Lecture #4 Flashcards

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1
Q

What are the functions of the skin and hypodermis?

A

BEPPS

  • Body temperature regulation: capillary network and sweat glands regulate heat loss
  • Excretion: urea, salts, and sweat glands regulate heat loss
  • Protection: cushions organs and protects from bumps, chemicals, water loss, and UV radiation
  • Production of vitamin D: epidermal cells use UV radiation to synthesize vitamin D
  • Sensory reception: contains sense organs associated with nerve endings
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2
Q

What type of tissue is the epidermis made of?

A

stratified squamous epithelium

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3
Q

Name the layers of the epidermis starting from the bottom to top most

A
  • stratum basale
  • stratum spinosum
  • stratum granulosum
  • stratum lucidum
  • stratum corneum
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4
Q

Describe the stratum basale: What is the stratum basale located? What happens in this area? What cells are in stratum basale? What do they do?

A
  • deepest layer of epidermis; attached to underlying dermis
  • cells actively divide
  • tactile epithelial cells: associated with sensory nerve endings
  • melanocytes: secrete pigment melanin
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5
Q

Describe the stratum spinosum: What is it made of? What cells are here and what do they do?

A
  • spiny appearance
  • thick bundles of intermediate filaments (resist tension; contain protein pre-keratin)
  • dendritic cells (keratinocyte): type of macrophage; function in immune system
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6
Q

Describe stratum granulosum: What does it consist of? Where keratinocytes are found here?

A
  • few layers of keratinocytes
  • keratohyaline granules: help form keratin
  • lamellar granules: contain waterproofing glycolipid
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7
Q

What layer of the epidermis is ONLY found in thick skin? What areas of the body can you find thick skin?

A
  • stratum lucidum
  • location: palms, soles
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8
Q

Describe the stratum corneum. What is this layers function?

A
  • thickened plasma membrane + thick layer of dead keratinocytes (no nuclei)
  • protects skin against abrasion and penetration
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9
Q

What are the four main cells types found in the epidermis? Describe their location and main function

A
  • keratinocytes: stratum spinosum; produce keratin (fibrous protein)
  • dendritic cells: stratum spinosum; part of immune system; macrophage-like
  • melanocytes: basal layer; manufacture and secrete pigment melanin
  • tactile epithelial cells: basal layer; attached to sensory receptors
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10
Q

Name the cell that is the most abundant in the epidermis, arises from the deepest layer of the epidermis, produces a tough fibrous protein, antibiotics, and enzymes, and is dead at the skin’s surface

A

keratinocytes

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11
Q

What layer of the skin contains strong, flexible connective tissue and is richly supplied with blood vessels and nerves?

A

dermis

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12
Q

Name they two layers of the dermis

A
  • papillary dermis (includes dermal papillae)
  • reticular dermis (80% of thickness of dermis, rich nerve supply)
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13
Q

What is the function of dermal papillae?

A

increases surface area for gas, nutrient, waste exchange

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14
Q

What do dermal papillae lie on?

A

dermal ridges

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15
Q

What are epidermal ridges? What do they do?

A
  • are elevations of dermal ridges
  • form fingerprints and increase the gripping ability of hands and feet
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16
Q

What tissue is the reticular dermis made of?

A

dense irregular connective tissue

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17
Q

What can be found in dense irregular connective tissue?

A
  • cleavage lines: separation between collagen fibers
  • collagen fibers give skin strength
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18
Q

What are flexure lines? What specific layer of the skin is this found in?

A
  • deep creases in palms, wrists, soles, fingers, and toes
  • reticular dermis
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19
Q

Describe the hypodermis. What tissue is it made of and what are its functions?

A
  • areolar + adipose CT
  • anchors skin to underlying structures
  • helps insulate body
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20
Q

What sensation is associated with free nerve endings?

A

light touch; hot; cold; pain

21
Q

What sensation is associated with Merkel’s discs?

A

sustained touch and indented depth (indentation)

22
Q

What sensation is associated with Ruffini corpuscles?

A

skin stretch

23
Q

What sensation is associated with Meissner’s corpuscles?

A

changes in texture; slow vibrations

24
Q

What sensation is associated with Pacinian corpuscle?

A

deep pressure, fast vibrations

25
Q

Name the receptor who’s structure is being described: unmyelinated dendrites of sensory neurons

A

free nerve endings

26
Q

Name the receptor who’s structure is being described: expanded dendritic endings associated with 50-70 specialized cells

A

merkels discs

27
Q

Name the receptor who’s structure is being described: enlarged dendritic endings with open, elongated capsule

A

ruffini corpuscle

28
Q

Name the receptor who’s structure is being described: dendrites encapsulated in connective tissue

A

meissners corpuscle

29
Q

Name the receptor who’s structure is being described: dendrites encapsulated by concentric lamellae of connective tissue structures

A

pacinian corpuscle

30
Q

Describe hair

A
  • flexible strand of dead, keratinized cells
  • hard keratin: tough and durable
31
Q

What are the chief parts of a hair

A
  • root (embedded in the skin)
  • shaft (projects above skins surface)
32
Q

Name the concentric layers of keratinized cells that make up hair. Describe the layer

A
  • medulla: central core
  • cortex: surrounds medulla
  • cuticle: outermost layer
33
Q

What describes the thing that “extend from the epidermis into the dermis”

A

hair follicle

34
Q

What is the name for “deep, expanded end of the hair follicle”

A

hair bulb

35
Q

What is the name for “knot of sensory nerves around hair bulb”

A

root plexus

36
Q

Describe the arrector pili muscle: What is it made of and what does it do?

A
  • bundle of smooth muscle
  • hair stands erect when arrector pili contracts
37
Q

Where are sebaceous glands found?

A
  • over entire body, except palms and soles
38
Q

What do sebaceous glands secrete?

A

sebum (an oily substance)

39
Q

What are the functions of sebum?

A

collects dirt; softens and lubricates hair and skin

40
Q

What is in sebum?

A

simple alveolar glands

41
Q

Name the process in which the entire cell breaks up to form secretion

A

holocrine secretion

42
Q

What is a blood filtrate?

A

sweat

43
Q

What does sweat contain?

A
  • 99% water w/ some salts
  • traces of metabolic waste (urea, ammonia, uric acid)
44
Q

What are the two types of sweat glands?

A
  • apocrine sweat gland
  • eccrine sweat gland
45
Q

What gland is the most numerous and produces true sweat?

A

eccrine sweat gland

46
Q

What areas is apocrine gland confined to?

A
  • axillary
  • anal
  • genital areas
47
Q

Describe the sweat the apocrine gland produces

A
  • musky odor (attracts a mate)
  • signals information about a person’s immune system
48
Q

What glands are modified apocrine glands?

A
  • ceruminous glands
  • mammary glands
49
Q

What is another name for the sweat gland

A

sudoriferous gland