THE SKIN

Question 1

what is the primary organ of the Integumentary System?

Answer 1

skin

Question 2

what is the largest organ of the body?

Answer 2

skin

Question 3

what forms the outer protective covering of the body?

Answer 3

skin

Question 4

what is the outermost layer of the skin?

Answer 4

epidermis

Question 5

what layer of the skin serves a the primary barrier between the body and environment, and contains 5 layers

Answer 5

epidermis

Question 6

what layer of the skin serves a the primary barrier between the body and environment, and contains 5 layers

Answer 6

epidermis

Question 7

what are the 5 layer of the epidermis? (from deepest to the superficial)

Answer 7

• Stratum Basale (Basal Layer)
• Stratum Spinosum (Prickly Layer)
• Stratum Granulosum (Granular Layer)
• Stratum Lucidum (Clear Layer)
• Stratum Corneum (Horny Layer)

Question 8

Stratum Basale

Answer 8

• new skin cells (keratinocytes) are continuously produced
• contains melanocytes
• contains merkell cells

Question 9

what cell/s produces melanin, responsible for skin color and protection against UV radiation?

Answer 9

melanocytes

Question 10

what cell/s functions as sensory receptors for touch?

Answer 10

merkell cells

Question 11

Stratum Spinosum

Answer 11

• consists several layers of keratinocytes bound by desmosomes that give them a spiny appearance under a microscope
• contains langerhan cells

Question 12

what cell/s play a role in immune defense through identifying foreign substances?

Answer 12

langerhan cells

Question 13

Stratum Granulosum

Answer 13

• composed of 2-5 layers of flattened keratinocytes that begin to die and become more keratinized and accumulate keratohyalin granules and lamellar bodies, which form a waterproof barrier

Question 14

what cell/s form a waterproof barrier due to the accumulation of keratohyalin granules and lamellar bodies?

Answer 14

flattened keratinocytes in the stratum granulosum

Question 15

Stratum Lucidum

Answer 15

• thin transparent later found only in skin such as the palms and soles
• composed of dead keratinocytes for additional layer of protection

Question 16

Stratum Corneum

Answer 16

• outermost sublayer made up of 20-30 layers of dead flattened keratinocytes (corneocytes) that are filled with keratin

Question 17

what cell/s constantly shed and are replaced by cells by moving up from the deeper layers and provides the main barrier against pathogens and water loss

Answer 17

“corneocytes” : dead flattened keratinocytes in the stratum corneum

Question 18

what are the functions of the epidermis?

Answer 18

• waterproof barrier to prevent water loss
• protect underlying tissues from infection, injury, and chemicals
• regulate skin pigmentation through melanocyte activity

Question 19

what is the middle, thicker layer of the skin located below the epidermis and above the hypodermis?

Answer 19

dermis

Question 20

what are the sublayers of the Dermis?

Answer 20

• papillary dermis
  
  • upper layer
  • contain loose connective tissue
  • form dermal papillae (fingerlike projections) that create fingerprints
• reticular dermis
  
  • deeper layer
  • made of dense connective tissue that provides structure and elasticity

Question 21

what contains loose connective tissue, forms dermal papillae and create fingerprints?

Answer 21

papillary dermis

Question 22

what is made of dense connective tissue and provide structure and elasticity?

Answer 22

reticular dermis

Question 23

what are the components of the Dermis?

Answer 23

• blood vessels
  
  • supply nutrients to the skin
  • helps in temperature regulation
• nerves
  
  • provide sensory infromation (pain, temperature, touch)
• hair follicles
  
  • structures where hair grows
  • anchored within the dermis
• sebaceous (oil) glands
  
  • produce sebum which lubricates the skin and hair
• sweat glands
  
  • help body temperature through perspiration

Question 24

what supplies nutrients to the skin and help in temperature regulation?

Answer 24

blood vessels

Question 25

what provides sensory information?

Answer 25

nerves

Question 26

where does hair grow?

Answer 26

hair follicles

Question 27

what helps body temperature regulation through perspiration?

Answer 27

sweat glands

Question 28

what are the functions of the Dermis?

Answer 28

- provide strength and elasticity to the skin because of collagen and elastic fibers - support thermoregulation through the dilation of blood vessels and sweating - act as a sensory organ, detecting pressure, heat, & pain

Question 29

what is the innermost layer of the skin and lies beneath the dermis?

Answer 29

hypodermis (subcutaneous tissue)

Question 30

what composes the hypodermis?

Answer 30

* primarily composed of adipose tissue (fat) * loose connective tissue

Question 31

what are the functions of the hypodermis?

Answer 31

- provide insulation to help body temperature regulation - act as a cushion that absorbs shocks and protect underlying muscles and bones - stores energy in the form of fat - allow some movement of the skin through anchoring the skin to underlying muscles and tissues

Question 32

structure of hair

Answer 32

- grow from follicles in the dermis - each follicle is connected to a sebaceous gland and arrector pili which can contract to make hair stand on end (goosebumps) - composed of keratin, a tough protein

Question 33

functions of hair

Answer 33

- provide protection through trapping dust and particles (nostrils & eyelashes) - assist temperature regulation (insulate the skin when cold by trapping air) (allow sweat to evaporate to cool the body) - sensory role (hair follicles contain nerve endings that detect movement)

Question 34

structure of nails

Answer 34

- made of hardened keratin - grow from the nail matrix which is located under the cuticle at the base of the nail - nail plate: visible part of the nail - nail bed: below the nail plate - lunula: whitish crescent area at the base of the nail

Question 35

functions of nails

Answer 35

- protect the tips of fingers and toes - fine motor functions (grasping, scratching) - tactile sensitivity: transmit pressure and vibrations to underlying nerves