Transport Systems in Animals and Organisms

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Questions and Answers

Why is a transport system necessary in larger animals?

To facilitate quick diffusion of nutrients only

To accommodate a small surface area to volume ratio (correct)

To reduce the need for oxygen

To allow diffusion to supply all necessary substances

What role does the heart play in the circulatory system?

It generates pressure to ensure mass flow (correct)

It regulates the temperature of the body

It diffuses oxygen directly into the cells

It removes waste products from the blood

Which feature is essential for a mass transport system?

Presence of only small vessels

Independent transport of nutrients and gases

A mechanism for moving fluids efficiently (correct)

No need for a transport medium

What distinguishes a closed circulatory system from an open one?

Blood is confined to closed vessels Signup and view all the answers

Why can single-celled organisms rely solely on diffusion for transport?

They have a high surface area to volume ratio Signup and view all the answers

What is a primary function of the respiratory system in relation to mass transport?

To provide a large surface area for gas exchange Signup and view all the answers

How does the circulatory system of mammals and birds function?

It features a closed double circulatory system Signup and view all the answers

What is the function of the system of branching vessels in the circulatory system?

To transport substances to specific body parts Signup and view all the answers

What challenge does a larger body size pose to animals in terms of transport?

Long diffusion distances for nutrients Signup and view all the answers

What is the primary reason cells in larger animals need efficient nutrient transport?

To maintain a constant body temperature Signup and view all the answers

What is one advantage of having a double circulatory system?

Maintains a steep gas concentration gradient Signup and view all the answers

What benefit does the double circulatory system provide in terms of pressure?

Higher pressure in systemic circulation for effective oxygen delivery Signup and view all the answers

What is a disadvantage of single circulation in fish?

Oxygenated and deoxygenated blood are mixed Signup and view all the answers

Why is the small size of red blood cells advantageous?

It slows down the movement for efficient gas exchange Signup and view all the answers

What role does thromboplastin play in blood clotting?

It converts prothrombin into thrombin Signup and view all the answers

What is the initial step in the blood clotting process?

Release of thromboplastin by plasma at damaged tissue Signup and view all the answers

What happens after thrombin is formed during blood clotting?

It traps platelets and red blood cells to form a clot Signup and view all the answers

How does the absence of a nucleus in red blood cells benefit their function?

Allows for more space for hemoglobin Signup and view all the answers

What is the primary purpose of the fibrin mesh formed during clotting?

To trap blood cells and platelets for clot formation Signup and view all the answers

What is NOT a role of blood in the body?

Contraction of muscle fibers Signup and view all the answers

Study Notes

Importance of Transport Systems in Animals

Larger animals need transport systems due to their small surface area to volume ratio, which requires long distances for nutrients to reach cells.
Diffusion alone would be too slow and inefficient for larger animals.
Heart pumps blood, which carries nutrients and oxygen throughout the body down a pressure gradient.
Circulatory systems efficiently supply cells with glucose, amino acids, and hormones.
Animals with a high metabolic rate have high energy demands, requiring efficient transport of oxygen, nutrients, and removal of carbon dioxide.

Transport System in Small Organisms

Single-celled organisms have a large surface area to volume ratio, allowing direct diffusion of oxygen, nutrients, and waste products.
The diffusion distance in single-celled organisms is small.
Single-celled organisms have a low metabolic demand and do not need to regulate temperature.
Diffusion alone is sufficient to supply their needs in small organisms.

Features of Mass Transport Systems

A mass transport system is an arrangement of structures that transports substances within a fluid.
The respiratory system provides a large surface area (lungs or gills) for gas exchange.
The heart generates pressure for mass flow, overcoming limitations of diffusion.
Branching vessels carry substances along specific routes to body parts.
Blood is a suitable transport medium for oxygen, nutrients, and waste products.

Circulatory System in Mammals and Birds

Mammals and birds have a closed double circulatory system.
Blood is contained within closed vessels.
Double circulation refers to systemic and pulmonary circulation.
Blood passes through the heart twice for each complete circuit of the body.
One side of the heart pumps blood to the lungs, and the other side pumps blood to the rest of the body.

Advantages of Double Circulation

Oxygen-rich and oxygen-depleted blood are separated, maintaining a steep concentration gradient for gas exchange.
Blood is pumped under two different pressures: higher pressure in systemic circulation to ensure glucose and oxygen reach all tissues and lower pressure in pulmonary circulation to protect delicate capillaries.

Transport System in Fish

Fish have a single circulatory system, where blood flows through the heart once per complete circuit of the body.

Disadvantages of Single Circulation in Fish

Mixing of oxygenated and deoxygenated blood reduces the concentration gradient for gas exchange.
Blood pressure is too low for efficient kidney function in mammals.

Importance of Blood

Blood plays a crucial role in transporting oxygen, nutrients, and waste products.
Red blood cells, white blood cells, and platelets are found in blood plasma.

Characteristics of Red Blood Cells

Small in size: 7µm, allowing them to squeeze through capillaries, maximizing gas exchange.
Lack a nucleus, mitochondria, and endoplasmic reticulum, providing more space for haemoglobin.
This placement of haemoglobin allows for shorter distances for diffusion.

Blood Clotting

Platelets release serotonin, causing vasoconstriction to reduce blood flow to the damaged area.
Platelets release thromboplastin, which initiates a cascade of chemical reactions leading to blood clotting.

Process of Blood Clotting

Thromboplastin converts prothrombin into thrombin.
Thrombin converts fibrinogen into fibrin, which forms a mesh that traps blood cells and platelets.
Platelet contraction tightens the clot, forming a scab to protect the wound and prevent bacteria invasion.

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Description

This quiz explores the importance of transport systems in animals, highlighting how larger animals rely on circulatory systems due to their size and metabolic needs. It also examines how single-celled organisms efficiently use diffusion for nutrient and gas exchange, given their small size and low energy demands.