Dogfish Shark Physiology Overview - Mr Null 2025 9th Grade

Dermal denticles

Reduce drag as the shark swims; prevent parasites from growing on the shark

Dorsal fin

Provides stability and prevents the shark from rolling side-to-side

Caudal fin

Tail fin; moves side-to-side to propel the shark forward

Pectoral fins

Steer left and right

Pelvic fins

Steer left and right

Anal fin

Provides stability

Claspers

Male reproductive organs that penetrate the female cloaca to deposit sperm

Cloaca

Common exit for the urinary, reproductive, and digestive systems

Lateral line

Line of holds with tiny "hairs" in them that shift and sense vibrations and motion in the water

Gill slits

Open to pass water out from the gills

Spiracle

Opens into the mouth to pass water over the gills

Nostrils

Used for smelling

Ampullae of Lorenzini

Detect electrical signals of other fish

Liver

Stores fat for energy and buoyancy; creates bile to aid digestion of fats

Gallbladder

Stores extra bile

Bile duct

Passes bile from the gallbladder into the intestine

Esophagus

Carries food from the mouth to the stomach

Cardiac stomach

First part of the stomach; equipped with muscles and strong acids to digest food

Pyloric stomach

Second part of the stomach

Pyloric valve

Between the stomach and small intestine; opens to pass food into the intestine

Intestine

Absorbs nutrients from food

Colon

Carries waste to the cloaca

Rectal gland

Collects salt from the shark's body and excretes it

Pancreas

Produces enzymes for digestion and hormones to regulate bodily functions

Spleen

Produces white blood cells to fight infections; produces red blood cells

Kidneys

Filter blood to remove waste

Testes

Produce sperm

Vas deferens

Carry sperm to the seminal vesicles

Seminal vesicles

Add secretions to sperm to form semen

Ovaries

Produce eggs

Oviducts

Two tubes that carry eggs from the ovaries to the uterus

Uterus

Stores fertilized eggs

Papillae

Bumps in the esophagus that form a tight seal to keep water out of the digestive tract

Rugae

Folds in the stomach that increase the stomach's surface area and help it expand

Mesentery

Membranous tissue that holds the intestine, stomach, and liver together

Gills

Feathery; extract oxygen from water and release carbon dioxide into the water

Atrium

Less muscular; pumps deoxygenated blood to the ventricle

Ventricle

Muscular chamber of the heart; pumps deoxygenated blood to the gills