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60 Cards in this Set
- Front
- Back
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What is the hierarchy of physiology functions?
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1. respiratory
2. body temperature & electrolyte balance 3. excretion 4. nutrition 5. reproduction |
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Difference between regulate and control
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one regulates the entire process whereas one control particular functions or variable within that process. i.e. the process of regulating body temperature is controlled by altering the amount of sweat that is produced
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Describe the graphs of conformer versus regulator
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The slope of the conformer graph is a perfect m=1 slope because as the external conditions increase the internal conditions change by the same amount. In the regulator graph, the internal conditions remain the same. However, at extreme external conditions, the internal conditions will change a little bit but this is dangerous for the organism
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maintenance of a constant internal environment
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milieu interieur
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why does equilibrium = death?
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because regulators need a state of consistency; they do not need to be equal to the environment. i.e. the set-point of human body temperature is higher than the outdoors, so body temperature is not in equilibrium to the external conditions
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Homeostasis comprises of the specialized functioning of ___
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individual cells, tissues, organs, and organ systems
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Which is more common: positive or negative feedback?
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negative feedback
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Examples of negative feedback
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body temperature, insulin and glucagon
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Examples of positive feedback
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when you eat, your body keeps producing more of this particular hormone ___ to signal to your stomach that you are full
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Receptor/sensor
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perceives changes in the external environment
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control center/integrator
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compares the changes with the set-point. also instructs the effector of what change to make
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efforter
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changes the parameter back to set point
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Negative feedback definition
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the activity of a system is regulated by the amount or concentration of its end product
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what part of the brain responds to stress?
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the hypothalamo-pituitary-adrenal axis responds to stress
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what is another name for the hypothalamo-pituitary-adrenal axis?
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endocrine access
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Once signaled, what does the hypothalamo-pituitary-adrenal axis do?
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Releases cortisol into the blood. this mobilizes stored fuels and allows the brain to function better and escape stress
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What must happen before the hypothalamo-pituitary adrenal axis is activated?
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stress signals the corticotroponin releasing factor
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How is parturition (giving birth) an example of positive feedback?
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First, the uterin lining stretched in late gestation. Later, the brain releases oxytosin which allows for an increase in contractions.
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Break down of parturition positive feedback: stimulus
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large distortion of the shape of the uterus
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Break down of parturition positive feedback: receptors
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the stretch receptors on the uterus walls
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Break down of parturition positive feedback: control center
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endocrine center in the brain
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Break down of parturition positive feedback: signal
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brain releases oxytosin
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Break down of parturition positive feedback: effector
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causes uterus wall to contract
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Break down of parturition positive feedback: signal to terminate
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birth!
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How is ovulation an example of positive feedback?
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Estrogen levels rise before ovulation. Rise in estrogen level causes luteinizing hormone (LH) to surge. This causes the follicle to rupture and ova is released/expulsed
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example of feedforward regulation
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skin arterioles sense the change in temperature and cause blood vessels to constrict which reserves heat within the body
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allostasis
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maintaining stability through change. the process of achieving or maintaining stability or homeostasis through physiology or behavioral change
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main difference between homeostasis and allostasis
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homeostasis is used to describe minor changes in external conditions whereas allostasis is used to describe major changes
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main difference between homeostasis and allostasis in regards to set point
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homeostasis does not change set points whereas allostasis does change set points.
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systems in which allostasis takes place
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autonomic nervous system, HPA axis, cardiovascular, metabolic and immune system
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allostatic load
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although the body may be in balance, the allostatic load is causing stress to the body and the body may eventually break
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example of allostatic load
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food deprivation: chronic stress which leads to muscle cell apoptosis, hypertension, supression of immune system and reproduction, Hirsutism, virilism in women, Amenorrhea, neurodegredation, impaired memory, learning, depression
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physiology acclimation
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physiology adaption to an isolated variable in a controlled setting i.e. wood frog body temperature in a lab
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physiological acclimization
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many variables that change as a result of natural changes. usually seaosnal and therefore reversible
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developmental acclimization
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irreversible changes that happen early in life. i.e. sherpas and their acclimization to high altitudes
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3 components of homeostatic control mechanism
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1. reflexes
2. local homeostatic responses 3. intercellular chemical messengers (hormones) |
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reflex arc
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stimulus
receptor afferent pathway control center/intergrating center efferent pathway effector |
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ultradian
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less than 24 hours
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circadian
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~24 hours, more like 25 hours
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circannual
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365 days
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entrainment
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resetting the biological clock. it reset the clock so that the internal rhythm is more aligned with the environment. i.e recovering from a long airplane flight
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dual thing about circadian rhythm
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its like a clock and is on a set schedule, but the time can be reset
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steps of the circadian cycle
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1. sharpest rise in blood pressure
2. melatonin secretion stops 3. bowel movements begin 4. highest testosterone secretion 5. high alertness 6. best coordination 7. fast reaction time 8. best cardiovascular and muscular strength 9. high blood pressure 10. high body temperature 11. melatonin secretion starts 12. bowel movement supressed 13. |
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what is the pacemaker/central controller of the circadian rhythm?
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the supraschiasmatic nucleus of the hypothalamus (SCN)
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what synchronizes/entraines the circadian rhythm?
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light and darkness
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What is melatonin?
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melatonin synchronizes the sleep wake cycle and is the chemical expression of darkness
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applying melatonin as treatment
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can be administered orally to counter jet-lag "jet-lag hormone"
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it usually takes several days to shift the circadian rhythm because...
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the rhythm cannot be shifter by moe than 30-60 minutes per day
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seasonal affective disorder (SAD)
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altered circadian rhythms related to short daylength in winter
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circannual rhythms are caused by
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varying hours of daylength across the year. i.e. june 21 is the longest day with the most sunlight whereas december 21 is the shorted day with the least sunlight
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examples of cirannual rhythm 1
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dormancy (hibernation(sleep in cold weather), estivation (sleep in hot/warm area), activity, weight lost and gain
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example of cirannual rhythm 2
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mountain goat sheds its wool in the springtime. this goes for any animal that sheds fur, skin, or antlers when the seasons change
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rate and pace of cirannual rhythm
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they are free-run but, but are entrained by the photoperiod (light and dark period). if cirannual was completely free-fun, than the rhythm would not align with the light-dark cycle
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gonadal recrudescence- gonadal growth
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species response to long photoperiod by initiating eproduction
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gonadal regression
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species response to long photoperiod by terminating reproduction
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who coined term homeostasis?
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claude bernard
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who coined allostasis?
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stering and eyer, refined by mcewen
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what controls the circadian rhythm?
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suprachiasmatic nucleus of hypothalamus SCN
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where is melatonin made?
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pineal gland
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at the poles, daylength...
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varies the least
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