Stations: Integumentary System
Activity 1: Visualizing Changes in Skin Color Due to Continuous External Pressure
Color of compressed skin: pale
What is the reason for this color change? Obstruction to capillary flow to the area
What would happen if the pressure was continued for an extended period in the area? Skin will turn blue (cyanosis); tissue will die
Re-read the paragraph on p. 114 about bedsores, or decubitus ulcers. What is a decubitus ulcer? Area of cell death
Why does it occur? A bedridden patient who is not turned of is repeatedly dragged – constant pressure restricts the blood supply.
How is a bedsore different from a blister?
Blister – separation between epidermis and dermis due to friction
Bedsore – cell death due to pressure
Activity 2: Effect of Vascularity on Skin Temperature Recovery
Estimate how long it would take for full recovery to be achieved for each of the two runs. Another minute or two (total – approx. 4 min)
Which area of skin tested (upper arm or face) had the most rapid recovery of temperature after cooling? Explain this result. Face – richer blood supply (blush response)
Alcohol causes dilation of the arterioles and a sensation of warmth. Would you recommend that someone who is stranded in the snow drink alcohol to keep warm? Why or why not? No – dilation of arterioles causes false sensation of warmth- but allows greater heat loss, hastening hypothermia.
A condition called hyperthermia can result when the body’s homeostatic mechanisms are no longer adequate to counter the effect of high external temperatures. On the basis of what you know about temperature regulation in the body, describe the skin color of someone who is in the first stages of hyperthermia. Flushed – red - due to dilated arterioles in an attempt to release heat
Activity 3: Determining the Two-Point Threshold
Which area has the smallest two-point threshold? Fingertips or lips
Examine the right side of the diagram of the brain on p. 238. the body parts represented by the larges portions of the brain are the most sensitive to touch. Do your results reflect the information on the diagram? Why or why not? It should because the most sensitive area will have the most sensory receptors & the largest area of the brain dedicated to making sense of the incoming information.
Activity 4: Testing Tactile Localization
Does the ability to localize the stimulus improve the second time? No
The third time? No
Explain. Density of Meissner’s corpuscles (touch receptors) doesn’t change
Which area has the smallest error of localization (is most sensitive to touch)? Fingertips
Why? Highest density of Meissner’s corpuscles (touch receptors) – most sensitive
Activity 5: Demonstrating Adaptation of Touch Receptors
Does the pressure sensation return after you stacked more coins on the second location? Yes
Are the same receptors being stimulated when the four coins, rather than the one coin, are used? Yes
Explain. Stronger stimuli produce larger potentials and therefore increased frequency of nerve impulses