INTEGUMENTARY SYSTEM Flashcards
1
Q
What type of membrane composes the skin?
A
- cutaneous membrane
2
Q
What are the two distinct layers of the skin?
A
- epithelial tissue overly CT.
- The dermis that is made up of CT
3
Q
What composes the epidermis?
A
- Stratified squamous epithelium
4
Q
What composes the dermis?
A
- thicker than the epidermis
- Is made up of CT containing collagen a, elastic fibers, and smooth muscle tissue, nervous tissue, and blood/lymphatic vessels
5
Q
What anchors the epidermis to the dermis?
A
A basement membrane
6
Q
Where is the hypo-dermis located?
A
- beneath the dermis
7
Q
What is the hypodermic composed of?
A
- areolar + adipose CT that binds the skin o underlying organs
- Collagen/elastic fibers of the subcutaneous layer are continuous with those of the dermis - and extend in all directions
- Because of this, there are no distinct boundaries between dermis and the hypodermis
8
Q
What does adipose do in the subcutaneous layer?
A
-acts to insulate to conserve body heat
9
Q
What does the subcutaneous layer contain?
A
- large blood vessels with branches forming a network between the dermis + subcutaneous layer
10
Q
What are the functions of the skin?
A
- protective barrier against harmful substances/ microorganisms
- contains sensory receptors
- Helps produce vitamin D
- Helps regulate body temp
11
Q
Where does mitosis occur in the epidermis?
A
In the deepest layer - stratum basal
12
Q
What are keratinocytes?
A
epidermal cells
13
Q
What happens when keratinocytes are pushed towards the surface?
A
- The farther the cells move from the dermal bloods vessels, the poorer nutrients they receive, so they die
14
Q
What’s keratinization?
A
- The hardening of keratinocytes
15
Q
What are the steps in keratinization?
A
- The cytoplasm fills with strands of tough, fibrous, waterproof keratin proteins.
- They layer and then form a protective non-nucleated outer skin barrier
16
Q
What is the stratum basal?
A
- Single row of rapidly dividing cells.
- Deepest layer in the epidermis
17
Q
What is the stratum spinosum?
A
- Many layers of cells with centrally located, large, oval nuclei and developing fibers of certain; cells becoming flattened
- Some rare mitotic cycles may occur
18
Q
What is the stratum granulosum?
A
Three-five layers of flattened granular cells that contain shrunken fibers of keratin and shriveled nuclei
19
Q
What is the stratum lucidum?
A
- only present in thick skin like the palms/soles
- cells appear clear; nuclei, organelles, and cell membranes are no longer visible
20
Q
Stratum corneum
A
- Many layers of keratinized, dead epithelial cells that are flattened and non-nucleated
21
Q
What are the four layers of the epidermis from lowest to highest
A
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum (only in THICK skin)
- Stratum corneum
22
Q
What are the three things that determine skin pigment?
A
- hemoglobin: blood pigments in lighter skin can make it appear blue/pinkish
- Melanin: Pigment produced by melanocytes
- Carotene: organa-pinkish pigment from built up food
23
Q
What three factors affect skin color?
A
- hereditary
- environmental
- physiological
24
Q
How does hereditary factors affect skin color?
A
- all people have the same # of melanocytes but vary in amount of melanin produced
- Varying distribution + size of melanin granules
25
How does environmental factors affect skin color?
- Oxygenation in blood of dermal vessels
- vasodilation/vasoconstriction of blood vessels
- accumulation of carotene pigment from diet
- diseases such as jaundice
26
What are dendritic cells?
- Are in the stratum spinosum
- act to protect skin and deeper tissues from pathogen invasion
- engulf microbes within the skin
27
What are tactile cells?
- scattered among the stratum basale are oval-shaped tactile cells.
- Corresponds with sensory nerve ending
- respond to light touch
28
What are melanocytes?
- specialized cells in the epidermis
- Produce the pigment melanin from the amino acid tyrosine in organelles called melanosomes
- Prevents mutations of DNA
29
What are dermal papillae?
- ridges that project separate the epidermis and the dermis
| - increase the surface area where epidermal cells receive oxygen/nutrients from dermal capillaries
30
Where are dermal papillae most abundant?
- hands/feet.
| - leaves fingerprints and is used for grasping
31
What are the two layers of the dermis?
- the papillary layer
| - The reticular layer
32
What is the papillary layer of the dermis composed of?
- composed of areolar CT
33
What is the reticular layer of the dermis composed of?
- composed of dense irregular CT that consists of tough collagen fibers, and elastic fibers in a gel-like substance.
34
What are the structures within the dermis?
- contains smooth muscle fibers
- blood vessels that supply the skin and motor nerve cell processes
- sensory receptors, and accessory structures such as nails, hair follicles, sweat glands, and sebaceous glands
35
What are lines of cleavage?
- lines deep in the dermis formed by orientation of collagen bundles
- incisions across these lines heal more slowly
- incisions along these lines heal quickly
36
What are pacinian touch receptors?
- sensitive to heavy pressure
37
What are Meisner's touch receptors?
- sensitive to light touch
38
What are nociceptors?
- detect tissue damage
- control blood flow
- control glandular secretions
39
What is the hypodermic?
- subcutaneous layer
- areolar + adipose CT
- protects underlying structures
- stores energy
- thermal insulation
40
What are accessory structures?
- hair follicles
- nails
- skin glands
41
What are the 3 parts of the nail?
- Nail plate
- Nail bed
- Lunula (the half crescent)
42
What are the functions of hair?
- protection
- heat retention
- facial expression
- sensory reception
- visual identification
- chemical signal dispersal
43
What produces the nail bed?
- epithelial cells with continuous deeper layers extending into the epidermis of the skin to produce the nail bed
44
What's the nail matrix?
- most active growing region.
| - cells divid and newly formed cells become heavily keratinized
45
Where are hair follicles present?
- on all skin surfaces except the palms, soles, lips, nipples and parts of the external reproductive organs
46
What is a hair follicle
- a group of epidermal stem cells at the base of a tubelike depression
47
What are the 3 parts of hair?
- hair bulb (dividing cells)
- hair root
- hair shaft (dead epidermal cells)
48
What nourishes hair cells?
- the epithelial cells are nourished by dermal blood vessels in a projection of connective tissue called the hair papilla
49
What muscle causes goose bumps?
Arrector pili
50
What are the four exocrine skin glands?
1. Sebaceous
2. sudorferous (sweat)
3. mammary
4. ceruminous
51
What are the general characteristics of sebaceous glands?
- contains groups of specialized epithelial cells and are usually associated with hair follicles
- they are holocrine glands (they shed the entire cell)
52
What is sebum?
- globules of a fatty material that accumulate, swelling and bursting the cell
- acne <3
- secreted into hair follicles thru short ducts and keeps the skin soft, pliable and waterproof
53
What are the general characteristics of sweat glands?
- also called sudoriferous glands
- widespread on skin
- respond throughout life to body temps elevated by environmental heat or physical exercise
54
What are merocrine sweat glands?
- sweat glands that are abundant on the forehead, neck, and back. They produce sweat on hot days or during exercise.
55
What are apocrine sweat glands?
- secrete thru ducts to hair follicles, are most numerous in axillary region + groin area
- responds to emotional distress
- develops odor
- secrete by exocytosis
56
What are ceruminous glands?
- these secrete ear wax
57
What are mammary glands?
- they secrete milk lol
