The skin is the largest organ composed of three layers: the epidermis, dermis, and subcutis. The epidermis is stratified squamous epithelium consisting of keratinocytes, melanocytes, Langerhans cells, and Merkel cells. It has several layers including the stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum. Keratinocytes in the basal layer contain organelles and produce keratin intermediate filaments called tonofilaments. As keratinocytes differentiate and move upwards, they lose organelles and accumulate keratohyline granules containing proteins like filaggrin. The fully differentiated ker
This is a powerpoint presentation on the epidermal keratinization and its associated disorders, presented by Dr. Jerriton, Dermatology resident of SVMCH, Pondicherry.
Glands in skin | Skin Specialist in Zirakpur | Dr. Isha V.Mittal | +91-72-93-...Dr. Isha V.Mittal
Gland in skin are accessory structure of skin. It originate in dermis layer of skin. Protrude through the epidermis layer of the skin resulting in sweat and sebum emerging from skin surface.
Type- exocrine gland ....
Dr. Isha V. Mittal is one of the top skin specialist Doctor / dermatologist in zirakpur, Panchkula and Dhakoli region. She is a Gold Medalist in Dermatology/ Skin Speciality and is a leading Dermatologist , Cosmetologist , Laser specialist and hair transplant expert.
This is a powerpoint presentation on the epidermal keratinization and its associated disorders, presented by Dr. Jerriton, Dermatology resident of SVMCH, Pondicherry.
Glands in skin | Skin Specialist in Zirakpur | Dr. Isha V.Mittal | +91-72-93-...Dr. Isha V.Mittal
Gland in skin are accessory structure of skin. It originate in dermis layer of skin. Protrude through the epidermis layer of the skin resulting in sweat and sebum emerging from skin surface.
Type- exocrine gland ....
Dr. Isha V. Mittal is one of the top skin specialist Doctor / dermatologist in zirakpur, Panchkula and Dhakoli region. She is a Gold Medalist in Dermatology/ Skin Speciality and is a leading Dermatologist , Cosmetologist , Laser specialist and hair transplant expert.
Dermoscopy or epiluminescence microscopy
A simple, noninvasive method to examine the subsurface features of the skin.
Structures seen
Epidermis
Dermoepidermal junction
Superficial dermis
3 types of dermoscope
1.Nonpolarized devices
2.Polarized devices
3.Hybrid devices
Dermoscopy is used in:
1.Evaluating pigmented skin lesions
2.Evaluating nonpigment skin lesions
3.Entomodermoscopy
4.Trichoscopy
5.Onychoscopy
different dermoscopic patterns are used to diagnose the dermatological diseases are
1. melanocytic patterns:
Pigmentary patterns: typical pigment pattern, atypical pigment patter, pseudonetwork
dots and globules
Blue white veil
star brust pattern
2, Non melanocytic pattern:
milia like cyst
comedo like opening
3. vascular patterns:
lacunae
arborizing vessels
comma like vessels
corkscrew vessel
red dots
glomerular vessels
linear vessels
etc
Dermoscopy or epiluminescence microscopy
A simple, noninvasive method to examine the subsurface features of the skin.
Structures seen
Epidermis
Dermoepidermal junction
Superficial dermis
3 types of dermoscope
1.Nonpolarized devices
2.Polarized devices
3.Hybrid devices
Dermoscopy is used in:
1.Evaluating pigmented skin lesions
2.Evaluating nonpigment skin lesions
3.Entomodermoscopy
4.Trichoscopy
5.Onychoscopy
different dermoscopic patterns are used to diagnose the dermatological diseases are
1. melanocytic patterns:
Pigmentary patterns: typical pigment pattern, atypical pigment patter, pseudonetwork
dots and globules
Blue white veil
star brust pattern
2, Non melanocytic pattern:
milia like cyst
comedo like opening
3. vascular patterns:
lacunae
arborizing vessels
comma like vessels
corkscrew vessel
red dots
glomerular vessels
linear vessels
etc
The skin is the largest organ of the body, accounting for about 15% of the total body weight in adult humans. It exerts multiple vital protective functions against environmental aggressions, rendered possible thanks to an elaborate structure, associating various tissues of ectodermal and mesodermal origin, arranged in three layers, including (from top to bottom) the epidermis (and its appendages), the dermis and the hypodermis.
Structure of Skin | Layers of Skin |Function of Skin
https://www.youtube.com/watch?v=IytTVigBQrI&t=172s
Dr. Nagendra Kr Meena
PG Resident
Hindu Rao Hospital,New Delhi
Keratinized tissue, also known as keratinized mucosa, refers to the band of tissue surrounding your teeth at the point where they meet the gums. The word "keratinized" is used to describe cells that produce large amounts of a protein called keratin, making them strong and better at forming barriers. Local irritation interferes with keratinization, and healthy gingiva is more keratinized than diseased, irritated gingiva. Nonepithelial cells are also present in the oral gingival epithelium. These include melanocytes, and Langerhans cells in the stratum spinosum. In the oral cavity, keratinized mucosa is found in the gingiva and palate mucosa, whereas the non-keratinized mucosa is found in the buccal mucosa.
Anatomy and Histology of Skin(Dermis & Epidermis).pptxMathew Joseph
Deep to the epidermis lies the dermis. It is a thick layer of connective tissue consisting of collagen and elastin which allows for skin's strength and flexibility, respectively. The dermis also contains nerve endings, blood vessels, and adnexal structures such as hair shafts, sweat glands, and sebaceous glands.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
2. SKIN
• Skin is the largest organ of the body accounting for 16 - 20% of total
body weight , with a surface area of 1.8 – 2 m2 .
• Two main kinds of skin - Glabrous Skin ( non-hairy skin).
- Non Glabrous Skin.(hairy skin).
• Skin is divided into 3 layers
a) Epidermis- outermost layer , serves as barrier between exterior &
body’s interior environment and is responsible for cornification.
b) Dermis- a deeper layer ,provides structural support to skin.
c) Subcutis- containing fat and connective tissue.
2
6. STRATUM BASALE
• Basal cell layer, consisting of 1-2 layers of columnar/cuboidal
keratinocytes ,with large oval nuclei & basophilic cytoplasm.
• The cells in basal layer(keratinocytes) are interconnected by
intercellular bridges Desmosomes.
• Basal keratinocytes are attached to subepidermal basement membrane
by modified desmosome-Hemidesmosome.
• Basal keratinocytes are interspersed with melanin producing cells,
melanocytes at regular interval.
• Stratum basale is the primary site for MITOTIC ACTIVITY
6
8. STRATUM SPINOSUM
• 8-10 layers of cells.
• Keratinocytes in this layer are Polyhedral in shape, with round
nucleus, basophilic cytoplasm.
• Spinous processes (abundant desmosomes) hence the name.
• The cells in upper spinous layer are larger & become more flattened
and contain organelles “lamellar granules”
• The cells in spinous layer contain large and conspicuous bundle of
keratin filaments Tonofibrils, that insert into desmosome peripherally.
• Limited cell division.
8
10. STRATUM GRANULOSUM
• 2-5 Cell layer thick.
• Diamond shaped cells with intracellular basophilic keratohyline
granules, with deeply basophilic cytoplasm.
• Cytoplasm of the keratinocytes in this layer contain lamellated
granules known as odland bodies.
• Discharge their lipid components into intercellular space, functions as
barrier & intercellular cohesion within the stratum corneum
• Keratohyline granules forms 2 structures.
a)Inter fibrillary matrix or filagrin- that cements keratin filaments
together
b) marginal bond- provides strength and flexibility.
10
11. STRATUM LUCIDIUM
• Is a thin layer of translucent cells seen in thick epidermis of Palms &
Soles.
• This layer is present between stratum granulosum and corneum.
• Cells in this layer are still nucleated and referred as “transitional
cells”.
11
12. STRATUM CORNEUM
• Outermost layer of epidermis.
• Composed of 20-25 layers of cornified cells.
• Made up of terminally differentiated, dead keratinocytes known as
Corneocytes.
• These cells are flat, anuclear & devoid of cytoplasmic organells.
• Corneocytes contain soft keratin
• Cells are arranged together like “ bricks in a wall”
• Fluorescent staining shows cells arranged in orderly vertically stacks.
• The journey of cells from basal layer to surface is called Epidermal
turnover or transit time – 52 to 75 days.
12
14. EPIDERMOPOISES
• The epidermal thickness and the number and size of epidermal cells
remain constant, with the rate of cell production matching the rate of
cell loss.
• 3 populations of cells exist in the basal layer:
- Stem cells.
- Transient amplifying cells
- Post mitotic cells.
14
15. • Keratinocyte stem cells give rise to all the layers of the epidermis,
with the majority of these cells committed to terminal differentiation.
• Stem cells have a large capacity for proliferation.
• A transient amplifying cells can undergo a limited number (up to 5
to 6 times) of mitotic divisions.
15
16. CELL CYCLE
• M or Mitotic phase of division
• G1 post mitotic phase or
interphase
• S or phase of DNA synthesis
• G2 or Premitotic phase or short
resting
• G-o phase or quiescent phase
16
17. • The time taken by keratinocytes to pass from the basal layer to the
stratum corneum and the skin surface is called the epidermal turnover
time.
• It ranges from 52 to 75 days.
• The approximate transit time from the basal layer to stratum
corneum is 12 to 19 days.
• through the stratum corneum is 14 days.
17
18. Regulation of Epidermopoiesis
• A) Stimulatory signals:
1.Human epidermal growth factor (EGF) –
6 kDa polypeptide.
Stimulates cell proliferation and differentiation.
2 Transforming growth factor-α (TGF-α)-
A polypeptide synthesized by epidermal keratinocytes.
Stimulates growth of keratinocytes by an autocrine method .
after binding to human epidermal growth factor receptor (EGFr).
18
19. • 3 Amphiregulin-
Autocrine keratinocyte growth factor regulated by cellular
glycosaminoglycans and upregulated by EGF and TGF-α.
• 4. cytokines –
interleukin-1 & 6 can also stimulate the growth of keratinocytes.
others -PDGF, IL-1β and TNF .
19
20. • B) Inhibitory signals:
Epidermal growth is inhibited by a negative feedback mechanism.
- Transforming growth factor-B, inhibits the growth of keratinocytes.
- IFN-α and -γ have cytostatic effects on keratinocytes.
- TNF-α is cytostatic on keratinocytes
20
21. • C) Apoptosis: programmed cell death
A major cellular homeostatic mechanism in the skin.
Terminal differentiation of epidermal keratinocytes occurs by modified
apoptotic programs.
• D) Signal transduction pathways:
Growth factors.
Cyclic 3,5-adenosine monophosphate (cAMP).
Protein kinase C, inositol phosphate and protein tyrosine kinase
21
22. • E) Integrins:
play role in bidirectional communication that can result in a change
in gene expression, pH and calcium fluxes.
• F) Others:
low calcium level inhibits differentiation of keratinocytes but
stimulates their proliferation.
Vitamin A and retinoic acids are required for normal morphogenesis
and differentiation
22
23. TONOFILAMENTS
• Basal and lower portion of spinous zone of keratinocyte-
• contain abundant Rough Endoplasmic reticulum Ribosomes,
Golgi apparatus ,mitochondria.
• Synthesize tonofilaments- 7.0nm in diameter .
• Also known as Keratin intermediate filaments
• Later becomes keratinous protein.
• They are oriented along major axis of cells.
• aggregate into bundles to form fibrous protein termed as
Alpha keratin.
23
24. FUNCTIONS OF TONOFILAMENTS
1. Flexibility and elasticity to cornified layer.
2. Cytoskeleton of keratinocytes,
3. Modulate shape of keratinocytes.
4. Promotes centralisation of nucleus.
5. Implement cell-cell adhesion via desmosomes.
24
25. KERATINS
• Filamentous cytoskeleton of all mammalian cells including
epidermal keratinocytes.
Contains-
• Actin containing microfilaments 7nm in diameter.
• Tubulin containing microtubules 20-25 nm in diameter.
• Intermediate filament 7-10nm in diameter.
• More than 30 keratins have been noted.
Distinct and separate genes and mol. Wt-40 to 67 KDa
25
26. • Keratin genes -2 groups
Type I (basic)- 1 to 8
Type II (acidic)-9 to 19
• one basic and one acidic forms
heterodimers which wrap around
by hydrophobic interaction
26
27. KERATOHYALINE GRANULES
• Source of protein (Profillagrin → Fillagrin).
• Electron-dense bodies devoid of internal structure but are
biochemically complex.
• They appear first in upper part of spinous zone& become prominent in
granular zone.
• Disappear as they enter cornified layer.
• Contains cysteine-rich proteins whose disulphide bonds contribute to
chemical inertness & strength of cornifed layer
27
28. FILLAGRIN
• Also known as Filament aggregating protein.
• Histidine rich, cat-ionic protein.
• Functions as an “Interfilamentous glue” to aggregate & align keratin
filaments within cornified cells.
28
29. LAMELLAR GRANULES
• Also known as odland bodies.
• Measures about 300 nm in diameter.
• Contain free sterols, polar lipids and hydrolytic enzymes.
• Appears at the top of spinous zone, near Golgi apparatus of
keratinocytes & migrate into cytoplasm, fuses with plasma membrane.
• Contents are discharged into intercellular spaces.
• Once contents are discharged, they become organised into lamellae
and provide structural basis for the barrier of epidermal permeability.
29
31. CELLS OF EPIDERMIS
MELANOCYTES
Dendritic cells, synthesize & secrete melanin containing organelles-
melanosomes.
• Derived from precursors in the neural crest.
• Found during 8th week of fetal life.
light microscope:
-Clear cells in the basal row of epidermis.
H & E
-Small basophilic nucleus & dendritic cytoplasm.
Dendrites of melanocytes may be revealed when melanin is stained black
with silver salt
31
34. • FUNCTIONS
1. Absorbs UV light and protect the skin from solar UV damage.
2.Melanin functions as a scavenger of free oxygen radicals and thus
protects cells
3.Imparts various colours to hair.
34
35. Langerhans cells
• Described by Paul Langerhan.
• Derived from mesenchymal precursors in bone marrow.
• Dendritic cells situated in middle of the epidermis.
• They constitute 2% to 8% of total epidermal cell population.
• Enter the epidermis at about 12 weeks
35
37. • Conventional microscope:
clear cells, pale staining and have convoluted nuclei.
• Electron microscopy:
-They demonstrate a lobulated nucleus, clear cytoplasm, well defined
endoplasmic reticulum ,Golgi complexes and lysosomes.
-Langerhans cells have distinctive rod or racquet shaped
granules [BIRBECK Granules].
-They resemble Tennis racquet.
37
40. • FUNCTIONS:
1. Plays role in immune process like ACD, allograft rejection, immune
tolerance.
2. Defence against micro organisms.
3. Regulation of epidermal differentiation.
40
41. MERKEL CELLS
• In 1875,FRIEDRICH MERKEL identified at base of rete ridges cells
that were in contact with nerve fibrils and named them tastzellen or
touch cells.
• They originate in the epidermis itself, presumably from germinative
keratocytes.
• Appear in fetal skin by 16th week of gestation.
41
42. • They have pale staining cytoplasm
• Nucleus is lobulated & the margins
of cells project cytoplasmic spines
towards keratinocytes.
• They have characteristic spherical
granules which are membrane
limited with a dense central core.
• These cells are embedded in basal
layer & form desmosomal
connections with the surrounding
basal keratinocytes.
42
44. FUNCTIONS
• Slowly adapting type I mechanoreceptor Low threshold touch
receptors.
• most sensitive to vibrations at low frequencies, around 5 to 15 Hz.
44
46. DESMOSOMES
-The major adhesion complex in
epidermis.
- Anchors keratin intermediate
filaments to the cell membrane.
- Bridges adjacent keratinocytes.
- Ultrastructure: cell membrane of
two adjacent cells forms a
symmetrical junction with a central
intercellular space of 30 nm
containing a dense line.
46
47. • Components of desmosomes in epidermis:
a) Desmosome cadherin's.
b) armadillo family of nuclear & junctional proteins.
c) Plakins.
Cadherins -1. Desmoglins (Dsg 1-4)
2. Desmocollins (Dsc 1-3)
They are trans membranous calcium rich glycoprotein.
47
48. • The intercellular parts of glycoproteins are attached to keratin filament
network via desmoplakin, plakoglobin and other macro molecules.
• Desmosomal proteins acts as autoantigen in various immunobullous
blistering disorders.
48
52. • mutations have subsequently been reported in the CDH3 gene, which
encodes P-cadherin; these mutations result in autosomal recessive
hypotrichosis with juvenile macular dystrophy.
• P-cadherin mutations are also found in a different disorder,
ectodermal dysplasia–ectrodactyly–macular dystrophy (EEM)
syndrome.
52
53. GAP JUNCTION
• clusters of intercellular channels, known as connexons, that directly
form connections between the cytoplasm of adjacent keratinocytes
(and other cells).
• Connexons originate following assembly of six connexin subunits
within the Golgi network that are then transported to the plasma
membrane.
• The connexins are divided into three groups (α, β and γ).
• The formation and stability of gap junctions can be regulated by
protein kinase C,calcium concentration, calmodulin, adenosine 3′,5′-
cyclic monophosphate (cAMP) and local pH
53
55. • FUNCTION : permits sharing of low-molecular-mass metabolites
(<1000 Da) and ion exchange between neighbouring cells, thus allowing
intercellular coordination and uniformity to maintain tissue/organ
homeostasis in multicellular organisms.
.
• Gap junction communication is essential for cell
synchronization
differentiation.
growth and metabolic coordination of avascular organs, including
epidermis.
55
56. TIGHT JUNCTION
• Tight junctions are the major regulators of permeability in simple
epithelia, are also present in skin.
• They key role in skin barrier integrity and maintaining cell polarity.
• The principal structural proteins of tight junctions are the claudins,
transmembranous proteins - junctional adhesion molecules (JAMs)
and the occludin group of proteins.
• The main claudins in the epidermis are claudin 1 and 4.
• Transmembranous proteins do not bind to one another but the
claudins and occludins can bind to the intracellular zonula occudens
proteins ZO-1, ZO-2, ZO-3.
56
57. • These proteins can also interact with actin thus providing a direct link
with the cytoskeleton.
57