Fish Anatomy

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Fish Anatomy
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Anatomy/Physiology

• Definition of terms
• Anterior (cranial) toward the head
• Posterior (caudal) toward the tail
• Cranial head region
• Caudal pertaining to the tail region
• Dorsal toward the back (top) of the animal
• Ventral toward the belly of the animal
• Medial toward the median line
• Distal away from the center or origin
• Proximal toward the center or origin

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Anatomy/physiology

• External Anatomy of fish
• The body divided into head, trunk, and tail.
• The scales primary protection, but still a place
  pathogens could infiltrate.
• Even the head is covered by epidermis and some
  scales.

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Anatomy/physiology

• External Anatomy of fish
• Lateral line is present along middle side of
  body.
• Head
• Nares located on dorsal side of the anterior end
  of head.
• Each naris is divided into two portions which
  permits water to circulate through the olfactory
  sac.

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Anatomy/physiology

• External Anatomy of fish
• Head
• Eyes located in lateral position at anterior
  end of head.
• Ears??
• Operculum Located at the posterior and lateral
  positions of the head.
• Gill arch Beneath the operculum are located four
  pair of gill arches.

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Anatomy/physiology

• External Anatomy of fish
• Head
• Gill arch
• Each arch bears a gill on its outer surface.
• Each gill consists of two rows of filaments.
• Each filament consists of numerous lamellae.
• Inner margin of arch bears a single row of
  tooth-like projections the gill rakers.

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Anatomy/physiology

• Sensory perception of the fish
• Sight
• Sight is the predominant sense of salmon.
• Hearing
• Lateral line perceives sounds of low wave length.
• Ear perceived sounds of higher wave length.
• Equilibrium
• Organs of equilibrium are the lateral line and
  the ear.

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Anatomy/physiology

• Sensory perception of the fish
• Touch
•  Smell
• Long range perception of chemicals
• Preceptors of smell through olfactory sac
• Taste
• Taste is the perception of chemicals upon
  contact.
• Taste buds
• Taste buds located on tongue and head.

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Anatomy/physiology

• Sensory perception of the fish
• Kinesthetic perception?
• Temperature
• Function of lateral line

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Anatomy/physiology

• Functions of various sense organs
• Eye
• Sight
• Ear Inner ear
• Equilibrium and hearing
• Nares
• Smell
• Lateral line
• Hearing, equilibrium, touch, perception, and
  temperature

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Anatomy/physiology

• Internal Anatomy
• Skeletal system
• The function of the skeletal system is one of
  support.
• Skeletal tissues
• Axial skeleton
• Head, trunk, and tail regions.
• Head
• Trunk skeleton modified portion of the vertebral
  column.
• Tail skeleton remainder of the vertebral column

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Anatomy/physiology

• Supporting tissues
• Connective tissue ligaments, tendons, septa,
  fascia, and mesenteries.
• Ligaments tough bands of tissue between bones.
• Tendons thick narrow bands by which muscles are
  attached to the skeleton.
• Septa are heavy tissues which separate various
  portions of the body.
• Fascia are the thin sheets of connective tissue
  which surround muscles.
• Mesenteries are delicate tissues which support
  the organs of the body cavity.

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Anatomy/physiology

• Muscular system
• Three types of muscle tissue smooth, striated,
  and cardiac.
• Smooth and cardiac muscles are involuntary.
• Striated muscle is voluntary.
• Smooth or involuntary muscles
• Found in various organs
• Cardiac muscle is striated but involuntary.
• Primary function of muscles is motion and
  locomotion.

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Anatomy/physiology

• Digestive system
• Mouth, pharynx, esophagus, stomach, small
  intestine, pyloric cecae, liver and pancreas.
• Mouth grasping organ teeth function to retain
  prey.
• Pharynx leads to the esophagus
• Esophagus muscular tube leading from the pharynx
  to the stomach.

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Anatomy/physiology

• Digestive system
• Stomach consists of two parts
• Cardiac
• Pyloric
• At end of pyloric section heavy muscle
• Pyloric sphincter

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Anatomy/physiology

• Digestive system
• Intestine duodenum, and small and large
  intestines.
• Duodenum short portion of the intestine
• pyloric caeca are attached and which receives the
  bile duct and the pancreatic duct
• Small intestine predominant portion of
  intestinal tract.
• Large intestine extremely short and located
  just anterior to the anus.

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Anatomy/physiology

• Digestive glands in the salmon and trout include
  the gastric and intestinal glands, the liver, and
  the pancreas.
• Gastric glands
• Intestinal glands
• Liver a bilobed organ located in the anterior
  and left lateral portion of the body cavity
• Gall bladder a thin-walled sac embedded in the
  liver,
• Bile duct

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Anatomy/physiology

• Pancreas diffuse gland located on the pyloric
  caeca
• Pancreatic duct discharge enzymes into the
  intestine
• Pancreatic juices contain 3 enzymes that act on
  proteins, carbohydrates, and fats

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Anatomy/physiology

• Respiratory system
• Gills Function to exchange gases
• Oxygen absorbed through gills into blood
• Gas exchange
• Flow from dense to less dense
• Air bladder doesnt function as respiratory
  organ in salmonids
• Fry and fingerling stages air bladder connected
  by duct to the esophagus (surface feeding?)

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Anatomy/physiology

• Circulatory system Blood and lymph systems
• Blood Fluid tissue liquid plasma and cellular
  components
• Plasma 80 water
• Proteins and carbohydrates
• Waste materials (urea and uric acid)
• Mineral salts
• Enzyme secretions from glands
• Antibodies

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Anatomy/physiology

• Blood cells
• Red cells (erythrocytes)
• Flattened, nucleated cells with hemoglobin
• White cells (leukocytes)
• Thrombocytes Present in blood and aid in
  formation of blood clots
• Blood vessels Closed system which blood
  circulates heart, arteries, veins, and
  capillaries
• Heart Consists of 2 chambers - auricle(atrium)
  and ventricle

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Anatomy/physiology

• Lymph system consists of plasma and leukocytes
• Starts in the intercellular spaces and eventually
  empty into veins
• Spleen is associated with lymphatic system
• GALT and MALT
• Blood producing organs
• Functions is same as bone marrow in mammals
• Spleen, lymph nodes, and thymus

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Anatomy/physiology

• Primary functions of major organs
• Pancreas
• Spleen produces leukocytes, serves as a storage
  space for RBCs, and destroys worn out red blood
  cells
• Kidney divided into 2 parts
• Anterior produces red and white blood cells
• Posterior
• Swim bladder hydrostatic organ

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Anatomy/physiology

• Heart serves to move blood through circulatory
  system consists of atrium, ventricle, and
  bulbous arteriosis (smoothes out pressure to
  steady flow)
• Liver
• Detoxification, digestion, excretion, and
  hematopoiesis
• Digestion secretion of bile salts
• Excretion destruction of worn out RBCs,
  conversion of hemoglobin into bile salts and
  ammonium salts into urea
• The liver also serves for storage of glycogen
  (animal starch)

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Anatomy/physiology

• Gastro-intestinal tract
• Cardiac and pyloric stomach
• Pyloric caeca
• Small intestine digestion and absorption of food
• Enzymes secreted by glands break down proteins
  and carbohydrates
• Carbs. and proteins absorbed directly in to
  bloodstream
• Large intestine serves as storage space for
  accumulation of waste before excretion

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