Cartilaginous Fishes - Physiology and Anatomy Flashcards
endoskeleton of cartilaginous fishes
cartilagnious endoskeleton with minimal calcification
notochord is replaced by vertebral column as they develop
Elasmobranchii
notochord remains unchanged throughout their lives
Holocephali
gives no support
vestigial ribs
partial calcification with what
- calcium phosphates and
- carbonates
shark’s cranium
single compact cartilaginous block which encloses the brain, olfactory and auditory capsules
where are red blood cells produced
- kidneys and
- epigonal
where are white blood cells created
- spleen
- spiral valve within intestine
red muscles
- aerobic
- contains myoglobin
- for cruising
white muscles
- anaerobic
- for sudden bursts of speed
when it contracts, it pulls myocomata which cause bending of backbone rest of body
myotomes
passes over myotomes from in front backwards alternately on left right side
metachronal contraction
about how many waves of contractions are produced every minute
54 waves
transaction is capable of producing swimming movements for several days
spinal cord behind medulla oblongata
governs rhythm of contraction
spinal cord
supports fins
cartilaginous rods
act like a keel preventing rolling and yawning from side to side
median fins
compensate for downward motion
paired pectoral fins
causes downward force
caudal fin
control steering and add lift as shark swim
pectoral fins
stabilize shark
- paired pelvic fins
- one or two dorsal fins
placoid scales are also known as
dermal denticles
have placoid scales
sharks and batoids
three layers of placoid scales
- outer layer of vitro-dentine
- dentine
- pulp cavity
arrangement of placoid scales in sharks
regular pattern
arrangement of placoid scales in batoids
iregular pattern
brain
8-10 paris of cranial nerves
poorly developed outgrowths of skin and immovable
eyelids
- situated antero-ventrally
- can be spread over eye in time of danger
movable nictitating membrane
where vision becomes more acute
15m from an object
why do nares not have respiratory function
not connected ot mouth cavity
detects changes in water pressure, vibrations and movement
lateral line system
what does the lateral line system detect
- changes in water pressure
- vibrations
- movement
how are prey located from long distances
sensing low-frequency vibrations with mechanoreceptors
lateral line system is composed of special receptor organs called what
neuromasts
main function of lateral line system
- distance perception
- detecting low frequency vibrations
- directional water flow
- sensitive to electrical fields and provide a means to locate potential prey or one another
- modified parts of the lateral line system
Ampullae of Lorenzini
the ampullae of lorenzini may also function in what
navigation
where do they breath through
gills, typically having 5-7 pairs of gill slits
gill coverings
opercula
absent in the respiratory system
swim bladders
also assist in respiration
spiracles
continuously swim to kep water flowing over their gills
pelagic species
use spiracles to draw in water, which is then expelled through the gills
bottom dwelling species
heart of cartilaginous fishes
two-chambered heart with pouch like conus arteriosus
dampens blood pressure oscillations before blood flows into delicate blood capillaries
conus arteriosus
where red blood cells are produced
- spleen
- Leydig’s organ
- epigonal organ
specialized immune structure
Leydig’s organ
gut of chimaeras
“stomach” merged with intestine
shape of stomach
J
slows passage of food and increases the absorptive surface
spiral valve
what do sharks do when they eat something upsetting
stomach eversion and retraction
reproductive organ of males
claspers
reproductive organ of females
- cloaca
- ovaries
reproduction in sharks
- viviparous
- ovoviviparous
- oviparous
give birth to live young
Viviparous
lay eggs that hatch outside the mother’s body
Oviparous
hatch from an egg retained within the mother and are born live
Ovoviviparous
cartilaginous skeleton adaptation
- more flexible and lighter structure that provides agility
- reduces density of their body
adaptations of rays
strong jaws that can crush hard-shelled prey
adaptations of chimaeras
upper jaw is completely fused to the skull
adaptations of shark
use caudal fin for propulsion and pectoral fins for stability
series of pores detects vibrations in the water
lateral line system
sensing weak electric signals from prey and electric fields
Ampullae of Lorenzini
allows them to see the size, shape, and color of their food
Sharp eyesight
suited for high-speed swimming
fusiform shape
adapted for life on the sea floor
flattened bodies
adaptations of chimaeras for defense
- large head
- prominent eyes
- poisonous spine
small opening behind the eye helps with water intake
spiracles for breathing
minimize friction with water
dermal denticles (tooth-like scales)
pointed snout at the front of its head
rostrum
use to maintain buoyancy
oil-filled liver
provide stability in sharks and open like wings in rays to glide gracefully in water
pectoral fins
cold-blooded and body temperature is regulated by surrounding environment
ectothermic
can retain nitroginous waste products
urea retention habitus
