+

Circulatory System

Zoo 2 :Comparative Anatomy of the

VERTEBRATE

+

CIRCULATORY

SYSTEM- Consist of Heart, Arteries,

Veins/Venous Sinuses,

Capillaries/Sinusoids and Blood, and

of Lymph channels and lymph.

+

CIRCULATORY SYSTEMis responsible for transporting materials throughout the entire body.

/circle of blood

Transport other wastes from cells

It helps maintain body temperature by transporting heat

+Arteries

-- Muscular and Elastic Walls capable of

distention with each intrusion of blood

-- Smaller Arteries with a length of 0.3mm or less

are Arterioles

-- Carries blood away from the heart

-Arterioles

--> dilate and and constrict reflexly and thereby

assist in regulating blood pressure.

-->Terminate in blood capillaries

-The arteries maintain pressure in the circulatory

system much like a balloon maintains pressure

on the air within it. The arteries therefore act as

pressure reservoirs by maintaining (storing)

pressure.

+ ARTERIESAorta: largest vessel (diameter of a garden

hose) –receives blood from left ventricle

Arteriole: smaller vessels connecting arteries to

capillaries

+Veins

-- Commence in capillaries

-- Carries blood towards the heart

-- Have proportionately less muscle

-- Elastic tissue and more fibrous tissues than

arteries therefore capable of less distention /

construction

-- Smallest are Venules

-The blood pressure in the veins is low so valves

in veins help prevent backflow.

-act as blood reservoirs because they contain

50% to 60% of the blood volume.

-Smooth muscle in the walls of veins can expand

or contract to adjust the flow volume returning to

the heart and make more blood available when

needed

+VEINS

+VEINS

+Capillaries

- Generally consist of endothelium (tissues that form single layer of cells lining various organs and cavities of the body) alone.

-- Certain are accompanied by mesenchyme (cells of mesodermal capable of developing into a connective tissue, blood and lymphatic and blood vessels) and scattering of smooth muscle fiber.

-- Lumen large enough to occupy red blood cells in single file.

-Portal System – System of veins terminating in a capillary bed.

-Renal Portal System – Where blood from the capillaries of the tail passes in vertebrate

-Hepatic Portal System – Blood from the digestive tract, pancreas, and spleen

-

+PORTAL SYSTEM

Hepatic Portal System Portal System

+BLOOD

- A fluid that is pumped by the heart and circulates throughout the body.

-- to carry nutrients, oxygen and hormones to all tissues of the body and to carry waste products and carbon dioxide away from the tissues.

-One of the Tissues in the Circulatory System

-Solids consists of blood proteins

~ Serum - an amber-colored, protein-rich liquid that separates out when

blood coagulates.

-Suspended in the plasma, and carried along in its flow are formed element :

-Red Blood Corpuscles (Erythrocytes) – Oxygen-Bearing

-White Blood Corpuscles (Leukocytes) – Disease-Fighting

-Platelets (Thrombocytes) – Blood-Clotting

-

+

BLOOD

+TYPES OF BLOOD

RED BLOOD -re responsible for carrying oxygen and carbon dioxide.

PLATELETS -are blood cells that help stop bleeding

+TYPES OF BLOOD WHITE BLOOD - help the body fight off

germs

+ WHITE BLOODGRANULOCYTES - help the body fight bacterial infections. The number

of granulocytes in the body goes up when there is a serious infection.

People with lower numbers of granulocytes are more likely to get bad

infections more often.

+GranulocytesNeutrophil - active phagocyte, number increases rapidly during short

term or acute infection.

Eosinophils - kills parasitic worms and increase during allergy attack.

+GranulocytesBasophils - contains histamine, which is discharged as site of

inflammation.

+ Agranular Leukocytes

LYMPHOCYTES MONOCYTES

White blood cell; a colorless blood corpuscle capable of amoeboid movement,

whose chief function is to protect the body against microorganisms causing

disease

+Heart-- a hollow muscular organ of vertebrate animals that by its rhythmic

contraction acts as a force pump maintaining the circulation of the blood

-- hearts muscles pulsates in response to specific electrolytes

-- Walls : Endocardium, Myocardium and Epicardium

-- Myocardium – Special type of striate muscles; Thick in the ventricular wall

-Epicardium – outer layer of the heart; Lying on its is the Visceral Epicadium

-Pericardial Cavity – the pace between pariental and and visceral pericardia

which are continous with one another, reflected over the blood vessels that

enter and leave.

-Coronary arteries – supply all of the heart muscle with blood

-Coronary veins - drain blood from the muscular tissue of the heart and

empty into the coronary sinus (a collection of veins joined together)

+

HEART DIAGRAM

Hagfishes’s heart has

no nerve supply

+HEART

+HEART DEVELOPMENT

-- The splanchnic layer of the hypomere posterior to the pharynx and ventral

to the gut become thicker on both sides of the body

-- These mesodermal folds form a longitudial tube

-- The tube is fixed to surroundings tissues at each end but otherwise

becomes free as it passes through an expanded portion of the coelom

-- The free section forms four chambers which begin to contract and become

the embryonic heart

-Newly-Formed embryonic heart has 2 layers :

-- The internal endocardium of mature heart has a thick layer of elastic

connective tissue under an endothelial lining

-- External epimyocardium divides into chambers

- -> Epicardium which becomes the serous membrane of organ

- -> Myocardium which comprise the cardiac muscle

-

+EPICARDIUMouter layer of the wall of the heart

+MYOCARDIUMthe middle and thickest layer of the heart wall, composed of cardiac

muscle.

+

HEARTS OF GILL-

BREATHING FISHES

Fishes other than dipnoans have 4 chambers in

a series : Sinus Venosus, Atrium, ventricle, and

conus arteriosus.

+Heart of Gill-Breathing Fishes

+Atrium

Large thin-walled muscular sac that is

a sort of staging are for blood that Is

about to enter the ventricle to be

propelled toward the gills.

From the atrium, blood pours into the

relaxing ventricle through an

atrioventricular aperture that is

guarded by a pair of a one-way valve.

These prevents ventricular blood from

being pumped back into the atrium

when the ventricle conracts.

+

Ventricle

Has a very thick muscular walls and is

the actual pumping portion of the

heart.

The anterior end is prolonged as a

muscular tube of small diameter, the

conus arteriosus, which extends to the

extreme cephalic end of the pericardial

cavity, at which point it is continuous

with the ventral aorta.

+Conus

Composed chiefly of cardiac muscle and elastic connective tissue.

A series of semilunar valves facing forward within the conus prevent backflow with each delivery of ventricular blood, and then slowly constricts, maintauning a steady arterial pressure in the ventral aorta for the flow of blood through the gill capillaries.

In teleost is short and has only one set of vavles.

Bulbus Arteriosus –the dilated part of the aorta just in front of the heart from which the aortic arches arise in vertebrate embryos and in the adult of many lower vertebrates.

+HEARTS OF LUNGFISHES AND

AMPHIBIANS

Modification in the heart of lungfishes and amphibians are correlated with

aerial respiration by means of swim bladders or lungs.

They are enable oxygenated blood returning from the lungs to be separated

from the deoxygenated blood returning from elsewhere.

Lungfishes and amphibians have bimodal gas exchange, but various

species employ air breathing with lungs to different degrees

Dynamics of inflow in the pulmonary and systemic veins

The extent and localization of atrial septation

The partial ventricular septum in lungfishes and the massive ventricular

trabeculation in both amphibians and lungfishes

Vasomotor reactions in the various outflow vessels from the heart.

+

+ LUNGFISHESHeart

+MODIFICATION OF THE HEARTS

One modification is the establishment of a partial or complete partition within

the atrium (atria), There is a left and right atria.

Pulmonary veins empty into the left atrium (the blood on this chamber is

oxygen rich)

2nd modification : Formation of a partial interventricular septum/ ventricular

trabeculae (shelves projecting form the ventricular wall into the chamber and

running mostly cephalocaudal (direction of head to tail)

3rd modification : Formation of spiral valve in the conus arteriosus in many

dipnoans and anuran. The valves directs oxygenated and

deoxygenatedblood into appropriate channels.

4th modification : Shortened the ventral aorta, so that it becomes nonexistent

as embryonic development progresses. Resulting oxygenated and

deoxygenated blood that has been kept separated from the heart by septa,

traculae, and spiral vales moves from the heart into appropriate vessels.

+The Hearts of AmniotesAmniotes - are animals who shield the embryos of their offspring using

extensive membranes or keeping them inside the body, in contrast to most

other animals, which lay free-floating eggs in water.

- a group of limbed vertebrates that includes all living reptiles (class

Reptilia), birds (class Aves), mammals (class Mammalia)

-2 atria, 2 ventrticles, and a sinus venoses ( except in adult birds and

mammals)

-In crocodile sinus is partially incorporates into the wall of right atrium.

-Birds and mammals have a sinus venosus during early development but

fails to keep pace with the growth of the right atrium into which it empties

and finally incorporated into the wall of that chamber.

-Sinoatrial Node – section of nodal tissue that is loacted in the upper wall of

the right atrium

-Interatrial Foramen – An opening of the septum between the right and left

atria of the heart, present in the fetus but usually close soon after birth

+The Heart of AmniotesThe right and left atria of adult amniotes are completely separated by an

interatrial septum

Right atrium -> receives blood from the sinus venosus (reptiles) or blood

that previously emptied into the sinus venosus (Bird and Mammals) also

receives blood from the pulmonary veins

Left atrium -> receives blood from the pulmonary veins

Mammals each atrium has a earlike flap (auricle), containing a blind, saclike

chamber

2 ventricles are completely separated in crocodiliansc (Reptiles), birds, and

mammals

Other amniotes, the interventrucular septum is incomplete

+Heart of a Bird

+Heart of Reptiles

+Heart of Mammals

+SINOATRIAL NODE

+INTERARIAL FORAMEN

+Morphogenesis of the Heart

The heart of all vertebrate commence as a single, almost straight, pulsating

tube that receives incoming blood at the caudal end and empties into the

embryonic ventral aorta anteriorly.

The tube, whether of sharks or human beings, bends to the animal’s right,

then twists in to an “S” shape, so that the atrial region, previously at the

caudal end, is carried dorsad and cephalad until it lies where it is found in

adult fishes.

The twisting and bending is probably correlated with the confinement of the

rapidly growing heart in a less expansive pericardial cavity.

In Amphibians and Amniotes the twisting is carried further, for the atrial

region finally lies cephalad to the ventricular region., while internally an

interventricular septum completes the division of the amniote heart into right

and left sides.

+Morphogenesis of the Heart

+Morphogenesis of the Heart

As hatching approaches in birds, the sinus venosus is incorporated almost

completely into the wall of the right atrium.

In mammals, the sinus venosus fails early to keep up in growth with the rest

of the heart and its incorporation into the right atrial wall occurs sooner in

organogenesis

Oxygen and nutrients from the heart is the first organ to function and does

not even before any nerves have reached it to impose a cardiac rhythm.

Initial straight tube that will become the heart of sharks and amphibians

organizations from paired mesenchymal masses of lateral-plate somatic and

splanchnic mesenchyme that aggregate beneath the pharynx to form a

single tube.

In amniotes a pair already organized endothelial tube is brought together

beneath the pharynx, they fus, and a single tube results,

In either case, the heart is bilateral contribution of lately-plate mesoderm.

+Primitive Heart (Two-

Chambered) : Single

Circulation Pattern

-- They are nearly straight with 4 chambers,

pumping a single stream of deoxygenated blood

forward in the body

-- A thin walled sinus venosus receives blood

from the major veins and empties it through a

simple sinutrial valves in a large thick-walled

ventricle

-- The Ventricle pumps into the conus arteriosus

which looks like an enlarged artery and is lined

with several rows of semilunar valves preventing

backflow of blood as the ventricle fills.

-

+

AMPHIOXUSHas no heart only a homologous

pulsating vessels in the same position

where the heart evolved in vertebrate

+CYCLOSTOMES AND

FISHES

Vary widely in detailed structure

The heart is relatively far forward in from the

pectorial girdle and under the posterior gills.

Atrium is relatively large and usually shifts to a

position dorsal to the ventricle

TELEOSTS - ventricle is conical with apex pointing

posteriorly

- have bulbus arteriosus within the

pericardial cavity in the position of the conus in the

other fishes

ELASMOBRANCES – its pericardial cavity is

bordered in party by the skeleton

As the ventricle contracts, blood enters the sinus

venosus and atrium by suction

+

CYCLOSTOMES AND

FISHES

Hearts of FISHES are relatively small due to

small volume of blood

- Cyclostomes and Fishes have accessory

hearts or pumping mechanisms

+INTERMEDIATE HEART ( THREE-

CHAMBERED) : Incomplete Double

Circulation PatternDIPNOANS, AMPHIBIANS, and REPTILES : Their heart usually receives

both kind of blood, oxygenenated and deoxygenated, without structural

separation allowing mixing of the two streams.

Atrium of DIPNOI is partly divided by an interatrial septum in to right and

left chambers

- The sinus venosus delivers deoxygenated blood to the right

chamber and the pulmonary veins supply oxygenated blood to the left

chamber

- The ventricle is partly divided by a large muscular

interventricular septum

- The large conus no longer contracts and is partly divided by

a spiral fold or flap of tissue

+

The Atrium of ANURANS is completely divided into right and left chambers

by the interatrial septum

- The right chamber received deoxygenated blood while the left

received blood oxygenated in the lungs

- Blood returning from the skin joint the systemic veins allowing

mixing of blood on the right side

- The ventricle is not divided but mixing of deoxygenated and

oxygenated blood is minimal

- Both blood may enter the left systematic arch and mix

depending on the resistance in the pulmonary circuit

INTERMEDIATE HEART ( THREE-

CHAMBERED) : Incomplete Double

Circulation Pattern

+

CHELOANS and SQUAMATE hearts appears during early embryonic

development but becomes divided in the adult to form the pulmonary

trunk and the independent right and left systemic trunk

- Atrium is completely divided into right and left atria

- The cavuum arteriosum received blood from the left atrium

but has no direct arterial output

- The cavuum pumonale does not receive blood directly from

the atria; It receives blood from the cavuum venosum through the

muscular ridge

- The cavuum venosum receives deoxygenated blood from

the right atrium

INTERMEDIATE HEART ( THREE-CHAMBERED) : Incomplete Double Circulation Pattern

+

CROCODILIAN heart is quite different from other reptiles

-The ventricle is divided by a complete interventicular septum into left and

right ventricle

-- The pulmonary trunk and left aortic arch open off the right ventricle

-- The right aortic arch open off the left ventricle

-- A narrow channel at the bases of the two systematic trunks, the foramen

of Panizza, connects

-- When CROCODILE dives, blood in the right ventricle travel through the

left aortic arch joining the systematic circulation and by passing lungs

-- Diversion of blood also happens when it is at rest on land going for long

intervals without taking a breath

INTERMEDIATE HEART ( THREE-CHAMBERED) : Incomplete Double Circulation Pattern

+CROCODILE HEART

+DOUBLE-CIRUIT HEART (FOUR-

CHAMBERED HEART): Complete Double

Circulation Pattern

ADULT BIRDS and MAMMALS – complete double circulation composed of : -Low-pressure pulmonary circuit on the right side of the heart

-> Needed to avoid edema and damage to delicate lung tissues

-- High-Pressure systemic circuit on the left side of the heart

- -> To drive blood through tissues that may have their own internal pressure like contracting muscles

-- Atrium is completely divided and smaller than in fishes

-- Ventricle is completely divide and stronger on the left side because of the resistance that is greater on the other side

-- Adult systematic arch is single

- -> It loops to the right in BIRDS and to the left in MAMMALS

+LYMPHATIC SYSTEM

The lymph system is a major part of the body's immune system.

Lymph and Lymphatic channels are found in all vertebrates

Consist of thin-walled lymph channels, lymph, lymph hearts, lymphoid

masses and Lymph nodes.

In contrast to blood, lymph moves in one direction : Toward the heart.

Either Lymph spaces or discrete lymph vessels penetrate most of the soft

tissue of the vertebrate other than the skeleton, liver and nervous system.

+ LYMPHATIC SYSTEMa network of organs, lymph nodes, lymph

ducts, and lymph vessels that make and move

lymph from tissues to the bloodstream.

+

Lymph Nodes act as filters or traps for foreign

particles and are important in the

proper functioning of the immune

system

+

Lymph Ducta great lymphatic vessel that empties

lymph into one of the subclavian veins

+FLOW