Integumentary System Flashcards
1
Q
A
2
Q
Functions of the Skin and Hypodermis
A
- Cushioning & insulation
- Protection
- Excretion (sweat, sebum, milk)
- Prevents water loss
- Temperature regulation
- Calcium/phosphate regulation
- UV protection
- Sensory reception
3
Q
Hypodermis
A
fatty layer deep to dermis
4
Q
Epidermis
A
- outermost layer of skin
- keratinizied stratified squamous epithelium
- 4 main cell types:
- Keratinocytes
- Melanocytes
- Merkel cells (tactile)
- Langerhans cells ( immune-related, AKA epidermal dendritic cells)
- 5 layers (deepest first):
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
5
Q
Keratinocyte
A
- most abundant cell type in epidermis
- arise from stratum basale
- produce keratin
- those at the skin’s surface (stratum corneum) are dead
6
Q
Melanocyte
A
- found in Stratum basale
- cells that secrete melanin
- have long, cytoplasmic processes that branch out into above layers, protecting cells below
- sends melanin to keratinocytes, where it is stored around their nuclei to protect their DNA from damage
7
Q
Merkel Cells
A
- oval receptor cells found in Stratum basale
- associated with sense of touch
- AKA tactile epithelial cells
8
Q
Langerhans Cells
A
- AKA dendritic cells
- perform receptor-mediated endocytosis to take up invading antigens and communicate with lymph nodes about it
9
Q
The Layers of the Epidermis
A
- in order from deepest to most superficial:
- Stratum Basale (or Germinativum)
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum (thick skin only)
- Stratum Corneum
- Big Stupid Guys Like Coors
10
Q
Stratum Basale
A
- AKA Stratum Germinativum
- borders the dermis
- mostly Keratinocytes, some Merkel Cells and Melanocytes
- cells undergo mitosis
11
Q
Stratum Spinosum
A
- cells have thick bundles of intermediate filaments of pre-keratin
- Langerhans cells found here (endocytosis)
12
Q
Stratum Granulosum
A
- contains** **flattened keratinocytes with keratohyalin granules to promote cross-linking and hydration of keratin and lamellar granules for waterproofing.
13
Q
Stratum Lucidum
A
- only found in thick skin of palms and soles of feet
- a few rows of flat, dead keratinocytes
14
Q
Stratum Corneum
A
- outermost layer of epidermis
- varies in thickness
- dead keratinocytes filled with keratin
- protection and water loss prevention
15
Q
Melanin
A
- endogenous pigment produced by melanocytes in the stratum basale of the epidermis
- genetics and sun exposure affect amount produced
- varies in color, yellow, brown or black
16
Q
Dermis
A
- vascular, innervated layer below epidermis
- made of connective tissue (areolar and dense irregular)
- made up of 2 layers:
- Papillary layer (superficial 20%)
- Reticular layer (deeper 80%)
- extends upward into epidermis in egg carton-like segments called Dermal Papillae
17
Q
Papillary Layer of the Dermis
A
- makes up superficial 20% of dermis
- made of areolar connective tissue with thin collagen and elastic fibers
- dermal papillae project upward toward epidermis, epidermal ridges project downward, which increases surface area for transportation of gases, nutrients and waste between layers
- Meissner’s Corpuscles extend into papillae for light touch reception
18
Q
Reticular Layer of the Dermis
A
- makes up bottom 80% of dermis
- made up of dense irregular connective tissue
- named “reticular” for its network of collagen & elastic fibers
- site of Lamellated Corpuscles, pressure sensing nerve endings
19
Q
Cleavage Lines
A
- less dense regions of collagen in reticular dermis
- useful in surgery because incisions made parallel to cleavage lines heal better
20
Q
Tactile Corpuscles
A
- AKA Meissner’s Corpuscles
- located in dermal papillae
- sense light touch
21
Q
Lamellated Corpuscles
A
- AKA Pacinian Corpuscles
- located in reticular layer of dermis
- sense heavier pressures than Meissner’s
22
Q
Root Hair Plexus
A
- groups of nerve fiber endings around bulb of hair follicle that sense movement of hair and skin
23
Q
Hypodermis
A
- technically not part of the skin
- contains areolar and adipose tissues
- insulates and anchors skin to underlying structures
24
Q
Appendages of the Skin
A
- hair & follicles
- sebaceous glands
- sweat glands
- nails
25
Q
Hair
A
- Long, flexible strands of keratinized cells
- Function: sense, guard, shield, protect
26
Q
Hair Follicle
A
A tubular invagination of the epidermis that contains the hair bulb, hair shaft and hair root
27
Q
3 Layers of Hair
A
- **Cuticle - **scaly-celled, overlapping outer layer
- Cortex - middle layer, several layers of flattened cells
- **Medulla - **inner layer, large cells
28
Q
Hair Bulb
A
Deep, swollen end of hair follicle
29
Q
Hair Papilla
A
Connective tissue that projects up into the bulb, much like dermal papillae into epidermis
30
Q
Hair Matrix
A
Epithelial cells directly above papilla where new hair cells divide rapidly and melanocytes contribute pigment
31
Q
Connective Tissue Root Sheath
A
- outer, dermal layer of sheathing around follicle
32
Q
Epithelial Root Sheath
A
Inner, epidermal layer of sheathing around follicle
33
Q
Arrector Pili
A
- Smooth muscle tissue that extends from the dermal papillae to hair follicles to pull hair upright
- process known as Piloerection
34
Q
Hair color
A
Eumelanin - black and brown hair
Pheomelanin - blonde and red hair
35
Q
Sebaceous Glands
A
- simple, alveolar holocrine glands that empty oily secretions (Sebum) into hair follicles
- found everywhere except palms and soles
36
Q
Sebum
A
- oily secretion from sebaceous glands
- lubricates skin, defends against bacteria, prevents water loss
37
Q
Sweat Glands
A
- AKA Sudoriferous Glands
- two types: Eccrine (or Merocrine) and Apocrine
- sweat is 99% water, salts, acidic excretions
- distributed all over skin
- function as excretory and heat-regulating system
38
Q
Holocrine Glands
A
- entire cell is shed to secrete product
39
Q
Eccrine or Merocrine Gland
A
- secretes product via exocytosis
- coiled simple tubular sweat glands that open to pores on skin surface
- don’t extend far into dermis
- produce acidic sweat (pH 4-6)
- especially dense in soles and palms
- narrower lumen than apocrine glands
40
Q
Apocrine Gland
A
- sweat glands that empty into hair follicles of the scalp, neck, axillary and genital areas
- secrete sweat that contains extra lipids and proteins whose breakdown by bacteria is responsible for body odor
- secrete by pinching off of apical cytoplasm with secretions bound within
- wider lumen than eccrine glands
41
Q
Ceruminous Glands
A
- modified sweat glands in the external ear canal
- secretions combine with sebum to form Cerumen (or earwax)
- Function: waterproofing, eardrum flexibility, block foreign particles, kill bacteria
42
Q
Mammary Glands
A
- modified milk-producing apocrine glands within breasts
- ducts open on nipple
- present in both sexes but functional only in women
43
Q
Nails
A
- scale-like modifications of epidermis
- heavily keratinized
- has distal free edge, visible body and embedded root
- overlapped by fold of skin known as nail fold
- pink due to visible vascularization
44
Q
Eponychium
A
- AKA cuticle
- thick proximal nail fold
45
Q
Nail Bed
A
- extenion of epidermal stratum basale underneath nail body
46
Q
Nail Matrix
A
- analogous to hair matrix
- proximal thickened area of nail bed responsible for growth via cell keratinization
47
Q
Lunula
A
- AKA White Crescent
- light region of thickened nail matrix
