Full Answer
What is the meaning of nerve ring?
Definition of nerve ring : a ring of nervous tissue especially : a ring of concentrated nervous tissue about the pharynx of various invertebrate animals
What are nerve rings in the eye?
Nerve rings are depressions in the iris stroma and also are referred to as neurovascular cramp rings, cramp rings, contraction rings or nerve rings. These may be inherited or acquired but either shows that the individual has some degree of nerve tension or anxiety.
What do white nerve rings indicate?
White nerve rings indicate an irritated, over stimulated condition of the central nervous system or of certain parts of it. If they show in certain confined parts or organs only, they often indicate the approach or present activity of healing crises.
Why are my nerve rings so heavy?
Stress rings are commonly seen in the anxiety tetanic constitutions. If your nerve rings are heavy, perhaps you ought to be giving some thought to an alteration of your lifestyle or taking up some relaxation techniques.
What do nerve rings do?
n. In echinoderms, a bundle of nerve cells encircling the mouth and connecting to radial nerves. It functions to relay the sensory and motor signals throughout the body.
Do nerve rings go away?
But some people's limbal rings last longer and stay prominent all the way into adulthood. If you have lighter-colored eyes, you're more likely to have limbal rings that remain visible as you age. Some people with darker-colored eyes have bluish limbal rings that can remain quite visible, as well.
Where is the nerve ring?
The nerve ring of hydra is a ring of neurons whose neurites make a bundle running circumferentially around the hypostome just above the tentacle zone. This nervous structure has unique features in the hydra nervous system.
What is the nerve ring of earthworm?
i) Nerve ring of earthworm : Nerve ring is an oblique ring around the pharynx in 3rd and 4th segments. Its mid-dorsal part comprises of a pair of small and fused supra-pharyngeal ganglia, also called cerebral ganglia or brain. Likewise, its mid ventral part is formed of a pair of small and fused sub-pharyngeal ganglia.
Why do my brown eyes have a blue ring around them?
Blue rings around the iris are caused by cholesterol deposits in the eye. The deposits are actually white or yellowish but can appear blue. This might sound dangerous, but it isn't. Researchers estimate that this condition impacts anywhere between 20 and 35 percent of people, becoming increasingly likely as you age.
Why do I have a gray ring around my brown eyes?
Arcus senilis is a gray or white arc visible above and below the outer part of the cornea — the clear, domelike covering over the front of the eye. Eventually, the arc may become a complete ring around the colored portion (iris) of your eye. Arcus senilis is common in older adults.
What animal does not have a brain?
Some of the other animals that survive without brains include the sea star, sea cucumber, sea lily, sea urchin, sea anemone, sea squirt, sea sponge, coral, and Portuguese Man-O-War.
Do humans have nerve nets?
Humans have a very complex nervous system composed of our 'supercomputer brains', the high-speed communication highway of our spinal cord, and an extensive network of nerves that spiderweb throughout our bodies.
Do crickets have brains?
Brain of Cricket - htmldocs - Invertebrate Brain Platform. Two ganglia are located in the insect head; the brain (supraesophageal ganglion) and the subesophageal ganglion.
Do worms pee and poop?
Worms have nephridia to filter out the dead cells and other wastes that are sloughed into the blood. Wastes from the nephridia are eliminated through the same opening as the digestive wastes. Worm urine is more dilute than ours, but has ammonia as well as urea.
What is brain ring in zoology?
From the brain a pair of thick stout circum or peri-pharyngeal connectives arise, one on each side, embracing the pharynx and meeting ventrally in4th segment by a pair of fused sub-pharyngeal ganglia. In this way, a nerve collar is formed around the pharynx called a nerve ring or brain ring.
What are ganglia?
A ganglion is a collection of neuronal bodies found in the voluntary and autonomic branches of the peripheral nervous system (PNS). Ganglia can be thought of as synaptic relay stations between neurons. The information enters the ganglia, excites the neuron in the ganglia and then exits.