6 The Skeleton The skeletons of most fish consist mainly of: Skull BackboneRibsFin raysSupports for fin rays or fins
7 Skullconsists chiefly of the brain case and supports for the mouth and gills
8 Backbone The central framework for the trunk and tail is the backbone. It consists of many separate segments of bone or cartilage called vertebrae.In bony fish, each vertebra has a spine at the top, and each tail vertebra also has a spine at the bottom.
10 Supports for fin rays or fins pectoral fins of most fish are attached to the back of the skull by a structure called a pectoral girdlepelvic fins are supported by a structure called a pelvic girdle, which is attached to the pectoral girdle or supported by muscular tissue in the abdomendorsal fins are supported by structures of bone or cartilage, which are rooted in tissue above the backbonecaudal fin is supported by the tailanal fin by structures of bone or cartilage below the backbone
12 Types of MuscleSkeletal MuscleSmooth MuscleHeart Muscle
13 Skeletal MuscleFish use their skeletal muscles to move their bones and finsA fish's flesh consists almost entirely of skeletal muscles. They are arranged one behind the other in broad vertical bands called myomeres.The myomeres can easily be seen in a skinned fish.Each myomere is controlled by a separate nerve.As a result, a fish can bend the front part of its body in one direction while bending its tail in the opposite direction.Most fish make such movements with their bodies to swim.
14 Smooth Muscle A fish's smooth muscles work automatically. The smooth muscles are responsible for operating such internal organs as the stomach and intestines.
16 Organs of the Respiratory System GillsMost fish have four pairs of gills enclosed in a gill chamber on each side of the headEach gill consists of two rows of fleshy filaments attached to a gill arch
17 How do fish breathe? (bony fish) fish gulp water through the mouth and pump it over the gillsthe breathing process begins when the gill covers close and the mouth opensat the same time, the walls of the mouth expand outward, drawing water into the mouth.the walls of the mouth then move inward, the mouth closes, and the gill covers open.this action forces the water from the mouth into the gill chambers.in each chamber, the water passes over the gill filaments.they absorb oxygen from the water and replace it with carbon dioxide formed during the breathing process.the water then passes out through the gill openings, and the process is repeated
19 What does the Digestive system do? changes food into materials that nourish the body cellseliminates materials that are not used
20 Organs of the Digestive System jawed mouth with a tongue and teethfish cannot move its tonguefish have their teeth rooted in the jawsPharynxa short tube behind the mouthEsophagusa tubelike organexpands easily, which allows the fish to swallow its food wholeStomach
21 Organs of the Digestive System… LiverBile-producing digestive glandGall BladderSmall sac containing the bilePyloric cecumcul-de-sac related to the intestinewhere a part of digestion mainly occurs, as well as fermentationIntestinesAnus
22 How does digestion work in fish? Fish use their teeth to seize prey or to tear off pieces of their victim's flesh.Most fish also have teeth in the pharynx, which they use to crush or grind food.Food passes through the pharynx on the way to the esophagusFrom the esophagus, food passes into the stomach, where it is partly digestedThe digestive process is completed in the intestines.The digested food enters the blood stream.Waste products and undigested food pass out through the anus.
24 What does the Circulatory System do? distributes blood to all parts of the body
25 Organs of the Circulatory System Heartconsists of two main chambers - the atrium and the ventricleBlood VesselsArteriesKidneysSpleenimpurities in the blood are destroyed
26 How does blood circulate in a fish? blood flows through veins to the atrium.blood then passes to the ventriclemuscles in the ventricle pump the blood through arteries to the gillshere the blood receives oxygen and gives off carbon dioxidearteries then carry the blood throughout the bodycarrying food and oxygen to cells and waste away from cellskidneys remove the waste products from the blood, which returns to the heart through the veins
28 Organs of the Nervous System Spinal Cordconsists of soft nerve tissueruns from the brain through the backboneBrainenlargement of the spinal cordis enclosed in the skullNervesextend from the brain and spinal cord to every part of the body
29 How does the Nervous System work? Nervessensory nervescarry messages from the sense organs to the spinal cord and brainmotor nervescarry messages from the brain and spinal cord to the muscles
31 Organs of the Nervous System MalesTestesproduce male sex cells, or spermFemalesOvariesproduce female sex cells, or eggsalso called roe or spawn
32 How does the Reproductive System work? Most fish release their sex cells into the water through an opening near the anus.The males of some species have special structures for transferring sperm directly into the females.Male sharks, for example, have such a structure, called a clasper, on each pelvic fin.The claspers are used to insert sperm into the female's body
34 Special Organs Swim Bladder below the backbone baglike organ is also called an air bladderprovides buoyancy, which enables the fish to remain at a particular depth in the watergain buoyancy by inflating their swim bladder with gases produced by their bloodthe nervous system automatically regulates the amount of gas in the bladder so that it is kept properly filled
35 Special Organs Light Producing Electricity Producing many deep-sea fish have light-producing organs developed from parts of their skin or digestive tract.some species use these organs to attract prey or possibly to communicate with others of their species.Electricity Producingother fish have electricity-producing organs developed from muscles in their eyes, gills, or trunk.Some species use these organs to stun or kill enemies or prey.