Anatomy & Physiology - moodle2.bgu.ac.il · Mucous glands- between the ... Mudpuppies – comparative anatomy Bullfrog, Leopard frog – physiology ... Amphibians Anatomy & Physiology

Fish Anatomy and

Physiology

IntroductionFish are the largest, most common and most

diverse vertebrate group in the world

Transition of fish out of the water and the invasio n of land by amphibians= Evolution

Introduction

Agnatha -Jawless Vertebrates (Fish)• Most species are prehistoric or extinct• 60 modern species divided into two classes:

� Class Myxini - the hagfish� Class Cephalaspidomorphi - the lampreys

Introduction

Gnathostomata - Jawed vertebrate (fish) • Comprises roughly of 60,000 species• 99% of all living vertebrates

� Class Chondrichthyes - cartilaginous fishes� Class Osteichthyes -bony fish, which has two

subclasses: � Sarcopterygii- lobe-finned fish� Actinopterygii- ray-finned fish

Introduction

Jawless Fishes• Cartilaginous skeleton• Anterior and posterior dorsal and caudal fins• Lateral line• Well- developed eye

Introduction

Jawed fishesCartilaginous Fish:• Cartilaginous skeleton• Covers in dermal denticles (placoid scales)• Fines are supported by flexible spines • Five to seven pairs of gill slits without a gill cover

(Operculum)• Internal fertilization- the male grasps the female and

releases sperm to fertilize the female's oocytes• No swim bladder

Introduction

Jawed fishesBony Fish : Lobe-finned fish• Fins with bony, leg-like supports (potentially useful for

supporting the body on land)

� Coelacanth- two known species

� Lungfish-freshwater fish long-life (80 years)

• Tetrapods- evolved from primitive lobe-finned fish:� Amphibians, reptiles, birds and mammals

Introduction

Jawed fishesBony Fish: Ray-finned fish• Rigid skeleton- true bone• Upper jaw consists of two bones• Gill cover (operculum)- pump water through the gills• Improved scales• Swim bladders • Fins supported by rays• 96% of all living fish- 25,000 species

Anterior caudal

fine Posterior

caudal fine

Pelvic fin

Anal finMating organ

female

Pectoral

fin

Gill openings

Tail

Nostrils

Cartilaginous

fish

cloaca

Anterior caudal

fine Posterior

caudal fine

Pelvic fin

Anal finMating organfemale

Pectoral

fin

Gill openings

Tail

Nostrils

Cartilaginous

fish

cloaca

Cartilaginous

fish

Bony fish

cloaca

Fish Anatomy

External Anatomy

Fish AnatomyExternal Anatomy

Eyes: Colors and short distance. They use their vision to escape predators and find food Nares: Used for smelling only not breathing.Mouth: consume foodOperculum : Bony flap that protects the gills from harm, allow water to pass over the gillsPectoral Fin: Changes in side-to-side direction and speed, a brake to decrease speed Pelvic Fin: Stabilizes the fish while swimming and allows for up-and-down movement Vent: Waste and extra water discharge, outlet for eggs or milt (sperm) during spawning Anal Fin: Stabilizes the fish while swimming Caudal Fin: Moves, propels or pushes the fish through the water Dorsal Fin: Helps maintain balance while swimming Scales: Protect the fish from injuryBarbels: Sensory organ to help track down prey or food

Fish AnatomyExternal Anatomy

Fish Senses:

Eyesight: Two directions, one eye focusing on an object independent of the other (human’s eyes can only focus on one object at a time) Hearing: No external ear openings, sound travels faster in water than in air. Fish have internal ears with pairs of inner ear bones called otoliths. Which allows fish to sense sounds in the water. Otoliths can be used to determine fish age and the health Smell: Locate food and to aid in migrating Taste: Some fish have taste buds located on the outside of the fish’s head and fins in small pores Lateral Line: Alongside a fish’s body from the operculum to the tail, senses vibrations or movements in the water. Fish can locate predators and find prey

Fish AnatomyInternal Anatomy


SWIM BLADDER: A hollow, gas-filled balance organ that allows a fish to conserve energy by maintaining neutral buoyancy in water

GILLS: Allow a fish to breathe underwater. These are very delicate structures and should not be touched

KIDNEY: Filters liquid waste materials from the blood; out of the body. The kidney is also extremely important in regulating water and salt concentrations within the fish’s body, allowing certain fish species to exist in freshwater saltwater or both

STOMACH AND INTESTINES: Break down (digest) food and absorb nutrients. Carnivore fish (bass) that eat other fish, have fairly short intestines because food is easy to chemically break down and digest. Fish that are herbivorous (tilapia ) eat plants require longer intestines because plant matter is usually tough and fibrous and more difficult to break down into usable components


PYLORIC CAECA: This organ with fingerlike projections is located near the junction of the stomach and the intestines. Secretes enzymes that aid in digestion

LIVER: Assists in digestion by secreting enzymes that break down fats, and also serves as a storage area for fats and carbohydrates. Destruction of old blood cells and in maintaining proper blood chemistry, as well as playing a role in nitrogen (waste) excretion

HEART: Circulates blood throughout the body. Oxygen and digested nutrients are delivered to the cells of various organs through the blood, and the blood transports waste products from the cells to the kidneys and liver for elimination


GONADS (REPRODUCTIVE ORGANS): Adult female orange mass of eggs is unmistakable during the spawning season, but identifiable at other times. The male organs, which produce milt for fertilizing the eggs, are much smaller and white; found in the same general location. The EGGS (or ROE) of certain fish are considered a delicacy (caviar from sturgeon)

MUSCLES: Provide movement and locomotion (fillet)

SPINAL CORD: Connects the brain to the rest of the body and relays sensory information from the body to the brain, as well as instructions from the brain to the rest of the body

BRAIN: The control center of the fish, where both automatic functions (such as respiration) and higher behaviors occur. All sensory information is processed here

Fish Physiology

1. Integumentary system

2. Musculoskeletal system

3. Digestive system

4. Respiratory system

5. Circulatory system

6. Excretory Organs

7. Nervous system

8. Reproduction system

Fish PhysiologyIntegumentary system

Epidermis (outer) layer-Epithelial cells, shed and replaced by new onesMucous glands-between the Epithelial cells produce, Mucoid secretions-protective covering (slime coat)Dermis- Connective fibroblasts, collagen and blood vesselsScales- Lie in dermal pockets, covered by the Epithelial layer; form a protective flexible armor to withstand blows and bumping

Fish Physiology



3. Digestive system



6. Excretory Organs

7. Nervous system


Fish PhysiologyMusculoskeletal system

Two types of skeletal muscles in fish:

White- most muscles in a fish are white muscles. Anaerobic, need carbohydrates to produce energy

Red- Around the white muscles. contains myoglobin, capillaries, glycogen and lipids. Aerobic, need fat to produce energy

Fish swimming in a sustained swimming speed -red muscles are used, in prolonged swimming or high speed swimming white muscles are used- may lead to fatigue

Fish PhysiologyMusculoskeletal system

Average bony fish looks like an arrow- easily move through water

Fish Physiology



3. Digestive system



6. Excretory Organs

7. Nervous system


Fish PhysiologyDigestive system

Fish Physiology

Digestive system• Pyloric ceca- some species of fish (Salmonids), secrete

the digestive enzymes for some food. Fish without the pyloric ceca have digestive enzyme production in the liver and pancreas

• There is no true division into large and small intestine • Hepatopancreas- some fish species exocrine pancreas is

present near the small veins off the hepatic portal vein• Pancreas is scattered in the mesentery, primarily near the

pylorus

Fish Physiology



3. Digestive system



6. Excretory Organs

7. Nervous system


Fish Physiology

Respiratory system

Fish Physiology

Respiratory system• Gill filaments are arranged in rows in gill arches,

and each filament has a lamellae that contain capillaries

• Gills filaments are highly branched and folded-increasing surface area for gas exchange

• When water passes over the gills, the dissolved oxygen in the water rapidly diffuses across the gills into the bloodstream

• Blood in the capillaries flows in an opposite direction to the flow of water around the gill filaments- good opportunity for absorption

Fish Physiology



3. Digestive system



6. Excretory Organs

7. Nervous system


Fish Physiology

Circulatory system

Sinus venosus - preliminary collecting chamber

Atrium - largest of the chambers and only weakly muscular, it pushes the blood, with weak contractions in the ventricle

Ventricle- well muscled chamber, as large as the atrium it is the work horse of the heart, its contractions drive the blood around the body

Bulbus arteriosus- The last chamber of the fish heart, elastic and work to reduce the pulsed of the blood leaving the ventricle -constant flow

Fish Physiology

Circulatory system

ventral artery

Dorsal artery

Fish Physiology



3. Digestive system



6. Excretory Organs

7. Nervous system


Fish Physiology

Excretory Organs

• Kidney –pro-nephrous(primitive)• Gills • Skin

Fish Physiology



3. Digestive system



6. Excretory Organs

7. Nervous system


Fish Physiology

Nervous system

Fish Physiology

Nervous systemVision - Sight varies according to habitat (deep sea, different wave lengths), no eye lids

Auditory- Fish can sense sound through their lateral line and their otoliths (inner ears). Fish can detect hydrodynamic stimuli via the lateral line, some fish can hear through their swim bladders

Touch - Nerve endings throughout the skin react to the slightest pressure and change of temperature

Lateral Line System - open to the environment via a series of openings called lateral line pors leading in to tiny canals under the skin consisting of an array of sensors called neuromasts along the length of the fish's body. Water flow around it creates a series of vibrations that the fish senses

Fish Physiology

Nervous systemPain-

Different species can use different brain structures and systems to handle the same

functions• Fish have pain and fear responses

• Neurobiologists recognized fish nervous systems comprehend and respond to pain

• Fish have neurotransmitters (endorphins) that relieve suffering—the only reason for their nervous systems to produce these is to alleviate pain

• Researchers detected more than 20 pain receptors (nociceptors) in fish’s mouths and heads

Fish Physiology



3. Digestive system



6. Excretory Organs

7. Nervous system


Fish PhysiologyReproduction system

Fish reproductive organs include testes and ovaries . gonads are mostly paired organs

Oviparous - Eggs development and fertilization takes place outside the mother's body. male and female fish shedding their gametes in the surrounding water

Ovoviviparous- Eggs develop inside the mother's body after internal fertilization no nourishment from the mother, only from the yolk. Each embryo develops in its own egg

Viviparous- Mother retains the eggs and nourishes the embryos

Ovoviviparous and Viviparous fish are livebearers

Fish Physiology

Reproduction systemThree modes of reproduction

heterosexual - Separate male and female parents, in some live-bearing fishes, the female can store sperm up to 8 to 10 months, fertilizing new batches of eggs as they develop or carry sperm from several males at once

Hermaphrodites - possess both ovaries and testes at the same time. External self-fertilization occurs shedding eggs and sperm simultaneously

Parthenogenetic (asexual) - unfertilized eggs develop into embryos; development proceeds without fertilization; in some of these females, mating with a male is still required to stimulate egg development

Amphibians

Anatomy and

Physiology

IntroductionAmphibians

Greek= “both kinds of life”

Class: AmphibiaOrders: Anura (frogs & toads); 88%, Tail-less oneCaudata (salamanders); 9%, Tailed oneGymnophiona (Caecilians); 3%, Leg-less one


Axolotol, Toads ( Bufo) – development, limb regenerationMudpuppies – comparative anatomyBullfrog, Leopard frog – physiologyXenopus -developmental studies, reproduction, biological research and teachingRana- environmental toxins


Anura - Xenopus laevis; African claw -toed frog:• Long hind limbs - fold underneath them

• Short forelimbs

• Webbed toes with no claws

• No tails

• Large eyes

• Glandular moist skin

Amphibians Anatomy & Physiology



3. Digestive & Excretory system



6. Nervous system


Amphibians Anatomy & PhysiologyIntegumentary system

• Epidermis and a thick dermis• Local thickenings (warts ) are common• Shed periodically• Skin is permeable to water• Gas exchange can take place through

the skin (cutaneous respiration) adult can respire without rising to the surface of the water

• Mucous glands - head, back and tail. Secretions produced by keep the skin moist.

• Granular glands - secrete distasteful or poisonous substances

• Skin color is produced by three layers of pigment cells







6. Nervous system


Amphibians Anatomy & PhysiologyMusculoskeletal system

• Bones are hollow and lightweight• Musculoskeletal system is strong to

enable it to support the head and body

• Radioulna: foreleg bone• Tibiofibula : hind leg bone• Urostyle : adaptation of one or

more vertebrae, stretching the hindquarters

• Lack a rib cage and have only short ribs

• Skeleton-moving muscles are "striated" muscle. Internal organs contain smooth muscle tissue







6. Nervous system


Amphibians Anatomy & PhysiologyDigestive & Excretory system

• Short digestive tract (carnivores)• Pipidae- primitive, tongue less frogs

(Xenopus)• Elongated tongue, sticky tip, seizing the

item with their jaws• Swallow their prey whole• Short Oesophagus• Voluminous stomach• Pancreas• Liver and Gall bladder• Small and large Intestine• Short Cloaca• Two kidneys - filtering the blood – urine

urinary bladder passed out of cloacal vent • Nitrogen waste excreted as ammonia in

dilute urine- aquatic species, Urea in terrestrial species.







6. Nervous system


Amphibians Anatomy & PhysiologyRespiratory system

• lungs in amphibians are primitive • Constant slow diffusion rate of

oxygen entering the blood• Ventilation is accomplished by

buccal pumping• 50% of exchange gases in water

or air is though skin

Larva – external gills+ skin

Adult- Lungs+ skin







6. Nervous system


Amphibians Anatomy & PhysiologyCirculatory system

Juvenile (or tadpole) stage- the circulation is similar to that of a fish; two-chambered heart

Adult stage- lose of gills and develop lungs. Heart consists of a single ventricle and two atria







6. Nervous system


Amphibians Anatomy & PhysiologyNervous system

• Lateral line system – larval and aquatic species lost in terrestrial amphibians

• Ears - well developed in frogs; no external ear; eardrum on the surface of the head behind the eye vibrates and sound - a single bone - inner ear

• high frequency sounds• low frequency patch of specialized hair cells in

the inner ear, detecting deeper sounds• Ears of salamanders and caecilians are less

developed; do not communicate with each other through sound

• Lack eyes lids , terrestrial adult have short lid or third eye lid

• Adult amphibians photoreceptors:� Red Rods: green wavelength� Green Rods: Unique to amphibians; blue

wavelength� Purple Rode: larval & aquatic amphibians,

ultraviolet range







6. Nervous system


Amphibians Anatomy & PhysiologyReproduction system

• Mostly external fertilization -Male grasps the female tightly with his forelimbs behind the arms or in front of the back legs, cloacae positioned close together while the female lays the eggs and the male covers them with sperm

• Internal fertilization - male possessed a “tail" extension of the cloaca, which is used to inseminate the female

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Anatomy & Physiology - moodle2.bgu.ac.il · Mucous glands- between the ... Mudpuppies – comparative anatomy Bullfrog, Leopard frog – physiology ... Amphibians Anatomy & Physiology