10R Transport in animals

Why do Multicellular organisms need a transport system?

To transport substances around the body of the organism

Why isn't it necessary for single-celled organisms (such as amoeba & paramecium)to have a transport system?

The movement of substances is facilitated through diffusion

What are the two circulatory systems in animals?

The blood vascular and lymphatic systems

What are the features of the blood vascular system?

1. It must have a circulatory fluid - blood

2. It must have tubes or vessels through which the fluid can circulate- blood vessels

3. It must have a contractile pumping device the propel the circulatory fluid around the body'- heart

What are the substances transported around the body?

1. Respiratory gases- such as O2, CO2

2. Hormones such as growth hormones, testosterone, estrogen, progesterone, and adrenaline

3. Nutrients such as vitamins and minerals

4. Blood cells such as erythrocytes and leukocytes

5. Nitrogenous waste such as urea

6. Heat

What is blood?

This is the liquid tissue that transports substances around the body

What are the components that make up blood?

55% of blood plasma and 45% of blood cells

What is blood plasma?

This is a pale yellow liquid consisting of 90% water and 10% various substances, including nutrients, heat, antibodies, hormones, and other clotting components in suspension and solution.

What are the types of blood cells present in the blood?

1. Erythrocytes (red blood cells) main types

2. Leukocytes (white blood cells) main types

3. Thrombocytes (platelets)

Where are erythrocytes produced?

These are produced in the marrow of long bones and are destroyed in the liver and spleen.

Describe the structure of the erythrocytes

• It contains the red pigment Haemoglobin which is most numerous in the blood and gives it its red colour

• They have a disc or biconcave shape which gives them a large surface area for diffusion

• They lack a nucleus, live for about 120 to 160 days and are smaller than leukocytes.

What is the function of the erythrocytes?

• They transport oxygen as oxyhaemoglobin from the lungs to the body cells.

• It contains iron

Describe the structure of leukocytes

• They are larger than erythrocytes

• They contain a nucleus and live for a long time

What are the types of leukocytes?

Lymphocytes and phagocytes

Describe the structure of lymphocytes

• It has a large nucleus surrounded by a thin cytoplasm

• It's divided into two main groups (T and B cells)

• It has a fixed shape

• They are larger than erythrocytes

What is the function of lymphocytes?

These produce antibodies that clump and neutralize the pathogens.

Where are lymphocytes produced?

These are produced in the bone marrow but mature in the thymus gland and lymph nodes

Describe the structure of phagocytes

• It has an irregularly shaped (lobed) nucleus and cytoplasm packed full of granules

• It lives for a long time

• It has an amoeboid shape- It can change shape/crawl

• They are larger than erythrocytes

What is the function of phagocytes?

This engulfs pathogens in the bloodstream and tissue fluid by surrounding and ingesting them

Where are phagocytes produced?

These are produced in the bone marrow and remain in the blood stream

What are thrombocytes?

These are broken-off pieces of large blood cells (megakaryocytes) of the bone marrow

Describe the structure of thrombocytes

• They are irregularly shaped

• Lack a nucleus and are fragments of cytoplasm

• They live for 5 to 10 days before being destroyed by the liver and spleen.

What is the function of thrombocytes?

These help form blood clots to stop or slow down bleeding and help to heal wounds

What are blood vessels ?

These are specialized tuɓes that transport blood around the body.

What are the types of blood vessels?

Arteries, veins, and capillaries

Describe the structure of arteries

• They are the largest blood vessels in the body

• They have a thick muscular elastic wall and are located deep in the muscles

• They have a small lumen without valves, which transports blood under high pressure creating a pulse.

What is the function of an artery?

This transports oxygenated blood from the heart to body cells, except for the pulmonary artery which transports deoxygenated blood from the heart to the lungs.

Describe the structure of veins

• These are smaller than arteries but larger than capillaries

• These have thin elastic walls and are located close to the surface of the muscles.

• They have a large lumen with valves to prevent the backflow of blood. Blood is pumped under low-pressure

What is the function of a vein?

These transport deoxygenated blood from body cells to the heart with the exception of the pulmonary veins which transports oxygenated blood from the lungs to the heart.

Describe the structure of a capillary?

• These are the smallest and most numerous blood vessels in the body

• They are composed of two layers of cells which facilitates diffusion of substances in and out of the cell.

What is the function of a capillary?

These facilitate the exchange of materials between the blood and tissue cells

Where is the heart located?

This is located in the centre of the thoracic cavity between the lungs and is tilted slightly to the left. It protected from external injuries by the sternum

What surrounds and protects the heart internally?

The pericardium which is a tough sac consisting of two membranes

What are the two membranes of the pericardium?

• The outer membrane and the inner membrane

Describe the structure of the outer membrane of the pericardium

This is made up of white elastic fibrous tissues attached to the sternum by ligaments.

What is the function of the outer membrane of the pericardium?

This protects the heart against blunt force and sudden external pressure changes.

Describe the structure of the inner membrane of the pericardium

This is made up of loose elastic connective tissues.

What is the function of the inner membrane of the pericardium?

This produces pericardium fluid which reduces the friction between the heart wall and surrounding tissues when the heart beats.

What is the function of the pericardium?

This prevents the heart from being overstretched or overfilled with blood.

What are the four Chambers of the heart?

The right and left atria and the right and left ventricles

Describe the structure and function of the atria

This has thin walls and collects blood

Describe the structure and function of the ventricles

These have thick muscular walls and pump blood away from the heart.

Which of the ventricles have the thickest muscular walls?

The left ventricle because it pumps blood all around the body.