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Homeostasis

Updated

QuestionAnswer
what is homeostasis? the control of an organisms internal environment in response to the changes in the external environment in order to maintain optimum conditions
why do we need homeostasis? maintaining homeostasis keeps our body temperature, blood glucose levels and many other things within a narrow perimeter, without these conditions, enzymes will denature and our cells will die
what are homeostatic mechanisms? they are mechanisms that work to bring conditions back to optimum, for example sweating to decrease body temperature
what is negative feedback, how does it work? the sensors find that conditions have returned to optimum, they send a signal to the communication center which switches off the effector
what is positive feedback? much less common and only used in extreme circumstances such as childbirth, the change is going further away from optimum conditions
what is stimulus? a change in conditions, whether internally or externally, deviating from a set point
what are sensors? they are constantly monitoring conditions such as blood glucose levels, temperature etc
what is a communication center? it compares the condition to a set point
what is an effector? a muscle or gland
what is a response? the conditions returned to optimum
what is conduction? heat transfer between two objects
what is convection? heat transfer between an organism and air current
what is radiation? heat released from a hot object as a wave
what is evaporation? heat lost when a liquid changes to a gas
what is the standard pathway of response? stimulus - sensors - communication center - effector - response
what is an endotherm? an animal that is capable of or dependent on the internal generation of heat
what is an ectotherm? an animal that relies on the sun for heat
what is an advantage of being an endotherm? you are able to live in colder areas as you do not rely on the sun for warmth, because of this you aren't lethargic at night as an ectotherm would be
what is a disadvantage of being an endotherm? you consume lots of energy maintaining body temperature
what is the smooth muscle in arterioles response to temperature increase and decrease? vasoconstriction (temperature decrease) & vasodilation ( temperature increase) (through radiation)
what is vasoconstriction? vasoconstriction is the constriction of blood capillaries close to the skins surface, this is a homeostatic mechanism used to prevent heat loss through radiation as the blood is forced to flow deep within the body
what is vasodilation? vasodilation is the dilation of blood capillaries close to the skins surface to allow blood to flow close to the skins surface, this is a homeostatic mechanism used to encourage heat loss through radiation
what is the sweat glands response to temperature increase? sweating (heat lost through evaporation of sweat)
what is the errector pili muscle in the skins response to temperature increase and decrease? hairs stand up (temperature decrease) (heat increased through convection) hairs lie flat (temperature increased)
what are the skeletal muscles response to temperature decrease? shivering (heat increased by convection)
what is the adrenal and thyroid glands response to temperature decrease? increase in metabolic rate (heat increased by conduction)
what is an example of negative feedback from temperature increase? stimulus- temperature increase. sensors- thermoreceptors in skin. communication center- thermoregulatory center in hypothalamus. effectors- sweat glands, blood vessels, errector pili muscle. response- sweat is released, vasodilation, hairs lie flat
what is an example of negative feedback from temperature decrease? stimulus- temperature decrease. sensors- thermoreceptors in skin. communication center- thermoregulatory center in hypothalamus. effector- skeletal muscles, blood vessels, errector pili muscle. response- shivering, vasoconstriction, hairs stand up
what is BMR? basal metabolic rate is the minimum amount of energy required to sustain the body's vital functions, it is the basic level of heat production by the body based solely on the chemical reactions of metabolism
what can affect the BMR? exercise can increase the basal metabolic rate by up to 5x, thyroxine released by the thyroid and stress hormones such as cortisol released by the adrenal gland can increase the BMR and dietary intake can increase the BMR
Created by: deannarosee