Integumentary System (EXAM #2) Flashcards
(37 cards)
1
Q
What do the Integumentary System consists of?
A
- Skin
- Hair, Nails, Glands
- Muscles
- Sense Receptors (nervous)
- Hypodermis
2
Q
What are the 2 Layers of Skin?
A
- Epidermis - superficial layer (outermost layer)
- Dermis - deep layer
3
Q
What are the characteristics of Epidermis?
A
- Stratified squamous epithelium
- Avascular
- Separated into 4-5 strata (sub-layers) based on cell types:
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum
- Stratum Corneum
4
Q
Stratum Basale
A
- Single row of cells
- 2 cell types:
- Keratinocytes (90%)
- Melanocytes (10%)
5
Q
Keratinocytes (90%)
A
- Actively undergo mitosis
- Make keratin (tough protein)
- Pushed towards surface as new cells are produced in basale
6
Q
Melanocytes (10%)
A
- Produce pigment (melanin) for UV light protection
- e.g. sunburns, wrinkles (collagen damage), cancer (DNA damage)
- Skin colour:
- We all have the same relative number of melanocytes, but cells produce different amounts/shades of melanin
- blood (hemoglobin) - in dermis can give a pinkish tinge to fair skinned people
7
Q
Stratum Spinosum
A
Low levels of mitosis
8
Q
Stratum Granulosum
A
- No mitosis
- Contains granules that help produce keratin (strength) and start to produce waterproofing glycolipids (prevents water loss)
- Last layer of living cells
9
Q
Stratum Lucidum
A
- No mitosis
- Flat, dead cells (too far from blood supply)
10
Q
Stratum Corneum
A
- Many layers of flat dead cells filled with keratin (tough protein)
- Glycolipids between cells create a waterproof layer (prevents water loss)
- Shed and replaced from below
11
Q
What are the characteristics of Dermis?
A
- Contains blood vessels, nerves, glands, hair follicles, arrector pili muscles
- 2 sub layers (connective tissue):
- Papillary Layer (connected to epidermis)
- Reticular Layer (between papillary layer and hypodermis)
12
Q
Papillary Layer (connected to epidermis)
A
- Areolar connective tissue
- Vascular
- Has projection into epidermis = dermal papillae
- In thick skin these form epidermal ridges = fingerprints (improve grip)
13
Q
Reticular Layer (between papillary layer and hypodermis)
A
- Forms most of dermis
- Dense irregular connective tissue
14
Q
Thin vs Thick Skin
A
Thickness refers to epidermis (not dermis)
15
Q
What are the characteristics of Thin Skin?
A
- Covers most of body
- Lucidum absent
- Has hair follicles, sebaceous glands, arrector pili muscles
16
Q
What are the characteristics of Thick Skin?
A
- Found on the palm of the hand and the sole of the foot
- Lucidum present
- No hair follicles, sebaceous glands, or arrector pili muscles
17
Q
What are all Epidermal Derivatives and Where are they form from?
A
- ALL derived (formed) from the epidermis
1. Hair
2. Nails
3, Skin Exocrine Glands
18
Q
Hair
A
- All dead cells
- Parts:
- Root = Part of hair embedded within skin
- Shaft = Visible part of hair above the skin surface
- Hair Follicle - surrounds root
19
Q
What are the parts of Hair Follicle?
A
- Epithelial root sheath = several epidermal layers extend into the dermis
- Bulb - expanded region at base of root
- Matrix = single layer of cells (derived from basale cells) - site of hair growth and melanin for hair colour
20
Q
What is associated with each hair follicle?
A
- Outer CT sheath → holds follicle in place (formed from the dermis)
- Hair papilla - extends upward beneath matrix
- Contains blood supply for growing hair
- Formed from dermis
- Root hair plexus - free nerve ending (touch)
- Sebaceous (oil) gland - opens into follicle
- Arrector pili muscle (Smooth Muscle) - causes “goosebumps”
21
Q
Nails
A
- Very heavily keratinized epidermal cells
- consists of:
- Nail root (buried in skin)
- Body (visible portion)
- Free edge
22
Q
What are the Skin Exocrine Glands?
A
- Sebaceous Glands
- Sudoriferous Glands
- Ceruminous Glands
- Mammary Glands
23
Q
Sebaceous Glands
A
- Connected mainly to hair follicles
- Secretes sebum (oily - mix of fats, salts, proteins)
- Softens, lubricates hair and skin, prevents drying out, antibiotic
24
Q
Sudoriferous Glands
A
- Sweat glands
- Secretory portions in dermis of thick and thin skin
- Ducts open onto skin surface
25
What are the Functions of Sudoriferous Glands?
- Temperature regulation - cool the body
- Antibiotic action (due to sweat being acidic)
- Waste removal (e.g. urea)
26
Ceruminous Glands
- Modified sweat glands
- in ear canal
- Produce ear wax - prevents insects etc from entering
27
Mammary Glands
- modified sweat glands
- Produce milk
28
What are Cutaneous Sense Receptors?
- Sensory receptors area sensory neuron (part of Nervous System)
- Specialized cell that responds to stimuli (touch, temperature, pain)
29
What are the 4 major types of Cutaneous Sense Receptors?
1. Touch Receptors
2. Pressure Receptors
3. Thermoreceptors
4. Nociceptors
30
Touch Receptors
- Free nerve endings
- In Epidermis
- Root Hair Plexuses
- Tactile (Meissner's) Corpuscles
- In dermis papillae
- Corpuscle is a connective tissue capsule surrounding a nerve ending
31
Pressure Receptors
- Free nerve endings
- In dermis
- Lamellar (Paciniaan) corpuscles
- Deep in dermis or hypodermis
32
Thermoreceptors
Free nerve ending for temperature
33
Nociceptors
- Free nerve endings for pain
- 3rd degree burns destroy nociceptors, causing lack of pain sensation in affected areas
34
What is Hypodermis?
- NOT part of skin
- Is also called the subcutaneous layer
- Is also called superficial fascia
- Fascia: connective tissue layers that surround and support organs
- Adipose connective tissue below skin that stores 1/2 of body's adipose tissue (insulation)
35
What are some related Medical Conditions?
1. Albinism
2. Psoriasis
36
What is Albinism?
Lack of melanin production by melanocytes
37
What is Psoriasis?
- Autoimmune disorder that causes accelerated mitosis of keratinocytes in the stratum basale
- Accelerated cell cycle delays maturation and differentiation of keratinocytes
- Immature keratinocytes accumulate in the epidermis and the stratum corneum fails to shed, resulting in a thick scaly area on the surface of the skin (plaque)
