Sleep and Sleep Disorders 11 20 2013 What does it mean for a pattern of behavior to have an endogenous circadian rhythm A pattern of behavior s endogenous circadian rhythm is its internally generated signal preparing for sleeping and feeding that occurs on a daily cycle What influence do zeitgebers have on these cycles Though endogenous rhythms occur without being prompted by the environment they must be maintained and reset Zeitgebers are stimuli that typically cycle along with endogenous rhythms These include light and temperature Other factors like visual impairments overseas flights and night shift jobs may also affect endogenous rhythms What brain area is necessary for the generation of endogenous cycles The superchiasmatic nucleus SCN is the portion of the hypothalamus just above the optic chasm that controls the biological clock In what specific way does it receive input The SCN receives information directly from the optic nerves via the retinohypothalamic path Describe how this brain area affects a hormone associated with biological clock regulation The SCN controls activities of other parts of the body including the endocrine pineal gland which releases melatonin the hormone that is produced at night to promote sleepiness Define the stages of sleep Wakefulness steady high frequency of alpha waves Stage 1 irregular waves with low amplitude Stage 2 emergence of sleep spindles and K complexes Stages 3 and 4 slow low frequency waves REM Rapid Eye Movement similar brain activity to Stage 1 complete muscle relaxation increased autonomic functioning associated with vivid dreaming facial twitching and eye movements What does the slowing of brain waves as sleep progresses indicate The slowing of brains waves and decreased frequency indicate synchronized neuronal activity and inhibition of the cortex How is REM sleep paradoxical During REM sleep the brain s activity is similar to that of Stage 1 even though the body is in a state of paralysis List the areas of the brain involved in arousal and wakefulness and the neurotransmitters that they signal with Pontomesencephalon part of the reticular formation that uses acetylcholine and glutamate to promote wakefulness Locus Coeruleus part of pons that uses norepinephrine to strengthen storage of recent emotional memories Hypothalamus uses histamine to be active during arousal and hypocretin or orexin to stay awake not for waking Basal forebrain uses acetylcholine to shift from non REM to REM Dorsal raphe part of pons that uses serotonin to shift from REM to non REM What is the main neurotransmitter that maintains sleep GABA is responsible for sleep How can a practitioner diagnose insomnia If a patient in unable to fall asleep or stay sleeping and it has an impact on their daily life they can contribute to behavior disorders and mental illnesses What causes narcolepsy Narcolepsy is defined by sudden attacks of extreme sleepiness similar to REM like sleep during the day wakefulness It may be genetic but is caused directly by a lack of hypocretin orexin production in the hypothalamus Thirst 11 20 2013 Describe the main components of a homeostatic system Homeostasis is a tendency to maintain a body variable i e temperature thirst hunger near a set point range that may change due to environment through use of negative feedback reduces discrepancies from the set point Why does fluid balance need to be so tightly controlled All chemical processes necessary for life take place in solution making fluid regulation essential What causes the two types of thirst Osmotic thirst is caused by increased salt content of extracellular Hypovolemic thirst is caused by fluid loss via sweating bleeding fluid diarrhea etc In which do you need both fluid and salt Hypovolemic thirst requires fluid to sustain proper blood pressure and heart function and to restore lost salts to regulate osmotic pressure How does ADH help re regulate both situations With osmotic thirst anti diuretic hormone ADH enables the kidneys to reabsorb water With hypovolemic thirst ADH constricts blood vessels What do angiotensin II and aldosterone each do With hypovolemic thirst renin release results in the activation of angiotensin II Ang II which constricts blood vessels and stimulates the adrenal glands The adrenal glands then release aldosterone which causes salt retention When combined what type of behavior do Ang II and aldosterone induce When combined they increase behavioral preference for salt Hunger 11 20 2013 Detail how insulin and glucagon can be described as a means by which food intake is homeostatically regulated Insulin allows glucose to enter the cells and be used when blood sugar levels are high Glucagon stimulates the liver to release glycogen form glucose takes when stored in liver as glucose when blood sugar levels are low By controlling the activity of glucose the body is regulating blood sugar levels at their set point What are some other peptides that work as negative feedback for promoting satiation Satiation is the state of feeling or being full opposite of hunger The duodenum part of the small intestine that stomach empties contents to releases peptides to increases satiety or promote satiation by stimulating the vagus nerve cranial nerve that conveys information about the stretching of stomach walls Oleoylethanolamid OEA stimulates the vagus nerve in response to fats and delays next meal Cholecystokinin CCK constricts passage from stomach to duodenum and stimulates the vagus nerve How does the stomach play an active role in monitoring and controlling eating behavior The stomach has stretch receptors that end a bout of food intake via the vagus nerve The stomach sends information regarding its nutrient content to the brain via the splanchnic nerves helping to determine how quickly the stomach will empty contents into the duodenum The stomach s production of the peptide ghrelin increases food intake and reported hunger What does leptin regulate Leptin regulates the body s storage of fat Why does leptin treatment not help reduce weight in most cases of obesity In most cases of obesity people s leptin receptors are no longer sensitive Leptin treatment will only work if an individual does not produce leptin but their receptors are intact Detail how the neuron types in the arcuate nucleus can be described as a means by which food intake is homeostatically regulated The arcuate nucleus is part of the hypothalamus whose neurons allow the activities of CCK insulin
View Full Document
Unlocking...