5.1 Flashcards
What are the 2 types if cell signalling? Give 3 features of these
Hormonal:
- blood used as transport medium
- long term effects
- slower response
- targets SPECIFIC cells complementary to hormone
Neuronal:
- rapid response
- short term effects
- reacts to fast changing stimuli
- uses synapses
Give the 6 factors that homeostasis controls
- blood temperature
- blood glucose levels
- blood salt concentration
- water potential of blood
- blood pressure
- CO2 concentration
What is the mechanism for homeostasis?
Stimulus > receptor > communication pathway (cell signalling) > effector > response
What is negative feedback?
Reverses the effects of any change away from optimum conditions. As environment get closer to optimum condition, the size of the stimulus reduces., hence decreasing effector’s activity
What is positive feedback?
Response increases original change away from optimum conditions. This destabilized the system and is harmful. Examples = oxytocin + core body temperature enzymes
Give the behavioural adaptations of ectotherms (6)
If too hot:
- move out of sun
- burrow underground
- reduce SA exposed to sun
If too cold:
- move into sunny area
- increase SA exposed to sun
- lie on warm surfaces
Give the behavioural and adaptations of endotherms(8)
Too hot:
- hide in shade
- orientated body to reduce SA exposed to sun
- remain inactive + sprawl limbs to enable greater heat loss
- wet skin to use evaporation for heat loss
Too cold:
- lie in sun
- orientate body so greater SA exposed to sun
- move about to generate heat or roll into a ball to reduce SA from which heat is lost
- remain dry
Give the physiological adaptations of endotherms (5)
Too hot: -skin, sweat -gas exchange system, panting -liver, reduce metabollism -skeletal muscles, fewer contractions means less heat generated -blood vessels, vasodialation (Vice versa for cold)
Advantages and disadvantages of adaptations in ectotherms
A:
- Less food used in respiration so more energy and neutrients used for growth
- red to find less food
- can survive long periods without food
D:
-less active in cooler temperatures
Cannot take advantage of available food while they are cold
-susceptible to predators
Give the advantages and disadvantages of adaptations in endotherms (6)
A:
- constant body temperature maintained
- remain active in cold temperatures
- inhabit colder regions of planet
D:
- use a significant amount of energy uptake to maintain temperatures in the cold
- need more food frequently
- less nutrients used for growth
What part of the brain is concerned with controlling temperature regulation?
Hypothalamus
Hat changes does the hypothalamus bring about in order to respond to a temperature stimulus?
If too hot: Changes on skin(hairs stand up to create insulation) Release heat through shivering Increased metabolism And vice versa if too hot
