Module 2 Anatomy & Physiology 241

The three layers of skin are the epidermis, dermis, and hypodermis. The epidermis is the outermost layer, the dermis is the middle layer, and the hypodermis is the innermost layer. Each layer plays a different role in protecting and maintaining the skin.

The epidermis consists of five layers: Stratum Corneum, Stratum lucidium (only in thick skin), Stratum granulosum, Stratum spinosum, Stratum Basale. Stratum Papillare, Stratum Reticulare, and Stratum Subcutaneum are not layers of the epidermis.

The Stratum Corneum is the outermost layer of the Epidermis consisting of dead cells. It acts as a protective barrier for the skin.

The Stratum Granulosum is a specific layer in the Epidermis located between the Stratum Corneum and Stratum Spinosum in thin skin, and between the Stratum Lucidum and Stratum Spinosum in thick skin. It consists of flat, deteriorating cells releasing lipids and keratin granules.

The correct answer describes the Stratum Lucidium as located below the Stratum Corneum and above the Stratum Granulosum, only present in thick skin areas like the palms and soles. It consists of clear, densely packed keratinocytes without nuclei or organelles.

The Stratum Basale is the deepest layer of the Epidermis, located below the Stratum Spinosum. It is made up of actively mitotic cells and also contains occasional Melanocytes.

The epidermis is composed of keratinized stratified squamous epithelium, which provides protection to the body's underlying tissues.

The epidermis is primarily composed of keratinocytes, melanocytes, dendritic cells (Langerhans cells), and Merkel cells. Fibroblasts, red blood cells, and neurons are not typically found in the epidermis.

Keratinocytes are specialized cells found in the epidermis of the skin, responsible for producing the protein Keratin which provides structural support and waterproofing to the skin.

Melanocytes are responsible for producing melanin, a pigment that provides protection against UV radiation by shielding the DNA. This process gives the skin its color and helps prevent damage from sun exposure.

Dendritic cells, also known as Langerhans cells, are a type of immune cell that play a crucial role in the immune system by helping to eliminate foreign material in the body. They are not involved in transporting oxygen, assisting in digestion, or regulating body temperature.

Dendritic (Langerhans) Cells are primarily found in the Stratum spinosum and Stratum granulosum layers of the epidermis, where they play an important role in the immune response of the skin.

Dendritic cells are found in the mucosal tissues and skin where they play a crucial role in the immune response.

Merkel (Tactile) Cells are specialized receptors located in the skin that are responsible for detecting touch sensations. They play a key role in the perception of tactile stimuli.

Merkel (Tactile) Cells are specialized sensory cells located in the Basal layer of the Epidermis. They are involved in the sense of touch and pressure.

The dermis is the middle layer of the skin, lying between the epidermis and hypodermis. It is composed of two main layers: the papillary dermis and the reticular dermis. The papillary dermis is the superficial layer, while the reticular dermis lies beneath it.

The Papillary layer of the Dermis is made up of Areolar Tissue, which is a loose connective tissue that contains collagen and elastic fibers.

The Reticular layer of the Dermis is composed of dense irregular tissue which provides strength and elasticity to the skin.

The receptors for sensation in the skin include Pacinian Corpuscle (Lamellar Corpuscle), Merkel Cells (Tactile Discs/Cells), and Meissner Corpuscles (Tactile Corpuscle), which are responsible for detecting different types of touch and pressure stimuli. Ruffini Corpuscles (Bulbous Corpuscle), Krause End Bulbs (Krause Corpuscle), and Free Nerve Endings are also sensory receptors but are not specifically related to sensation in the skin.

Pacinian corpuscles are responsible for deep pressure touch, stretch, tickle, and vibration, not temperature sensation, pain perception, or fine touch discrimination.

Merkel cells, also known as tactile discs or cells, are responsible for providing a fine sense of touch and pressure. They are not involved in regulating body temperature, detecting colors, or controlling muscle movement.

Meissner (Tactile Corpuscles) are located in the dermal papillae of specific areas of the body related to touch sensitivity. They are not found in the epidermis, hypodermis, or muscles.

Meissner Corpuscles are nerve endings responsible for light touch and texture sensation.

The correct labels for the given question are Hair Follicle, Arrector pili muscle, and the Hair Root. The incorrect answers provided do not accurately identify the specified structures within the question.

Eccrine (Merocrine) glands secrete sweat to the outside of the body through ducts on the skin surface, mainly found on areas such as the hands, soles, and forehead. They are not glands that secrete internally, found mainly on the back, or have closed ducts.

The Eccrine gland's primary function is to help cool the body by regulating temperature and also excretes some waste products. It does not produce hormones, aid in digestion, or regulate blood pressure and circulation.

Eccrine (Merocrine) glands are predominantly found on areas of the body where sweat production is needed for temperature regulation and can be easily localized.