paper 2 p1 Flashcards
(42 cards)
What is homeostasis?
Keeping the conditions in your body at the right level
3 examples of control systems that keep the body steady?
Body temperature, glucose level, water level.
How can you control the body systems?
Using the nervous system or hormones.
3 main parts of control systems
- receptors
- coordination centers (including brain, spinal cord and pancreas)
- effectors
How the control system works
If the level of something changes-
A receptor deflects a stimulus which sends information to a coordination center. The coordination center receives and processes the information. It then organises the response. An effector produces a response. This returns to its optimal level.
What is a stimuli?
A change in the environment.
What does the central nervous system consist of? How is it connected to the body?
The brain and spinal cord. It is connected to the body via sensory and motor neurons.
What are receptors? 1 example
Receptors are the cells that detect stimuli. For example the ear detects sound.
What are the sensory neurons?
These carry information as electrical impulses from the receptor to the CNS.
What are effectors? Examples
They respond to the electrical impulses and bring about a change. For example muscles and glands. Muscles contract and glands release hormones.
What are motor neurons?
They carry electrical impulses from the CNS to the effectors.
What does the CNS do?
It coordinates the response.
What is a synapse?
Where two neurons join together.
What is passes from one neuron to the next and how?
Electrical impulses and by chemicals.
What do the chemicals in a synapse set off?
A new electrical impulse in the next neuron.
What are reflexes?
Automatic responses.
How do reflexes help you?
They help you avoid injury.
What is the passage of information in a reflex called? ( from receptor to effector )
A reflex arc
What is reaction time?
The time it takes to react to a stimulus
What can affect reaction time?
Age,gender,drugs
What are hormones?
Chemicals released by glands that go straight into the bloodstream.
What are the glands called that release hormones?
Endocrine glands.
What is the pituitary gland?
Sometimes called the master gland, produces many hormones that regulate the body conditions, these hormones react on other glands, these glands release hormones that bring around change.
What is the thyroid?
Produces thyroxine, is involved in regulating things like the rate of metabolism, heart rate and temperature.
