Staying in balance Flashcards
What is homeostasis?
- Keeping in a constant internal envirnonment is called homeostasis.
- Homeostasis involves balancing bodily inputs and outputs.
How are cell kept at their optimum?
Automatic control systems keep the levels of temperature, water and carbon dioxide steady. This makes sure all cells can work at their optimum level.
What does negative feedback do in homeostasis?
Negative feedback controls are used in homeostasis. Negative feedback systems act to cancel out a change such as a decreasing temperature level.
Why is the body temperature 37 ºC?
The body temperature of 37 ºC is linked to the optimum temperature for many enzymes.
A high temperature can cause:
- Heat stroke (skin becomes cold and clammy and pulse is rapid and weak)
- Dehydration (loss of too much water)
- Both heat stroke and dehydration can be fatal is not treated.
What does a low temperature cause?
A very low temperature can cause hypothermia (slow pulse rate, violent shivering), which can be fatal if not treated.
How does the body try to prevent overheating?
- To avoid overheating, sweating increases heat transfer from the body to the environment.
- The evaporation of sweat requires body heat to change the liquid sweat into water vapour.
How is blood temperature monitored?
Blood temperature is monitored by the hypothalamus gland in the brain. Reaction to temperature extremes are controlled by the nervous and hormonal systems, which trigger vasoconstriction or vasodilation.
What is vasoconstriction?
Vasoconstriction is the constriction of small blood vessels in the skin. This causes less blood flow and less heat transfer.
What is vasodilation?
Vasodilation is the dilation of small blood vessels in the skin. This causes more blood flow near the skin. surface resulting in more heat transfer.
Which hormone controls blood sugar levels.
Insulin
Why are hormone actions slower than nervous reaction?
Hormone action is slower than nervous reaction as the hormone travels in the blood.
What causes type 1 and and type 2 diabetes?
- Type 1 diabetes is caused by the pancreas not producing any insulin, so must be treated by doses of insulin.
- Type 2 diabetes, which is caused by either the body producing too little insulin or the body not reacting to it, can be controlled by diet.
What does insulin do?
Insulin converts excess glucose in the body into glycogen, which is stored in the liver. This regulates the blood sugar level.
Insulin dosage for a person with type 1 diabetes.
The insulin dosage in type 1 diabetes needs to vary according to the person’s diet and activity. Strenuous exercise needs more glucose to be present in the blood, so a lower insulin dose is required.
