Homeostasis Flashcards
What are 2 major systems for coordination and controlling responses to stimuli?
1)Nervous system
2)Endocrine system
How endocrine system works?
Signaling molecules(hormones) released into bloodstream by endocrine cells are carried to all locations in body
But hormones act only on cells with its specific receptors so response are limited to cells that have receptors for signal
How nervous system works?
Neurons transmit signals(nerve impulses) along dedicated routes connecting specific location in the body
Response are limited to cells that connect by specialized junction to axon
Effects of hormones and nerve impules
Hormones are released into bloodstream within seconds and its effects long-lasting and it remains in bloodstream for minutes or hours
Transmission in nervous system is extremely fast;nerve impulses take only a fraction of a sec to reach the target and last only a fraction of a sec
endocrine system is well suited for_____
coordinating gradual changes (i.e. growth and development, reproduction, metabolic processes and digestion)
Nervous system is well suited for_____
Directing immediate and rapid response to environment (i.e.reflexes and other rapid movement)
What is a regulator?
An animals if it uses internal mechanisms to control internal change during fluctuation in external environment.
(external changesတွေရှိတိုင်းမှာinternal environment ကိုchanges မဖြစ်အောင်control လုပ်)
What is a conformer?
An animal that allows its internal condition to change according to external changes
(external changesအတိုင်းအလိုက်သင့်လိုက်ပြောင်း)
What is Homeostasis?
Maintenance of internal balance
How animals achieve homeostasis?
Animals maintains steady state (constant internal environment) even when external environment changes significantly
Animals achieve homeostasis by maintaining _____ within_____
variable within set point
below or above of normal state eg.temp-36~38•C is set point
How body react if there is fluctuations above if below set point?
Fluctuation was detected by sensor and it send signal to control center.
Control center generates response to stimulus
Major feedback regulation in animals
Negative feedback
Eg.During vigorous exercise,body produce heat and increase temperature which is detected and triggers sweating leading to evaporation of moisture from skin and cools and decrease the body temperature
Response inhibits the initial stimuli
Homeostasis is _____
Dynamic equilibrium
(external factorsတွေကinternalကိုchange ဖို့ကြိုးစားပေမဲ့internalကလက်မခံ)
Are physiological responses instantaneous?
No
Explain positive feedback
Response that amplifies the stimulus
Eg.During child birth, near uterusမှာရှိနေတဲ့baby’s head pressureကြောင့်uterusပိုပွင့်လာ
Regulated changes in body
1)Particular stage in life(eg.hormones change at puberty)
2)Cyclic regulated changes (eg.menstrual cycle)
What is circadian rhythm?
a set of physiological changes that occur roughly every 24 hrs
eg.body temp rise and fall 1•C in 24 hrs
Is circadian rhythm same to all?
No,it’s intrinsic to body and response to light and dark of external environment
Eg.Melatonin is secreted at night but more is released during long nights of winter
Can biological clock reset?
Yes, external stimuli can reset biological clock
Acclimatization is_____
physiological adjustment to changes to its external environment
What is difference between acclimatization and adaptation?
Acclimatization-temporary change in lifetime
Adaptation-process of change in a population over many generations
What is thermoregation?
Maintaining body temperature within normal range
What will happen if body temperature is out of normal range?
1)reduce efficacy of enzymatic reactions
2)Alter fluidity of membrane
3)affect temperature sensitive biochemical processes
Endotherm
Humans and mammals
They receive heat energy from metabolism and can maintain stable temperature
Ectotherm
Amphibian,reptile,fishes and invertebrates
They receive heat energy from external sources and maintain body temperature by behavioral means
They consume less food than endotherm(metabolicကheatပေါ်မမှီခိုလို့)
Can withstand during extreme fluctuation in internal temperature
Animal with constant body temperature are called_____
Homotherm
Animal with various body temperature according to environment are called_____
Poikilotherm
NOT ALL ENDOTHERM ARE HOMOTHERM AND NOT ALL ECTOTHERM ARE POIKILOTHERM
Thermoregulation depends on animal’s ability to_______
control the exchange of heat with its environment
Methods of heat exchange
1)Radiation
2)Evaporation
3)Convection
4)Conduction
Thermoregulation is ____
maintaining rate of heat loss that is equal to rate of heat gain
Heat transferred from ____ to _____
high temperature- low temperature
How mammals exchange heat?
By integumentary system( skin,hair and nails)
Explain radiation
emission of heat by all objects warmer than absolute zero
Explain evaporation
removal of heat from surface of liquid by losing its gas molecules
Explain convection
the transfer of heat by movement of air or liquid past a surface