Page 12 - Shark

Inside a shark

Danger below
packaged neatly inside this spinner shark’s body are all Sharks have been
the organs that keep it alive. To breathe, sharks have gills that known to attack
people coming
absorb oxygen from the water and release carbon dioxide back down into water,
into it. These gases are transported to and from the gills by the as this Australian
parachutist will
blood. The heart pumps the blood around the body, delivering soon discover.
oxygen and nutrients, while taking away carbon dioxide and
other wastes. To get energy for all their activities, including Paired kidneys regulate waste
growth and repair, sharks need to eat. Food passes into the products to keep concentration
digestive system, which is like a large tube. From the mouth of body fluids just above
that of sea water,
the food goes down the gullet into the stomach, where digestion or sharks will
begins, and then into the intestine where digested food is absorbed. dehydrate
Indigestible wastes collect in the rectum to be passed out of the
body. Digested food is further processed in the large liver, which also
increases the shark’s buoyancy. Kidneys remove wastes from the blood
and regulate blood concentration. Large muscles in the body wall keep
the shark swimming, while the skeleton and skin provide support.
The brain coordinates the shark’s actions with signals or instructions
passed back and forth along the spinal cord. Finally, sharks, like
all animals, cannot live forever and must reproduce to carry
on the species. Female sharks produce eggs from their
ovaries and males sperm from their testes. When sperm
meets egg, a new life begins.

Segmented swimming muscles
contract alternately, sending a
wave motion from head to tail

Model of a female spinner
shark, showing internal anatomy
Scroll valve
in intestine, or gut—other
Vent between claspers sharks have spiral or Left
for disposing of body Rectal gland (third ring valves lobe of
wastes kidney) passes excess large
salt out of the body liver
Male through the vent
or feMale
All male sharks
have a pair of
claspers that are
Clasper (male formed from the Caudal fin
reproductive organ) Male shark
inner edge of their
pelvic fins. During
Female shark mating, one of the all in the tail Vertebral
(claspers claspers is rotated Sharks have a backbone, or column
absent) forward and inserted vertebral column, which extends
into the female’s into the upper lobe of their tail,
body opening, or or caudal fin. This type of caudal
cloaca. Sperm is fin is called a heterocercal tail, as Cartilaginous
pumped down a opposed to those in most bony rod
groove in the clasper fish, where the upper lobe does
into the female, so not contain an extension of the Dermal
fertilization of her vertebral column. Cartilaginous filament
Cloaca (opening eggs takes place rods and dermal filaments help
for reproduction, and vent for waste disposal) inside her body. to strengthen the shark’s tail.

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