Topic 3: Elasmobranch Anatomy 1 Flashcards
(91 cards)
Three topics covered in this chapter?
- external anatomy
- skeletal anatomy
- tooth morphology
In terms of external anatomy what are some topics covered? (6)
- body design
- pitch, yaw and roll
- scales (not true scales)
- hydrodynamics
- sensory
- skin
Scales are modified what?
teeth derived from the skin
Body Design:
- Give a general description of the body shape
- Sleek, fusiform shape for most sharks, narrow caudal peduncle, streamlined tail with high aspect ratio ( fast swimming)
- large pectoral fins
- Large first dorsal fin
Body Design:
- Explain aspect ratio in terms of a fast swimming shark .
- length is long and narrow and very thin width for tail = high aspect ratio
Body Design:
- caudal peduncle ?
- a narrow one is seen in sharks that are fast swimmers!
Body Design:
- Pectoral fins originate ___ of the sharks centre of gravity and have _____ like cross section.
- forward
- hydrofoil-like ( flat on lower surface, convex on upper)
Body Design:
- Pectoral fins generate ___% of the sharks lift. They also carry heavy ___ and ___ stalling speed for___. They are also ____ for maneuvers.
- 25
- load
- low
- stalking prey
- flexible
- allows a shark to swim slowly without sinking
Body Design:
- what does the angle of the pectoral fin impact? (2)
- it impacts the sharks stalling speed and drag!
Body Design:
- Pectoral fins are used in ___ displays.
threat
l> down= annoyed…expect rapid burst of speed
L> straight out= mellow
Body Design:
- Pelvic fins can be ___ controlled.
finely
Body Design:
- Dorsal fins have a short what?
free rear trip (reduces turbulence from water…reducing drag)
L> provides stabilization from rolling and is dexterous
Body Design:
- Explain the leading and trailing edge of the dorsal fin!
- leading edge: straight edge
- trailing edge: curved in edge
Body Design:
- cartilage of a shark is reinforced with?
- calcium
Explain what yaw, pitch and roll are!
- Yaw: up and down
- Pitch: left to right via pectoral?
- Roll: side to side via nose
Body Design:
- Caudal fin can be deeply ____ and ___ aspect ratio. (maximum thrust with minimum drag)
- forked
- high
Body Design:
- lateral keel is present on some sharks and is located where?
- on tail…..for high speed sharks….reduces drag
Body Design:
- Second dorsal and anal fins are important because?
- they have pivoting base and long free rear tip and may help store laminar flow (resistance while moving through water) over posterior part of body.
Body Design:
- denticle bristling??
- when the scales are lifted from the body enhancing water flow…
Body Design:
- lamina boundary layer?
- straight…..not much resistance..boundary layer is fine.
- when the shark flexes it causes boundary layer separation which creates vortices from water flow…(via moving tale side to side)
- When denticle bristling occurs they hold the boundary layer in place enhancing water flow.
Body Design:
Shark scales are also called ____. What do they do?
- denticles
- reduce turbulence and enhance laminar flow.
L> reduces energy requirement as well. - smal grooves which enhance flow of water.
- keeps flow of water close to the body
Body Design:
Where are the most moveable scales located?
- mouth and the sides of the body.
Body Design:
- Explain the components of denticles.
- Enamel: outside portion of scale (spine)
- Dentine: inside of the spine
L> attaches to a basal plate - Melanophore: colour of scale
* pulp cavity
**dermis: melanophore and basal plate
Body Design:
Describe a short fin mako’s scales.
- they differ in size and flexibility all over the body.
L> shark controls the scales via skin