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What is homeostasis?
- The condition of a relatively stable internal environment maintained within narrow limits
- eg. core temperature, water levels, glucose, pH of blood
What are affector neurons?
- Detect change in internal or external environment
- Sends electrical impulses to CNS
What are effector neurons?
Neurons that carry impulses away from the CNS to produce a response (muscles and glands)
What is the endocrine system and what is it responsible for?
- A system of internal control in animals that involve the release of hormones into the blood.
- Hormones reach the site of action through diffusion
- Much slower than nervous system however long lasting.
- Responsible for maintaining homeostasis
What is negative feedback?
The response reduces the effect of the original stimulus. That is, the response has a negative effect on the stimulus, cancelling or counteracting it.
What are ways of losing heat?
- Radiation: Heat in the form of infrared rays
- Conduction: movement of heat away from the body in water
- Convection: movement of heat away from the body in air
- Evaporation of sweat
- Less adrenaline and thyroxine produced for slower metabolism
What are ways of gaining heat?
- Shivering: contraction and relaxation of small muscle groups
- More thyroxine and adrenaline =Metabolic processes
- Vasoconstriction: less heat lost through blood
- Piloerection: goosebumps, thin layer of insulation
What is the difference between ectothermic and endothermic animals?
- Ectothermic: rely on external temperatures to gain body heat
- Endothermic: rely on internal mechanisms to generate body heat
What is the difference between poikliothermic and homethermic animals?
- Poikliothermic: fluctuating internal temperatures
- Homeothermic: constant internal temperatures
Describe the processes involved in maintaining water balance in mammals
- ·Regulated by kidneys. Also called osmo-regulation
- ·Two Significant hormones are involved– Vasopressin and Renin
- ·Osmo-receptors detect changes in water balance in the body – When there is a drop in water concentration, Vasopressin is released into the bloodstream.
- ·Vasopressin increases re-absorption of water in the kidneys