Flashcards in Chapter 5 - Integumentary System Deck (136)
What is the integumentary system?
A group of organs working together - the skin, hair, oil and sweat glands, nails and sensory receptors
What are the 6 functions of the integumentary system?
1. Regulates body temperatures
2. Stores blood
3. Protects body from external environment
4. Detects cutaneous sensations
5. Excretes and absorbs substances
6. Synthesizes vitamin D
What does a bluish skin colour indicate?
Hypoxia - oxygen deficiency at the tissue level
A sign of heart failure
What is the dermatology?
The medical specialty that deals with the diagnosis and treatment of integumentary system disorders
What is the cutaneous membrane?
Covers the external surface of the body
What are the two main parts that make up the skin?
Describe the epidermis.
The superficial, thinner portion which is composed of EPITHELIAL TISSUE
Describe the dermis.
The deeper, thicker, CONNECTIVE TISSUE portion
What is the subcutaneous layer?
Also called the hypodermis
Consists of areolar and adipose tissues
Fibers that extend from the dermis anchor the skin to the subcutaneous layer
What does the subcutaneous layer serve as?
Storage deposit for fat and contain large blood vessels that supply the skin
What are pacinian (lamellated) corpuscles?
Nerve endings in the subcutaneous layer, and sometimes in the dermis that are sensitive to pressure
What is the epidermis composed of? What 4 kinds of cells?
Keratinized stratified squamous epithelium cells
3. Langehans cells
4. Merkel cells
What do keratinocytes do?
Produce the protein keratin - a tough fibrous protein that helps protect the skin and underlying tissues from abrasions, heat, microbes, and chemicals
Arranged in 4 or 5 layers
What are lamellar granules?
Release a water-repellant sealant that decreases water entry and loss and inhibits the enters of foreign materials
What do melanocytes do?
Produce the pigment melanin
Their long slender projections extend between keratinocytes and transfer melanin granules to them
What is melanin?
A yellow-red or brown-black pigment that contributes to skin colour and absorbs damaging ultraviolet light
What do melanin granules do once they're inside keratinocytes?
They cluster to form a protective veil over the nucleus, on the side towards the skin surface
They shield nuclear DNA from damage
What are langerhans cells?
Also called epidermal dendritic cells
Arise from red bone marrow and migrate to the epidermis
They participate in immune responses against microbes that invade the skin
What are merkel cells?
Located in the deepest layer of the epidermis, where they contact the flattened process of a sensory neuron called a merkel disc
Detect touch sensations
What are the layers of thin skin called?
1. Stratum basale
2. Stratum spinosum
4. Thin stratum corneum
What are the layers of thick skin called?
1. Stratum basale
2. Stratum spinosum
3. Stratum Granulosum
4. Stratum lucidum
5. Thick stratum corneum
Describe the stratum basale.
Composed of a single row of cuboidal or columnar keratinocytes
Some cells in this layer are stem cells that produce new keratinocytes
Describe stratum spinosum
Superficial to the stratum basale
Consists of keratinocytes arranged in 8-10 layers
Cells in more superficial layers become flattened
Some cells retain their ability to divide
Describe the stratum granulosum
Superficial to the stratum spinosum
Consists of 3-5 layers of flattened keratinocytes that are undergoing apoptosis - programmed cell death
Father away from their source of nutrition
What is the distinctive feature of the cells in the stratum granulosum layer?
The presence of darkly staining granules of protein called keratohyalin
What is keratohyalin?
It assembles keratin intermediate filaments into keratin
What marks the transition between the deeper, metabolically active strata and the dead cells of the superficial strata?
The stratum granulosum
What is stratum lucidum?
Present only in thick skin
Consists of 4-6 layers of flattened CLEAR, dead keratinocytes that contain large amounts of keratin and thickened plasma membranes
What is the stratum corneum?
Consists of 25-30 layers of flattened dead keratinocytes
Can range from a few cells to many
Cells no longer contain organelles
Cells are continuously shed