Reflexes and touch Flashcards
What is the difference between reflexes and responses?
Responses are conscious decisions whereas reflexes are ways in which the bod can sense what is happening in the environment and change how the effector responds. No conscious thinking is required.
Give an example of a reflex pathway.
The knee jerk reflex - a monosynaptic reflex.
What are the two neurotransmitters involved in excitation and inhibitation of muscles?
Glutamate is involved in the excitatory circuit and the inhibitory circuit involves GABA.
What does the word oculomotor relate to?
Motion of the eye.
Where must reflected light be focused in the eye?
The retina.
Describe the steps in the pupil reflex.
Light is sensed by rods and cones in the retina. Action potentials go to the visual cortex and brainstem. The optic tract innervates the brainstem, and area called the pretectal
nucleus .
The action potentials go back down the oculomotor nerve to tell eye muscles to make the pupil smaller. The iris muscles are made larger in order to do this. This protects the eye from damage when light is too bright.
What are Pacinian corpuscles?
Mechanoreceptors that are found on the end of axons that respond to pressure.
What are Meissner’s corpuscles?
Mechanoreceptors that have a much smaller receptive field - more precise than Pacinian.
How do touch receptors show adaptation?
Action potentials are only created during change rather than the degree of pressure - you are not able to constantly feel clothes on your skin.
What are the 5 types of taste?
Salty, bitter, sour, sweet and umami (savoury e.g. parmesan, seaweed).
How is the sensation of taste created?
Ligand gated ion channels are opened by agonists (the chemicals in food) which creates action potentials. There is sensory input into the gustatory cortex which creates the sensation of taste.
How is the sensation of smell created?
Odours are inhaled through the nose and go through the nasal cavity. These odorants are dissolved in the mucus lining and interact with specialised cells to cause the response. The agonist for the response is the airborne chemicals.
How is such a wide variety of taste created, despite there only being 5 different types?
A lot of the sensation of taste is created through the different smell receptors.
how do skeletal muscles work
only have 2 states: contracting and not contracting
there is no input when they are relaxed
How does GABA work
causes hyperpolarisation, so depolarisation is less likely
