Chapter 15 - Homeostasis Flashcards
Outline two ways in which thermoregulation in naked mole rats is different from thermoregulation in most mammals.
Naked mole rats have a lower body temp
Naked mole rats do not have hair so no insulation
Naked mole rats use more behavioural responses
Core body temp falls. Hypothermia.
Explain how positive feedback helps accelerate the process of hypothermia.
Positive feedback is when an initial biological change is increased further. When body temp keeps falling, the kinetic energy lowers and in turn causes reduced enzyme activity.
Therefore less heat generates and body temp drops further.
Many insects are insulated with scales and hair, known as facultative endotherms.
Their metabolism during flight can cause temp to increase.
Explain how insects are described as endothermic.
Endothermic as they rely on heat being produced from metabolic reactions. In addition physical features such as scales and hair help to reduce heat loss.
It is more difficult for (smaller insects i.e. moths) to maintain their body temperature than for mammals and birds to maintain their body temperature.
Explain why.
Insects have greater heat loss as they are smaller.
In addition mammals have more effective systems and thicker insulation.
Hypothermia is a condition in which the body core temperature is lowered. Alcohol causes vasodilation. Explain why it is not a good idea to give alcohol to someone with hypothermia.
Vasodilation is when blood comes closer to skin surface.
Therefore more heat will be lost further and temperature decreases so organs cannot maintain metabolism.
During a fever, the bodys thermoregulatory set point rises. Fever is accompanied by sweating. Explain the effect of sweating.
Sweating is when the body detects high temperature, heat is taken from the blood and used in evaporation to reduce body temp.
A feature of fever may be uncontrollable shivering. Suggest why shivering occurs during fever.
the core temperature decreases due to the fever. Shivering is needed to increase body temperature to new set point.
Describe two similarities in the action of plant and animal hormones in cell signalling
- Hormone bind to receptor
- Causes enzyme reactions
A pump stands in a pond to circulate the water. In cold weather, fish gather around the pump. Suggest an explanation as to why fish gather around the pump.
Fish are ectotherms - The body temp is similar to surrounding water
In cold weather, the pump would be producing heat that warms the surrounding weather.
