A water pipe at 58C runs above ground between two buildings. The surrounding air is at 358C. What is the maximum relative humidity the air can have before condensation occurs on the pipe?
Monday, March 7, 2016 Week 6 Arousal - Review: Arousal level is taken into consideration on an inverted U shaped curve. Many of these curves exist per individual, based on the complication of a task and interest in the subject matter. - Humans are curious, but what is the motivation behind that • We are processors of information, which could be our reason for appreciating art; to maintain the optimum level of arousal. - There is not one kind of inverted U shaped curve, there is no overarching optimum level of arousal - Some interests can change as we get older, which may reﬂect a change in the optimal level of arousal due to biological differences, however these tend to be content speciﬁc. - All of this can be supported using statistical analysis, using experiments measuring biological arousal - There are three types of arousal: • Behavioral Arousal: Can be shown through an increase in activity, however bear in mind that sometimes arousal can be tightened but activity not so; when prey freezes in fear or for camouﬂage, it is still biologically aroused and showing motivation, but shown through internal cues rather than external movement. - Dopamine is the precursor to endorphins being released, therefor dopamine itself does not provide the “feel good happiness”, but rather the endorphin chemicals. • Interesting Note: Every time you release dopamine, you release less and less • Autonomic vs Somatic Nervous System, Parasympathetic (anabolic) vs Sympathetic, Central (encased in bone) vs Peripheral (nerve tendrils branching out) - Somatic Nervous System is in charge of muscular reﬂexes - Automatic Nervous System is in charge of smooth muscles, glands, cardiac tissue 1 Monday, March 7, 2016 - Increased heart rate, respiration, blood pressure, glucose, adrenaline (epinephrine), and Cortisol • Essentially the ﬁght or ﬂight response! • Cortical Arousal Arousal Continued; Biological Level - Your iris is made with the same tissue as your gut, and when in an emergency situation your iris will expand your pupils to allow for more light. - Autonomic Nervous System • Sub-Division - Sympathetic: Fight or Flight • Unnecessary processes stop, such as digestion, sexual arousal, etc. • Increases heart rate, expands pupils - Parasympathetic: Rest and Digest Increases anabolic functions, such as digestion • • Decreases heart rate, constricts pupils - Axoaxonic synapses: Axons branching off of other axons Sympathetic NS Parasympathetic NS - Norepinephrine - Acytelcholine 2 Monday, March 7, 2016 - Neurotransmitters directly affect the arousal of organs and muscles Cortical Arousal - Arousal Wave Types • Alpha Waves: Unfocused Attention, 8-12 Hertz • Beta Waves: Focused Attention, 3.5-7.5 • Theta Waves: Shown when falling asleep and during REM sleep, 13-30 Hertz, tend to be universal • Delta Waves: Shown when asleep, less than 4 Hertz - These waves can be seen in an electroencephalogram (EEG) • Can give us a picture of cortical arousal • Gives us the “mode” of brain measures, the average activity level of a population of neurons - When more aroused, the ﬁring of the neurons becomes more and more irregular (a- synchronis) - When falling asleep, theta waves are shown (in all mammalian species), which are not as quick as Beta waves, and not as slow as Delta waves, sort of an intermediate to the two; has the most interesting wave pattern. Some theorists believe that Theta waves are important for memory consolidation, however this has not yet been proven. Physiological Mechanisms of Arousal - Cat study with Bremer is a perfect example • Bremer used two groups of cats (one with an incision at the medulla level thus separating the brain from the spinal cord, and one with an incision at the level of the colliculi, or midbrain) and hooked them up to an EEG. - Group 1 was of course paralyzed due to the insolé isolé incision, but the sleep wake cycle remained intact 3 Monday, March 7, 2016 - Group 2, cerveau isolé, was still paralyzed, but more importantly the sleep / wake cycle was dramatically affected, as in a permanently comatose animal; the animal only slept - Moruzzi and Magoun then continued Bremer’s study, though focusing on the entire brainstem, mostly in the pons • Discovered the Reticular Activating System, or Reticular Formation - Monitors External and Internal Sensory Info • Descending Reticular Formation - Deactivates arousal • Ascending Reticular Formation - Arouses brain, particularly the cortex, such as when surprised - Arouses the rest of the brain when appropriate - Reacts to novelty - Sleep is the default condition - Can be altered by experience! - Drugs may be addicting because they shut down perception Dreams - Everyone dreams, about 100 minutes a night, every 90 minutes • 65% of dreams are negative 4