Fish Respiratory system
1- Fish Gills extract 02 dissolved in water.
2- Water enter through mouth ,then flows
over gills then to outside.
3- Water pumping occurred by opening
mouth and operculum while swimming.
تتنفس السمماك الكسسجين الذائب
في الماء ويمر الماء في تيار
مستمر في اتجاه واحد من الفم ثم
الخياشيم ثم الى الخارج ويضخ
الماء بهذا الشكل نتيجة فتح الفم
وغطاء الخيشوم اثناء السباحة.
GILLS = BRANCH = خياشيم
THE GILLS :
1- Gill ARCH.
2- Gill Filaments.
2- Gill Rakers .
3- Branchial Arteries (Afferent and
4- Adductor and Abductor Muscles.
The Gills two sets
Four on each side
1- Gill Filaments :
Each Gill arch attached to it two Rows of Gill
Two rows of filaments = Holobranch.
One row = Hemibranch .
So each Holobranch formed of two
Long thin gill filament called primary lamellae.
Each primary lamellae has semilunar folds
across their dorsal and ventral surfaces called
2- Gill Rakers :السمنان الخيشومية
cartilaginous or bony tubercles on cranial
aspect of gill arch prevent food particles from
reaching respiratory components of gills. So
save fish from suffocation.
Complete the following
Mechanism of respiration in fishes :
1- Oxygen taken by diffusion through thin
membranes of gill secondary lamellae.
2- Blood and water move in opposite directions allow
gas exchange and that called counter current
?Differ between gills of Bony and cartilaginous fishes
Fish cardiovascular system:
1- Fish Heart.
2- Fish Blood Circulation.
Afferent Branchial arteries carry non oxygenated blood
.from Ventral Aorta to Gills
Efferent Branchial arteries carry oxygenated blood from
.Gills to Dorsal Aorta then to different parts of body
Labrynthine organ or
Arborescent organ in
Cat Fish caudal to
Gill help it to
Swim bladder (gas or air ) bladder:
The organ of Buoyancy
Is a blind sac present on
dorsal aspect of body just
ventral to vertebral column and
.dorsal to gut
.May be one chamber :Tilapia
.Two chamber : carp
Physostomous fish the swim bladder is
connected to gut by pneumatic duct.
Physoclistous' = The connection with the
gut is closed and no gas can be moved from
the gut to the swim bladder,
Gas exchange is through the capillaries
‘Rete mirabile', and the membrane of the air
bladder. The capillaries arranged in a
counter-current system to facilitate the
creation of high gas pressures within the
Methods of Reproduction
:OVIPAROUS FISHES -1
)Demersal eggs. (fresh water fishes- 1
Eggs with adhesive membranes: stick
to bottom and to each other
Eggs with adhesive threads : cling to
.plants and objects
Non adhesive : Mouth brooding : eggs
carried by parents in buccal cavity as in
).male tilapia (buccal incubation
).Pelagic eggs (sea water fishes- 2
Contain oil drops so suspend in water
Egg cases or baskets.(coral reef - 3
Horny cases produced by sharks and
skates cling to rocks or coral , shape: box
.like, flat, spiral
)fry escape into mouth of male (father )fry stored in mouth of male (father
.Fertilization internally- 1
Eggs have enough yolk to embryo - 2
..In Electric rays and Dog fish shark- 3
.Fertilization internally- 1
.Mother has PLACENTA LIKE ORGAN- 2
))..In SURF PERCH (ovary) and shark (( UUTTEERRUUSS- 3
FISH REPRODUCTIVE SYSTEM
:)TESTIS : (MALE SEX ORGAN
.TRIANGULAR – FLAT – CREAMY OR WHITE IN COLOR
SITUATED IN COELOMIC CAVITY – DORSOLATERAL TO
.SUSPENDED BY MESORCHIUM
):OVARIES : ( FEMALE SEX ORGAN
LONGITUDINAL ORGAN – PINKISH IN IMMATURE AND
.AMBER YELLOW IN MATURE
.SUSPENDED BY MESOVARIUM
THE COPULATORY ORGANS
.IN CHODROSTS : CLASPERS
IN TELEOSTS: GENITAL PAPILLA ( projection form male
.genital opening) to pour semen for fertilization
: THE KIDNEY
In fishes kidney is Mixed Organ : Hematopoitec (blood forming) ,
.Endocrine and Excretory
).Located Retroperitoneal ( ventral to vertebral column
Fish has : Cranial (Head ) kidney Hematopoitec and Caudal kidney
<Embryo has two kidneys fused completely in adults . As in Salmon
.Or two separate organs as in Anglerfish
.Open Caudal To Anus
.Form a bladder in Tilapia
THE PHARYNX : البلعوم
.It form with oral cavity , the Oropharynx- 1
It contains Gill arches ,pharyngeal teeth occurred - 2
.in these arches
The esophagus : المرىء
.short tube- 1
separated from stomach by slight constriction- 2
.Histologically : not contain gastric glands- 3
The stomach :المعدة
U or V shaped tube :
Cardia = at which esophagus open.
Pyloric opening = between it and intestine المععاء
Blind ending diverticula = ردوب اعورية
Arise from distal part of pyloric region in
stomach and cranial part of intestine.
Their number 70 or more.
Histologically resemble those of intestine
rather than stomach.
The intestine is a simple tube has nearly the
Short in Carnivores fishes and long in Herbivore
Shape of intestinal mass may be straight
.segmoid (s shaped) or coiled
Following small intestine the Rectum
. Rectum wider than it and contain rectal glands
.Rectum ends in Cloaca in Chondrosts
.as Anus in Teleosts
Reddish brown in carnivores.
Lighter brown in herbivores.
In Tilapia forms with The Pancreas a compound organ
Bilobed in common
Unilobed in Salmon and Trout.
Trilobed in mackerel.
Its Bile Ducts fuse to form Gall Bladder containing
greenish yellow bile.