Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Receptors p1
AQA A-level biology nervous system year 13
| Term | Definition |
|---|---|
| Generator potential | A small, local electrical change that occurs in a sensory receptor cell in response to a specific stimulus such as sound, pressure, or light |
| Pacinian corpuscle structure: capsule | The several layers of connective tissue which form a protective outer covering of the receptor |
| Pacinian corpuscle structure: lamellae | Concentric layers of flattened cells separated by layers of gel which convert mechanical pressure and vibrations into energy of mechanical transduction |
| Pacinian corpuscle structure: nerve ending | A myelinated nerve fibre which begins in the centre of the corpuscle which is stimulated by the mechanical pressure and transmits the action potential down the sensory neurone |
| Function of the pacinian corpuscle | Deforms when mechanical pressure is applied which leads to an influx of sodium ions (causing voltage gated channels to open) and changes the electrical potential of the nerve ending causing an action potential to be transmitted to the CNS |
| Stretch mediated sodium channels | Specialised protein channels found in the membrane of the pacinian corpuscle which open in response to the cell membrane being stretched or deformed, allowing sodium ions to enter the cell |
| Effect of constant pressure on pacinian corpuscle | Constant pressure will not continually generate action potential as there is a refractory period. An action potential will be generated when pressure is removed |
| Refractory period | A brief period of time during which a neurone is temporarily unable to respond to a stimulus, even if it is a strong stimulus |
| Mechanoreceptor | Specialised receptors responsible for detecting mechanical stimuli or changes in position, pressure or movement |
| Mechanoreceptors in muscle | Myelinated neurones which either go through muscle and detect pressure or wrap around them and detect stretch. This is how we feel our muscles contracting and relaxing |
| Frequency (light) | The length of a wave of visible light will determine its colour (hue) and is detected by the cone cells |
| Amplitude (light) | The height/intensity of a wave of light (distance from midpoint to peak or trough) will determine the brightness of light |
| Bipolar neurones | Neurones with just one dendrite and just one axon allowing it to transmit one signal at a time from one source to another |
| Ganglion neurones | Specialised neurones only found in the periphery nervous system which carry impulses from the periphery nervous system down their axons, which weave together to for the optic nerve |
| How cones function | Separated into red, blue, and green receptors and detect detail but are not very sensitive and only activate in bright conditions, contain photopigments which are broken down by certain wavelengths of light generating an action potential |
| How rods function | Contains a pigment called rhodopsin (made of molecule retinal and protein opsin) and is absorbed by the retinal which causes an action potential |
| How rods and cones are attached to the retina | As many as 100 rods may connect to a single ganglion cell making it hard for the brain to decipher what individual rods have been activated whereas each cone is attached to only one ganglion which allows for detailed, coloured vision |
| Anatomy of the eyes: lens | Converges light so that it focuses on the retina and is held in position by suspension ligaments and ciliary muscles |
| Anatomy of the eyes: retina | Contains the photoreceptors |
| Anatomy of the eyes: fovea | Contains most of the cones and is where the image is the clearest |
| Anatomy of the eyes: choroid | Pigmented black layer (melanin) which absorbs the light that hasn’t been used by the photoreceptor to stop the light from reflecting, also contains blood vessels to deliver glucose and oxygen |
| Anatomy of the eyes: aqueous humour & vitreous humour | Transparent liquid that maintains the shape of the eye & transparent gel that supports the shape of the eye |
| Anatomy of the eyes: iris | Sphincter which adjusts diameter of pupil according to changes in light intensity |
| Anatomy of the eyes: cornea | Transparent layer that converges light as it passes over the pupil |
| Anatomy of the eyes: conjunctiva | Transparent layer that protects the cornea |
| Anatomy of the eyes: circular ciliary muscles | Contracts and relaxes to change the shape of the lens so that light from different distances can be focused on the retina |
| Anatomy of the eyes: suspensory ligaments | Holds the lens in position |
| Anatomy of the eyes: optic nerve | Carries nerve impulses from the rods and cones to the brain |
| Anatomy of the eyes: blind spot | Part of the retina where all nerve cells exit the eye, contains no rods and cone cells |
| Anatomy of the eyes: sclera | Fibrous protective layer that enables muscle attachment |
Created by:
Study_B
Popular Biology sets