Vertebrate Circulatory System #1

8/7/2019 Vertebrate Circulatory System #1

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VERTEBRATESVERTEBRATESCIRCULATORYCIRCULATORY

SYSTEMSYSTEM


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CIRCULATORY SYSTEMCIRCULATORY SYSTEM

Cardiovascular system

heart

blood

blood vessels

Pulmonary Circuit- leads to the lungs

Systemic Circuit- carries blood to all organs except

the lungs


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HEARTHEART

Different number of heart chambers (2, 3 or 4 chambers) Two types of heart chambers

Atrium (plural is atria) receives blood

Ventricle forcefully pump blood from the heart to the

body and lungs

Left ventricle aorta body (systemic circuit)

Vena cava Right Atrium Right Ventricle

pulmonary arteries Lungs (pulmonary circuit)

Pulmonary veins Left Atrium


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General ProcessGeneral Process

Theblood received by theatrium is thenpumped from theatrium

into the second chamber called theventricle

The right atrium pumps blood to the right ventricle, and the left

atrium pumps blood into the left ventricle

Heart Sound

lub-dupp, lub-dupp, lub-dupp

Lub Contractionof theventricle, Atrioventricular valve closes

Dupp Semilunar valvecloses


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The ventricles are much larger than the atria and their thick,

muscular walls are used to forcefully pump the blood fromthe heart to the body and lungs (or gills).

The atria function to receive blood when they are relaxed

and to fill the ventricleswhen theycontract. Theventricles function

to pump blood to the body(left ventricle) or to the lungs (right

ventricle).

Valves

Valves allow blood to flow through in one direction but not

the other. They prevent backflow.


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Functions to supply the tissues with oxygen and nutrients,

while removing carbon dioxide and other metabolic wastes

WhatWhat happenshappens whenwhen bloodblood flows??flows??

as oxygen-rich blood from the heart flows to the tissues of

the body, oxygen and other chemicals move out of the blood

and into the fluid surrounding the cells of the body's tissues

waste products and carbon dioxide move into the blood to

be carried away

IMPORTANCE OFCIRCULATORYIMPORTANCE OFCIRCULATORY

SYSTEMSYSTEM


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as blood circulates through organs such as the liver and

kidneys some of these waste products are removed

blood then returns to the lungs (or gills, in the case of

fish), receives a fresh dose of oxygen and gives off carbon

dioxide

then the cycle repeats itself

This process of circulation is necessary for continued

life of the cells, tissues, and ultimately the whole organism. Upand down the evolutionary ladder, there are different forms of

cardiovascular systems with different levels of efficiency, but

they all perform this same basic function.

continue...continue...


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Reptile HeartReptile Heart

Double Circulation

3 Chambered Heart

Except Alligators and Crocodiles

(has 4 chambered heart)

1 Ventricle 2 Atrium

VENTRICLEVENTRICLE

Partially divided by a septum wall


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RED BLOOD CELLS


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CROCODILEHEART


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Reptile Blood CirculationReptile Blood Circulation

Blood from the lungs is received by the atria (left atria-

blood from the body); (right atria- blood from the lungs)

Then these atria pumps the blood to the ventricle

The ventricle may be partially separated or fullyseparated

The ventricle pumps blood to the lungs or to the body...

The blood then will return to the heart through veins.

The processwill repeat itself

.


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In most reptiles, the ventricle is partially divided. This

reduces mixing of oxygenated and deoxygenated blood in theventricle. The partial division of the ventricle is represented

by a dashed line below.


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Alligators and Crocodiles have a four-chambered heart

which acts as two separate pumps. After passing through the body,

blood is pumped under high pressure to the lungs. Uponreturning from the lungs, it is pumped under high pressure to the

body. The high rate of oxygen-rich blood flow through the body

enables birds and mammals to maintain high activity levels.


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Fish HeartFish Heart

Single Circulation

2 Chambered Heart

1 Atrium

1 Ventricle

muscular walls and a valve

between its chambers


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the heart is position very far forward in the body and lies

adjacent to the gills

Teleosts have lost the conus arteriosus and have developed the

bulbus arteriosus, which is elastic and not muscular like theconus arteriosus

Blood is moved through contraction of the respiratory hypobranchial muscles

The venous side of the heart is preceded by an enlarged

chamber called the sinussinus venosusvenosus. The arterial side of the heart

is followed by a thickened muscular cavity called the bulbusbulbusarteriosusarteriosus.


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Some tunas (familyScombridae, subfamily Thunninae) maintain a

body temperature several degrees higher than that of the

surrounding water. This heat is due to the modified circulatorysystem associated with the red muscle.

As red muscle functions, it generates heat. Muscle-generated heat

warms the blood circulating through the red muscle, which then

travels back to the heart through veins. Thus, blood returning to the

heart from the muscle is warmer than blood traveling from the heartto the muscle.

Due to the nearness of arteries and veins, heat passes from warmer

veins to cooler arteries within the fish's body, rather than dissipating

to the cooler environment. This modified circulatory system retains

heat in the red muscle.

A higher body temperature is an adaptive advantage for high-speed

swimming.

A similar modified circulatory system warms the brain and eye of

some species of tunas and billfishes (family Istiophoridae).

SOMESOME TUNASTUNAS


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RED BLOOD CELLSRED BLOOD CELLS


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Redblood cellsRedblood cellsto transport oxygen to the cells in the fish and

transport carbon dioxide away from the cells. Red bloodcells are high in hemoglobin which is high in iron. The iron

binds with the oxygen for transport. Red blood cells areproduced in the spleen, kidney and in the bones

according to some authors.

Whiteblood cellsWhiteblood cellsare made up of several types

PlateletsPlatelets help with coagulation of the blood to stop bleeding. Thereare also other coagulation components.

PlasmaPlasma is the liquid part of the blood to suspend the other

components of the blood with in it, including food for thecells (broken down into various components by the

digestive system), hormones, and waste products from the

cells to the liver and kidneys.

BLOOD CELLSBLOOD CELLS


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FORMATION OF WHITE BLOOD CELLSFORMATION OF WHITE BLOOD CELLS

In higher vertebrates such as mammals, formation of white

blood cells is restricted to bone marrow, the spleen and the lymphnodes. In fishes, organs such as the kidney, spleen and thymus take

part in haematopoeisis.

SPLEEN: Organ comprising a mass of lymphoid tissue in the mesentery;

unlike lymph nodes it is interposed in the blood circulation.

THYMUS: A paired lymphoid gland situated dorso-laterally in the gillchamber. The site of T-lymphocyte production, it is regulated by

hormones produced by thymic epithelial cells. In fish (and in all

vertebrates) the thymus gradually atrophies after the onset of sexual

maturity but does not completely disappear

HAEMATOPOIEISIS: A general term referring to the formation of alltypes of blood cells, a process occurring in the haematopoeitic tissue.


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Fishes' blood is approximately 2% of their body weight, compared to 10%

in humans.

BLOOD VESSELSBLOOD VESSELS

Arteries carry blood from the heart to the gills and then to the rest of the

organs and body tissues. The oxygenation process in the gills will be

discussed in another topic about the gills and how they work.

From the arteries the blood goes into smaller vessels called capillaries

and then into fluid surrounding the cells called interstitial space (around

cells).

Veins carry carbon dioxide and waste products away from the cells, back

to the heart.


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Fish Blood CirculationFish Blood Circulation


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The sequence of contraction in a fishs heart propels blood fromthe atrium, to the ventricle, to the conus arteriosus, to the ventral aorta: (a)

atrial contraction; (b) ventricular contraction; (c) conal contraction. The

pericardial compartment around the heart chambers is rigid, so contraction

of one of the chambers tends to expand the others.


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Blood pump by the ventricle Blood travels first to the gills where it picks up oxygen and

disposes of CO22 across the walls of capillaries

The gill capillaries reconvene to form a vessel that carries the

oxygenated blood to capillary beds to the body

Blood returns to the atrium through veins

Blood passes through 2 capillary beds

resistance is great because the diameter of the vessel is so

small

Blood pressure drops substantially (hydrostatic pressure) Oxygenated blood leaving the gills flows to other organs quite

slowly

Circulation is aided by swimming



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The gills contain many capillaries for gas exchange,

so the blood pressure is low after going through the gills.Low-pressure blood from the gills then goes directly to the

body, which also has a large number of capillaries. The

activity level of fish is limited due to the low rate of blood

flow to the body.


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Amphibian HeartAmphibian Heart

Double Circulation

3 Chambered Heart

1 Ventricle

2 Atrium

Ventricle is not separated There is a mixture of oxygenated

blood and deoxygenated blood


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RED BLOOD CELLS


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The advantage of this system is that there is

high pressure in vessels that lead to both the lungs andbody.


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Vertebrate Circulatory System #1