Lecture 2: Integumentry System Flashcards
List the major layers of each and describe the functions of each layer:
1. Epidermis
babies sigh greatly like cats
- Layers of the epidermis:
A) stratum basale: deepest epidermal layer firmly attached to the dermis
-melanocytes found here
-single row of stem cells
B) stratum spinosum (prickly layer)
-contains prekeratin filaments which gives it strength
-abundant melanin granules
C) stratum granulosum
-thin
-keratohyaline and lamellated granules accumulate
D) stratum lucindum (clear layer)
-in thick skin
-thin transparent band superficial to the stratum granulosum
-a few rows of flat, dead keratinocytes
E) stratum corneum (hornet layer)
-20-30 rows of flat keratinized membrane sacs
-makes up 3/4 of the epidermal thickness
Functions of layer 5 stratum corneum:
-protects from abrasions and penetrations
-water proofs
-barrier against biological, chemical and physical assaults
List the major layers of each and describe the functions of each layer:
2. Dermis
Dermis is strong flexible connective tissue
-cells include fibroblasts, macrophages, and sometimes mast cells and white blood cells
Two layers:
A) papillary layer: areolar connective tissue with collagen and elastic fibres and blood vessels
-capillary loops
-meissners corpuscles
-free nerve endings
B) reticular layer:
-80% of the thickness of the dermis
-collagen fibres provide strength
-elastic fibres provide stretch recoil properties
Friction ridges (fingertips) are found in the dermis layer?
Describe the factors that contribute to skin colour
3 pigments contribute to skin colour
- Melanin: yellow, reddish-brown to black, responsible for dark skin colors. Freckles are a accumulation of melanin
- carotene: yellow to orange (like a carrot), most obvious in palms and soles
- Hemoglobin: responsible for the pinkish of skin
Appendages of the skin
Compare the structure and locations of sweat and oil glands
Two main types of sweat glands 1. Eccrine (merocrine) sweat glands -abundant on palms, soles, and forehead Sweat: 99% water, NaCl, vit C, antibodies, metabolic wastes -ducts connect to pores -function in thermoregulation
- Apocrine sweat glands: or (sebaceous glands) confined to axillary and anogenital areas because that is we’re the hair is?
- sebum: sweat + fatty substances and proteins
- ducts connect to hair follicles
- functional from puberty onwards
List the parts of a hair follicle and their function
Function: alerts the body to presence of insects on the skin
-guarding the scalp against physical trauma, heat loss, and sunlight
Hair consist of dead keratonized cells.
Hair pigments: Melanins (yellow, rust brown, black) grey and white hair is due to decreased melanin production and increase in air bubbles in the shaft
Hair follicle: extends from the epidermal surface into the dermis
-2 layered wall: outer connective tissue root sheath, inner epithelial root sheath
Hair bulb is the expanded deep end
Hair follicle receptorsc: sensory nerve endings around each hair bulb and is stimulated by bending hair
Arrector pili: smooth muscle attached to follicle responsible for good bumps
What are the two types of hair?
Vellus: pale, fine body hair of children and adult females
Terminal: coarse, long hair of eyebrows, scalp, axillary, and pubic regions (and face and neck of males)
What is the name for balding?
Alopecia: hair thinking in both sexes after age 40
True (frank) baldness: genetically determined and sex influences condition
-male pattern baldness is caused by follicular response to increases DHT (dihydrotestosterone)
Describe the structure of nails
Be able to label a diagram of a nail
Describe how the skin accomplishes at least 5 different functions
Mums body brings cute ex
- Protection: 3 types of barriers
A) physical/ mechanical barriers
-the keratin and glycolipids block most water and water soluble substances
-limited penetration of skin by lipid soluble substances
B) biological barriers: dendritic cells, macrophages, and DNA
C) chemical: low pH secretions (acid mantle) and defensins retard bacterial activity - Body temperature regulation:
-at elevated temps, dilation of dermal vessel and increased sweat gland activity cool the body - Cutaneous sensations: temp, touch, and pain
4.metabolic functions: synthesis of vitamin D precursor and collagenase
-chemical conversions of carcinogens and some hormones - Blood reservoir- up to 5% of body’s blood volume
- Excretion- nitrogenous wastes and salt in sweat
What are the three major types of skin cancer
Mel swims
So she gets skin problems
- Basal cell carcinoma: least malignant, most common
- stratum basal cells proliferate and slowly invade dermis and hypodermis - Squamous cell carcinoma: second most common
- involves keratinocytes of stratum spinosum
- most common on scalp, ears, lower lip, and hands
- treated by radiation therapy or removal surgically - Melanoma: most dangerous
- involves melanocytes
- highly meats tic and resistant to chemotherapy
- treated by removal or immunotherapy
Burns
Name the 3 levels of burns and the layers of skin that are affected
1st degree: epidermal damage only
-redness, swelling and pain
2nd degree: epidermal and upper dermal damage
-blisters appear
3rd degree: entire thickness of skin damaged
-grey white, cherry red, or black
-no initial pain as nerve endings are destroyed
-skin grafting unusually necessary
