comparative anatomy integumentary system
TRANSCRIPT
Comparative anatomy( Chordates)
Integumentary system 1-Human 2-Ruminant 3-Avian 4-Fish5-Horse
Dr.Omer
Comparative anatomy (Chordates)
Human integumentary systemThe Integument
Is the largest system of the body
The integument is made up of two parts:
1. Cutaneous membrane
a. Epidermis– Superficial epithelium
b. Dermis – underlying CT with blood supply
2. Accessory structures
a. Hair
b. Nails
c. Exocrine Glands
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Functions of Skin1-Protection2-Prevention of water loss3-Temperature regulation4-Metabolic regulation5-Immune defense6-Sensory reception7-Excretion
STRUCTURE OF SKINThe layers of the skin:-
The Epidermis Epithelial tissue
Dermis Dense connective tissue proper – irregular
Hypodermis Subcutaneous tissue- loose connective tissue proper and
adipose tissue
STRUCTURE OF SKIN
Epidermis
Dermis
Hypodermis or
subcutaneous layer
Skin Structure: Epidermis
The Epidermis Is a vascular stratified squamous epithelium
Nutrients and oxygen diffuse from capillaries in the dermis
There are four or five layers of the epidermis, depending upon the
degree of friction and mechanical pressure applied to the skin
Four Principle Cells of the Epidermis • Keratinocytes Produce the protein keratin, which helps protect the skin and
underlying tissue from heat, microbes, and chemicals, and lamellar granules, which release a waterproof sealant
• Melanocytes Produce the pigment melanin which contributes to skin color
and absorbs damaging ultraviolet (UV) light• Langerhans cells – Derived from bone marrow– Participate in immune response
• Merkel cells – contact a sensory structure called a tactile (Merkel) disc and
function in the sensation of touch
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Skin Structure: Epidermis
Thin Skin
Covers most of the body
Has four layers of keratinocytes
Thick Skin
Covers the palms of the hands and soles of the feet
Has five layers of keratinocytes
Skin Structure: Epidermis
Structures of the Epidermis The five strata of keratinocytes in thick skin From basal lamina to free surface
1. Stratum basale2. Stratum spinosum3. Stratum granulosum4. Stratum lucidum5. Stratum corneum
Epidermal LayersStratum corneum - nuclei and organelles are destroyed by lysosomes
and the cells fill with keratin
Stratum lucidum - only found in the palms and soles of feet 3-5 layers of clear, flat, dead keratinocytes -Dense packed intermediate filaments thick plasma membranes
Stratum granulosum - cells start to become keritanized --Secretes lipid-rich secretion that acts as a water sealant
Stratum spinosum - 8-10 layers of keratinocytes skin both strength and flexibility
Stratum basale - Also referred to as stratum germinatum -where new cells are formed -
Thick skin LM 210
Surface
Stratumcorneum
Stratumlucidum
Stratumgranulosum
Stratumspinosum
Stratum basale
Basementmembrane
DermisPapillary layer of dermis
EPIDERMIS
Sources of Skin Color
• Most significant factor is melanin • Black or brown color due to eumelanin produced by melanocytes
and transferred to keratinocytes in follicle.
• Red color produced by pigment called pheomelanin
• Blonde color produced by intermediate levels of pheomelanin and low levels of eumelanin
• Other factors include hemoglobin (red to pink) and carotene (yellow)
• Different races have the same of melanocytes, but amount of melanin produced differs
• Melanin accumulates in keratinocytes
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Skin Structure: Dermis
The Dermis Located between epidermis and
subcutaneous layer Anchors epidermal accessory
structures (hair follicles, sweat glands)
Two components1. Outer papillary layer 2. Deep reticular layer
Derm
is
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Skin Structure: Dermis The Papillary Layer
Consists of areolar tissueContains smaller capillaries, lymphatics, and sensory neuronsHas dermal papillae projecting between epidermal ridges
The Reticular LayerConsists of dense irregular connective tissueContains larger blood vessels, lymphatic vessels, and nerve fibersContains collagen and elastic fibersContains connective tissue proper
Hair
Papillarylayer
Reticularlayer
Cutaneousplexus
Papillaryplexus
Epidermalridges
Dermalpapillae
Capillary loopof papillary
plexus
DERMIS
Skin Structure: HypodermisThe Hypodermis (Subcutaneous Layer)
Lies below the integumentStabilizes the skinAllows separate movement Made of elastic areolar and adipose tissuesConnected to the reticular layer of integument by
connective tissue fibers
Skin Structure: Hypodermis
Hypodermis
Functions – Hair & Nails
• Functions of Hair – Hair on the head protects scalp from injury and sunlight– Eyelashes and eyebrows protect eyes– Nostril and ear hairs protect from foreign particles– Help in sensing light touch due to the touch receptors associated with the
hair root plexuses.• Functions of the Nails
– Grasping objects– Manipulating objects– Protects ends of digits from trauma– Scratching
Hair Anatomy Shaft: portion of hair that projects from skin surfaceRoot: portion of hair deep to the shaft penetrating the dermis
•Has 3 layers: medulla : Core, dead cells contain soft keratin and air to provide flexible
Cortex: Middle layer, dead cells contain hard keratin to provide stiffness
Cuticle : Outermost, overlapping dead keratinized cells form shiny surface
Base of the hair follicle•Bulb: houses the papilla which contains the blood vessels that nourishes the
growing hair follicle.•Matrix: responsible for hair growth and produces new hair Arrector pili: smooth muscle •Extends from the dermis to the side of hair follicle.Hair root plexus - dendrites of neurons which are sensitive to touch
Anatomy of the hair
Nails • Made of tightly packed, hard, keratinized epidermal cells• Consist of:
Nail body: portion of the nail that is visible- Free edge: part that exten
Nail root: the distal end of the digit portion buried in a fold of skinLunula: means little moon - Crescent shaped area of the nailHyponychium: secures the nail to the fingertip -Thickened stratum corneumEponychium or cuticle: narrow band of epidermis-Growth of nails is in the nail matrix.
Aging Skin •In our 20s, the effects of aging begin to be visible in the skin. •Stem cell activity declines: skin thin, repair difficult•Epidermal dendritic cells decrease: reduced immune response•Vitamin D3 production declines: calcium absorption declines and brittle bones•Glandular activity declines: skin dries, body can overheat•Blood supply to dermis declines: tend to feel cold•Hair follicles die or produce thinner hair•Dermis thins and becomes less elastic – wrinkles
Fish integumentary system Fish like other vertebrates have Three layers of skin1-Outer epidermis 2- Inner dermis.3-Hypodermis • Multicellular glands also occur in some fishes, e.g. electric organs of eels and electric rays, • luminescent glands in deep sea fishes. •Mucous glands are all unicellular. • Important modifications of skin are dermal scales that cover the body for protection.
Types of unicellular glands :
-Club cells - elongated, binucleated cells - secretes mucus
• Granular cells - secretes mucus in skin of lampreys & other fishes
• Goblet cells - narrowed base and wide apical end secretes mucus in chodrichthyes and osteichthyes
• Sacciform cells- secrete large, membrane-bound toxic products to repel enemies
Epidermis
• Generally the epiderm of vertebrates consists of
five layers• stratum corneum In fish keratin is replaced with
mucous ( glycoprotein = mucin)
Dermis
• Thicker than epidermis• Contains blood vessels, nerves, sense organs, connective tissue and
pigment cells Dermis consists of two layers 1- Upper looser layer - Stratum spongioso in this layer Scales are
imbeded with their bases2- Lower tighter layer Stratum compactum contains lipid cells and ‐
connective tissue• Fish dermis connects directly onto myosepta of the muscles and to
the caudal fin.
Colors of the skin
• Melanophores – Black• Erythrophores – Red• Xanthaphores – Yellow• Cyanophores – blue• Leucophores – light scattering• Iridiophores – light reflecting silver‐
Avian intgumentary system• Birds possess thin skin that is loosely attached to body to
allow free movement of wings during flight. • Feathers are characteristic modifications of bird skin, which
not only cover the entire body but also help in flight.
The skin is composed of three layers :1-The Epidermis2-The dermis or corium 3-The hypodermis
.
The fowl’s skin is divided into a number of separate areas
These areas are:• The feathered skin.• The scale covered skin on the lower legs and feet.• The hard, horny areas of the beak and toenails.• The pad of the foot (or plantar).• The skin of the comb and wattles • The areas where they do grow are called pterylae• The areas where they do not grow are called apteria.
Glands
• Birds do not possess sweat glands.• The uropygial gland secretes an oil (preen oil) bird will
typically transfer preen oil to its body during preening by rubbing its beak
• Feathers are an extremely efficient insulator.• Heat is lost from the respiratory tract and by radiation from
featherless surfaces. • The feet and legs of starlings loose a substantial amount of
the body’s heat.• Heat loss at night is also a probable reason for sleeping with
their head (really their beak) under their wing, and one leg raised.
cattle and Horse
• The skin of animals consists of three layers, • The epidermis • The dermis. • Hypodermis• Epidermis of thick keratinized stratified squamous epithelium• Special keratinized features include hair, nails, claws, horns,
hooves.• Numerous multicellular glands• Chromophores present
Hoofs and Horns
• True horns are made of keratin and are found in sheep, goats and cattle.
• They consist of a core of bone arising in the dermis of the skin and are fused with the skull.
• Hoofs are found in sheep, cows, horses .• These are animals that have lost toes in the process of
evolution and walk on the “nails” of the remaining toes.
• The hoof is a cylinder of horny ,material that surrounds and protects the tip of the toe
1. Heel bulb2. Periople at the heel3. Heel4. Quarter5. Toe6. Periople7. Coronary band