Topic 4: Shark Physiology 1 Flashcards
Sharks heal very slowly/quickly when wounded.
- quickly
Elasmobranchs ability to heal has been given a lot or very little research attention by scientists?
- very little
Most focus that has been done on elasmobranch wound healing has focused on what?
- the immune system ( tumour angiogenesis), arthritis (cartilage) and the liver (detoxify).
A sharks liver can detoxify many/few things in the environment.
(extreme example?)
- many
- it can detoxify lead!!
Even though a sharks liver can detoxify a wide range of things in the environment, ___ can still accumulate in them such as____ BUT??
- toxins
- mercury
- they do nt affect them as much as it would mammals
Big difference between elasmobranchs and teleost fish in regards to healing?
- teleost fish usually do not replace their scales.
Do sharks need both gill sets to be fully functional to survive in the wild?
- no
- they can live fine off of just one functional gill set.
How do most sharks solve their disputes?
- just threat displays because they recognize that they could injury each other very easily if it was full blown.
What other organisms are similar in their healing factor to elasmobranchs?
- Dolphins
With the injured shark example in class that took significant damage to its right gill set to the point it was probably nonfunctional, how long did it take to heal (seal) over?
- 1 year
L> that was observed in wild though
-
Did the example shark have fully functional gills back?
- no probably not….there may still be a few gill slits that function.
What is one hindering question when examining the rate of a sharks healing factor?
- we do not understand how they heal so quickly since the marine environment is so fility and would have a high bacteria concentration therefore an increased risk to infection.
What is the Imp Factor??
- dermal denticles are continually replaced along the body of elasmobranchs
One report in 1974 on shark healing found what about dermal denticle regeneration in sharks? (think pattern)
- that the original pattern of denticles was not regenerated.
In 1998 what was published by Wolf-Ernst Reif?
- the first paper that looked at the form and arrangement of repair scales in Nurse Sharks and leopard sharks.
Since the imp factor is always occurring what is not surprising ?
- that their healing ability occurs at such amazing feats but the rate at which it occurs is astonishing!!
Wolf-Ernst Reif’s Study on Shark Healing:
-what did he do to the sharks?
- he surgically removed 7 by 7 millimetre (1/2 inch) piece of skin from his test subjects
Wolf-Ernst Reif’s Study on Shark Healing:
- what subjects were involved in his study?
- Leopard shark
2. Nurse shark
Wolf-Ernst Reif’s Study on Shark Healing:
- what did he note in the following two weeks after removing the skin?
- the wound area secreted mucus, later it contracted 2/3 original length and the epidermis (outer layer of skin) regenerated.
Wolf-Ernst Reif’s Study on Shark Healing:
- After four months what did he note in the nurse shark?
- most of the scar area was covered with denticles
Wolf-Ernst Reif’s Study on Shark Healing:
- what was a main difference in the surgical procedure with the nurse shark and leopard shark?
- the leopard shark had most of its skin removed while the nurse only had half.
- Nurse: inner most layer was still there
- Leopard: collagen fibres were exposed
Wolf-Ernst Reif’s Study on Shark Healing:
- whats a key factor with both of the animals he examined?(a good control)
- BOTH were mature sharks
- he wanted to see the repair sequence in adults because there may be differences via age…metabolic rates etc
Wolf-Ernst Reif’s Study on Shark Healing:
- what is a concern with how much skin he removed off of the leopard shark vs nurse?
- he left some skin intact on the nurse shark but ( he took a portion and left a portion) he cut deeper on the leopard shark and never explained why he did in the paper.
Wolf-Ernst Reif’s Study on Shark Healing:
- What was found on both wounds of the shark>
- secretion of copies amounts of mucous…it seals off the wound from bacteria (thats what is thought anyways )
Wolf-Ernst Reif’s Study on Shark Healing:
- did he do any chemical analysis of the secreted mucous?
NOPE
Wolf-Ernst Reif’s Study on Shark Healing:
- Comparing the regeneration what is the noticeable difference between the nurse and leopard?
- leopard has more gaps in scales and is thought to be because of them taking more skin off .
Wolf-Ernst Reif’s Study on Shark Healing:
- What did they damage in the process of surgery?
some denticles
Wolf-Ernst Reif’s Study on Shark Healing:
- what was seen at 8 weeks?
- new scales start to repair
Wolf-Ernst Reif’s Study on Shark Healing:
- at four months what are the scales like?
- they are replaced but they are much different than the original ones
L> seen both in the nurse and leopard shark
L> assume seen in all species
Wolf-Ernst Reif’s Study on Shark Healing:
- describe the scale situation seen in the diagrams of the nurse shark and leopard shark?
- Nurse shark….the new scales are much larger than the older ones and are slightly misaligned
- Leopard: there is a gap seen which is attributed to possibly too much skin being taken
L> if thats the case…where did the scales come from?
L> scales are also slightly larger in size vs old ones but not to the extent of the nurse shark…they are also not in original alignment
Wolf-Ernst Reif’s Study on Shark Healing:
- why are the confused about where the scales came from on the healing leopard shark?
- they believed they took so much skin that they removed the cells responsible for scale production.
Wolf-Ernst Reif’s Study on Shark Healing:
- The scar area differed from the original in what five ways?
- size
- variability
- shape
- arrangement
- orientation
Wolf-Ernst Reif’s Study on Shark Healing:
- The scar area differed from the original in five ways:
1. Size?
1.they didn’t do actual measurements but took estimates that there was a +60% size difference vs old scales.
Wolf-Ernst Reif’s Study on Shark Healing:
- The scar area differed from the original in five ways:
2. Variability?
- for both the nurse and leopard the scales were pretty much similar to the original scales so you wouldn’t mistake them for a different species of shark. It is important to remember that over the length of the body normally the denticles do vary in size etc depending on where they are located when talking about their ability to flare….which they never examined to see if they still flared or not.
Wolf-Ernst Reif’s Study on Shark Healing:
- The scar area differed from the original in five ways:
3. Shape ?
- The only thing that varied here was the number of crowns present…this was highly variable compared to the original typical crown pattern seen before the wound. (noted by hash marks o scales)
Wolf-Ernst Reif’s Study on Shark Healing:
- The scar area differed from the original in five ways:
4. Arrangement??
- they SAID it would be a good idea to measure the angle of the control scales to see how much they deviated from the normal arrangement. No statistics were done for this ( they all angle towards to tail region
Wolf-Ernst Reif’s Study on Shark Healing:
- The scar area differed from the original in five ways:
5. Orientation?
- angle of the new scales are well for from the normal arrangement!
Wolf-Ernst Reif’s Study on Shark Healing:
- Which shark did they say had the greatest deviation seen in the scales from the normal polarity?
- leopard shark