Integumentary System

1
Integumentary System

• Human Skin A sample human systems presentation

2
A Little Background

• Organization of the Human Body
• Types of Tissues
• Homeostasis

3
The Bodys Organization
Systems
Organs
Tissues
Cells
4
Types of Tissue

• Epithelial (derived from embryonic endoderm,
  mesoderm, ectoderm)
• Cells in close contact with little intercellular
  substance.
• Connective (derived from embryonic mesoderm)
• Cells widely separated by fibers embedded in an
  amorphous ground substance.
• Nervous (derived from embryonic ectoderm)
• Found in the central and peripheral nervous
  systems.
• Two cell types glial cells and neurons.
• Muscle (derived from embryonic mesoderm)
• Three types striated, smooth, cardiac

5
Stable Internal Environment

• Homeostasis
• Feedback Loops
• Negative Feedback (Most body control systems work
  through this type of feedback system.)
• Positive Feedback (Effect bringing completion to
  child birth increase contractions in mother
  Cause babys head against pressure sensors on
  uterine opening)

6
What does skin do?

• Roles of skin are varied
• Protection first line of defense
• Prevention of Water Loss Homeostasis
• Sensation/Sensory Reception touch, temperature,
  pain
• Temperature Regulator Homeostasis

7
Where does skin come from?

• Embryonic Origin
• ectoderm (blue)

8
What does skin look like?
9
Function Prevention of water loss

• Outermost Layer Epidermis
• Dead, keratinized layer that continually
  exfoliates and needs replacement is called the
  stratum corneum.
• A mitotically dividing layer called the stratum
  germinativum (BASAL LAYER) replaces cells of the
  s. corneum.
• The epidermis forms a very effective waterproof
  barrier.

10
Function Protection

• Blood vessels
• Are scattered throughout the dermis, or, inner
  layer.
• Blood vessels carry cells of the immune system
  that respond to infectious agents.
• Sebaceous Glands (clusters of secretory cells)
• They form close to hair follicles.
• They secrete oils and enzymes.
• Melanocytes
• Scattered throughout the basal layer (stratum
  germinativum) and produce melanin protects from
  harmful suns rays I.e. UV rays.

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Function Sensation/Sensory Reception

• Pain, Pressure, Temperature sensors are
  distributed throughout the Dermal Layer.
• These sensors are called sensory neurons, and
  they receive and transmits nervous impulses to
  the nervous system for processing.

12
Function Temperature Regulation

• Vasodilation Vasoconstriction
• In one case, blood vessels can increase blood
  flow to the outermost layers of the body. In the
  other, they restrict blood flow to these areas.
• Evaporative Cooling
• Sweat glands release water and salts when the
  body senses added heat.
• Fatty Deposits Hair
• Fatty deposits and hair are insulators.
  Specifically, arrector pili attached to hair
  follicles may contract and hold the hair erect,
  to increase the thickness of fur and its
  insulating capacity.

13
Summary
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References

• Campbell, N. A., J. B. Reece, L. G. Mitchell.
  1999. Biology. 5th Edition. Menlo Park, CA
  Pearson-Benjamin/Cummings. (ISBN0805365737)
• Campbell, N. A., J. B. Reece, L. G. Mitchell.
  1999. Biology Concepts and Connections. 3rd Ed.
  Menlo Park, CA Pearson-Benjamin/Cummings.
• Miller, K. J. Levine. 2002. Prentice Hall
  Biology. Menlo Park, CA Pearson-Prentice Hall.
• Morgan, J. G. M. E. Brown Carter. 1999.
  Investigating Biology. 3rd Ed. Menlo Park, CA
  Pearson-Benjamin/Cummings.