Integumentary System Flashcards
What are three functions of the integumentary system?
- Barrier
- Thermoregulation
- Sensory
What are the 5 layers of the epidermis in order from deep to shallow?
Dermis
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
Surface of skin
What are the two layers of the dermis?
- Papillary layer
- Reticular layer
What are two synonyms for subcutaneous tissue and what is it?
Hypodermis, subcutis
The deepest layer of the integumentary system (below the dermis)
What types of cell dominates the stratum basale?
Melanocytes
What types of cells dominate the stratum spinosum?
Spinosum cells filled with melanin granules
What is found in spinosum cells?
Melanin granules
Where do sebaceous glands secrete to?
Hair follicles
Where are dermal papillae?
Between the dermis and epidermis
What do epidermal ridges interdigitate with? Why?
Dermal papillae, to strengthen adhesion between the dermis and epidermis.
The epidermis mostly consists of ____ epithelium composed of cells called ______
The epidermis mostly consists of stratified squamous keratinized epithelium composed of cells called keratinocytes
What are the four cells of epidermis?
- Keratinocytes
- Melanocytes
- Langerhans cells (antigen producing)
- Merkel cells (somatosensory receptor cells)
The designation of thick and thin skin refers to?
The thickness of the epidermal layer
What is the stratum basale? (epithelial type, defining characteristic)
- Single layer of basophilic cuboidal or columnar cells on the basement membrane at the dermal-epidermal junction
- Intense mitotic activity for progenitation of keratinocytes
What is the stratum spinosum? (epithelial type, defining characteristic)
- Central nuclei and actively synthesizing keratins
- Many layers of epithelium, this is the thickest layer of the epidermis
What is the stratum granulosum? (epithelial type, defining characteristic)
- Three to five layers of flattened cells undergoing keratinization
What is the stratum lucidum? (epithelial type, defining characteristic)
- Found only in thick skin
- thin translucent layer layer of flattened, dead eosinophilic keratinocytes
What is the stratum corneum? (epithelial type, defining characteristic)
- Consists of 15 to 20 layers of squamous, keratinized cells filled with keratins
- Protects against friction and water loss
What are three components of the papillary layer of the dermis?
- Areolar (loose) connective tissue
- Dermal papillae
- Subpapillary vascular plexus
What are six components of the reticular layer of the dermis?
- Dense irregular connective tissue with elastin
- Hair follicles
- Sebaceous glands
- Sweat glands
- Nerves
- Blood vessels extending into the subcutaneous layer
What are the two components of the subcutaneous layer? Is it part of integument?
- Areolar (loose) connective tissue
- Adipose tissue
Not part of integument
What part of the body are merkel cells most commonly found?
Where sensitive touch is needed, eg. fingertips and the base of hair follicles
What do free nerve endings detect?
Pain, itching, high and low temperature
What three encapsulated receptors are mechanoreceptors in the skin? What does each detect?
- Meissner corpuscles (light touch, low frequency touch)
- Pacinian corpuscles (Coarse touch, pressure and vibrations)
- Ruffini corpuscles (tension or torque)
What provides the capillary network required to sustain a hair follicle?
A dermal papillae inserted into the base of the hair bulb
What are the two parts of hair?
- Hair root (under skin surface)
- Hair shaft (projecting from skin)
Where do sebaceous glands empty?
The upper portion of a hair follicle
What is the product of sebaceous glands and how is it released?
Sebum (lipids)
Released by holocrine secretion, where proliferating basal epithelial cells push other developing gland cells further towards the duct where the cell disintegrates and releases its product.
What are the two types of sweat glands?
- Eccrine sweat glands (coiled secretory region and extended duct region to sweat pore, small lumens, stratified cuboidal epithelium)
- Apocrine sweat glands (large lumens, simple cuboidal epithelium, empty into hair follicles, develop mostly after puberty)
In eccrine sweat glands, what part (duct or secretory) is more pale staining?
The secretory part is more pale staining
What are the three major exocrine glands in skin?
- sebaceous glands
- Eccrine sweat glands
- Apocrine sweat glands
What is leather?
Cross linked reticular layer collagen in the dermis (dense irregular connective tissue)
What are 6 features of the hypodermis?
- Highly vascular
- Loose connective tissue
- Adipose tissue
- Touch receptors
- Glands
- Best place to inject drugs via hypodermic needle
Hair follicles are surrounded by what type of epithelium?
stratum basale
All hair follicles are slanted ___ or more
45 degrees
What do arrector pili muscles do? what are they attached to?
Stand hairs up from 45 degrees to 90 degrees
Attached to epidermis and hair follicle base
The stratum basale makes ___ and ___ around the hair bulb
Keratinocytes and melanocytes
Keratinocytes die at about the medulla
Matrix cells of the hair bulb cover a vascular dermal papillae, matrix cells are actively dividing into ___?
Hair cortex
What are hair cells? What type of epidermal layer do they best represent?
Dead, flat keratinocytes, similar to stratum corneum
What are the three components of sweat secreted by eccrine sweat glands?
- Water to cool skin by evaporation
- Nitrogenous waste and other metabolite
- Chemical messengers
What are the two components of sweat secreted by apocrine sweat glands found in the armpits/groin?
- Hormone secretion
- Antibacterial material
What type of epithelium exists in eccrine sweat gland ducts and secretory portion?
2 layers of of cuboidal epithelium, the duct wall is thinner than the coiled secretory portion
Stratified cuboidal epithelium in secretory portion
