Bony Fishes - Physiology (6-10) Flashcards
regulate sexual activity and reproduction, growth, osmotic pressure, general metabolic activities such as the storage of fat and the utilization of foodstuffs, blood pressure, and certain aspects of skin colour.
endocrine system
secrete calcitonin
ultimobranchial glands
- unique glandular islets found only in the kidneys of bony fishes
- secrete hypocalcin or stanniocalcin
Corpuscles of Stannius
elicits a typical antihypercalcemic and antihypophosphatemic response on undefined target cells in the gill, intestine, and kidney
hypocalcin
known to produce urotensin I and urotensin II
urophysis
chemically related to a family of peptides that includes somatostatin
Urotensin I
member of the family of peptides that includes mammalian corticotropin-releasing hormone (CRH)
Urotensin II
- covers the external surfaces of a fish’s body, including the fins
- comprised of the epidermis and dermis of the skin
- includes skin extensions such as barbels and flaps.
integumentary system
- hard, enamel-like outer layer, an inner layer of cosmine (a form of dentine), and then a layer of vascular bone (isopedine)
- characteristics of extinct lungfishes and not found in any fishes today
- similar to ganoid scales
cosmoid scales
components of cosmoid scales
- hard, enamel-like outer layer
- cosmine (form of dentine)
- layer of vascular bone (isopedine)
- usually rhomboid in shape and have articulating peg and socket joints between them which makes them quite inflexible, but very protective
- have a bony basal layer, a layer of dentin (also found in human teeth), and an outer layer of ganoine which is the inorganic bone salt
ganoid scales
components of ganoid scales
- bony basal layer
- layer of dentin
- outer layer of ganoine
- thin, large, round or oval
- arranged in overlapping pattern which allow for greater flexibility
- surface layer is composed of calcium-based salts and inner layer is predominantly made of collagen
- As a fish grows, its scales grow, adding concentric layers, similar to tree rings.
cycloid scales
- similar to cycloid, except that they have spines or comblike teeth along their free edges
- arranged in overlapping pattern which allow for greater flexibility
- surface layer is composed of calcium-based salts and inner layer is predominantly made of collagen
- As a fish grows, its scales grow, adding concentric layers, similar to tree rings.
ctenoid scales
components of cycloid and ctenoid scales
- calcium-based salts surface layer
- collagen inner layer
skin extensions
- barbels
- flaps
- “whiskers” found on the head area of fish
- thought to be a sensory organ to help track down prey or food
barbels
- Or the operculum
- bony flap that protects the gills from harm
- opens and closes to allow water to pass over the gills.
flaps
protection of the integumentary system
- mucous secretions
- nonkeratinized epithelial cells
- hyperplasia
- scales
- noxious substances and venoms
- wandering leukocytes
- skin pigmentation
- fright pheromones
- help to keep the skin surface free of pathogens by means of continual sloughing and renewal
- help to clear suspended material from the gills and skin of fish in highly turbid or polluted waters
- mucus of tropical reef fishes contains compounds that can absorb ultraviolet (UV) radiation and may function in screening out both UVA and UVB radiation.
mucous secretions
- key component of the unique wound repair mechanism of fish integument
- also protect the skin surface from pathogen invasion by means of phagocytic activity
nonkeratinized epithelial cells
- result in epidermal thickening
- has been reported in fish infested with skin parasites or exposed to pollutants
- also occur at times that fishes are exposed to increased skin abrasion, as during spawning activity.
hyperplasia
provide mechanical protection for deeper tissues, and bony encasements and spines discourage attacks by predators.
scales
elaborated by specialized cells in the skin and produced by glands associated with spines on the fins or opercula can also help to dissuade such attacks.
noxious substances and venoms
for innate and adaptive immune systems of fishes
Wandering leukocytes
- conceal a fish via cryptic coloration, countershading, or disruptive coloration
- in deep sea, multiple bioluminescent organs or photophores distributed over the body surface can provide camouflage via counterillumination
Skin pigmentation
bioluminiscent organs
photophores
can alert other fish of the same species to the presence of predators
Fright pheromones
- functionally in charge of important processes such as digestion, absorption, and transportation of necessary nutrients
- food structural component include the mouth, teeth and gill rakers, esophagus, stomach, pylorus, pyloric caeca, pancreatic tissue, liver, gallbladder, intestine and anus.
digestive system
mouth of predatory fishes
- large
- teeth and tongue present
- gill rakers short
- pharyngeal teeth short and pointed
mouth of omnivorous fishes
- smaller
- devoid of teeth exc. pharyngeal teeth
- fine gill rakers
blunt and flat teeth
molariform
- lubricated by mucus, leads to the stomach
- short and expandable so that large objects can be swallowed
- layered with muscle.
esophagus
stomach of predatory fishes
muscular and elastic
stomach of omnivorous fishes
small
a sphincter that prevents premature movement of the food bolus out of the stomach
Pylorus
- found around the pylorus
- role of pyloric caeca in digestion has been widely speculated upon.
- Histologically, they are very similar to the intestine.
Pyloric Caeca
- around the pyloric caeca (or in that same area in fish lacking them)
- usually diffuse, not a discreet body
Pancreatic Tissue
two digestive functions of the pancreas
- exocrine secretion
- endocrine secretion
- produces bile which is stored in the gall bladder until a bolus passes the stomach, at which time the bile is expelled into the intestine
- key in the anabolism and catabolism of amino acids absorbed during digestion
- also the site of storage of food energy in the form of glycogen.
liver
- where most absorption of nutrients occurs
- lined with villi that increase surface area for absorption
intestine
intestine of predatory fishes
shorter
intestine of plant-eating fishes
long, coiled intestines
where digestive system terminates
anus
- removes metabolic waste and excess water and salt from the body
- freshwater fish have dilute urine, whereas marine fish have more concentrated urine
excretory system
includes the gonads, which are the testes and ovaries, and other secondary organs
reproductive system
under the reproductive system
- sexual maturity
- reproductive modes
- fertilization and embryonic development
- parental care
an organism having both male and female sex organs or other sexual characteristics, either abnormally or (in the case of some organisms) as the natural condition
hermaphrodites
two types of hermaphrodites
- sequential hermaphrodites
- synchronous hermaphrodites
begin life as one sex then to another
sequential hermaphrodites
organism that possesses both male and female reproductive organs and can produce both sperm and eggs at the same time
synchronous or simultaneous hermaphrodite
trade roles to maintain genetic variability
egg trading
bony fishes release eggs, and the developing embryo is nourished by a yolk sac
Oviparous
- one parent (usually female) retains the fertilized eggs in her body
- developing embryo is nourished by a yolk sac formed prior to fertilization
- no nutrient connection between the parent and the developing embryos
Ovoviviparous
- female retains the fertilized eggs in her ovary or uterus, and the developing embryo is nourished by connection with the mother.
- rare
Viviparous
brood fertilized eggs in its mouth
male jawfish
fiercly guard their young
male bowfins
make elaborate nests and provide parental care to the developing fishes
sticklebacks
unisexual fish
Amazon molly
self-fertilizing fish
Mangrove killifish
sexually mature at birth
dwarf perch
become sexually mature shortly after birth
western mosquitofish
sexually mature between one and five years
bonefish
may take ten years or more to become sexually mature
- eels
- sturgeon
