Communication And Homeostasis Flashcards
Why coordination is needed
Cells within organisms have become specialised
As a result organisms need to coordinate the function of different cells and systems
How do cells transfer signals
Locally, between neurones at synapses, the signal used is a neurotransmitter
Large distances, using hormones
Principal of homeostasis
Process of maintaining a constant internal environment
Receptors and effectors role in homeostasis
Sensory receptors detect changes in the internal and external environment of an organism.
Information from the sensory receptors is transmitted to the brain, and impulses are sent along the motor neurone to the effectors to bring about change.
Effectors are muscles or glands that react to the motor stimulus
Negative feedback system
Reverses change that has happened in the body
Effectors work on restoring bodies equilibrium
Changes that would stimulate negative feedback
Water levels, oxygen levels, co2 levels, ph, temperature , glucose concentration, ion levels
Positive feedback systems
Change in internal environment is amplified and increased
Example of positive feedback systems
Platelet production when you get a cut
Vaginal contraction during childbirth
Ectotherms
Use outside surroundings to warm their bodies
Core body temperature relies heavily on the environment
Behavioural adaptations to thermoregulate
Physiological adaptions: darker or lighter skin, altering heart rate
Endotherms
Mammals and birds
Rely on metabolic processes in their body to maintain their temperature
Very stable core temp
Detecting temperature change
Peripheral temperature receptors are in the skin and detect changes in the surface temperature
Temperature receptors in the hypothalamus detect body temperature
Combination of the 2 is a good sensor
Thermoregulation when body is too hot
Reduce body temp
Sweating , water then evaporates taking away heat
Vasodilation widening of arterioles close to skin to allow heat to diffuse out
Hairs lie flat, erector pili muscle relaxes
Thermoregulation when body is too cold
Shivering
Less sweating increases metabolism, energy relaxed from food
Vasoconstriction
Hairs stand up straight, vasoconstriction
Hormones, adrenaline and thyroxine released to increase metabolism
