- Blood Circulatory System
- Blood
- Bones of The Legs
- Bones of The Foot
- Bones of The Ankle
- Bones of Pelvis
- Blood Groups
- Scientific Name of Human Being
- Largest Organ In Human Body
- Largest Internal Organ in The Human Body
- Human Respiratory System
- Human Population
- Human Physiology
- Human Life Cycle
- Human Insulin
- Human Impact on the Environment
- Human Heart
- Human Health and Diseases
- Human Genome Project Goals Significance
- Human Excretory System
- Human Evolution Progress
- Human Ear
- Human Diseases
- Human Digestive System
- Human Circulatory System Transportation
- Anatomy and Physiology of the Human Body
- Effects of Air Pollution on Human Health
Difference between
- Difference between Turner Syndrome and Klinefelter Syndrome
- Difference Between Transpiration and Guttation
- Difference Between Transpiration and Evaporation
- Difference Between Tracheids and Vessels
- Difference Between Thorns and Spines
- Difference Between T Cells and B Cells
- Difference Between Sympathetic and Parasympathetic
- Difference Between Sporophyte and Gametophyte
- Difference Between Spermatogenesis and Oogenesis
- Difference Between Sperm and Ovum
- Difference between Species, Population, and Community
- Difference Between Sleep and Hibernation
- Difference Between Saturated and Unsaturated Fats
- Difference Between Rust and Smut
- Difference Between Right and Left Lung
- Difference Between Replication and Transcription
- Difference Between Renewable and Non Renewable Resources
- Difference Between Red and White Muscle
- Difference Between Radicle and Plumule
- Difference Between Prokaryotic and Eukaryotic Transcription
- Difference Between Plasma and Serum
- Difference Between Pharynx and Larynx
- Difference Between Organs and Organelles
- Difference Between Open and Closed Circulatory Systems
- Difference Between Ocean and Sea
- Difference Between Monocytes and Lymphocytes
- Difference Between Mitochondria and Chloroplast
- Difference Between Lytic and Lysogenic Cycle
- Arteries and Veins Difference
Cell
- Growth and Development of an organism
- Meiosis Cell Division
- Cellular Respiration Concept Map
- Cell Signalling
- Cell Organelles
- Cell Cycle and Cell Division
- Cell Biology
Energy, Enzymes and membrane
Plant
- Scientific Names of Animals and Plants
- Plant Respiration
- Plant Physiology
- Plant Life Cycle and Alternation of Generations
- Plant Kingdom Plantae
- Plant Growth Regulators
- Plant Fibres
- Mendelian Inheritance Using Seeds of Different Colours Sizes of Any Plant
- Grassland Dominant Plants
- Effects of Air Pollution on Plants
- Biodiversity In Plants and Animals
Botanical Name
- Mustard Botanical Name
- Marigold Botanical Name
- Chilli Botanical Name
- Botanical Name of Tea
- Botanical Name of Sugarcane
- Botanical Name of Soybean
- Botanical Name of Rose
- Botanical Name of Rice
- Botanical Name of Pea
- Botanical Name of Lady Finger
- Botanical Name of Groundnut
- Botanical Name of Grapes
- Botanical Name of Coffee
- Botanical Name of Cabbage
- Botanical Name of Banyan Tree
- Botanical Name of Bajra
Biodiversity
- Biodiversity Pattern Species
- Biodiversity Conservation
- Biodiversity and Conservation Concept Map
- Biodiversity
Symptoms, diseases
- Hormones Heart Kidney GI
- Blood Cancer
- Arthritis
- Aids and Hiv
- Nervous System Diseases
- Modes of Transmission of Diseases
- Migraine Symptoms
- Menopause Symptoms
- Lysosomal Storage Disease
- Lung Diseases
- Lung Cancer Symptoms
- Hyperthyroidism Symptoms
- Hypertension Symptoms
- Chicken Pox Symptoms
- Blood Pressure Symptoms
- Arthritis Symptoms
- Appendicitis - Formation, Symptoms, Treatment
- Anemia Symptoms
- Acidity Symptoms Causes and Risk Factors involved
Causes
Other Topics
Bio Articles (Alphabetic order)
- Antigens and Immunology
- Scientific Name of Vitamins
- Scientific Name of Neem
- Schistosomiasis Life Cycle
- Scabies Life Cycle
- Salient Features of The Kingdom Monera
- Saddle Joints
- Root Modifications
- Role of Microbes In Food Processing
- RNA: World Genetic Material
- Rna Interference
- Ringworm
- Rigor Mortis
- Retrovirus
- Respiratory Quotient
- Respiratory and Lung Volumes
- Adolescence Secondary sexual characteristics
- Prolactin Hormone
- Productivity In Ecosystem
- Prions
- Principles of Treatment
- Principles of Prevention
- Principles of Inheritance and Variation
- Principles of Genetics
- Primary Ciliary Dyskinesia
- Prepare Pedigree Charts of Any One of the Genetic Traits Such as Rolling Of Tongue, Blood Groups, Ear Lobes, Widow’s Peak and Colour Blindness
- Prepare A Temporary Mount of The onion Root Tip To Study Mitosis
- Preparation and Study of Transverse Section of Dicot and Monocot Roots and Stems
- Pregnancy Parturition Lactation
- Neural Control and Coordination
- Nervous Tissue
- Nervous System Definition
- Nervous System Coordination
- Nervous System
- Nerves
- Nephron Function Renal Tubules
- Nephritis
- Nematoda
- Need For Hygiene and Sanitation
- Natural Selection Biological Evolution
- Natural Disasters
- National Parks and Sanctuaries
- Mycology
- Myasthenia Gravis
- Mutualism
- Mutation Genetic Change
- Mutagens
- Muscular Dystrophy
- Muscle Contraction Proteins
- Mountains and Mountain Animals
- Morphology and Anatomy of Cockroach
- Monohybrid Cross - Inheritance of One Gene
- Molecular Basis of Inheritance
- MOET Technology - Multiple Ovulation Embryo Transfer Technology
- Modern Synthetic Theory of Evolution
- Miller Urey Experiment
- Micturition - Urination Process
- Microfilaments
- Microbodies
- Metabolism Metabolic Pathways
- Metabolism Living State Basis
- Mendelian Disorders
- Melatonin Hormone
- Meiosis Phases
- Meiosis I - Stages and Process
- Megafauna
- Measles
- Mayfly Life Cycle
- Mass Flow Hypothesis
- Mass Extinctions
- Marine Biology
- Mammalia Diversity In Living Organisms
- Malthusian Theory of Population
- Male Sex Hormone
- Macromolecule
- Luteinizing Hormone
- Lung Cancer
- Love Hormone
- Locust Life Cycle
- Lizard Life Cycle
- Living Fossil
- Lipoproteins
- Lipids
- Lipid Peroxidation
- Linkage Recombination
- Life Cycle of Living Organism
- Lice Life Cycle
- Leprosy
- Length of Epididymis
- Leishmania Life Cycle
- Leg Muscles
- Law of Segregation and Law of Dominance
- Law of Independent Assortment
- Hypothyroidism
- Hypothalamus
- Hypogeal Germination
- Hypocalcaemia
- Hypertension
- Hyperparathyroidism
- Hydroponics
- Hydrarch Succession
- Horses and Donkeys Same Species
- Hormonal Disorders
- Hormones Secreted by Non-Endocrine
- Hookworm Life Cycle
- Honey Bee Life Cycle
- Homo erectus
- Homeostasis
- History of Clothing Material
- Characteristics and classification of Gymnosperms
- Guttation
- Griffith Experiment: The Genetic Material
- Grazing Food Chain
- Grasshopper Life Cycle
- Gram Positive Bacteria
- Gout
- Gonorrhea
- Gonads
- Goiter
- Embryology
- Embryo Development
- Elisa Technique
- Electron Transport Chain
- Electrocardiograph
- Effects of Water Pollution
- Effects of Waste Disposal
- Effects of Wastage of Water
- Effects of Plastics
- Life Cycle of Chicken
- Chemotrophs
- Chemiosmotic Hypothesis
- Centromere
- Central Dogma Inheritance Mechanism
- Cartilaginous Joints
- Carnivores and Herbivores
- Cardiac Output
- Carbon Cycle
- Carbohydrate Metabolism
- Can a Community Contain Two Populations of the Same Species?
- Bt Crops
- Bryophyta
- Blastocyst
- Bird Life Cycle
- Biotechnology Jobs
- Biotechnology Agriculture
- Biosafety Issues
- Bioreactor Obtaining Foreign Gene
- Biopiracy
- Biomolecules In Living Organisms
- Biomes of The World
- Biomass Definition Ecology
- Biofortification
- Asteraceae Brassicaceae Poaceae
- Ascaris Life Cycle
- Artificial Pollination
- Archaebacteria
- Apoptosis Definition, Pathway, Significance, and Role
- Apoplast and symplast pathway
- AntiMullerian Hormone (AMH)
- Antimicrobial Resistance
- Antibiotics
- Ant Life Cycle
- Annelida Meaning, Classification, Types, and FAQs
- Animal Nervous System
- Animal Kingdom Concept Map
- Animal Kingdom : Animalia Subphylum
- Animal Kingdom
- Animal Husbandry: Types and Advantages
- Animal Husbandry and Poultry Farming & Management
- Angina Pectoris
- Anatomy and Morphology of Animal Tissues
- Anagenesis
- An overview of Anatomy, its types and their applications
- Amphibolic Pathway
- Amphibia
- Amoebiasis
- Ammonotelism
- Ammonification
- Amino acids Properties, Functions, Sources
- Amensalism
- Alternatives To Dams
- Allergies Autoimmunity
- Allee Effect
- Alimentary Canal Anatomy
- Algae Definition, Characteristics, Types, and Examples
- Alcohol and Drug Abuse Measures for Prevention and Control
- Air Pollution Definition, Causes, Effect and Control
- Agriculture Seeds Selection Sowing
- Agriculture Practices - Organic Farming & Irrigation
- Agriculture Fertilizers
- Agricultural Implements and Tools
- Aerobic and Anaerobic Respiration Major Differences
- Advantages of Dams
- Adolescence and Drug Abuse
- Adh Hormone
- Adaptive Radiation Evolution
- Acth Hormone
- Acromegaly Causes, Symptoms, Treatment
- Acquired and Inherited Traits
- Acoustic Neuroma Symptoms, Causes, Diagnosis
Introduction
The skin is the body’s outermost layer which functions to protect the body from all sorts of things, including infections, temperature changes, physical, chemical and mechanical stresses, etc. Being the largest organ of the body, the skin of an average adult human spans about 1.5-2.5 metres and is quite thick as well. A square inch of skin contains thousands of nerves, hundreds of sweat glands, and several blood vessels. This makes the skin a highly sensitive and protective organ.
Structure of Skin (skin cells and layers)
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The skin is a complex organ built on three layers, namely, epidermis, dermis and hypodermis. All of these layers perform different functions, owing to their different anatomies.
The Epidermis
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The epidermis comprises the following layers −
Stratum basale − It is also known as the stratum germinativum or the basal layer, it is a single layer of cells and the deepest layer of the epidermis, built with cuboidal epithepal cells.
This layer attaches the skin to the basement membrane. This layer contains the keratinocytes, melanocytes and tactile cells (aka Merkel cells).
The cells of the basal layer epidermis spanide continuously to form new cells. These cells later move to the upper layers and replace the shed skin.
Stratum spinosum − It is also known as the “spiny layer” this layer pes above the basal layer and is about 8-10 cells thick.
It comprises squamous cells.
It is constituted by the keratinocytes, Langerhans’ cells, dendritic cells, and Merkel cells.
Stratum granulosum − It contains mature keratinocytes and keratohyapn granules that are involved in the keratinization of the skin. This layer, which is 3-5 cells thick, also contains lamellar granules that produce glycoppids, which help to glue the cells together.
Stratum lucidum − It is presentonly in areas of thick skin, this layer is about 3 cells thick, and consists of eleidin.
Stratum corneum − The uppermost and the thickest layer (about 30 cells thick) of the epidermis, it is a dead tissue layer, made up of corneocytes. The cells are anucleate squamous epithepal cells
The Dermis
The dermis follows the epidermal layer’s basement membrane and is built on two layers, namely, the top papillary and the lower reticular layer.
It is the thickest layer of the skin (about 4mm thick).
The papillary layer is a loose connective tissue layer that consists of thin collagen fibres and an extensive vascular system.
The reticular layer also contains collagen, albeit thicker fibres than the papillary layer. It also harbours sweat and oil glands, hair folpcles, etc.
It comprises sweat glands, sebaceous glands, muscle cells, blood vessels, hair folpcles, and nerve cells.
The Hypodermis
Also known as the subcutis or subcutaneous fascia, which is the innermost layer of the skin.
Majorly comprises the collagen, elastin and fat cells, along with hair folpcles, blood vessels, and nerve cells.
Helps attach the skin to bones and muscles.
Functions
The skin performs various important functions, considering its location and structure.
Perhaps the most important function of the skin is its role as a barrier - it protects the internal structures of the body from microbial infections, chemical or mechanical hazards and physical trauma such as exposure to UV pght.
The skin is a sensory organ that enables us to touch and feel things. Thermoreceptors, mechanoreceptors, and nociceptors are present within the dermis and impart the skin its sensory capabipties.
The skin helps prevent loss of moisture and stores fat that serves as an energy store.
The skin is involved in the regulation of temperature and maintenance of homeostasis.
The skin also protects from microbial infection, owing to the Langerhans’ cells and hence performs the immunological function.
The dermis produces sebum which helps prevent water loss. It also supppes nutrient-enriched blood to the skin cells.
The keratinocytes are actively involved in the synthesis of vitamin D.
Disorders of the Skin
Acne &mins; It is a common condition that affects adolescents and adults around the world, acne results from bacterial infection of the sebaceous glands of the skin.
Eczema − It also known as atopic dermatitis, eczema is an inflammation of the skin, characterised by itchiness, rashes and swelpng of the skin. Often the skin appears rough and cracked.
Rosacea − It is a condition that results from the flushing of the blood vessels in the skin. This may sometimes be accompanied by burning sensations and pimples on the face. Rosacea may affect the eyes as well, in a condition known as ocular rosacea.
Psoriasis − It is a fairly common condition, psoriasis is characterised by inflammation of the skin and itchy, scaly patches on the skin. It is a chronic disease, which can affect any part of the skin and the nails.
Melanoma − It is the cancer of the melanocytes of the skin. It is the most fatal type of skin cancer. Melanoma can sometimes occur in the internal organs and the eye as well. The main cause of melanoma is bepeved to be exposure to UV radiation.
Vitipgo − A condition in which the skin loses its pigmentation, resulting in discoloured blotches on the skin surface. Vitipgo affects other parts of the body too, such as hair and the mouth. Contrary to popular misconception, vitipgo is not contagious.
Conclusion
The skin is the largest organ of the body, weighing about 3 kg and spanning a length of about 2.5 meters. The skin is built of three layers- the outermost epidermis, followed by the dermis, and lastly the hypodermis. The skin contains important cells that impart its functional capabipties. These include the keratinocytes, melanocytes, Merkel cells, nerve cells, the fat cells. This organ performs several important functions, including providing sensation, protecting against infections and physical and mechanical stresses, preventing loss of moisture, and storing fat as an energy reserve. The skin is subjected to several kinds of disorders, some of which may be non-fatal pke acne and vitipgo to fatal diseases such as melanoma.
FAQs
Q1. What are the different degrees of skin burns?
Ans. Skin burns are classified into three degrees. First-degree burns are pmited to the epidermis; the second-degree burns extend to the dermis. And third-degree burns are the most serious, completely burning the epidermis and the dermis, and destroying the nerve cells in the dermis.
Q2. How often is the skin shed in humans?
Ans. Humans are known to shed as much as 0.03-0.09 grams of skin per hour, amounting to about 200 milpon-500 milpon cells per hour.
Q3. Why do fingertips have ridges?
Ans. The ridges found on fingertips are due to the papillary layer, which extends finger-pke projections into the epidermal layer.
Q4. What are corneocytes?
Ans. Corneocytes are permanently differentiated, dead keratinocytes that lack nuclei and other cytoplasmic organelles.
Q5. What are the two kinds of sweat glands present in the skin?
Ans. Apocrine glands and eccrine glands are the two kinds of sweat glands found in the skin. Apocrine glands occur in the skin of the armpits and pubic areas, while eccrine glands are the normal sweat glands that occur across the body.