Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Human Anatomy ppt lectures Topic 104 Skin & Fascia Notes. - anatomy ppt free download human anatomy ppt lectures, medicine notes ppt, anatomy handwritten notes pdf, mbbs 1st year anatomy notes pdf download, best anatomy notes pdf, human anatomy notes pdf, anatomy easy notes pdf, anatomy notes online, anatomy short notes, Anatomy ppt, Powerpoint Presentations and lecture notes.
OBJECTIVES
? Describe layers of skin.
? Enlist the functions of skin.
? Define appendages of skin.
? Define Fascia.
? Differentiate between Superficial and Deep
Fascia.
? Applied Anatomy
Tissues of the body
The tissue: is a group of cells which
perform a specific function
There are four basic tissues:
1.Epithelium
2.Connective tissue
3.Muscular tissue
4.Nervous tissue
Skin
IMPORTANCE OF SKIN
qNormalskinisaverycomplexorgan
Theskinisoneofthelargestorgansofthe
body:76oosqcm
FUNCTIONS OF THE SKIN
1-Protection
continuousandcoversthebodyaswellas
protectsthedeeptissues
abrasion, invasion, water loss, UV protection
2-Vitamin D synthesis
epidermal keratinocytes when exposed to UV
light
helps maintain health of skeleton by increasing
absorption of Ca2+
3-Sensation
receptors for heat, cold, touch,
pressure, vibration and pain
4- Thermoregulation
thermo receptors and sweat glands
hypothalamus controls cutaneous
arteries and sweat glands to retain or
dissipate heat
5- Excretion
through the secretion of sweat.
6- Psychological and social functions
appearance and social acceptance
facial expression and nonverbal
communication
q Keratinized stratified squamous
epithelium devoid of blood vessels
Connective tissue
containing (bl. v.
lymph v., sensory
nerve endings,
smooth m, hair
follicles, sweat and
sebaceous glands)
In its deep part the
collagen bundles
are arranged in
parallel rows
? Keratinocytes (90%)- waterproofs & protects skin,
nails, hair, stratum corneum
? Melanocytes (8%)- produce melanin
? Merkel Cells- slow mechanoreceptors
? Langerhans' Cells- immunological defense
?
Stratum Corneum
?
Stratum Lucidum
?
Stratum Granulosum
?
Stratum Spinosum
?
Stratum Basale-
(Germinativum)
Epidermis
Thickness is increased:
The epidermis is generally thin except in :
? The palms of the hand.
? The soles of the feet.
Why?
To protect these parts and withstand friction,
wear and tear that occurs in these regions.
Dermis
papillary dermis
reticular dermis
a. Cellular
Fibroblasts (synthesize collagen, elastin, and reticulin),
histiocytes, endothelial cells, perivascular macrophages and
dendritic cells, mast cells, smooth muscle, and cells of peripheral
nerves
b. Fibrous
Collagen & reticulin - provide tensile strength
Elastic fibers- provide for restoration of shape after a deformation
c. Ground substance
glycosaminoglycans: hyaluronic acid, chondroitin sulfate, and
dermatan sulfate.
Hypodermis
This layer contains adipose tissue and serves to attach the dermis to its underlying tissues.
Lines of cleavage
? The collagen fibers, arranged in parallel rows,
called:
Lines of cleavage (langer's lines):
? The direction of the rows of collagen fibers in the
dermis:
It runs
?Longitudinally in the limbs.
?Circumferentially in the neck and the trunk.
Lines of cleavage
These lines are important
to determine the direction
for an incision (cut) during
a surgery to avoid obvious
scars.
? A surgical incision along or between these lines
causes the minimum disruption of collagen so that the
wound heals with a small scar.
? Conversely, an incision made across the rows of
collagen makes a disruption resulting in the massive
production of fresh collagen and the formation of a
broad scar.
Skin creases
Folded skin over the
joints.
Skin is thin and is
firmly adherent to
underlying structures.
Some variations in human skin color
Sub-Saharan African, Indian, Southern European, Northwest European
Skin Color
? Due to Melanin, a pigment in the
epidermis and Carotene,
? Melanin is synthesized in cells called
Melanocytes (found in basal layer).
? Number of Melanocytes is essentially the
same in all races.
? The differences in skin color is due to the
amount of pigment the melanocytes
produce.
? Cyanotic
? Jaundice
? Erythema
? Pallor
? Pigmentation levels usually increase with age.
- exception: premature graying
? Normal pigmentation may be altered by
genetic defects or by acquired diseases.
-Hyperpigmentation- age spots
-Hypopigmentation- vitiligo,
albinism
External agents can also alter skin color.
? lightening agents
? carotene
? dyes
? Some internal compounds--such as the byproducts
of hemoglobin metabolism--may color the skin.
SKIN IN ANAEMIA
CHICKEN POX
SKIN ERUPTIONS
ACNE
Skin infections
Pathogenic organisms can
enter to the tissue through :
? Nail Folds
? Hair Follicles
? Sebaceous Glands
Staphylococcus:
A type of bacteria that causes
skin infections.
Ring worm
Malignant melanoma
?
2% of all cancers
Risks:
1.
Skin type
2. Sun exposure
3.
Family history
4. Age
Normal mole Melanoma
5. Immunological status
?
A= asymmetry
?
B= border
?
C= color
?
D= diameter
Skin Cancers
The appendages of the skin
? Nails
? Hairs
? Sebaceous glands
? Sweat glands
Nails
A nail is a flat horny plate on
the dorsal surface of tips of
the fingers and toes
It has:
Root: proximal edge (part
embedded in skin)
body: exposed part & has a
free distal edge
Nail fold: folds of skin
? Nail bed is very vascular causing
surround and overlap the
pink color of the nail
? The germinative zone lies beneath
nail
the root& is responsible for growth
of nail
Hair
Cover whole surface of
the body except some
areas as lips, palms, soles,
some genital areas
Hair
Hair follicles: invaginations of the
epidermis into the dermis, the
hair grows out of these follicles
(hair shaft).
Hair bulb: the expanded extremity
of the follicle, concaved at the
end (located deep in the dermis).
Hair papilla: a vascular connective
tissue that occupies the
concavity of the bulb.
Arrector Pilli muscle
? A band of smooth muscle
connects the undersurface of the
follicle to the superficial part of
the dermis.
? It is innervated by sympathetic
nerve fibers.
? It is involuntary.
Arrector Pilli muscle
Functions:
?Its contraction causes the
hair to move into a more
vertical position.
? It compresses the
sebaceous gland and
causes it to extrude sebum.
Sebaceous glands
Function
It secrets sebum to oil
(lubricate) hair and
skin.
Sebum
An oily material that
keeps the flexibility of
the hair and oils the
epidermis around the
mouth of the follicle.
Sebaceous cyst
It occurs because of the
obstruction (blocking) of the
sebaceous duct.
Sweat glands
? long tubular glands with deep
coiled part.
? All over the body except red
margins of lips, nail beds, glans
penis and clitoris.
? The most deeply penetrated
structure.
Skin burns
Superficial
Deep
Heals rapidly from the edges,.
Heals slowly from the edges.
Heals quickly.
Usually needs skin grafting.
Doesn't need a skin graft.
Clinical notes
Graft is transferring tissue from one site to another.
Skin graft is needed when the skin is damaged ( usually by deep
burning )
Clinical notes
Skin Graft
Split thickness grafting
Full thickness grafting
Transferring epidermis only
Transferring both
epidermis and dermis.
Fascia
Fascia
Collection of connective tissue
Superficial fascia
Deep fascia
Superficial fascia
Deep Fascia
Superficial fascia
Superficial fascia:
?
Loose, mixture of adipose and loose areolar tissues.
?
It unites the skin to the underlying structures.
?
It is dense in some places as scalp, palm of hand and sole of foot
and contains collagen bundles
?
It is thin in the eyelids, auricle, scrotum (devoid of adipose
tissue).
Functions:
?
Facilitates movement of skin over underlying structures.
?
Passage for cutaneous vessels, nerves.
?
Protects the body against heat loss.
Superficial fascia
Deep fascia
It is more dense than superficial fascia
Collagenous bundles are more compact and
more regularly arranged
It is usually present in the form of membranes
Examples of deep fascia
A. Intermuscularsepta
liebetweenmusclesdividing
thelimbintocompartments
Examples of deep fascia
B. Investing fascia
? Covers the surfaces of muscles
? In the neck: it forms well-defined layers,
bounds fascial spaces so limits spread of
infection or determine the path of infection
? In the abdomen: it is thin
? In the limbs: forms a definite sheath around the
muscles
Examples of deep fascia
C. Retinacula
Localized thickening of deep fascia around joints, hold the tendons
in place, prevent bowstringing of tendons
This post was last modified on 05 April 2022