Select your language

Suggested languages for you:
Log In Start studying!
StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free

All-in-one learning app

  • Flashcards
  • NotesNotes
  • ExplanationsExplanations
  • Study Planner
  • Textbook solutions
Start studying

Mass Transport in Animals

Save Save
Print Print
Edit Edit
Sign up to use all features for free. Sign up now
X
Illustration You have already viewed an explanation Register now and access this and thousands of further explanations for free
Biology

Mass transport is when the bulk movement of gases or liquids in one direction occurs, usually via a system of vessels in animals.

The key highlight of mass transport is the bulk movement of such substances in one direction (unidirectionality). Unidirectionality is important to maximise bulk movement efficiency and quickly bring substances from one region to another in the body. Therefore, this ensures effective cell activity.

Animals need a specialised exchange surface because of their large surface area to volume ratio. Diffusion alone would not be sufficient for an adequate exchange of substances (more on this in our surface area to volume ratio article).

Another way to look at mass transport is the transport networks of a city. With the high population density and the need to commute, roads systems for different modes of transportation are necessary to reduce congestion. In contrast, motorways are built for vehicles to travel in a specific direction to prevent road accidents: similar to organisms whereby the unidirectionality of mass transport ensures more precise control of substance exchange.

Diffusion in mass transport in animals

You may wonder, how do animals obtain substances such as oxygen and glucose into their vessels for mass transport? Or how do tissue metabolic wastes enter the vessels for mass transport?

Diffusion plays this significant role in mass transport, as substances travel down a concentration gradient from the external environment into mass transport systems. Capillaries of specialised exchange systems are mass transport vessels where diffusion occurs and have specific adaptations for that purpose.

See our surface area to volume ratio and gas exchange articles to find out more about the adaptations of specialised exchange systems!

A good example of diffusion’s role in mass transport is the gas exchange in the alveoli. There is an article on human gas exchange to learn about the mechanism in more detail.

Ultimately, mass transport systems help maintain the diffusion gradients at sites of substance exchange, minimising the disruption of any substance exchange processes.

What is mass flow transport like in larger animals?

Mass flow transport is mass transport where liquids move down a pressure gradient, i.e., a form of mass transport dependent on the flow of liquid. As larger animals have smaller surface area to volume ratios, they require mass flow transport systems to meet their high metabolic demands.

Circulatory systems as mass flow transport systems

You may then ask, how do the bodies of large animals supply a continuous flow of liquid necessary for mass transport? This supply is the responsibility of circulatory systems. Circulatory systems are organ systems where all vessels involved in mass flow transport are linked to a muscular, pump-like organ called the heart.

Animals with closed circulatory systems have blood transport their substances, whilst animals with open transport systems, such as insects have haemolymph.

The heart beats continuously throughout its lifetime to maintain fluid circulation for mass flow. Fluid in the circulatory system is contained in pipe-like structures called vessels. There are two major categories of vessels: arteries and veins.

Arteries carry oxygenated blood from the heart to other parts of the body, whereas veins carry deoxygenated blood from the body parts to the heart. The only exception is the pulmonary artery and vein. The pulmonary artery carries deoxygenated blood from the heart to the lungs, and the pulmonary vein carries oxygenated blood from the lungs to the heart. The pulmonary and systemic circulation makes up the system of double circulation.

Capillaries are small vessels that link arteries and veins together.

Given how diffusion occurs in capillaries of specialised exchange systems, one can say mass flow systems work together with specialised exchange systems (e.g. lungs) for efficient substance exchange.

Role of water in mass flow transport in animals

From the definition of mass flow transport, whereby liquids move down a pressure gradient, you may wonder what liquid is involved? Blood is involved in the mass flow transport of animals. It is a mixture of blood cells, protein molecules, carbohydrates, micronutrients, fats, and electrolytes suspended in plasma and contains large amounts of water.

Water as a universal solvent allows substances to be dissolved easily for smooth mass flow around the body. Blood is contained in blood vessels and pumped by the heart around the body.

Wondering further about the composition of blood and how this composition relates to the role of blood in mass flow? The main components of blood crucial in mass transport include:

  • Plasma is made of water and solutes, dissolves nutrients such as glucose transported into respiring tissues and metabolic wastes such as carbon dioxide that are rid from respiring tissues.
  • Red blood cells are adapted to carry the majority of oxygen molecules around the body.

Mass Transport in Animals [+] composition of blood erythrocytes red blood cells white blood cells lymphocytes granulocytes monocytes platelets [+] StudySmarterFigure 3. Composition of blood: blood plasma, erythrocytes (red blood cells), white blood cells (granulocytes, monocytes and lymphocytes) and platelets, Source: brgfx, via Freepik

More importantly, water in blood makes blood such an effective medium in mass flow because of its chemical stability. In other words, water won’t be broken down easily in the body. This property of water allows a smooth one-way flow of blood within the blood vessels and allows blood to carry essential nutrients and gases to all the cells of the body.

Mass Transport in Animals - Key takeaways

  • Mass transport in animals is the bulk movement of gases or liquids in one direction via a system of vessels. Unidirectionality in mass transport is important to ensure more precise control of substance exchange.
  • Diffusion is crucial in mass transport to allow substances to enter and leave the mass transport system.
  • Mass flow transport requires the movement of fluids under a pressure gradient. Larger animals have circulatory systems where the heart generates the pressure gradient necessary for mass flow transport.
  • Water in blood is the liquid involved in the mass flow transport in animals. Blood components - plasma and red blood cells, play an important role in the transport of substances.

Mass Transport in Animals

Mass transport in animals is the bulk movement of gases or liquids in one direction through structures called vessels.

Mass flow transport is a form of mass transport that is dependent on the flow of liquid.

Because their surface area to volume ratios are too small for substance exchange to occur via diffusion only, and animals have high metabolic rates which require efficient substance exchange.

Blood is the media of transport in animals. Whereas in animals with open circulatory systems (eg: insects), the media is termed haemolymph.

Animals have circulatory systems to transport materials, which allows the mass flow of blood that is controlled by the heart.

Final Mass Transport in Animals Quiz

Question

The heart is made up of specialised muscle cells that contract voluntarily (True/ False)

Show answer

Answer

False - the heart is made up of specialised muscle cells that contract INVOLUNTARILY


Show question

Question

Multicellular organisms have a large surface area to volume ratio (True/ False)


Show answer

Answer

False - multicellular organisms have a SMALL surface area to volume ratio

Show question

Question

Fill in the blanks.

Multicellular organisms require circulatory systems due to their _____ surface area to volume ratio. Therefore they cannot rely on _____ alone like unicellular organisms (e.g. yeasts) for the exchange of substances. This is because their large _____ require substances to travel large ______ to enter. Subsequently, the surface for substances to enter proportionately______, ultimately becoming too _________if diffusion is the only means of exchanging substances .


Animals need a _____ because of their high metabolic rate necessary for generating sufficient energy (ATP). As animals are unable to ______ like plants, they have the capacity for _______ to obtain food. A biological pump is then essential for maximal _____ of the exchange of metabolic substances across cells.

Show answer

Answer

Multicellular organisms require circulatory systems due to their small surface area to volume ratio. Therefore they cannot rely on diffusion alone like unicellular organisms (e.g. yeasts) for the exchange of substances. This is because their large sizes/volumes require substances to travel large distances to enter. Subsequently, the surface for substances to enter proportionately reduces, ultimately becoming too time-consuming if diffusion is the only means of exchanging substances.


Animals need a heart because of the high metabolic rate necessary for generating sufficient energy (ATP). As animals are unable to photosynthesise like plants, they have the capacity for locomotion to obtain food. A biological pump is then essential for maximal efficiency of the exchange of metabolic substances across cells.


Show question

Question

Double circulatory systems are found in organisms where oxygen demand is low (True/ False)

Show answer

Answer

False - single circulatory systems are found in organisms where oxygen demand is low

Show question

Question

Venules are a type of blood vessel (True/ False)


Show answer

Answer

True

Show question

Question

The circulatory system produces hormones such as insulin (True/ False)


Show answer

Answer

False - insulin is produced in the pancreas, the circulatory system TRANSPORTS insulin to target cells

Show question

Question

Outline the four different functions of circulatory systems.

Show answer

Answer

  • supply respiring cells with nutrients such as glucose (e.g. from small intestines to respiring tissues)
  • maintain a constant supply of oxygen to cells undergoing aerobic respiration (e.g., from lungs to respiring tissues)
  • rid metabolic waste products (e.g., carbon dioxide in respiring tissues back to the lungs)
  • transporting substances made from one part of the body to another (e.g., hormones such as insulin made in the pancreas to muscle cells)

Show question

Question

The blood pressure in the systemic circulation is higher than in the pulmonary circulation (True/ False)


Show answer

Answer

True

Show question

Question

Oxygenated and deoxygenated blood are mixed together to allow cells to receive as much oxygen as possible (True/ False)


Show answer

Answer

False - oxygenated and deoxygenated blood are separated to allow cells to receive as much oxygen as possible

Show question

Question

Fill in the blanks.

A single circulatory system has only ____ circulatory route that involves _____ sets of capillaries. The first set of capillaries facilitate the exchange of gases  _____ and ______,  whereas the second set is where the exchange of substances between the ______ and ______ occurs. Blood is said to travel _______ through the heart on one complete circuit. The single circulatory system is common in organisms where _____ ______ is ____, such as fish, echinoderms and earthworms.


On the other hand, a double circulatory system has ____circulatory routes. The ____ route carries ____ blood to the body, then _______ back to the heart after cellular gas exchange. Whereas the ______ route carries _______ blood to the lungs and back to the _____ upon oxygenation. Blood is said to travel _____ through the heart on one complete circuit. The double circulatory system is found in all _____- blooded animals and also _____.

Show answer

Answer

A single circulatory system has only one circulatory route that involves two sets of capillaries. The first set of capillaries facilitate the exchange of the gases oxygen and carbon dioxide,  whereas the second set is where the exchange of substances between the blood and cells occurs. Blood is said to travel once through the heart on one complete circuit. The single circulatory system is common in organisms where oxygen demand is low, such as fish, echinoderms and earthworms.


On the other hand, a double circulatory system has two circulatory routes. The systemic route carries oxygenated blood to the body, then deoxygenated blood back to the heart after cellular gas exchange. Whereas the pulmonary route carries deoxygenated blood to the lungs and back to the heart upon oxygenation. Blood is said to travel twice through the heart on one complete circuit. The double circulatory system is found in all warm-blooded animals and also reptiles.

Show question

Question

The circulatory system moves ammonia produced via deamination in the liver to the kidneys (True/ False)

Show answer

Answer

True


Show question

Question

The heart as a biological pump is crucial for maximal efficiency of the exchange of metabolic substances across cells (True/ False)


Show answer

Answer

True

Show question

Question

Describe the two main advantages of a double circulatory system.

Show answer

Answer

  • Ensures no mixing of blood allows cells to receive as much oxygen as possible and directs blood flow more precisely to the organs that need the most oxygen and nutrients.
  • Enables pressure differences - the systemic circulation has a higher pressure to receive oxygenated blood rapidly. The pulmonary circulation has a lower pressure to prevent damage to vessels and allow gas exchange.

Show question

Question

In single circulatory systems, blood travels once through the heart on one complete circuit (True/ False)

Show answer

Answer

True


Show question

Question

Lymphocytes are found in the blood (True/ False)


Show answer

Answer

False - lymphocytes are found in the lymph

Show question

Question

The diagram of the heart on paper usually has the left side of the heart on the right-hand side and the right side of the heart on the left-hand side. (True/ False)


Show answer

Answer

True

Show question

Question

How is the heart adapted to prevent over-distending with blood?


Show answer

Answer

It is surrounded by an inelastic pericardial membrane.

Show question

Question

Explain the need for two sides of the heart.


Show answer

Answer

Each side of the heart is composed of separate pumps lying side by side. The left side receives oxygenated blood from the lungs and pumps it to the body and the right side receives deoxygenated blood from the body and pumps it to the lungs. Blood has to pass through the lungs first to be oxygenated before passing through the rest of the body. As there is a large drop in blood pressure after passing through the lungs, the heart needs to pump this blood to increase its pressure for it to pass through the rest of the body. Hence, the heart is split into two separate pumps lying side by side instead of one pump.


Show question

Question

Name the two veins that connect to the heart and outline their roles.


Show answer

Answer

  • Vena cava – brings deoxygenated blood from both the lower and upper body 
  • Pulmonary vein – brings oxygenated blood from the left and right lungs 

Show question

Question

Name the two arteries that connect to the heart and outline their roles.


Show answer

Answer

  • Aorta – large and arching, also branches into several smaller arteries to transport oxygenated blood up to the head and the rest of the lower body
  • Pulmonary artery – branches into two to transport deoxygenated blood into the left and right lungs

Show question

Question

Describe how the heart obtains its own blood supply.


Show answer

Answer

The heart obtains its own blood supply by having specialised arteries that branch from the aorta called coronary arteries. These arteries supply oxygenated blood to cardiac muscles to facilitate their necessary contraction and relaxation.

Show question

Question

Name the structure of the heart that stops blood of the left and right sides of the heart from mixing together.


Show answer

Answer

Septum

Show question

Question

Fill in the blanks

The upper chambers that are smaller in size are the ____ (singular _____). They are connected to the veins, with the _____ ______ connected to the vena cava and whereas the _____ _____  connected to the pulmonary vein. 

Show answer

Answer

The upper chambers that are smaller in size are the atria (singular atrium). The atria are connected to the veins, with the right atrium connected to the vena cava and whereas the left atrium connected to the pulmonary vein. 


Show question

Question

 Explain why the atria have thin walls.


Show answer

Answer

The atria have thin walls as they only pump blood into the ventricles that are small structures, whose lower pressure of pumping prevents the ventricles from bursting.

Show question

Question

Fill in the blanks

The lower chambers that are larger in size are the ______. The ventricles are connected to the _______, with the ____ ________ connected to the pulmonary artery whereas the ____ ______ is connected to the aorta.

Show answer

Answer

The lower chambers that are larger in size are the ventricles. The ventricles are connected to the arteries, with the right ventricle connected to the pulmonary artery whereas the left ventricle is connected to the aorta.

Show question

Question

Explain why the walls of the left ventricles are thicker than the right ventricles.


Show answer

Answer

The walls of the left ventricles are thicker than the right ventricles because the blood is pumped from the left ventricles to the extremities. This blood also needs to overcome the elastic recoil of arteries. As for the thinner walls of the right ventricles, the lungs that receive blood from the right ventricles not only are closer to the heart and are smaller than the rest of the body, but the capillaries of the lungs are extremely delicate.

Show question

Question

Valves serve to prevent backflow of blood. Valves in the arteries that connect to the heart are called semilunar valves. As for atrioventricular valves between the atria and ventricles, the right side of the heart has bicuspid valves whereas the left side of the heart has tricuspid valves. (True/ False)


Show answer

Answer

False - the right side of the heart has tricuspid valves whereas the left side of the heart has bicuspid valves

Show question

Question

Outline the role of tendinous cords found connected to atrioventricular valves.

Show answer

Answer

To prevent pressure from the heart from turning the valves inside out when the ventricles contract.

Show question

Question

Name the process given to the coordination of the different components of the heart in the organ’s series of contractions and relaxations.


Show answer

Answer

The cardiac cycle


Show question

Question

Outline the four roles of the heart.


Show answer

Answer

  • Pumping oxygenated blood to the other body parts.
  • Pumping hormones and other vital substances to different parts of the body.
  • Receiving deoxygenated blood and carrying metabolic waste products from the body and pumping it to the lungs for oxygenation.
  • Maintaining blood pressure

Show question

Question

The pressure in the atria is greater than in the ventricles. What is the direction of blood flow in this case?

Show answer

Answer

Blood flows from the atria to the ventricles as the direction of blood flow in the heart is from a region of high pressure to a region of low pressure.

Show question

Question

Choose the correct options

When the heart muscle (contracts/ relaxes), this results in a region of (high/ low) pressure. Whereas when the heart muscle (contracts/ relaxes), this creates a region of (high/ low) pressure. (Systole/ diastole) is the term to describe the contraction of the heart muscle, whereas (systole/ diastole) is when the heart muscle relaxes.

Show answer

Answer

When the heart muscle contracts, this results in a region of high pressure. Whereas when the heart muscle relaxes, this creates a region of low pressure. Systole is the term to describe the heart muscle contraction, whereas diastole is when the heart muscle relaxes.


Show question

Question

Valves ensure blood flows in one direction (True/ False)



Show answer

Answer

True

Show question

Question

Valves contract and relax, whereas the heart muscle opens and closes. (True/ False)


Show answer

Answer

False - valves open and close

Show question

Question

Choose the correct options.

Pressure changes affect the function of valves. Valves (open/close) when the pressure difference is against the direction of blood flow and (open/ close) when the pressure difference follows the direction of blood flow.


Show answer

Answer

Pressure changes affect the function of valves. Valves close when the pressure difference is against the direction of blood flow and open when the pressure difference follows the direction of blood flow.


Show question

Question

Name the three stages of the cardiac cycle.


Show answer

Answer

Atrial systole, ventricular systole, and ventricular diastole.

Show question

Question

Describe the events that occur during atrial systole.


Show answer

Answer

Muscles in both atria contract

  • Atrial pressure > ventricular pressure

  • Blood flows from atria to ventricles

  • Atrioventricular valves open, semilunar valves shut

Show question

Question

Describe the events that occur during ventricular systole.


Show answer

Answer

Muscles in both ventricles contract

  • Pressure in ventricles > atria

  • Atrioventricular valves shut

  • Pressure in ventricles > arteries

  • Blood flows from atria to arteries, semilunar valves open

Show question

Question

Describe the events that occur during ventricular diastole.


Show answer

Answer

The whole of the heart muscle relaxes

  • Pressure in veins > atria and ventricle

  • Blood flows in

  • Pressure in arteries > ventricles

  • Semilunar valves close

Show question

Question

Blood flow in ventricular systole is higher in pressure than in atrial systole. (True/ False)


Show answer

Answer

True

Show question

Question

Atrioventricular valves shut during atrial systole to prevent blood from flowing back into the vena cava or pulmonary vein. (True/ False)


Show answer

Answer

False - semilunar valves shut during atrial systole


Show question

Question

The closing of valves generates heart sounds. (True/ False)

Show answer

Answer

True


Show question

Question

The ‘lub’ sound is from the (atrioventricular/ semilunar) valves whereas the (atrioventricular/semilunar) valves make the ‘dub’ sound.


Show answer

Answer

The ‘lub’ sound is from the (atrioventricular) valves whereas the (semilunar) valves make the ‘dub’ sound.


Show question

Question

A woman whose cardiac output is 8000cm3min-1 completes one cardiac cycle in 0.5s during that timeframe. Calculate her stroke volume.


Show answer

Answer

66.67 cm3 

Show question

Question

Mass transport is the process where the bulk movement of gases or liquids in one direction occurs, usually via a system of vessels in animals. (True/ False)

Show answer

Answer

True 

Show question

Question

Explain why unidirectionality is important in mass transport.

Show answer

Answer

Unidirectionality is important to maximise the efficiency of bulk movement, to bring substances from one region to another in the body quickly. Therefore, this ensures effective cell activity.

Show question

Question

Glucose can move towards and away from tissues via the same vessel. (True/ False

Show answer

Answer

False - mass transport is unidirectional, so two blood vessels are needed: one to allow glucose to move towards the tissues and another to allow the movement of glucose away

Show question

Question

In diffusion, substances travel against a concentration gradient from the external environment into mass transport systems. (True/ False)

Show answer

Answer

False - substances travel DOWN a concentration gradient

Show question

Question

Name the vessel where diffusion takes place as part of mass transport.


Show answer

Answer

the capillaries

Show question

Question

Suggest how gas exchange takes place in the alveoli.

Show answer

Answer

Gas exchange takes place in the alveoli through diffusion between the capillaries and the alveolar walls. Oxygen diffuses into the capillaries whereas carbon dioxide diffuses out of the capillaries into the alveoli.

Show question

60%

of the users don't pass the Mass Transport in Animals quiz! Will you pass the quiz?

Start Quiz

Discover the right content for your subjects

No need to cheat if you have everything you need to succeed! Packed into one app!

Study Plan

Be perfectly prepared on time with an individual plan.

Quizzes

Test your knowledge with gamified quizzes.

Flashcards

Create and find flashcards in record time.

Notes

Create beautiful notes faster than ever before.

Study Sets

Have all your study materials in one place.

Documents

Upload unlimited documents and save them online.

Study Analytics

Identify your study strength and weaknesses.

Weekly Goals

Set individual study goals and earn points reaching them.

Smart Reminders

Stop procrastinating with our study reminders.

Rewards

Earn points, unlock badges and level up while studying.

Magic Marker

Create flashcards in notes completely automatically.

Smart Formatting

Create the most beautiful study materials using our templates.

Sign up to highlight and take notes. It’s 100% free.