Nervous System and Hormones Flashcards
Is the nervous system or the hormonal system faster method of communication?
The nervous system is a rapid form of communication.
Summarise hide a nervous system works.
Stimulus -> receptor -> effector -> response
Describe one major difference between plants and animals.
Major difference between plants and animals is that animals can respond to the environment in a more rapid and complex way.
In the system of responding what is the link between the reception and effector called?
A co-ordinator
What three things are at the receptors in our hands and fingers sensitive to?
Touch, pressure and temperature.
What are the three main types of neurones?
Sensory neurone - link receptors to the CNS
Association (also called connector or relay) neurones - link within the CNS
Motor (also called effector) neurones - link with CNA with the effector
Neurones do not make direct contact with each other but instead there are small gaps or junctions between them. What are these called?
Synapses
What a reflex actions?
Reflex actions are rapid responses that protect the body from unnecessary damage.
List four characteristics of reflex actions.
🚝 They occur very rapidly
🚝 They do not involve conscious thought
🚝 They are automatic and always occur in the same way
🚝 Few synapses are involved -> very fast
What is the reflex arc?
The reflex arc is a short pathway that links pain receptors in, for example, the finger tips to the muscles in the arm. The result is rapid movement of the hand from the source of pain.
List three examples of reflexes.
🚝 Coughing if food is heading into the trachea
🚝 Adjustment of pupil diameter in bright light
🚝 Knee-jerk reaction
What are the two types of light sensitive cells contained in the retina?
Rods - these work in low light intensity but cannot distinguish between colours
Cones - these provide colour vision and provide greater precision then roads but they only work in bright light
What is the optic nerve?
The optic nerve contains the sensory neurones that carry electrical impulses from the retina to the brain.
What is the blind spot?
The blind spot is the part of the retina where the optic nerve leaves to go to the brain and no image can be formed here, as there are no light sensitive cells.
What is the iris?
That Iris is a coloured disc that contains muscles that contract and relax to control the size of the pupil.
Describe three ways that the eye can protect itself against damage.
🚝 The eyelids and eyelashes trap dirt and dust, preventing these from reaching the eye.
🚝 Tears are produced by a gland under the eyelids and are washed across the eye by blinking. The tears contain an enzyme called Iysozyme that destroys bacteria.
🚝 The blinking reflex and the ability of the iris to restrict the amount of entering the eye further protects the eye.
What is a hormone?
A hormones is a chemical produced in one part of the body that exerts its effects elsewhere.
What is insulin?
Insulin is the hormone that prevents blood glucose (sugar) levels from becoming too high.
How is insulin produced by the body?
Insulin is produced by special cells in the pancreas in response to increasing or high blood glucose levels.
What is it glucagon?
Glucagon is the hormone responsible for raising blood glucose levels. Like insulin, it is produced in the pancreas and acts on the liver.
What is diabetes?
Diabetes is a condition where the body does not produce enough insulin to keep blood glucose levels at a controlled level. Individuals that develop diabetes are unable to control their blood glucose levels without treatment.
List some of the symptoms that are often associated with diabetes.
They are often thirsty because the high glucose levels draw water out of the cells by osmosis and the cells become dehydrated.
🚝 They have to visit the toilet frequently to eliminate the water drawn into the blood by osmosis.
🚝 There will be sugar in their urine. This happens because blood glucose levels are so high that some sugar is excreted through the kidneys.
🚝 They may become irritable and confused.
🚝 If not treated they can fall into a coma.
List the changes in the environment that plants are able to respond to.
Plants can respond to the presence of water, light and they can detect gravity.
Plants are particularly sensitive to light. What is their response to light known as?
Phototropism
What causes plants to bend towards light?
This response is caused by a plant hormone called Auxin which causes cell elongation.
What are the advantages to the plant of moving towards the light?
More light -> more photosynthesis -> more growth
But of the human bodies two main communication systems?
The nervous system and the hormonal system.
