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
Wolf-Ernst Reif’s Study on Shark Healing:
- After four months the scales were not all completely ___.
- mineralized
L> enamel
L>degree of mineralization
Wolf-Ernst Reif’s Study on Shark Healing:
- On the leopard shark the ____ differ vs original control.
crowns
Wolf-Ernst Reif’s Study on Shark Healing:
- Repair scales were no longer what?(think arrangement and orientation)
- arranged in diagonal rows nor were they oriented in a caudal direction with the cusps pointing towards the tail as seen in the control scales.
Wolf-Ernst Reif’s Study on Shark Healing:
- The study did not indicate what in its conclusion?(was it even investigated?)
whether or not the replacement denticles were eventually replaced by normal ones.
L> it was never investigated
Wolf-Ernst Reif’s Study on Shark Healing:
- did they ever follow up with the sharks?
NOPE
L> they only cut them a second time for more diagrams…never followed them though
L> THIS WAS DONE IN AN AQUARIUM WHY DIDNT THEY FOLLOW UP DERP
Wolf-Ernst Reif’s Study on Shark Healing:
- In present day do they know how long it would take replacement scales to position back to the original ones?
no
L> 2 years= estimate fem another study
L> they don’t know how they regenerated or the spacing occurrence
Wolf-Ernst Reif’s Study on Shark Healing:
- what does this study beg the question about?
- whether they haeb pain receptors…maybe they do not because of the lifestyle of sharks..maiting etc
How many great whites have been recorded in the wild for wound healing?
1
Describe the nature of the injury of the great white we discussed in class.
- sustained an injury that would probably have killed any other animal
- It was behind the dorsal fin and it went deep enough exposing the vertebrae….possibly even nicked them.
What was noted about the white shark and its wound a few months later ?
- the gap was visibly closed…almost gone
L> very little blood lose bc they were all constricted to prevent it.
L> mucous was thick…sealing it off
L> no signs of infection
L> the shark was behaving normally
L> but it did lose some weight
How big was the GW in the wild with the large wound behind its dorsal fin?
2.3 m
Nine months later after the wounded great white disappeared it reappeared. What was noted about it?
- weight loss but was seen feeding
- all that was left of the wound was a little slash mark….which was very dark in colouration due to probably a high concentration of melanin …shark denticles are very transparent.
- no evidence of long term damage
- scar is mostly collagen fibbers. What couldn’t be repaired was filled with them and melanin for coloration.
- scale morphology was not examined
What caused the injury in the great white?
prop mark via boat
Mote Marine Lab:
- Explain their study and goals
- new study of wound healing in stingrays and related species with the goal of finding new infection fighting substances that could help injured humans especially members of the military wounded in combat heal.
- role of mucous and how it fights off infection .. this could be the new age antibiotics
Mote Marine Lab:
- are they looking at dermal denticles?
L> how much was funding?
- NOPE not looking at pattern just healing!
- stingrays heal the same as sharks..they are more manageable.
- 1.3 million dollars…..lasting 3 years
Mote Marine Lab:
- downside of this study?
- medical advancement may come at the cost of sharks, skates and rays if a synthetic method is not formulated
Mote Marine Lab:
Goals:
- Testing to see if what are effective against harmful bacteria and fungi that infect wounds?
- mucus and beneficial bacteria
Mote Marine Lab:
Goals:
- Determining how these substances affect?
- rate of healing and resistance to infection in elasmobranch fishes
Mote Marine Lab:
Goals:
- to single out and describe what?
- the types of infection fighting molecules produced by elasmobranch fishes
What is the purpose of the grove in a stingrays spine?
- it channels the venom…there is a thin coating of epithelial around the spine and when it strikes this is torn away and the venom channels down the sine into the organism it has hit.
Why should you not just pull out a stingrays spine when it has punctured you?
- the way it is serrated on both sides resembles an arrow had so when it is roomed out the way it came in via pulling it…..it will cause extensive tissue damage…more than when it simple entered.
What is the primary function of a stingrays spine?
- a defence mechanism….but its primary predator would be sharks and they do not seem to be affected at all by them. So it really is a waste of energy possibly?
L> they have been found embedded in organs of sharks causing no bother at all
**mucous may be protected them?
How many stinger spines do rays have?
- commonly just one but some species have multiple
Stingray barb replacement:
- How long can the barb be?
37 cm <- largest….but average is 4 cm long.
Stingray barb replacement:
- Many stingrays replace their spine how often?
- seasonly if not used… ( 6 months to one year) L> they get to a certain length and then it is shed and replaced …IF USED it is regenerated but somewhere else on the tail in a different location…. thin layer of tissue is what keeps it in place.
Stingray barb replacement:
- what is found between the spine and tail?
loose connective tissue
Stingray barb replacement:
- what happens after the spine is used?
- it is replaced shortly after but noting he same place…
Stingray barb replacement:
- growth rate of a new sting barb?
1-2 cm a month
Stingray barb replacement:
- what happens if they lose their tail?
- if lost….the tail does not regernate back and it can no longer regenerate a spine without the tail.
Stingray barb replacement:
- does the venom from the ray cause necrosis in sharks?
hmmm NOPE
Stingray barb replacement:
- what produces the venom?
- specialized cells in epithelial along the spine secretes the venom…
Stingray barb replacement:
- is there a difference in epithelial cells around the barb in freshwater species?
YEP
- they are in a greater amount around the spine…so they produce more venom <– not stronger venom just in higher concentration
Stingray venom:
- what is the thin layer of skin that covers the spine called?
- integumentary sheath
Stingray venom:
- The integumentary sheath covers what?
- grooves that control venom glands
Stingray venom:
- ____ secretes venom
- epithelial cells
Stingray venom:
- When the spine embedded into a predator etc what happens?
- the epithelial sheath is torn open and venom is released
L> fresh water species are more toxic
Stingray venom:
- When is the venom less active?
high temperature
L> thermolabile
** warm water deactivates it
Stingray venom:
- The venom of marine stingrays is made up of a number of components such as? (3)
- polypeptides with large molecular mass
- serotonin
- hyaluronidases
* ** venom degrades tissues using powerful enzymes that break down the extracellular matrix …the ETM is what holds cells together…so with it gone nothing keeps the tissues together and they degrade.
Stingray venom:
- LD50?
- In 24 hours… at 100mg/kg^-1 it killed 3/6 animals
- At 48 hours with that same dose 4/6 died.
Stingray venom:
- LD100?
- 400 mg/kg^-1
- 6/6 died at 24 hours and 6/6 at 48…
Stingray venom:
- Initial: After getting stung, the pain typically peaks when? How does it radiate? Description of pain?
- at 30-60 minutes following the injury and it radiates centrally lasting around 48 hours.
L> described as a constant burning and throbbing
Stingray venom:
- What is the first phase after being stung?
- Phase= Envenomation
L> it involves erythema and edema of the skin and tissues respectively…
(massive swelling in the injection site)
Stingray venom:
- What is the phase that follows envenomation?
L> effects? (2)
L> forms?
- Phase 2= Necrosis
L> central necrosis of the fat and muscle causing tissue flabbiness and the formation of a pink ulcer about 96 hours after the sting
** skin loses all texture and tone….
Stingray venom:
- What are some further effects of the stingrays venom on an organism? (13)
- fever
- paresthesia
- dizziness
- nausea
- vomiting
- salivation
- diarrhea
- abdominal cramps
- sweating
- muscle fasciculations
- convulsions
Describe the reactivity in seconds for 1, 4, 16 and 64 micro grams of tissue extract dose of sting ray venom.Comparing marine and freshwater species.
- no difference found in control and freshwater species.
- FW has a higher reactivity at 1ug
- FW has a higher reactivity at 4ug
- FW has a higher reactivity at 16ug
- FW has a higher reactivity at 64ug
*significant differences btw (massive)
** Freshwater spp= Potamotrygon falkneri
Marine spp= Dasyatis guttata
Respiration:
-Water flows in through the ____ (____) and passes over the ____ and out the ___.
- mouth (spiracles)
- gills ….gill slits
Respiration:
- what do spiracles do?
- they enhance water flow in bottom dwelling sharks or when a shark is feeding!
- they draw in water over the gills
Respiration:
- Some sharks can do Buccal pumping. What is that?
- they pump water into the mouth ….this is why they can rest on the bottom
L> flaring of the gills! ….<- crucial role in stress response of sharks as well!
-buccal, or cheek, muscles that pull the water into the mouth and over the gills.
Respiration:
- Ram ventilation?
- these sharks must continually move
( porbeagle, mako, great white ex) - “ramming” the water into the mouth and letting it flow out through the gills slits
Respiration:
- Are some ram ventilator sharks able to also do buccal pumping?
- if they do its a very weak version
L> example = tiger shark…it can switch back and forth - When they start swimming fast enough to force the water in more quickly than they could pump it, then they stop pumping. The sand tiger shark is an example of a shark that switches back and forth.
Respiration:
- The heart pumps oxygen depleted blood to the gills through the ____, into ____ in the secondary ___.
- afferent branchial artery
- capillaries
- lamella
- picks up oxygen from water into blood.
Respiration:
- Primary and Secondary lamellae?
In fish gills there are two types of lamellae, primary and secondary. The primary gill lamellae come out of the interbranchial septum to increase the contact area between the water and the blood capillaries. The secondary gill lamellae are small lamellae that come out of the primary ones and are used to further increase the contact area. Both types of lamellae are used to increase the amount of oxygen intake of the blood.
Respiration:
- what kind of exchange system do elasmobranchs have?
counter current exchange system aka blood and water are moving in opposite directions
- water is moving to caudal direction and blood is moving towards the anterior portion.
- deoxygenated blood is pumped fro the heart into the ventral aorta…..which brings it to the afferent branchial artery….etc
Respiration:
- Once the blood is oxygenated what takes it away to the rest of the body?
- efferent branchial artery
Respiration:
- How efficient are sharks at extracting oxygen from the water?
- very efficient
- they take ~87% of O from H2O…indicating that they have a fairly high demand for it…
- they are not that different in respiration from bony fish.
A sharks range of tolerance for stress response is based on what?
- physiological makeup and life history of the animal !
- no blanket terms…each species is unique
Those that respire strictly via ram ventilation are they do well in stress response?
poorly
