Do giraffes have a recurrent laryngeal nerve?

Do giraffes have a recurrent laryngeal nerve?

The recurrent laryngeal nerve is an often cited example of “unintelligent design” in biology, especially in the giraffe. The nerve appears early in embryonic development, before the pharyngeal and aortic arches are separated by the development of the neck.

How long is a giraffe recurrent laryngeal nerve?

The tallest giraffes have necks up to 2.4 m long (Toon and Toon 2003), so the total length of the nervous pathway from the brainstem to the larynx along the descending vagus and ascending recurrent laryngeal nerves approaches 5 m in the largest individuals.

What animals have a recurrent laryngeal nerve?

I’ve written about the recurrent laryngeal nerve before, in Wedel (2012) and in this post. It’s present in all tetrapods, from frogs and salamanders on up. The frog RLN is shown in ventral view above, and in lateral view below, both from Ecker (1889:plate 1, figures 114 and 115).

What is the specific meaning of laryngeal nerve?

Laryngeal nerve, recurrent: One of the branches of the vagus nerve, a long and important nerve that originates in the brain stem. After the recurrent laryngeal nerve leaves the vagus nerve, it goes down into the chest and then loops back up, to supply nerves to the larynx (the voice box).

What is laryngeal nerve damage?

Laryngeal nerve damage is injury to one or both of the nerves that are attached to the voice box. Laryngeal nerve damage can be caused by injury, tumors, surgery, or infection. Damage to the nerves of the larynx can cause hoarseness, difficulty in swallowing or breathing, or the loss of voice.

Why would giraffes need a strong heart?

In order to reach the brain, the heart has to pump blood not only against gravity but also against the hydrostatic pressure of the blood already in the long vertical artery, requiring a tremendous amount of force.

Where does recurrent laryngeal nerve enter?

Both recurrent laryngeal nerves pass deep to the inferior constrictor muscle and enter the larynx at the junction between the inferior cornu of the thyroid with the cricoid cartilage.

What does laryngeal mean?

1 : of, relating to, or used on the larynx a laryngeal obstruction. 2 : produced by or with constriction of the larynx laryngeal articulation of sounds.

Can laryngeal nerve damage be repaired?

Superior laryngeal nerve injuries are not repaired, and they are treated with voice rehabilitation. Recurrent laryngeal nerve injury results in vocal cord paralysis in up to 6% of patients. The vocal cord on the injured side is usually fixed in the median position, and the voice is usually—but not always—hoarse.

What is the recurrent laryngeal nerve in a giraffe?

Giraffe Weekend: The Recurrent Laryngeal Nerve. The extreme detour of the recurrent laryngeal nerves, about 4.6 metres (15 ft) in the case of giraffes, [26]:74–75 is cited as evidence of evolution, as opposed to Intelligent Design. The nerve’s route would have been direct in the fish-like ancestors of modern tetrapods, traveling from the brain,…

Why do giraffes have such long necks?

The long way round. The giraffe is a mammal known most famously for its long neck. True to biological homology, the recurrent laryngeal nerve of the giraffe also routes via the thorax and under the aortic arch, taking the detour to hilarious degrees. While in humans this is a detour of mere inches, in the giraffe the nerve is around 15 ft long.

Did giraffes and whales have nerves?

The same can be said for whales, although the dissections to remove such a nerve from a whale would be tricky. While the giraffe’s RLN is about 5 metres (15 feet) in length, other long-necked animals such as the Supersaurus would have had nerves up to 30 metres (~100 ft) long.

Is the recurrent laryngeal nerve an example of evolution?

It’s the recurrent laryngeal nerve. The extreme detour of the recurrent laryngeal nerves, about 4.6 metres (15 ft) in the case of giraffes, [26]:74–75 is cited as evidence of evolution, as opposed to Intelligent Design.