The document discusses the structure and functions of the skin, with a focus on the dermis layer. The dermis consists of two layers - the papillary and reticular layers. The papillary layer contains projections called papillae that contain blood vessels and nerve endings. The reticular layer contains collagen and elastin fibers that give the skin flexibility and strength, and houses structures like hair follicles, sweat and sebaceous glands. The dermis regulates temperature, protects the body, and stores water. Below the dermis lies the subcutaneous layer, made of fat and connective tissue that provides insulation and cushioning.
The branch of science concerned with the bodily structure of humans, animals, and other living organisms, especially as revealed by dissection and the separation of parts.
Integumentary system
-The organs of the integumentary system include the skin and its accessory structures including hair, nails, and glands, as well as blood vessels, muscles and nerves.
-Dermatology is the medical specialty for the diagnosis and treatment of disorders of the integumentary system.
Structure Of The Skin
The skin (cutaneous membrane) covers the body and is the largest organ of the body by surface area and weight.
Its area is about 2 square meters (22 square feet) and weighs 4.5-5kg (10-11 lb), about 7% of body weight.
It is 0.5 – 4 mm thick, thinnest on the eyelids, thickest on the heels, the average thickness is 1 – 2 mm.
It consists of two major layers:
Outer, thinner layer called the epidermis, consists of epithelial tissue. Inner, thicker layer called the dermis.
Beneath the dermis is a subcutaneous layer (also called hypodermis) which attaches the skin to the underlying tissues and organs.
1. EPIDERMIS
-Covers, protects and waterproofs.
Contains five main layers:
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum lucidum
- Stratum corneum
The epidermis has a number of important characteristics:
The epidermis is composed of keratinized stratified squamous epithelium.
-It contains four major types of cells:
Keratinocytes (90% of the cells): It produce keratin which is a tough fibrous protein that provides protection.
-Melanocytes: which produce the pigment melanin that protects against damage by ultraviolet radiation.
-Langerhans cells: involved in immune responses, arise from red bone marrow.
-Merkel cells: which function in the sensation of touch along with the adjacent tactile discs.
2. DERMIS
-It is a deeper layer of skin, composed of connective tissue containing collagen and elastic fibers.
-It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands.
-The epidermis is avascular and cells of this layer get their oxygen and nutrients from capillaries in the dermis.
-The dermis can be divided into papillary layer and reticular layer.
Hypodermis :
- The hypodermis (also called the subcutaneous layer) is a layer directly below the dermis and serves to connect the skin to the underlying fascia (fibrous tissue) of the bones and muscles.
--Two types of glands are present in the skin over most of the body
These are sweat glands and sebaceous glands.
--Function Of Skin
Protection:
Sensation:
Heat regulation:
Storage and synthesis:
Synthesis of vitamin D:
Excretion and homeostasis:
Secretion:
Absorption:
Water resistance:
Colour :
Healing of wounds:
Aids in the diagnosis:
The integumentary system is the physical system that forms the barrier between the external environment and the internal systems of the body. In humans, this system consists of skin, hair, nails, and related glands.
Altogether, the integumentary system forms the largest organ in the body. The main function of this system is to protect bones, organs, and other internal structures from harm. In addition, the integumentary system performs important immune functions, cell fluid maintenance, synthesis of Vitamin D, body temperature regulation, and detection of stimuli.
Students, digital devices and success - Andreas Schleicher - 27 May 2024..pptxEduSkills OECD
Andreas Schleicher presents at the OECD webinar ‘Digital devices in schools: detrimental distraction or secret to success?’ on 27 May 2024. The presentation was based on findings from PISA 2022 results and the webinar helped launch the PISA in Focus ‘Managing screen time: How to protect and equip students against distraction’ https://www.oecd-ilibrary.org/education/managing-screen-time_7c225af4-en and the OECD Education Policy Perspective ‘Students, digital devices and success’ can be found here - https://oe.cd/il/5yV
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
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2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
1. Unit 321: Apply microdermabrasion
The skin
The dermis and appendages
The subcutaneous layer
Functions of the skin
2. The dermis
Where is the dermis located?
It is located beneath the epidermis and above the
subcutaneous layer
It is the largest layer, and varies from 1.5 mm to 4 mm in
thickness
What are the functions of the dermis?
The main functions of the dermis are to regulate temperature, and to
protect, support and nourish the skin.
Much of the bodys water supply is stored within the dermis
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3. What is the structure of the dermis?
It is composed of two layers of areolar connective tissue and contains:
Sensory receptors/nerve endings
Sweat glands:
- Eccrine: found all over the body
- Apocrine: found in the groin and axillae
Sebaceous glands
Hair follicles/hair shaft/hair bulb
Arrector pili muscle
Blood and lymphatic vessels
Handout 17
5. The dermis consists of two layers:
1. 1. The papillary layer
2. 2. The reticular layer
The papillary layer
The upper, papillary layer, contains small cone–
shaped projections called papillae, which contain
looped blood capillaries carrying blood and lymph.
There are also tactile corpuscles and nerve
endings.
The papillary layer supplies nutrients to the
epidermis and regulates temperature.
5
6. The reticular layer
The lower, reticular layer, is thicker and contains fibroblast cells, which
are responsible for the formation of collagen fibres and elastin.
Yellow elastin fibres give the skin its flexibility and elasticity.
White collagen fibres plump the skin and give strength and firmness.
Specialised cells are also found in the reticular layer:
Macrophages destroy bacteria and tissue debris
Mast cells secrete histamine, which causes vasodilation, and
heparin, which stops blood clotting (anti-coagulant).
The reticular layer supports other components of the skin, such as hair
follicles, sweat glands, and sebaceous glands.
Handout 17
7. Nerve endings of the dermis
Meissner's corpuscles are for light touch and lie immediately
beneath the basement membrane of the epidermis
Pacinian corpuscles are for deep pressure, and lie deeper in the
dermis
Free nerve endings are for pain and temperature, and these
endings lie at the superficial aspect of the dermis
7
8. Subcutaneous layer (hypodermis)
The deepest layer lying directly above the muscles of the body and
below the dermis of the skin.
It is made up of two main types of connective tissue:
Adipose tissue forms a network of fat cells providing the body
with insulation, as well as acting as a source of energy
Areolar tissue gives strength to protect underlying structures.
Elasticity to cope with increases in size, and support for blood
vessels and nerve endings found in this layer
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9. Learner activity
Label the cross section diagram of the skin
9
Arrector Pili
muscle
Sensory Nerve
Sweat
Duct
Endings
Hair shaft
Epidermis
Subcutaneous
Layer
Adipose
Tissue
Dermis
Sweat
gland
Blood & Lymph
Vessels
Nerve
Sebaceous
gland
Hair Follicle
Muscle
10. Functions of the skin
• SECRETION
• HEAT REGULATION
• ABSORPTION
• PROTECTION
• EXCRETION
• NUTRITION – Production of Vitamin D
• SENSATION
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