TRANSPORT

TRANSPORT

www.lbl.gov

Adaptations for Transport

TRANSPORT: It is the process by which substances move into or out cells or are distributed within cells.

• In simple organisms no special system is needed to move materials within cells and between cells.

• In complex organisms many cells are far from the outside environment. These organisms need a special system called the circulatory system to transport materials to and from all parts of the organism.

Circulatory System

A circulatory system is made up of three parts:

1. a fluid in which materials are transported

2. a network of tubes or body spaces through which the fluids flow

3. a means of driving the fluid through the tubes or spaces

Transport in Protists

• Protists are usually one-celled animals that have no circulatory systems.

• Diffusion and active transport are used to move materials into and out of the cell.

• Within the cell, the movement of the material is aided by cyclosis, the streaming of the cytoplasm.

Transport in Hydra

• Hydra is a simple multicellular organism and has no circulatory system.

• The body wall of the hydra is composed of two layers of cells.

• By diffusion both cell layers can exchange dissolved oxygen, carbon dioxide, and wastes with their surroundings.

Transport in Hydra

• Planarian has no circulatory system.

• O2 and CO2 diffuse into and out of individual cells

Transport in Planaria

Transport in Earthworm

• Most of earthworm cells are not in direct contact with their surroundings. It is the circulatory system of the earthworm that makes possible the exchange of materials between its outside environment and its body cells.

• The blood carries dissolved nutrients, gases, wastes, water, and other substances.


• It is red because it contains the red, iron- containing pigment hemoglobin.

• Hemoglobin increases the amount of oxygen the blood can carry.

• The circulatory system of the earthworm is an example of a closed circulatory system.

• In closed circulatory system, the blood is always contained within tubes or vessels in the body.


Transport in Grasshopper


• The grasshopper has an open circulatory system.

• In an open circulatory system, the blood is not always enclosed in blood vessels. Instead it flows directly into body spaces where it bathes the tissues.

• The colorless blood of grasshopper (and other insects) does not contain hemoglobin and it does not transport oxygen and carbon dioxide.


• The respiratory gases are transported through a series of tubes that are separate from the circulatory system.

• In the grasshopper the blood serves mainly to transport nutrients and nitrogen-containing wastes.


(a) open circulation e.g. mollusc, arthropods

Types of Circulatory Systems

(b) closed circulation e.g. vertebrate, annelid, worms, squid

Types of Circulatory Systems

OPEN CIRCULATORY SYSTEM CLOSED CIRCULATORY SYSTEM

blood moves slow blood moves fasterblood flows in the body spaces (body sinuses), not always in vessels

blood flows always in the blood vessels

blood does not contain respiratory pigment

blood contains respiratory pigments (ex: hemoglobin)

blood does not carry O2

and CO2 but transports nutrients and nitrogenous – wastes

blood transports O2, CO2, nutrients and nitrogenous wastes

no blood capillaries capillaries form between arterioles and venules

Ex: grasshopper Ex: human, earthworm

Circulatory Systems in Vertebrates

• Vertebrates that use gills for respiration, such as fishes and larval amphibians ( e.g. tadpole ) have a single loop circulatory system. – Blood travels from the heart to the gills to the body and

back to the heart. – The heart in fish is simple. It consists of two chambers:

an atrium that recieves blood from the body and a ventricle that pumps the blood to the gills.

– As the deoxygenated (oxygen-poor) blood passes through the gill capillaries, CO2 diffuses out whereas O2 diffuses into the blood.

– Then the oxygenated blood (oxygen-rich blood) is directly transported to the body capillaries. The heart in fish always contains deoxygenated blood.

• Vertebrates that use lungs for respiration ( frogs, reptiles, birds and mammals ) have a double-loop circulatory system. – The first loop carries the blood between the heart and

the lungs. – Oxygen-poor blood from the heart is pumped to the

lungs, oxygen-rich blood from the lungs returns to the heart.

– The second loop carries blood between the heart and the body. Oxygen-rich blood from the heart is pumped to the body, oxygen-poor blood from the body returns to the heart.

– During the course of vertebrate evolution, the heart developed chambers and partitions that help separate the blood travelling in the two loops of the circulatory system.


• In frog heart there are two atria and one ventricle. – This means the oxygen-rich and oxygen-poor blood

cannot mix in the atria. – However, oxygen-rich and oxygen-poor blood can mix

in the ventricle. – Thus, the concentration of oxygen in the blood

travelling to the body is not as high as it could be. The oxygen-poor blood from the body enters the right atrium and the oxygen-rich blood from the lungs enters the left atrium.

– Since there is only one ventricle, the blood mix up in the ventricle and from there the mixed blood is pumped to the body.


• Most reptiles have a three chambered heart consisting of 2 atria and 1 ventricle. But there is a partial partition in the ventricle. This partial partition minimises the mixing of oxygen-rich and oxygen-poor blood, but it does not completely eliminate it.

• In crocodiles the heart is completely partitions into four chambers: 2 atria and 2 ventricles. But in a canal, placed just at the leaving point of blood from the heart, oxygen-rich and oxygen-poor blood mix. (Türkçe’de bu kanal Panizza Kanalı olarak adlandırılır).


• In birds and mammals, the heart is four chambered: 2 atria and 2 ventricles.

• This means that the lung loop and the body loop of the circulatory system are completely separated: There is no mixing of oxygen-poor and oxygen-rich blood in the heart.

• The four chambered heart is sometimes described as double pump:– One pump moves blood through the lung loop. – The other pump moves blood through the body loop.


THE HUMAN CIRCULATORY

SYSTEM

Blood Vessels

ARTERY CAPILLARIES VEIN

Wall structu

re

thickestepithelial tissuesmooth muscle

connective tissue

thinnestepithelial tissue

middleepithelial tissuesmooth muscle

connective tissue

Direction of

blood flow

from heartto body

betweenartery and vein

from bodyto heart

Velocity of

bloodhighest slowest middle

Blood pressu

rehighest middle lowest

http://www.nurse-prescriber.co.uk/education/visual_lib/pp109.jpg

http://www.infovisual.info/03/img_en/061%20Blood%20vessels.jpg

http://www.sirinet.net/~jgjohnso/vesselstructure.jpg

http://distance.stcc.edu/AandP/AP/imagesAP2/bloodvessels/bloodflow.gif

Blood Vessels

• Arteries and veins are distinguished by the direction in which they carry blood, not by the quality of the blood that they contain.

• Most of the arteries in human circulatory system carry oxygenated blood, whereas pulmonary artery carries deoxygenated blood. Also pulmonary vein carries oxygenated blood.

Factors Affecting the Flow of Blood in Veins

Contraction of skeletal muscles

Valves

Gravity

Pressure decrease at chest cavity

Smooth muscles on the walls of the vein

During diastole (relaxing of heart), pressure decrease in atria

Varicose Veins

Varicose veins develop when one of the valves in a vein ruptures. This condition develops from poor blood flow in which blood accumulates in a vein and places so much weight on a closed valve that is ruptured. Varicose veins develop most often in surface veins, which are not surrounded by skeletal muscle in the legs, especially when a person sits or stands for long periods of time.

Varicose Veins

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TRANSPORT