Topic 5a The nervous system Flashcards
Define Homeostasis
Homeostasis is the regulation of conditions inside the body and cells to maintain a stable internal environment, in response to changes both internal and external conditions
Give two example conditions in your internal environment that need regulating and maintaining
Blood glucose content Body temperature Body water content
What is a stimulus
A change in your environment which may require a response
Name the part of the automatic control system that receives information about a stimulus and organises a response
Co-ordination centre
The water content in the body is monitored by a control system. If it gets to low, a negative feedback mechanism is triggered. Briefly outline the stages in this feedback system
- Receptors of detect a stimulus when the water content of the body is to low -This information is sent to the co-ordination centre, which organises an appropriate response from the effectors - The effectors respond to counteract the change bringing its level back to the optimum level. Receptor detect stimulus - co-ordination centre organises response - effector bring water level to optimum
What categories are the control systems which regulate your internal environment categorised into
Nervous and Hormonal (chemical communication systems)
What type of effector secretes hormones
Glands secrete hormones
A sensory neurone is a type of neurone. Name two other types of neurone
Relay found in CNS Relay neurone = Carry electrical impulses from the sensory neurones to the motor neurones and are found in the Central Nervous System Motor neurone = The neurones that carry the electrical impulses from the CNS to the effectors
A dog hears a cat moving in the garden and runs toward it. - What is the stimulus in this situation. - What detects the stimulus in this situation - What type of neurone transmits the information about the stimulus to the CNS
Stimulus - That sound of the cat moving Receptors in the dogs ears detect the stimulus (receptors sensitive to sound) Sensory neurone transmits the information to the CNS
What type of neurone transmits information from the CNS to an effector
Motor Neurone
How do nerve impulses travel between two neurones
The nerve signal is transferred by chemicals which diffuse across the synapse which sets off an electrical impulse in the next nuerone
What is a reflex
Reflexes are fast automatic responses to specific stimuli
Give an example of the bodies natural automatic reflex response
Bright light shinning in the eye. Your pupils automatically get smaller to prevent excessive amounts of light getting into your eye and damaging your sight.
Do reflex arcs travel through conscious parts of your brain
No - they are automatic responses which bypass your conscious part of the brain completely when a fast response is required
What trick can be used to remember the reflex arc
SRSRMER Stimulus - Receptor -Sensory N - Relay N - Motor N -Effector - Response
David steps on a drawing pin and immediately pulls his foot up What is the stimulus in this response? What is the effector in this response, How does it respond?
Stimulus = would be the pain felt from stepping on the pin The effector in this response would be the muscles contracting in order for David to lift his foot off the ground (moving foot away from the source of pain)
What is reaction time
The time taken to respond to a stimulus
Name the region of the brain that is important for consciousness
Cerebral Cortex - outer wrinkly layer of the brain responsible for consciousness, intelligence, memory and language Cerbral cortex = memory, intelligence, conciousness
Where in the brain is the cerebellum located
At the back of the brain behind the medulla and spinal cord on diagram. It is responsible for muscle co-ordination.
Where is the Medulla located
The medulla is at the base of the brain, at the top of the spinal cord. It controls unconscious activity (thing that you don’t have to think about) like breathing and your heart beat.
Ataxia is brain condition which can cause difficulty with walking. What part of the brain may be affected with ataxia.
The cerebellum as this is the part of the brain responsible for muscle co-ordination
What ways can neuro-scientists associate different parts of the brain with specific functions
- Studying patients with brain damage e.g. If a patient has a stroke damaging the back of the brain and the patient loses their vision we can identify that the back of the brain has something to do with vision
- Electrically stimulating the brain using electrodes to send electrical impulses to different parts of the brain and observing response
- MRI Scans Magnetic Resonance Imaging scanner to monitor brain activity
What type of organ is the eye
The eye is a sense organ
Name the different parts of the eye and their function
Sclera - Tough supporting wall of the eye
Cornea - Transparent outer layer found at the front of the eye. It refracts (bends)light into the eye
Pupil - The hole at the centre of the eye through which light enters Iris - Contains muscles which allow it to control the diameter of the pupil and therefore control how much light enters
Retina - Layer at the back of the eye which contains 2 light receptor cells one for light intensity and the other which is sensitive to colour
Lens - focuses the light into the Retina Cillary muscles and Suspensory ligaments control the shape of the lens
Optic nerve - carries impulses from the receptors on the retina to the brain