Layers on Layers
Statum Basale
These cells make up the bulk of the epidermis and produce keratin.
keratinocytes
What are the four major types of tissue found in the body
Epithelial, connective, muscle, and nervous tissue.
This skin cancer originates from melanocytes and is described in the slides as the most fatal skin cancer.
malignant melanoma
These sweat glands are a primary component of thermoregulation and are especially numerous on the palms, soles, and forehead.
eccrine sweat glands
The epidermal layer contains keratohyalin granules that help form keratin and lamellar granules containing water resistant glycolipids.
Stratum granulosum
These epidermal immune cells are particularly abundant in the stratum spinosum and participate in immunosurveillance.
dendritic cells or Langerhans cells
A tissue has cells arranged in parallel bundles, very few cells, and relatively poor blood supply. It is adapted to resist tension in one direction. What tissue is it, and where would you find it?
Dense regular connective tissue, found in tendons and ligaments
A burn produces blisters and takes approximately 3–4 weeks to heal. What degree of burn is described?
second degree burn
Name the receptor associated with deep pressure and vibration.
Pacinian corpuscle
A patient has damage to stratum basale but intact dermis. Explain why this injury could interfere with normal replacement of the epidermis.
The stratum basale contains actively dividing cells. Damage to this layer decreases mitosis and therefore reduces the production of new keratinocytes needed to replace cells lost from the surface.
After increased UV exposure, these cells increase pigment production. The pigment is then transferred to another epidermal cell type where it accumulates above the nucleus. Name both cell types and explain the purpose of this arrangement.
Melanocytes produce melanin and transfer it to keratinocytes. Melanin accumulates on the superficial side of the keratinocyte nucleus, helping protect nuclear material from UV radiation.
A histology slide shows a tissue with multiple layers of cells and flattened cells at its apical surface. The tissue is located in an area exposed to significant abrasion. What tissue is this, and how does its structure support its function?
Stratified squamous epithelium. Its multiple layers provide protection against abrasion, with the flattened cells at the surface forming the protective apical layer.
A patient has a third-degree burn. Explain why regeneration is much more difficult than after a more superficial burn and why grafting may be necessary.
In a third-degree burn, destruction is deep enough that new skin can regenerate only from the edges of the wound. Because normal regenerative structures have been extensively destroyed, surgery and skin grafting are often required
A person steps barefoot onto a small sharp object. Which skin receptor is most directly responsible for detecting the painful stimulus, and in which layer of the dermis would it be found according to your slides?
Pain receptors in the papillary layer of the dermis.
This layer is only present in thick skin. What layer is this? And what areas on the body do you find this in?
Stratum lucidum
With aging, melanocytes and dendritic cells become less active. Give two physiological consequences and connect each one to the affected cell.
Reduced melanocyte activity can contribute to paler skin, while reduced dendritic/Langerhans cell activity can decrease immune protection in the ski
A patient suffers an injury to tissue that must regenerate itself to restore normal function. Which three tissue types have poor or no regenerative ability, according to your slides?
Nervous tissue, cardiac muscle, and cartilage
An older adult has a thinner epidermis, slower wound healing, and reduced cushioning beneath the skin. Identify the anatomical change responsible for each finding and connect it to the physiological consequence.
Decreased mitosis in the stratum basale → thinner epidermis; reduced regenerative ability of the dermis → slower wound healing; and reduction/redistribution of hypodermal fat → reduced structural support/cushioning and sagging or thinning of the skin
A patient has significant damage to the reticular layer of the dermis. They can still detect light touch, but have difficulty detecting deep pressure and vibration. Explain why this pattern makes anatomical sense.
Meissner’s corpuscles, which detect light touch, are located in the dermal papillae/papillary layer, while Pacinian corpuscles, which detect deep pressure and vibration, are associated with the deeper reticular dermis. Damage primarily to the reticular layer could therefore impair deep pressure/vibration sensation while leaving light touch relatively intact
Name the two layers of the skin.
1. What kind of tissue is found in each layer (hint there are two layers of the skin).
2. For the second layer of the skin, what are the 2 subcategories?
Epidermis and dermis
stratified squamous epithelium; areolar connective tissue and dense irregular connective tissue and adipose beneath all that
reticular and papillary layer
Name the four major cell types of the epidermis and identify the epidermal layer where each is predominantly found.
A patient develops edema after an inflammatory response. Fluid begins accumulating in the loose connective tissue beneath the epithelium. Identify the tissue involved and explain why its structure allows edema to occur there. Then name the predominant cell type, the three fiber types present, and one additional function of this tissue.
A patient develops a rapidly growing, red, scaly lesion on a sun-exposed area of the face. A biopsy shows malignant cells originating in the stratum spinosum. Identify the cancer and explain why early detection is especially important.
Squamous cell carcinoma. It originates from cells of the stratum spinosum and is described in the slides as fast growing with a tendency to metastasize to the lymph nodes. When it is removed early, the chances of being cured are high
During prolonged vigorous exercise, a person loses a large amount of sweat. Explain how sweating initially helps maintain homeostasis, but how excessive sweating could eventually interfere with homeostasis. Name two substances besides water that are lost in sweat
Evaporation of sweat dissipates heat, helping regulate body temperature. However, excessive sweating causes substantial water loss and can also remove substances such as NaCl and nitrogen-containing wastes (ammonia, urea, and uric acid). Continued fluid and electrolyte loss can therefore make it increasingly difficult to maintain homeostasis. vigorous activity can result in the loss of as much as 12 L of body water in one day.