B5 Homeostasis and Response Flashcards
What is homeostasis?
The regulation of the internal conditions of a cell or organism to keep optimum conditions.
What 3 things does the human body need to control?
Blood glucose concentration, body temperature, water levels.
What are the 3 parts of all control systems?
Receptors (detect stimuli) –> coordination centres (e.g. brain, pancreas) –> effectors (muscles or glands).
What is a stimulus?
A change in the environment (can be inside or outside of you).
How does the information get from receptors to coordination centres in the nervous system?
Along cells called neurones, as electrical impulses.
What are the 3 types of neurone?
Sensory (from receptor to central nervous system), Motor (from central nervous system to effector), Relay (between the sensory and motor in reflex pathway).
What is a synapse?
The junction between 2 neurones where the signal passes across as a chemical (neurotransmitter).
How are reflex actions different?
Automatic and rapid. Don?t involve the brain.
Why do we have reflexes?
To protect us.
How are nerve cells (neurones) adapted for their function?
Long, Surrounded in fat to insulate, branched ends to connect.
What factors can affect human reaction times?
Alchohol, drugs, age.
Describe how you can measure the effect of one of these factors on human reaction time.
- Measure your normal reaction time by dropping a ruler and catching it as fast as you can. 2. Repeat several times (remove anomalies before calculating the mean). 3. Drink a caffeinated drink. 4.Measure your reaction time in the same way.
List the independent, dependent and control variables for the experiment to investigate reaction times.
IV ? amount of caffeine DV ? reaction time CVs ? position of ruler at the start, volume of drink, amount of caffeine in the drink.
What is the endocrine system?
A system of hormones (chemical messengers) secreted from glands into the blood.
How is the endocrine system different to the nervous system?
The messages are transported as chemicals not electrical impulses so its effects are slower but last longer.
