Ch 6 Flashcards
(53 cards)
1
Q
Functions of Integumentary System
A
- Protection against environmental hazards (e.g. protect organs from infection, radiation, desiccation)
- Control of body temperature
- Sensation of touch
- Production of Vitamin D
- Water Homeostasis
- Metabolic Regulation|
- Excretion & Absorption
2
Q
What are the three layers of the skin and which of these are considered part of the integument?
A
- Epidermis: (included in integument)
- Dermis: (included in integument)|
- Hypodermis: (NOT included in integument
3
Q
What is another name for hypodermis?
A
Subcutaneous or subcutis layer
4
Q
Cells found in the epidermis
A
Keratinocytes
Melanocytes
Langerhans cells (intra-epidermal macrophages)
Merkel cells or tactile epithelial cells
5
Q
Keratinocytes
A
- produces keratin, a protein that protects the skin and underlying tissues from heat, microbes, and chemicals
- make up most of the cells found in the epidermis
6
Q
Melanocytes
A
- produce the pigment melanin (this function protects keratinocytes)
- contributes to skin color and absorbs damaging ultraviolet
(UV) light - highly vulnerable to UV and can develop into metastatic cancer a.k.a. melanoma
- these cells are found in the basal layer
7
Q
Langerhans cells
A
(intraepidermal macrophages)
- participate in the immune response by presenting antigens to other immune cells
- can be found in layers of epidermis, but mostly found in the stratum spinosum
8
Q
Merkel cells/tactile epithelial cells
A
- these cells are in contact with a sensory structure, called a Merkel Disc and are able to provide one of the components of the sensation of touch (light touch)
- found in basal layer of epidermis
9
Q
List 5 layers of epidermis (deepest to superficial)
A
Stratum basal
Stratum spinosum
Stratum Granulosm
Stratum Lucidum
Stratum Corneum
10
Q
Stratum Basal
A
Stratum Basale or “basal layer”
- innermost layer
- also called stratum germinativum
- stem cells undergo mitosis to replace the cells in the layers above
- important role in wound healing and regeneration of epidermis
- * epidermal stem cells, melanocytes, Merkel cells found here
11
Q
Stratum Spinosum
A
- Skin cells (keratinocytes) start to look spiky because they’re forming strong connections (called desmosomes)
with each other - These connections are held together by tiny fibers inside the cells (tonofibrils), which pull tight and make the cells appear spiny.
- The layer is about 8 to 10 cells thick and gives the skin strength and flexibility.
- Melanocytes (cells that give skin its color) and Langerhans cells (part of the immune system) are still found here, helping protect the skin
12
Q
Stratum Granulosum
A
- portion of the epidermis where keratin begins to be laid down in lamellar granules to form the water-repelling sealant function of the integument
- cells flatten, and because water is critical for cell function, the keratinocytes here lose their nuclei and organelles
- the cell membranes thicken and eventually the cells die
13
Q
Stratum Lucidum
A
- present only in thick skin
- found in areas of the body where skin is subject to friction (e.g. fingertips, palms, souls of feet
- about 2 to 3 cells thick and made up of flat, dead skin cells.
- These cells are packed with a special protein called eleidin, which is rich in lipids (fats) and helps protect the skin from friction.
14
Q
Stratum Corneum
A
- outermost layer
- It’s made of flat, dead cells that are tightly packed and constantly shed and replaced from the layers below.
- This layer forms a protective barrier and can be thin or very thick, depending on how much friction the area gets.
- In places like the fingertips or soles, it can be up to 300 cells thick.
- If the skin is rubbed or used a lot, it may build up this layer more, forming a callus for extra protection.
15
Q
Where are the stem cells for the epidermis?
A
The stem cells for the epidermis are located in the Stratum Basale (also called the basal layer or Stratum Germinativum).
16
Q
Importance of Melanocytes
A
- produce the pigment melanin (this function protects keratinocytes)
- contributes to skin color and absorbs damaging ultraviolet
(UV) light - highly vulnerable to UV and can develop into metastatic cancer a.k.a. melanoma
- these cells are found in the basal layer
17
Q
Where is the blood supply for the epidermis?
A
Blood supply goes from the cutaneous plexus (found in the hypodermis) to the papillary plexus (a.k.a. the superficial cutaneous plexus) which provides blood to the epidermis
18
Q
Structures of the dermis
A
- Hair follicles
- Exocrine glands - sweat glands (eccrine and apocrine) and sebaceous glands)
- Sensory receptors (two types)
19
Q
What are the two layers of the dermis?
A
1) Papillary Layer
* Areolar (loose) CT
* Dermal papillae
2) Reticular Layer
* Dense, irregular CT
20
Q
What structures make up fingerprints
A
- Epidermal Ridges
- Ducts of sweat glands (this is what leaves the “print” on surfaces)
21
Q
Six types of cutaneous sensory receptors
A
Unencapsulated: found in superficial areas and respond to lighter sensations
- free nerve endings
- root hair plexus
- Merkel cells
Encapsulated: found in deeper layers of skin, encapsulated by connective tissue, require more pressure or sensation to respond
- Meisner’s corpuscle
- Pacinian corpuscle
- Ruffini corpuscle
22
Q
Free nerve endings
A
- sensation of fine touch and light pressure
- found in epidermis, epithelia covering certain mucus membranes, and cornea of the eyes
23
Q
Root hair plexus
A
- sensation of fine touch and light pressure
- Adapt quickly
24
Q
Merkel cells
A
- Respond to light touch and pressure
- Adapt slowly
- found in Stratum Basal
25
Meisner Corpuscle
- Respond to light touch, movement, and vibration
- very fast adapting
- found in dermal papillae (great concentrations in the fingertips, lips, etc)
26
Pacinian Corpuscle
- only respond to deep pressure and vibration
- found in deeper layers of the dermis, as well as the mesenteries of the gut and joints
27
Ruffini Corpuscle
Response to pressure and distortion (pinching or stretching) of the skin
28
Which cutaneous sensory receptors are used for fine touch discrimination?
Free nerve endings
Root hair plexus
Merkel cells
Meissner corpuscle
29
Which cutaneous sensory receptors respond to deep pressure
Pacinian corpuscle
30
Structures of a hair follicle
* Hair papilla
- hair matrix (this is where the hair actually grows from)
- melanocytes
* Hair bulb
* Hair root
* Hair shaft
- arrector pili muscle
- sebaceous gland
31
Clinical importance of cleavage lines
Cleavage lines are natural patterns in the skin formed by collagen and elastin fibers. Surgical incisions made parallel to these lines heal faster and scar less, while cuts made perpendicular may heal poorly and scar more due to skin tension pulling the wound apart.
*** this is why C-section incisions are made parallel
32
Significance of the papillary and cutaneous plexus of blood vessels
Blood supply goes from the cutaneous plexus (found in the hypodermis) to the papillary plexus (a.k.a. the superficial cutaneous plexus) which provides blood to the epidermis
33
What makes up the hypodermis
Adipose tissue (fat) - stores energy, insulates the body, and cushions organs
Areolar connective tissue - provides flexibility and connects the skin to muscles and other structures
Blood vessels and nerves - supply the skin above and help regulate temperature
34
What are the structures in a nail?
* Body
* Bed
- proximal fold
- lateral folds
* Root
* Eponychium
- aka cuticle
- stratum corneum
* Lunula
* Hyponychium
- stratum corneum
35
What are the two types of exocrine glands found in the integument and their functions?
1) Sweat Glands
* Produce watery solution by merocrine (eccrine) secretion
* Assist in thermal regulation through the formation of sweat
* Excrete waste products
2) Sebaceous Glands
* Secrete sebum in hair follicles
* Provide lubrication for hair shaft and skin
* Provides antibacterial function
36
What are the two types of sweat glands? (name and function.)
1) Apocrine Sweat Glands
* larger than eccrine glands
* limited, found only in axillae, groin, nipples, & beard region
* Appear during and after puberty, secretion is influenced by hormones
* Results in musky "body odor"
2) Merocrine Sweat Glands (Eccrine)
* Widespread
* Secret sweat onto skin surface (mostly water)
* Sensible perspiration
* Controlled primarily by nervous system
* Important in thermoregulation, protection, and excretion
37
What are the two types of sebaceous glands? (name and function.)
a) Typical Sebaceous Glands
* Secret into hair follicles
b) Sebaceous Follicles
* Secret onto skin surface
38
How is sweat secreted
Sweat is secreted by sweat glands through a process called exocytosis
39
How does the epidermis heal after trauma?
1) abrasion or minor burn occurs
2) Basal cells migrate across the wound
3) Contact inhibition with other cells stops migration
4) Epidermal growth factor stimulates basal cells to divide and replace the ones that have moved into the wound
5) Full thickness of epidermis results from further cell division
40
Four phases of deep wound healing?
1) inflammatory phase
* blood clot forms from the damaged blood vessels and white blood cells move into the area to remove bacteria/pathogens that may have entered
* scab formation
2) Migratory phase
* Epithelial cells divide; formation of scar tissue by fibroblasts
3) Proliferative phase
* Completion of tissue formation
4) Maturation phase
* Scan falls off
41
Three types of burn?
1) 1st Degree
* only epidermis (sunburn)
2) 2nd Degree
* entire epidermis and part of dermis
* Fluid filled blisters, separate, epidermis, and dermis
* Hair follicles, sweat glands, sebaceous glands are usually not damaged
* Heals without grafting in 3 to 4 weeks, but may scar
3) 3rd Degree aka full-thickness
* Epidermis, dermis, and epidermal derivatives
* Damaged area is numb due to loss of sensory nerves
(DOES NOT HURT)
42
Keratinization
Replacement of cell contents with the protein keratin (occurs over 2 to 4 weeks as cells move to the skin surface)
43
Functions of dermis?
Sensation
Thermal regulation
Excretion (salt and urea)
Production of vitamin D
44
Homeostatic relationships: integumentary system and skeletal system
Skin activates, vitamin D, which is required for calcium absorption for bone deposition
45
Homeostatic relationship: integumentary system, and nervous system
Nerve endings in skin provide afferent sensation for touch, pressure, heat, cold, pain
46
Homeostatic relationships: integumentary system, and muscular system
Skin protects, underlying muscles and activates vitamin D to provide calcium for contraction
47
Homeostatic relationships: integumentary system, and endocrine system
Keratinocytes, activate, vitamin D, causing the formation of calcitriol (the hormone that causes calcium absorption in the intestine)
48
Homeostatic relationships: integumentary system, and cardiovascular system
Blood flow in the skin assists thermoregulation of the body
49
Homeostatic relationships: integumentary system, and lymphatic/immune system
The skin is a barrier to entry (first line of defense in the immune system). White blood cells in the dermis phagocytize pathogens and participate in recognition of foreign antigens
50
Homeostatic relationships: integumentary system, and respiratory system
Hairs in the skin of the nose filter dust from inhaled air
51
Homeostatic relationships: integumentary system, and urinary system
Kidney receive vitamin D from skin and converted to calcitriol. Sweat formation assists the kidneys and removal of urea.
52
Homeostatic relationships: integumentary system, and digestive system
Vitamin D promotes absorption of calcium and phosphorus in the small intestine
53
Homeostatic relationships: integumentary system, and reproductive system
Nerve endings in skin participate in the sexual response. Modified sweat glands (mammary glands) produce milk. Suckling simulates nerve endings in skin for milk ejection
