Anatomia Układu Powłokowego | Integumentary System anatomy

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“Naskórek”, “Dermis”: “Skóra właściwa”, “Subcutaneous tissue”: “Tkanka podskórna”, “Hazards”: “Zagrożenia”, “Mechanical injury”: “Uszkodzenie mechaniczne”, “Pathogens”: “Patogeny”, “Dehydration”: “Odwodnienie”, “Keratinocytes”: “Keratynocyty”, “Keratin”: “Keratyna”, “Durability”: “Trwałość”, “Avascular layer”: “Warstwa bez unaczynienia”, “Stratum Corneum”: “Warstwa rogowa”, “Stratum Lucidum”: “Warstwa jasna”, “Stratum Granulosum”: “Warstwa ziarnista”, “Stratum Spinosum”: “Warstwa kolczysta”, “Stratum Basale”: “Warstwa podstawna”, “Corneocytes”: “Korneocyty”, “Shed”: “Złuszczać”, “Thin”: “Cienka”, “Thick”: “Gruba”, “Transparent”: “Przezroczysta”, “Soles of the feet”: “Podeszwy stóp”, “Keratohyalin granules”: “Ziarna keratohialiny”, “Spiny layer”: “Warstwa kolczysta”, “Desmosomes”: “Desmosomy”, “Langerhans cells”: “Komórki Langerhansa”, “Immune response”: “Odpowiedź immunologiczna”, “Mitosis”: “Mitoza”, “Merkel cells”: “Komórki Merkla”, “Sense of touch”: “Zmysł dotyku”, “Pressure changes”: “Zmiany ucisku”, “Pigmentation”: “Pigmentacja”, “Harmful pathogens”: “Szkodliwe patogeny”, “Fine touch”: “Delikatny dotyk”, “Pressure”: “Ucisk”, “Skin cell turnover”: “Wymiana komórek skóry”, “Collagen”: “Kolagen”, “Elastin fibers”: “Włókna elastynowe”, “Well-vascularized”: “Dobrze unaczyniony”, “Nerve endings”: “Zakończenia nerwowe”, “Hair follicles”: “Mieszki włosowe”, “Glands”: “Gruczoły”, “Papillary layer”: “Warstwa brodawkowata”, “Reticular layer”: “Warstwa siateczkowa”, “Meissner’s corpuscles”: “Ciałka Meissnera”, “Connective tissue”: “Tkanka łączna”, “Loose connective tissue”: “Tkanka łączna luźna”, “Dermal papillae”: “Brodawki skórne”, “Surface area”: “Powierzchnia”, “Nutrient exchange”: “Wymiana składników odżywczych”, “Rich in capillaries”: “Bogaty w naczynia włosowate”, “Nutrients”: “Składniki odżywcze”, “Dense, irregular connective tissue”: “Gęsta nieregularna tkanka łączna”, “Collagen rich in elastin fibers”: “Kolagen bogaty we włókna elastynowe”, “Tensile strength”: “Wytrzymałość na rozciąganie”, “Stretch”: “Rozciąganie”, “Recoil”: “Sprężystość”, “Tearing”: “Rozdarcie”, “Follicles”: “Mieszki”, “Oil glands”: “Gruczoły łojowe”, “Sweat glands”: “Gruczoły potowe”, “Lubricates”: “Natłuszcza”, “Arrector pili muscles”: “Mięśnie przywłośne”, “Goosebumps”: “Gęsia skórka”, “Hypodermis”: “Hipoderma”, “Sebaceous glands”: “Gruczoły łojowe”, “Sebum”: “Łój skórny”, “Brittle”: “Kruchy”, “Absorb”: “Pochłaniać”, “Adipose tissue”: “Tkanka tłuszczowa”, “Insulation”: “Izolacja”, “Fibrous connective tissue”: “Włóknista tkanka łączna”, “Binds the skin”: “Wiąże skórę”, “Lymphatic vessels”: “Naczynia limfatyczne”, “Drain excess fluid”: “Odprowadzają nadmiar płynów”, “Tissues”: “Tkanki”, “Nails”: “Paznokcie”, “Sensory perception”: “Percepcja sensoryczna”, “Protection”: “Ochrona”, “Anagen (Growth Phase)”: “Anagen (faza wzrostu)”, “Catagen (Transitional Phase)”: “Katagen (faza przejściowa)”, “Shrink”: “Kurczyć się”, “Telogen (Resting Phase)”: “Telogen (faza spoczynkowa)”, “Moisturized”: “Nawilżona”, “Cooling”: “Ochładzanie”, “Excreting waste”: “Wydalanie produktów przemiany materii”, “Eccrine Sweat Glands”: “Gruczoły potowe ekrynowe”, “Apocrine Sweat Glands”: “Gruczoły potowe apokrynowe”, “Palms”: “Dłonie”, “Soles”: “Stopy”, “Forehead”: “Czoło”, “Evaporation”: “Parowanie”, “Armpits”: “Pachy”, “Groin”: “Pachwiny”, “Nipples”: “Sutki”, “Sweat odorless”: “Pot bezzapachowy”, “Broken down by skin bacteria”: “Rozkładany przez bakterie skóry”, “Body odor”: “Zapach ciała”, “Puberty”: “Okres dojrzewania”, “Dry brittle”: “Suche i łamliwe”, “Nail Plate”: “Płytka paznokcia”, “Nail Bed”: “Łożysko paznokcia”, “Nail Matrix”: “Macierz paznokcia”, “Eponychium”: “Obrąbek naskórkowy płytki paznokcia”, “Congenital Anomalies”: “Wrodzone anomalie”, “Benign”: “Łagodny”, “Significant health implications”: “Istotne skutki zdrowotne”, “Appearance”: “Wygląd”, “Malignancies”: “Nowotwory złośliwe”, “Infections”: “Infekcje”, “Congenital Melanocytic Nevus”: “Wrodzone znamię melanocytowe”, “Epidermal Nevus”: “Znamię naskórkowe”, “Port-Wine Stain”: “Naczyniak płaski”, “PWS”: “Naczyniak płaski”, “Albinism”: “Albinizm”, “Ichthyosis”: “Rybia łuska”, “Epidermolysis Bullosa”: “Pęcherzowe oddzielanie się naskórka”, “EB”: “Pęcherzowe oddzielanie się naskórka”, “Congenital Hypertrichosis”: “Wrodzona hipertrichoza”, “Birthmarks”: “Znamiona wrodzone”, “Nevi”: “Znamiona”, “Diameter”: “Średnica”, “Melanoma”: “Czerniak”, “Surgical removal”: “Usunięcie chirurgiczne”, “Atypical lesions”: “Nietypowe zmiany”, “Skin lesions”: “Zmiany skórne”, “Pigmented patches”: “Plamy barwnikowe”, “Further medical evaluation”: “Dalsza ocena medyczna”, “Capillary malformation”: “Malformacja kapilarna”, “Systemic conditions”: “Choroby ogólnoustrojowe”, “Moisturization”: “Nawilżanie”, “Skin cancer”: “Rak skóry”, “Flat”: “Płaski”, “Reddish-purple”: “Czerwono-fioletowy”, “Sturge-Weber Syndrome”: “Zespół Sturge’a-Webera”, “Genetic condition”: “Choroba genetyczna”, “Increased risk”: “Zwiększone ryzyko”, “Evaluations”: “Oceny”, “Dry”: “Suchy”, “Scaly”: “Łuskowaty”, “Mild”: “Łagodny”, “Severe”: “Ciężki”, “Lamellar ichthyosis”: “Ichtioza lamelarna”, “Cracking”: “Pęknięcia”, “Blisters”: “Pęcherze”, “Cell”: “Komórka”, “Minor friction”: “Niewielkie tarcie”, “Excessive hair growth”: “Nadmierny wzrost włosów”, “Psychological well-being”: “Psychiczne samopoczucie”, “Melanocytes”: “Melanocyty”, “Sensory cells”: “Komórki czuciowe”, “Meissner’s corpuscles”: “Ciałka Meissnera”, “Light touch”: “Delikatny dotyk”, “Fibers”: “Włókna”, “Subcutaneous”: “Podskórne”, “Follicle”: “Mieszek włosowy”, “Sebaceous gland”: “Gruczoł łojowy”, “Contract”: “Kurczyć się”, “Stimuli”: “Bodźce”, “Prominent areas”: “Wyraźne obszary”, “Wound care”: “Pielęgnacja rany”, “Infection prevention”: “Zapobieganie infekcji”, “Severe cases”: “Ciężkie przypadki”, “Condition”: “Stan chorobowy”, “Inherited”: “Dziedziczony”, “X-linked dominant inheritance”: “Dziedziczenie dominujące sprzężone z chromosomem X” }; // 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Szacowany czas lekcji: 33 minuty
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Introduction to Skin Anatomy

Did you know?

Did you know that the skin on your lips is actually thinner than the skin on the rest of your body?
The skin on your lips is different from the rest of your body because it is thinner and more delicate. Skin on your face can be up to 16 cell layers thick while the skin on your lips is only 3 to 5 layers thick. This means your blood vessels are more apparent, giving your lips their pink or red colour.

Figure 1.1 generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license

The skin is not only the largest organ of the human body but also one of the most complex. As a dynamic structure, it serves as a critical barrier between the external environment and the internal organs, while providing structural integrity, thermoregulation, and sensory feedback. The skin is composed of three primary layers: the epidermisdermis, and subcutaneous tissue.

Epidermis

The epidermis is the outermost layer of the skin, serving as the body’s first line of defense against environmental hazards. This layer is thin, yet it performs essential roles in shielding deeper tissues from mechanical injury, pathogens, and dehydration. It is composed primarily of keratinocytes, cells that produce keratin, a tough protein that provides durability and strength. The epidermis is an avascular layer, meaning it lacks blood vessels and relies on nutrient exchange with the underlying dermis. The epidermis is divided into several distinct sublayers.

Figure 1.2, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license

Sublayers of the Epidermis

LayerDescription
Stratum CorneumThe outermost layer of the epidermis, composed of dead, flattened keratinocytes known as corneocytes. These cells are filled with keratin and arranged in overlapping layers to form a strong, protective barrier. Cells are continuously shed and replaced.
Stratum LucidumA thin, transparent layer present only in thicker areas of the skin, such as the palms of the hands and soles of the feet. It consists of flattened, dead keratinocytes that add an extra layer of protection.
Stratum GranulosumThis layer contains keratohyalin granules, essential for the production of keratin. Keratinocytes in this layer lose their nuclei and become flattened as they move upwards, contributing to the formation of the stratum corneum.
Stratum SpinosumKnown as the “spiny layer” due to the appearance of cells under a microscope, this layer contains desmosomes, which provide strength and flexibility. Langerhans cells, involved in immune response, are also found in this layer.
Stratum BasaleThe deepest layer, where new keratinocytes are generated through mitosis. This layer also contains melanocytes, which produce melanin for skin color and UV protection, and Merkel cells, which contribute to the sense of touch by detecting pressure changes.

Cell Types in the Epidermis

  • Keratinocytes: The most abundant cells in the epidermis, responsible for producing keratin, which forms the waterproof barrier of the skin.
  • Melanocytes: Cells that produce melanin, providing pigmentation to the skin and protecting it from UV radiation.
  • Langerhans Cells: Immune cells that patrol the epidermis, identifying and capturing harmful pathogens.
  • Merkel Cells: Sensory cells located in the stratum basale, responsible for detecting fine touch and pressure.

The constant renewal of the epidermis ensures that the skin can maintain its protective functions, with old cells being shed and replaced by new cells generated in the deeper layers. The process of skin cell turnover takes approximately 28-30 days in healthy adults.

Dermis

Beneath the epidermis lies the dermis, a much thicker and more structurally complex layer. The dermis provides the skin with its strength and elasticity, owing to its rich network of collagen and elastin fibers. Unlike the epidermis, the dermis is well-vascularized and contains a variety of structures, including blood vessels, nerve endings, hair follicles, and glands. The dermis is composed of two main sublayers: the papillary layer, closer to the epidermis, and the reticular layer – deeper within.

Figure 1.3, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license

Sublayers of the Dermis

LayerDescription
Papillary LayerThis upper layer of the dermis is composed of loose connective tissue and forms dermal papillae, which are small, finger-like projections extending into the epidermis. These projections increase the surface area for nutrient exchange and help anchor the dermis to the epidermis. The papillary layer is rich in capillaries, supplying nutrients to the avascular epidermis, and contains Meissner’s corpuscles, specialized nerve endings that detect light touch.
Reticular LayerThe deeper and thicker layer of the dermis is composed of dense, irregular connective tissue rich in collagen and elastin fibers. These fibers provide the skin with tensile strength and elasticity, allowing it to stretch and recoil without tearing. The reticular layer also contains various structures such as hair follicles, sebaceous glands (oil glands), sweat glands, and larger blood vessels.

Hair Follicles and Associated Structures

The dermis is home to hair follicles, which are responsible for the growth of hair. Each follicle is anchored deep in the dermis, and its root extends down into the subcutaneous tissue. Sebaceous glands are attached to hair follicles and secrete sebum, an oily substance that lubricates the skin and hair, preventing them from becoming dry and brittle. Hair follicles also contain arrector pili muscles, small muscles that contract in response to cold or fear, causing “goosebumps.”

Subcutaneous Tissue

The subcutaneous tissue, also known as the hypodermis, is the deepest layer of the skin, located beneath the dermis. This layer serves as a critical interface between the skin and the underlying muscles and bones. It is primarily composed of adipose tissue (fat), which acts as a cushion to absorb mechanical shocks and insulate the body from extreme temperatures.

Figure 1.4, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license

Components of the Subcutaneous Tissue

  • Adipose Tissue: The primary component of the hypodermis, adipose tissue stores fat, which serves as an energy reserve and provides insulation. The thickness of this layer varies across different parts of the body and among individuals.
  • Connective Tissue: In addition to adipose cells, the subcutaneous layer contains fibrous connective tissue that binds the skin to underlying structures, such as muscles and bones.
  • Blood Vessels and Nerves: Larger blood vessels and nerves pass through the subcutaneous tissue to supply the dermis and epidermis. This layer also contains lymphatic vessels, which help drain excess fluid from the tissues and return it to the bloodstream.

Associated Skin Structures: Hair, Nails, and Glands

The skin not only serves as a protective barrier but also houses several specialized structures that play critical roles in maintaining its overall function. These structures include hair folliclesnails, and glands, all of which contribute to sensory perception, protection, and homeostasis.

Hair Follicles

Hair follicles are complex tubular structures responsible for producing hair, a keratinized filament that extends from the epidermis through the dermis and sometimes into the subcutaneous tissue. Hair provides insulation, protects against UV radiation, and enhances sensory perception. Each hair follicle undergoes a growth cycle, composed of the following phases:

  • Anagen (Growth Phase): This is the active phase of hair growth, which can last for several years, depending on the location of the hair.
  • Catagen (Transitional Phase): Hair growth slows, and the hair follicle begins to shrink. This phase typically lasts a few weeks.
  • Telogen (Resting Phase): The follicle remains inactive, and eventually, the old hair is shed, making way for new growth.

As you already know each hair follicle is associated with a sebaceous gland that secretes sebum to keep the hair and surrounding skin moisturized. 

Arrector pili muscles are small smooth muscles attached to hair follicles that contract in response to cold or emotional stimuli, causing the hair to stand up, a phenomenon known as “goosebumps.”

Figure 1.5, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license

Sweat Glands

Sweat and sebaceous glands are vital for maintaining the health and functionality of the skin. Together, they regulate body temperature, manage hydration, and protect the skin from external elements.

While sweat glands are primarily responsible for cooling the body and excreting waste, sebaceous glands ensure the skin and hair remain moisturized and protected

Figure 1.6, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license

Types of Sweat and Sebaceous Glands

Gland TypeDescription
Eccrine Sweat GlandsFound throughout the body, especially on the palms, soles, and forehead, eccrine glands secrete a watery sweat directly onto the skin surface. This sweat is primarily composed of water, salts, and waste products, and its evaporation helps cool the body.
Apocrine Sweat GlandsLocated mainly in the armpits, groin, and around the nipples, apocrine glands secrete a thicker, milky fluid into hair follicles. This sweat is initially odorless, but when broken down by skin bacteria, it produces body odor. These glands become active during puberty and are linked to emotional and hormonal changes.
Sebaceous GlandsFound throughout the skin except on the palms and soles, sebaceous glands are closely associated with hair follicles. They secrete an oily substance called sebum, which lubricates the hair and skin, preventing them from becoming dry and brittle. Sebum also plays a role in maintaining the skin’s barrier function, protecting against environmental damage and the growth of harmful microorganisms. Unlike sweat glands, sebaceous glands do not play a direct role in thermoregulation but are essential for skin health and hydration.

Nails

Nails are hardened structures composed of keratin and are located at the tips of fingers and toes. Nails serve multiple purposes, including protecting the delicate tissues of the fingertips and enhancing fine motor skills. The primary parts of the nail include:

  • Nail Plate: The visible, hard part of the nail.
  • Nail Bed: The skin beneath the nail plate, rich in blood vessels, which give the nail its pinkish color.
  • Nail Matrix: The area beneath the skin at the base of the nail where new nail cells are produced, leading to nail growth.
  • Cuticle (Eponychium): A thin layer of skin that protects the area between the nail and the skin from infection.
Figure 1.7, generated using Servier Medical Art, provided by Servier, licensed under a Creative Commons Attribution 4.0 unported license


Nails grow continuously throughout life, with the growth rate influenced by factors such as age, nutrition, and overall health.

Common Congenital Anomalies

Congenital anomalies of the integumentary system, which includes the skin, hair, nails, and associated glands, are often visible at birth and can range from benign to conditions with significant health implications. These anomalies can affect appearance, skin function, and, in some cases, increase the risk of complications like infections or malignancies. Below are some frequently observed congenital anomalies in the integumentary system:

Congenital AnomalyDescription
Congenital Melanocytic Nevus (CMN)CMNs are pigmented birthmarks that vary in size and can appear anywhere on the body. Small CMNs are generally benign, but larger nevi (greater than 20 cm in diameter) may increase the risk of melanoma. Regular monitoring and, in some cases, surgical removal may be recommended for larger or atypical lesions.
Epidermal NevusThese are skin lesions formed by an overgrowth of epidermal cells, often appearing as raised, pigmented patches. Epidermal nevi are generally benign but may become pigmented patches.. Some cases are associated with systemic conditions, requiring further medical evaluation and monitoring.
Port-Wine Stain (PWS)A type of capillary malformation, PWS presents as a flat, reddish-purple birthmark typically on the face or neck. Although usually asymptomatic, PWS can darken and thicken over time. Laser therapy is often used to reduce visibility, particularly if located in prominent areas. In rare cases, PWS can be associated with Sturge-Weber syndrome.
AlbinismAlbinism is a genetic condition characterized by reduced or absent melanin production, affecting skin, hair, and eye pigmentation. Individuals with albinism are more sensitive to sunlight and have an increased risk of skin cancer. Management includes protective sun measures and regular dermatological evaluations.
IchthyosisIchthyosis encompasses a group of disorders that cause dry, scaly skin due to abnormal skin cell turnover. Symptoms range from mild to severe, with certain types, like lamellar ichthyosis, appearing at birth. Treatment focuses on regular moisturization and specialized skincare to prevent cracking and infection.
Epidermolysis Bullosa (EB)EB is a group of genetic conditions causing fragile skin that easily blisters from minor friction. Symptoms can range from mild to life-threatening, depending on the type. Management includes wound care, infection prevention, and, in severe cases, supportive therapies to address complications.
Congenital HypertrichosisOften called “werewolf syndrome,” is a rare genetic condition that causes excessive hair growth from birth. It results in abnormal hair growth, typically on the face, arms, and other parts of the body. The condition is caused by genetic mutations and can be inherited in an X-linked dominant pattern. While it has cosmetic effects, there are no specific treatments beyond hair removal methods.