Integumentary System Notes
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Transcript of Integumentary System Notes
Integumentary System
Chapter 5
• Skin & Accessory organs: Hair & hair follicles sebaceous (oil) glandssudoriferous (sweat) glandsnails
Functions of the Integumentary System
1. Protection: from exterior elements2. Sensation: feeling3. Excretion of wastes: sweat4. Synthesis of Vitamin D in sunlight5. Temperature regulation: release/retain heat6. Coloration: pigment of skin7. Water proof: water does not enter inside8. Growth and repair: regenerate
Skin structure 3 main layers1. Epidermis:outer, thinner layer connected to the
basement membrane
2. Dermis:inner, thicker layer
3. Hypodermis / subcutaneous layer (Sub Q): Under the dermis (adipose tissue)
List & Describe the 4 Cells in Epidermis
Found on pg. 152 in textbook 5 Minutes to locate & write…GO!
Cells of the Epidermis
Keratinocytes – produce the strong protein keratin.
Melanocytes – produce the brown pigment melanin
Langerhans’ cells –macrophages that help activate the immune system response
Merkel cells – function as touch receptors in association with sensory nerve endings
General Epidermis Info
Basement membrane= located right underneath the stratum basale and connects epidermis to the dermis
Layers of the Epidermis
Figure 5.2b
Epidermis
outermost layer Made of keratinized stratified squamous
tissue, so it: Lacks blood vessels Is mostly dead
There are 5 distinct layers MITOSIS does occur in bottom layers
5 layers of the Epidermis
Pg 154 in textbook
Stratum basale innermost layer directly above the
basement membrane location
• Merkel Cells• Melanocytes
Simple cuboidal Cells undergo mitosis
here
Stratum spinosum
composed of many layers of rounded cells with large nuclei
Langerhans’ cells are abundant in this layer
Stratum granulosum
composed of 3-5 layers of flattened granular cells
Cells start keratinization process here the process of cells formed in the stratum basale moving up, flattening, dying, and becoming hard and waterproof
Stratum lucidum
translucent layer Not shown in book…
why? Because only
located in thick skin of soles and palms
Stratum corneum
Top layer composed of dead
epithelial cells being flaked off (keratinized)
Functions include: Waterproofing Protection from
abrasion and penetration
Dermis inner layer Much thicker than the epidermis Dermis aka. “True Skin” Contains nerve endings, muscle fibers, hair
follicles, sudoriferous glands, sebaceous glands, and blood vessels.
Does not continually shed and regenerate itself
Dermis: 2 Layers 1. Papillary Layer
Arranged in ridges The fingertips and toe tips Ridges allow us to grip things
Dermis: 2 Layers…cont’d2. Reticular Layer
Collagenous fibers: make our skin tough Elastic fibers: make our skin stretchable. Reticular fibers: gives skin its strength & resilience Location of smooth muscle called arrector pili
Stands hair on end when “goose bumps”
Subcutaneous layer or hypodermis
adipose tissue and blood vessels beneath the dermis Function – insulation
Cutaneous Sensation
1. Light touch detection:
Meissner’s Corpuscles located in dermal
papillae of dermis
Cutaneous Sensation
2. Pressure detection =
Pacinian Corpuscles located deep in dermis
and subcutaneous regions
Hair
Shaft: visible part of the hair Medulla: inner core of
the hair Cuticle: layer covering
medulla Cortex: Superficial
portion of hair Root: in dermis
No need to know for test… Just an Interesting FACT:
Straight hair has a rounded follicle Wavy hair has a flattened follicle Kinky or curly hair has a kidney shaped follicle
Are you ready to be grossed out?................
...…
Eye Lash Mites
Skin Color 3 pigments contribute to skin color
Melanin – yellow to reddish-brown to black pigment, responsible for skin colors, related to genetics• Freckles and pigmented moles – result from local
accumulations of melanin
Carotene – yellow to orange pigment
Hemoglobin – reddish pigment responsible for the pinkish hue of the skin
PigmentMore about Melanin: Is produced by melanocytes in stratum
basale layer
People of different races have essentially the same # of melanocytes, but the amount of melanin produced varies
The quantity of Melanin produced depends on 3 factors:
1. Heredity: MOST IMPORTANT• enzyme tyrosinase is absent at birth, then
melanocytes are unable to produce melanin and a condition known as albinism is formed
2. Sunlight Exposure• Causes melanocytes to increase melanin
production and darkening skin color
3. Hormones: ACTH (Adrenocorticotropic Hormone ) and MSH (melanin stimulating hormone)• Hypersecretion of either hormone may darken the
skin
Albinism
Carotene
Hemoglobin
Nails cont’d… Tightly packed hard, keratinized epidermal
cells Functions = manipulation and protection
Ripley’s Believe It or Not Lady
Sudoriferous Glands
Two types1. Eccrine more common, mainly in forehead,
palms, & soles. These function right at birth. -no odor in secretion
Secretion = water plus salts and wastes (urea and uric acid)
2. Apocrine Mainly in armpits, groin, & breasts. Don’t function until puberty. These cause the “cold-sweat” during stress. -odor in secretion
Sebaceous Glands
-Connected to every hair follicle -Secrete sebum (oil) into hair follicle
Function – sebum keeps skin and hair soft
Disorders acne = overproduction of sebum – ducts
clog and inflame
Ceruminous Glands Associated with ears Produces cerumen (earwax)