AS 2 ASSIGNMENT INTEGUMENTARY SYSTEM GEN ANA 1 LECTURE DR. VALENTIN (1).pdf

Dinero, Hailie Jade M. August 19, 2024 DMD2G Dr. Ross Valentin AS 2 ASSIGNMENT INTEGUMENTARY SYSTEM GEN ANA 1 LECTURE INTEGUMENTA...

Dinero, Hailie Jade M. August 19, 2024 DMD2G Dr. Ross Valentin AS 2 ASSIGNMENT INTEGUMENTARY SYSTEM GEN ANA 1 LECTURE INTEGUMENTARY SYSTEM A. Give your responses to the following: 1. Describe the Integumentary system? The Integumentary system is the body's largest organ system, responsible for protecting the body from external damage, regulating body temperature, and aiding in the senses of touch and feel. 2. List the structures that form the Integumentary system. Skin ○ Epidermis ○ Dermis ○ Hypodermis Hair Nails Sweat glands Sebaceous glands Ceruminous glands Mammary glands (in females) 3. Describe the structure of the skin. The skin is a dynamic and complex organ system that provides a barrier against external damage and regulates various bodily functions. It is composed of multiple layers. The outermost layer, the epidermis, detects sensations such as touch and temperature. The dermis provides strength, flexibility, and elasticity, while the hypodermis separates the skin from underlying muscles and organs. The skin also contains glands and structures that aid in maintaining overall health, including sweat glands, sebaceous glands, and hair follicles. 4. List the layers of the skin and describe each layer Epidermis - The outermost layer, the epidermis, consists of five to six layers of cells. This layer is richly innervated with nerve endings, allowing it to detect sensations such as touch, pressure, and temperature. Melanocytes, which produce melanin, are located in the epidermis and are responsible for pigmentation. It is made up of several types of cells, including keratinocytes, melanocytes, and Langerhans cells. Dermis - The dermis is composed of a dense network of collagen and elastin fibers, which provide strength, flexibility, and elasticity to the skin. It also contains blood vessels, lymph vessels, and nerve endings that supply the skin with oxygen and nutrients. The dermis is divided into two sublayers: the papillary dermis and the reticular dermis. The papillary dermis is a thin layer of loose connective tissue that lies immediately beneath  the epidermis, while the reticular dermis is a thicker layer of dense connective tissue that provides strength and support to the skin. Hypodermis - Also known as subcutaneous tissue. This layer is a thick layer of fatty tissue that separates the skin from underlying muscles and organs. The hypodermis contains adipocytes (fat cells), fibroblasts, and blood vessels that supply the skin with oxygen and nutrients. In addition to these structural components, the skin also contains various glands and structures that play important roles in maintaining overall health. Sweat glands produce sweat, which helps to regulate body temperature and maintain hydration. Sebaceous glands produce sebum, an oily substance that helps to lubricate the skin and hair. Hair follicles anchor hair shafts to the skin, while nerve endings allow the skin to detect sensations such as touch, pressure, and temperature. 5. List the layers of the epidermis and describe each. Enumerate the structures found in each of its layers Stratum Corneum - Is a layer of dead, flattened cells that provide a barrier against external factors such as water, wind, and bacteria. It is constantly being replaced by new cells from the layers below. Structure found: Desmosome and Dead keratinocytes Stratum Lucidum - A thin, clear layer of dead cells that lies beneath the stratum corneum. It is not present in all areas of the skin. Structure found: Keratinocytes and Eleidin Stratum Granulosum - A layer of cells that contains keratin and other proteins. These cells are in the process of dying and becoming part of the stratum corneum. Structures found: Keratinocytes, Keratohyalin granules, and Lamellar bodies. Stratum Spinosum - A layer of cells that contains keratin and other proteins. These cells are alive and are responsible for producing keratin, which helps to maintain the skin's barrier function. Structure found: Langerhans cells, Lymphocytes, Desmosomes, and Keratinocytes. Stratum Basale - The innermost layer of the epidermis, the stratum basale is a layer of living cells that are constantly producing new cells to replace those that have died and become part of the stratum corneum. Structure found: Melanocyte, Lymphocytes, Langerhans cells, and Merkel cells. 6. Formulate a mnemonic that will help you remember the different layers of the epidermis A mnemonic to remember the different layers of the epidermis is: "Cats Love Gigantic Sailing Boats" 7. What are epidermal lipids? List the lipids that are synthesized in the epidermis Epidermal lipids are lipids that are synthesized in the epidermis and play a crucial role in maintaining the barrier function of the skin to trans epidermal loss of water. Lipids that are synthesized in the epidermis includes: Triglycerides Fatty Acids  Phospholipids Cholesterol Cholesterol Esters Glycosphingolipids Ceramides 8. What are keratinocytes? Describe its structure. Where are they present ? Keratinocytes are the main type of cells in the epidermis, the outermost layer of the skin. They are responsible for producing keratin, a protein that provides strength and rigidity to the skin. Keratinocytes are also involved in the production of sebum, a natural moisturizer that helps to keep the skin hydrated. Keratinocytes are epithelial cells that have a unique structure. They have: Nucleus, Cytoplasm, Cell membrane, Keratin filaments, Desmosomes, Tight junctions. Keratinocytes are present in the epidermis, which is the outermost layer of the skin. The epidermis is divided into several layers, and keratinocytes are found in all of them, except for the deepest layer, which is called the stratum basale (also known as the basal layer). The stratum basale is where new keratinocytes are produced and mature through a process called keratinization. 9. What is keratin ? List the types of keratin and describe each Keratin is a type of protein that is found in the skin, hair, and nails of humans and many other animals. It is a key component of the skin's outer layer, known as the epidermis, and is responsible for providing strength, rigidity, and elasticity to the skin. Keratin is also a major component of hair and nails, giving them their structure and strength. ○ Type I - These keratins are acidic in nature and have lower molecular weights than Type II keratins. Type I keratins combine with Type II keratins to produce heterodimers, which assemble into intermediate filaments. ○ Type II - These keratins are basic or neutral, with a higher molecular weight. They combine with Type I keratins to generate stable keratin filaments. 10. Describe the structure of the Dermis The dermis is located underneath the epidermis. The dermis is a complex layer of skin that provides support, structure, and nourishment to the skin. It is composed of two main layers: the papillary dermis and the reticular dermis, which contain various types of fibers, cells, and vessels that work together to maintain skin health and function. 11. Enumerate the layers of the dermis and describe each. What are the structures found in each of its layers? The dermis is the layer of skin that lies beneath the epidermis, the outermost layer of the skin. It is a thick, fibrous layer that provides support, structure, and nourishment to the skin. The dermis is composed of two main layers: the papillary dermis and the reticular dermis. Papillary dermis is the uppermost layer of the dermis, extending from the epidermal-dermal junction to a depth of about 0.1-0.2 mm. It is a thin, loose layer of connective tissue that contains:  Papillary fibers: Thin, parallel fibers that are anchored to the epidermis and provide mechanical support to the skin. Papillary vessels: Small blood vessels that supply oxygen and nutrients to the skin. Papillary nerve endings: Sensory receptors that transmit sensory information to the brain. Reticular dermis is the lower layer of the dermis, extending from the papillary-dermal junction to a depth of about 1-2 mm. It is a thicker, denser layer of connective tissue that contains: Collagen fibers: Thick, fibrous strands that provide mechanical support and structure to the skin. Elastic fibers: Fibers that are able to stretch and return to their original shape, allowing for skin elasticity. Adipocytes: Fat cells that store energy and provide insulation. Nerve endings: Sensory receptors that transmit sensory information to the brain. 12. List the two main skin types and describe each. How are they different structurally? Thick Skin - is characterized by a thicker epidermal layer. This increased thickness provides additional protection against mechanical stress, abrasion, and environmental factors. Additionally, the stratum corneum (outermost layer of the epidermis) is thicker and more compact, with a higher concentration of keratinized cells, making it more resistant to water loss and mechanical stress. The papillary dermis in thick skin is also thicker and more prominent, with a higher concentration of blood vessels and nerve endings, which helps to maintain the skin's barrier function and provide sensation. Furthermore, thick skin tends to produce more sebum, which helps to lubricate the skin and provide additional protection against environmental stressors. Thin Skin - is characterized by a thinner epidermal layer. This decreased thickness makes it more susceptible to damage and water loss. The stratum corneum in thin skin is thinner and less compact, with a lower concentration of keratinized cells, making it more prone to water loss and mechanical stress. The papillary dermis in thin skin is also thinner and less prominent, with fewer blood vessels and nerve endings, which can make it more difficult to maintain the skin's barrier function and provide sensation. Additionally, thin skin tends to produce less sebum, which can make it more susceptible to dryness and irritation. 13. Enumerate the locations where the main skin types are present in the body Thick Skin: Locations: Palms of the hands Soles of the feet Fingertips and toes Flexor surfaces of the digits Thin Skin: Locations:  Everywhere else on the body 14. What are melanocytes? Describe its structure. In which skin layer/s are they found ? Melanocytes are specialized cells that produce melanin, a pigment responsible for skin and hair color. They are found in the epidermis, the outermost layer of the skin, and play a crucial role in protecting the skin from the harmful effects of ultraviolet (UV) radiation. Melanocytes are found in the epidermis, specifically in the basal layer (also known as the stratum basale). This layer is the deepest layer of the epidermis, adjacent to the dermal-epidermal junction. 15. What is melanin? What are the different types of melanin? Melanin is a pigment produced by cells called melanocytes in the skin, hair, and eyes. It is responsible for skin and hair color, as well as provides protection against the harmful effects of ultraviolet (UV) radiation. Melanin is a complex molecule that is composed of various amino acids and is synthesized from the amino acid tyrosine. Eumelanin - Eumelanin is the primary type of melanin responsible for brown and black pigmentation. It is produced in the skin, hair, and eyes and is responsible for the color of skin, hair, and eyes. Pheomelanin - Pheomelanin is a type of melanin that produces red or yellow pigmentation. It is also produced in the skin, hair, and eyes and is responsible for the color of freckles, red hair, and red eyes. 16. Describe the structure of the following: Langerhans cells, Merkels cells, Pacinian corpuscles. Where are they located? What are their functions? Langerhans Cells - are a type of dendritic cell found in the epidermis, the outermost layer of the skin. They have a characteristic rod-shaped organelle called an "Birbeck granule" which is involved in the processing and presentation of antigens. Langerhans cells are found in the epidermis, specifically in the stratum spinosum and stratum granulosum. It is involved in the recognition and processing of antigens, particularly in the context of the immune system. Merkel Cells - are small, polygonal cells found in the basal layer of the epidermis. They have a unique morphology, characterized by large amounts of intermediate filaments and dense cytoplasm. Merkel cells are found in the basal layer of the epidermis, specifically in the stratum basale. It is involved in the sensation of touch and pressure. Pacinian corpuscles - are specialized sensory receptors found in the dermis, the layer of skin beneath the epidermis. They consist of a nerve fiber wrapped around a core of connective tissue. Pacinian corpuscles are found in the dermis, particularly in areas with high sensitivity to touch, such as fingertips and palms. It is responsible for detecting vibrations and pressure. 17. In which layer/s of the skin are blood vessels found? The dermis and hypodermis layer. 18. What are fingerprints? How are they formed? Fingerprints are unique patterns of ridges and valleys on the surface of an individual's fingers, toes, and other parts of the body. They are formed by the unique arrangement of sweat pores, fat ridges, and other microscopic features on the skin. Fingerprints are a natural part of human anatomy and are present from birth. Fingerprints are formed through a combination of genetic and environmental factors. 19. Describe the structure and composition of the Hypodermis/Subcutaneous tissue The hypodermis, also known as the subcutaneous tissue, is a layer of fatty tissue located beneath the dermis, the outermost layer of the skin. It is a thick, loose connective tissue that provides cushioning, insulation, and support to the skin. 20. Describe the Innervation and Blood supply of the skin. The skin is innervated by a complex network of nerve fibers that transmit sensory information to the central nervous system. The skin receives blood supply from three main sources: the direct cutaneous, musculocutaneous, and fasciocutaneous systems. Each of these systems originates from different major arteries and supplies blood to different layers and structures of the skin. The skin is also well-innervated with a complex network of sensory and autonomic nerve fibers that transmit sensations and control various functions. These nerve fibers include free nerve endings, Merkel's cells, Meissner's corpuscles, Pacinian corpuscles, Ruffini endings, and spinal and cranial ganglia. 21. The sense of touch, pain, pressure can be felt on the skin due to which structure/s? The sense of touch, pain, and pressure can be felt on the skin due to the following structures: Free nerve endings, Merkel's discs, Meissner's corpuscles, Pacinian corpuscles, Ruffini's corpuscles 22. List the structures of the Pilosebaceous unit and briefly describe each Hair follicle - A tubular structure that anchors the hair shaft to the skin. It is surrounded by a ring of sebaceous glands. Sebaceous gland - A small, oil-producing gland that surrounds the hair follicle. It secretes sebum, a type of oil, into the follicle. Arrector pili muscle - A small, smooth muscle that connects the hair follicle to the surrounding skin. It causes the hair to stand upright when stimulated (e.g., in response to cold temperatures or stress). Apocrine Sweat Gland - Apocrine glands produce a thick, milky secretion that is often referred to as "sweat". This secretion is composed of proteins, lipids, and water. 23. Describe the structure of the hair. In which parts of the body can hair be found? Which parts of the body are devoid of it? Hair Follicle: A tubular structure in the dermis that surrounds the hair root and extends from the skin surface to the hair bulb, where hair growth occurs. Hair Root: The base of the hair that anchors it to the skin.  Hair Shaft: The visible part of the hair that extends from the root. Hair Bulb: The rounded, base part of the hair follicle where hair growth begins. It contains the hair matrix and dermal papilla, essential for hair production. Parts of the Body Where Hair Can Be Found: Head: Scalp, eyebrows, eyelashes, and facial hair. Face: Eyebrows, eyelashes, mustache, beard, and sideburns. Body: Pubic area, chest, abdomen, back, arms, and legs. Pubic area: Pubic hair, which is thicker and coarser than body hair. Parts of the Body Devoid of Hair: Palms: Palms of the hands are usually smooth and hairless. Soles: Soles of the feet are usually smooth and hairless. Lips: Lips are usually smooth and hairless. 24. Describe the structure of the hair follicle. Enumerate and describe its regions and corresponding parts. The hair follicle is a complex tubular structure that surrounds the hair root and extends from the skin surface to the hair bulb, where hair growth occurs. The structure of the hair follicle can be divided into several regions and corresponding parts: ○ Infundibulum: The outermost part of the hair follicle, extending from the skin surface to the opening of the follicle. It is lined with stratified squamous epithelium. ○ Isthmus: The middle part of the hair follicle, connecting the infundibulum to the bulb. It is also lined with stratified squamous epithelium. ○ Bulb: The base part of the hair follicle, where hair growth begins. It contains the hair matrix and dermal papilla, essential for hair production. ○ Hair Root: The base of the hair that anchors it to the skin. ○ Hair Shaft: The visible part of the hair that extends from the root. ○ Dermal Papilla: A small, highly vascularized structure located at the base of the bulb, which supplies nutrients and oxygen to the hair matrix. ○ Hair Matrix: A layer of cells at the base of the bulb, responsible for producing hair. ○ Sebum Glands: Small glands located in the isthmus, which produce sebum (oil) to lubricate and protect the hair. ○ Arrector Pili Muscles: Small smooth muscles attached to the follicle, which cause hair to stand upright (goosebumps) and aid in sebum secretion when contracted. 25. Enumerate and describe each of the concentric zones of the hair shaft and corresponding Parts. Cuticle: The outermost layer of the hair shaft, composed of overlapping scales that provide a protective barrier against the environment. ○ Inner Cuticle: The inner layer of the cuticle, which is composed of flat, overlapping scales that are tightly packed together. ○ Outer Cuticle: The outer layer of the cuticle, which is composed of more loosely packed scales that are prone to damage. Cortex: The middle layer of the hair shaft, comprising the majority of the shaft's diameter.  ○ Cortical Cells: The cells that make up the cortex, which are responsible for hair strength and elasticity. ○ Cortical Keratin: The protein structure that gives the cortex its shape and strength. Medulla: The innermost layer of the hair shaft, which is present in some but not all hair types. ○ Medullary Cells: The cells that make up the medulla, which are responsible for providing cushioning and shock absorption to the hair. 26. Describe the structure of the hair bulb The hair bulb produces hair. It consists of three regions: the hair matrix, dermal papilla, and Hensen's layer. The hair matrix produces hair cells, while the dermal papilla supplies nutrients and signals for growth. Hensen's layer separates the matrix from the surrounding tissue, protecting the growth process. The dermal papilla responds to hormonal signals to regulate growth. The surrounding blood vessels and nerve fibers provide essential nutrients and signals for hair growth. 27. Describe the structure of the nail. The nail is a keratinized plate that grows from the nail matrix, located underneath the cuticle. The nail structure is designed to provide protection and support to the sensitive tips of fingers and toes. 28. What structures comprise the nail apparatus? Describe each Nail plate: The visible part of the nail that grows outward. Nail bed: The area underneath the nail plate where the nail grows. Nail matrix: The area beneath the cuticle where the nail cells are produced. Cuticle: A thin layer of skin that covers the nail bed and protects the nail. Nail folds: The skin that folds over the nail bed, creating a small crease. Hyponychium - area under the free nail, it is an epidermal ridge that demarcates the junction between the finger pulp and the subungual structures 29. Describe the structure of the sebaceous glands. What do they secrete? In which areas of the body are they present? Sebaceous glands produce sebum, a type of oily substance. They're connected to hair follicles and help maintain skin health. These glands are found on the face, scalp, back, armpits, and genital area. Sebum helps regulate body temperature and keeps skin hydrated. On the face, it's especially prominent on the nose, forehead, cheeks, and chin. On the scalp, it helps keep hair healthy and shiny. 30. Describe the structure of Sweat glands. In which part of the body are they present Sweat glands, also known as eccrine glands, are small, tubular glands that produce sweat. They have a single layer of epithelial cells surrounding a central lumen, with coils increasing in diameter as they approach the skin surface. Sweat glands are present all  over the body, but are more abundant in areas where the skin is thick and dense, such as: Palms and soles, Face (forehead, cheeks, and nose), Neck and chest 31. Enumerate the different types of sweat glands and describe each. How are they different from each other? What do each secrete? In which areas of the body are each located? Eccrine - are found all over the body, regulating body temperature through sweat production in response to heat, exercise, or emotional stress. They produce a clear, watery liquid and are most abundant in areas with thick skin. Apocrine - are primarily found in areas with hair follicles, such as the armpits and groin. They produce pheromones, which communicate information about an individual's reproductive status or social cues. Apocrine glands are larger than eccrine glands and produce a thick, milky liquid. 32. Describe the structure of the breast and its parts The breast is a complex organ that consists of several layers of tissue, including fatty tissue, glandular tissue, and connective tissue. The breast is made up of the following parts: ○ Glandular tissue: The glandular tissue is responsible for producing milk during lactation. It is composed of lobules, which are small clusters of milk-producing glands called alveoli. The lobules are connected to the nipple by ducts. ○ Ducts: The ducts are narrow tubes that carry milk from the lobules to the nipple. There are usually 15-20 ducts in each breast. ○ Lobules: Lobules are small clusters of milk-producing glands called alveoli. They are responsible for producing milk during lactation. ○ Alveoli: Alveoli are small, grape-like structures that produce milk in response to hormonal stimulation. ○ Connective tissue: Connective tissue provides support and structure to the breast. It is made up of fibers, such as collagen and elastin, which give the breast its shape and flexibility. ○ Fatty tissue: Fatty tissue provides insulation and support to the breast. It is made up of adipose cells that store fat. ○ Areola: The areola is the dark-colored area surrounding the nipple. It contains Montgomery glands, which produce a fluid that helps to lubricate the nipple and aid in breastfeeding. ○ Nipple: The nipple is the small, raised area at the center of the areola. It is surrounded by muscle fibers that help to control milk flow during lactation.