L23 - Reflexes And Senses Flashcards
How do reflex pathways work in terms of antagonistic pairs of muscles?
There’s an inhibitory interneuron
- inhibits input from getting to antagonist muscle
What is an example of an inhibitory neurotransmitter?
GABA
What do inhibitory neurotransmitters do in terms of action potentials?
They hyperpolarise membrane
- more difficult to generate AP
How does the flexor/extensor reflex work?
- one input
- many motor neurones (lots of muscles involved)
- some inhibit, some stimulated
What does the iris sphincter muscle control?
The diameter of the pupil
What does the ciliary muscle controls?
thickness of lens
- to focus light on the retina
What is the pretectal nucleus?
The area in the brainstem that the optic tract innervates
What does the pretectal nucleus innervate?
Oculomotor nerve (cranial nerve III)
What happens to the signal of one eye when it reaches brain?
It crosses over to the opposite cortex that the eye is on
Why does the pupil constrict?
To prevent diverging light rays hitting the periphery of the retina
- blurred image
How does the eye focus a far point?
Lens flatten
= less refraction
How does the pupil focus on a near point?
Fattened lens
= defracts light to a greater degree
What does the parietal lobe association area do?
Contains knowledge about what is seen through eyes
What does the frontal lobe association area do?
Emotions
(Different responses)
What are the touch receptors?
- merkel’s disk
- meissner’s corpuscle
- pacinian corpuscle
- ruffini’s ending
