MEMBRANES Membranes are sheets of tissues that cover or line surfaces or that separate organs or parts(lobes) of organs from one another.

1
MEMBRANESMembranes are sheets of tissues that
cover or line surfacesor that separate organs or
parts(lobes) of organs from one another.

• Types of membranes
• 1-Epithelial membranes
• 2-Connective tissue membranes

2
EPITHELIAL MEMBRANES

• two types of epithelial membranes
• serous
• and mucous.
• Each type is found in specific locations
• within the body and secretes a fluid.
• These fluids are called
• -serous fluid
• -and mucus.

3
Mucous Membranes

• Mucous membranes line the body systems that have
  openings to the environment. (respiratory,
  digestive, urinary, and reproductive).
• The epithelium of a mucous membrane (mucosa)
  varies
• - mucosa of the esophagus and of the vagina is
  stratified squamous
• mucosa of the trachea is ciliated epithelium
• mucosa of the stomach is columnar epithelium

4
Mucous Membranes

• Mucosa is composed of epithelium resting on a
  loose connective tissue membrane called a lamina
  propria
• The mucus secreted keeps the lining epithelial
  cells wet and acts as lubricant

5
Serous Membranes

• Serous membranes are sheets of simple squamous
  epithelium that line some closed body cavities
  and cover the organs in these cavities
• 1-pleural membranes are the serous membranes of
  the thoracic cavity.
• The parietal pleura lines the chest wall.
• and the visceral pleura covers the lungs.
• It secrete serous fluid, which prevents
• friction between them

6
2-pericardium

• The heart, has its own set of serous membranes.
• The parietal pericardium lines the thorasic
  cavity
• the visceral pericardium,
• or epicardium, is on the surface of the heart
  muscle
• Serous fluid is produced to prevent
• friction as the heart beat

7
3-Peritoneal Membranes
8
Pleural Pericardial Membranes
9
CONNECTIVE TISSUE MEMBRANES

• These are made of connective tissue with no
  epithelial cells at all
• It cushions organs moving against each other
  during muscle activity

10
(No Transcript)
11
(No Transcript)
12
The Integumentary System

• consists of
• -the skin,
• - its accessory structures such as hair and
  sweat glands,
• -and the subcutaneous tissue below the skin.
• The skin is considered an organ.

13
Functions of the skin

• 1-Protects deeper tissues from
• -mechanical damage
• -chemical damage (acids bases)
• -bacterial damage
• -ultraviolet radiation (sunlight)
• Thermal (heat or cold) damage
• -desiccation (drying out)

14
Functions of the skin (cont.)

• 2-aids in heat regulation
• -in cold vasogonstriction
• -in hot vasodilatationsweat
• 3-aids in excretion of urea uric acid
• 4-synthesize vitamin D

15
STRUCTURES OF THE SKIN

• two major layers the epidermis dermis.
• The epidermis
• made of stratified squamous keratinizing
• epithelial tissue and is thickest on the palms
  and soles. The cells that are most abundant are
  called keratinocytes, and there are no
  capillaries present between them.

16
The epidermis

• Although the epidermis may be further
• subdivided into four or five sublayers, two of
  these are of greatest importance
• the innermost layer, the stratum
• germinativum,
• and the outermost layer, the stratum
• corneum .

17
Stratum Germinativum (BASALE)

• To germinate means to sprout or to
• grow. Basal means the base or lowest part.
• The stratum germinativum is the base of the
  epidermis, the innermost layer in which mitosis
  takes place. New cells are continually being
  produced, pushing the older cells toward the
  skin surface. These cells produce the protein
  keratin, and as they get farther away from the
  capillaries in the dermis, they die.

18
Stratum Corneum

• the outermost epidermal layer,
• consists of many layers of dead cells all that
  is left is their keratin which is a fibrous
  protein that makes the epidermis
• - a tough protective layer
• - relatively waterproof (prevent evaporation,
  prevents the entry of water).
• -a barrier to pathogens and chemicals.
• Stratum Corneum rubs and flakes slowly leading
  to totally new epidermis every25-45 days

19
Langerhans Cells

• are also called dendritic cells(branched
  appearance ) .These cells originate in the red
  bone marrow, and are quite mobile.
• They are able to phagocytize foreign
  material, such as bacteria that enter the body
  through breaks in the skin. With such ingested
  pathogens, the Langerhans cells migrate to lymph
  nodes and present the pathogen to lymphocytes.
  This triggers an immune response such as the
  production of antibodies.

20
Melanocytes

• Another type of cell found in the lower epidermis
  
• Melanocytes produce another protein, a pigment
  called melanin.
• In people with dark skin, the melanocytes
  continuously produce large amounts of melanin.
  The melanocytes of lightskinned people produce
  less melanin. The activity of melanocytes is
  genetically regulated.

21
Melanin

• In all people, melanin production is increased by
  exposure of the skin to ultraviolet rays, which
  are part of sunlight and are damaging to living
  cells.
• People with dark skin already have good
  protection against the damaging effects of
  ultraviolet rays.
• Melanin also gives color to hair,iris choroid.

22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
DERMIS

• It is a strong stretchy envelope that hold the
  body together
• It is made of an irregular type of fibrous
  connective tissue.
• . Fibroblasts produce both collagen and elastin
  fibers.
• Collagen fibers are strong, and elastin fibers
  are able to recoil after being stretched.
• Strength and elasticity are two characteristics
  of the dermis.
• With increasing age, however, the deterioration
  of the elastin fibers causes the skin to lose its
  elasticity.

26
papillary layer of dermis

• IT is the uneven junction of the dermis with the
  epidermis
• Capillaries are abundant here to nourish not only
  the dermis but also the stratum germinativum.
• N.B. The epidermis has no capillaries of its own.
• Within the dermis are the accessory skin
  structures
• hair and nail follicles, sensory receptors, and
  several types of glands.

27
Colour of skin

• Three pigments contribute to skin golour
• 1-melanin
• 2-karotine
• 3-oxyhemoglobin

28
Appendages of the skin

• 1-Hair folliclesmitosis takes place in the hair
  root new cells produce keratin, die, and become
  the hair shaft.
• Hair of the scalp provides insulation from
• cold for the head eyelashes keep dust out of
  eyes
• nostril hairs keep dust out of nasal cavities

29
(No Transcript)
30

• 2. Nail folliclesat the ends of fingers and
  toes mitosis takes place in the nail root the
  nail itself is dead,keratinized cells.
• -Nails protect the ends of the fingers and toes,
  enable the fingers to pick up small
• objects, and provide for efficient scratching

31
(No Transcript)
32

• 3. Receptorsdetect changes in the skin touch,
  pressure, heat, cold, and pain provide
  information about the external environment that
  initiates appropriate
• responses.
• sensitivity of the skin depends on the number of
  receptors present.

33

• 4. Sebaceous glands(oil glands) secrete sebum
  into hair follicles or to the skin surface.
• sebum inhibits the growth of bacteria and
  prevents drying of skin and hair.
• If its duct is blocked by sebum,whitehead
  appears,with oxidation become blackhead
• Active infection leads to acne

34

• 5. Ceruminous glandssecrete cerumen in the ear
  canals.
• cerumen prevents drying of the eardrum.

35

• 6. Apocrine sweat glandsmodified scent glands in
  axillae and genital area
• activated by stress and emotions
• Their secretions contains fatty acids and
  proteins
• Secretion is odorless
• Begins function at puberty
• Minimal role in thermoregulation

36

• 7. Eccrine sweat glandsall over the body, most
  numerous on face, palms, soles.
• Activated by high external temperature
• or exercise sweat on skin surface is
  evaporated by excess body heat.
• Excretion of small amounts of NaCl and
• urea is a very minor function.

37

• 8. Arteriolessmooth muscle permits constriction
  or dilation.
• Vasoconstriction in cold temperatures
• decreases dermal blood flow to conserve heat in
• the body core.
• Vasodilation in warm temperatures increases
  dermal blood flow to bring heat to the surface to
  be lost.
• Vasoconstriction during stress shunts blood away
  from the skin to more vital organs, such as
  muscles, to permit a physical response, if
  necessary.

38
Subcutaneous Tissue

• Subcutaneous Tissuealso called the superficial
  fascia connects skin to muscles
• 1. Areolar tissue, called loose connective
  tissue
• the matrix contains tissue fluid and WBCs that
  destroy pathogens
• 2. Adipose tissue stores fat as potential energy
  cushions bony prominences provides some
  insulation from cold.

39
(No Transcript)
40
(No Transcript)
41
AGING AND THEINTEGUMENTARY SYSTEM

• become thinner as mitosis slows and fibroblasts
  die and are not replaced repair is slower.
• becomes wrinkled as collagen and elastin fibers
• deteriorate.
• - Sebaceous glands and sweat glands become less
  active the skin becomes dry, and temperature
  regulation becomes more difficult.
• Hair follicles become inactive and hair thins.
• Melanocytes die so white hair
• Less fat in subcutaneous tissue so more
  sensitivity to cold

42
(No Transcript)