B3.1 Flashcards
What are receptor cells?
Receptor cells:
- Detect change in environment
What is an effector?
Effector:
- Muscle or gland that will bring about a response
What happens in a nervous system reaction (simple)?
Reaction:
- Receptor cell will detect stimulus (change in environment)
- It will send signal to coordination centre
- Signal will be sent to an effector, which will bring about a response
What is CNS?
CNS:
- Central nervous system
- Made up of spinal cord and brain
What are the steps involved in a nervous reaction?
Steps involved in nervous reaction:
- Stimulus, receptor cell, sensory neurone, spinal cord, brain, spinal cord, motor neurone, effector, response
What is a synapse?
Synapse:
- Small gap between nerve cells
How does a signal travel across a synapse?
Signal across synapse:
- Electrical impulse will travel to end of one neurone
- Trigger release of chemical neurotransmitter molecule
- Neurotransmitters fuse with membrane
- Open up and release chemical which diffuses across gap to next receptor molecules
What is the reflex arc?
Reflex arc:
- Stimulus, receptor cell, sensory neurone, spinal cord, motor neurone, effector, response
What is the sclera?
Sclera:
- Transparent
- Protects from damage
What is the cornea?
Cornea:
- Bends shape, funnelling light through pupil
What is the pupil?
Pupil:
- Hole that is adjusted by iris according to light levels
What are lens?
Lens:
- Held by suspensory ligaments to focus on near and distant objects
What is the retina?
Retina:
- Light falls on light receptors
- Convert signals to electrical impulses
- Sent to brain
What are receptor cells for colour called?
Receptor cells for colour:
- Cones
What are the three colours cones respond to?
Cones colour:
- Red, green and blue light
What are adaptations to dim light?
Adaptation to dim light:
- Radial muscles (like spokes on a bike) contract
- Circular muscles relax
- Pupils dilate
How does light pass through eye
Light:
- Suspensory ligaments contract and ciliary muscle relax
- Stretches lens (less refraction of light)
- Far objects
What are concave lens?
Concave lens:
- Inward facing curves
- For light which meets before retina
What are convex lens?
Convex lens:
- Thick lens
- Alters light from in front of retina to retina
What is the hypothalamus?
Hypothalamus:
- Regulates temperature and water balance
What is the pituitary gland?
Pituitary gland:
- Stores and releases hormones
What is the medulla?
Medulla:
- Controls breathing and heart rate
What is the cerebrum?
Cerebrum:
- Thinking part of brain (calculations)
What is the cerebellum?
Cerebellum:
- Coordinates muscular activity and balance
What are CT scans?
CT scans:
- Computed tomography
- Firing x-rays at brain to map 3D image
- Overexposure can cause damage
What are MRI scans?
MRI scans:
- Magnetic resonance imaging
- Magnet maps blood flow to active regions of brain
What are fMRI scans?
fMRI scans:
- Functional magnetic resonance imaging
- Maps blood flow in real time when patient is carrying out specific task
- No radiation so less risk
What are nervous system damages caused by?
Nervous system damage:
- Injury
- Disease
What is PNS?
PNS:
- Peripheral nervous system
- All neurones that connect CNS to rest of body
What are treatments for nervous system damage?
Treatments:
- Surgery (removes tumour)
- Radiotherapy
- Deep brain stimulation (inserting electrode to stimulate brain functions)
