscle, blood vessels and lymphatic channels, fibroblasts, adipocytes and macrophages

Question 21

What are the layers of the dermis?

Answer 21

papillar, reticular *indistinct boundary between papillar and reticular

Question 22

What is the papillary layer?

Answer 22

Thin, superficial that lies beneath epithelial layer of epidermis. composed of loose connective and loose woven fibers and ground substance. has nerve endings/pain receptors and meissner’s corpsules. sensitive to temperature changes. Dermal papillae are projections rising into epidermis to connect epi+dermis together. Looping blood vessels provide nourishment to activate cells of stratum basale, help remove waste, assist in temp. control

Question 23

What are the meissner’s corpsules?

Answer 23

touch receptors, sensitive to light touch

Question 24

Describe the reticular layer

Answer 24

Thick, deep, consisting of dense irregular, accounts for 80% of the dermis

Question 25

Important parts of the Indistinct boundary:

Answer 25

fibrous bundles that run parallel to each other, orientation depends on direction of stress placed, tension lines important for surgeons