Biology Chapter 6

Waste products can be rapidly removed from the cell by simple diffusion.(T/F)

True

What is the purpose of a transport system?

To carry substances from one part fo the body to another

What are the parts of the circulatory system?

Blood vessels

Heart

Blood

What is the purpose of blood?

Blood transports substances around the human body and defends it against diseases

What are the main components of blood?

Plasma

Red blood cells

White blood cells

Platelets

How does plasma look?

Plasma is the yellowish liquid in blood

What does plasma contain?

It contains mainly water and substances like glucose, amino acids, salts, proteins, fats, vitamins, hormones and excretory products like urea

What are the functions of plasma?

Transports blood cells around the body

Transports nutrients from the small intestine to other parts of the body

Transports excretory products from organs to excretory organs for removal

Transports hormones from the endocrine glands to target organs

What are the features of a red blood cell?

Circular, biconcave shape

Contains a red pigment called haemoglobin

Flexible

No nucleus

What is the main function of the red blood cell?

Their main function is to transport oxygen from the lungs to other parts of the body

What are the adaptations of the red blood cell?

Contains haemoglobin that reversibly binds to oxygen

Biconcave shape to increase surface area to volume ratio

Flexible and can change into a bell-shaped structure so it can easily flow through narrow blood capillaries

No nuleus so there is more space for haemoglobin

How does an increase in the surface area to volume ratio of red blood cell benefit the body?

This increases the rate of absorption and release of oxygen

What is formed when haemoglobin binds with oxygen?

Oxyhaemoglobin

What does oxyhaemoglobin do when the oxygen concentration in tissues is low?

Oxyhaemoglobin releases its oxygen to the tissue cells

What are the main 2 types of white blood cells?

Phagocytes

Lymphocytes

What is the function of phagocytes?

To perform phagocytosis

What is phagocytosis?

Phagocytosis is the process by which a white blood cell engulfs and destroys foreign particles like bacteria

Lymphocytes produce antibodies that:

Recognise foreign particles

Destroy disease-causing organisms like bacteria and viruses

Cause bacteria to clump together for easy ingestion by phagocytes

Neutralise the toxins produced by bacteria

White blood cells are regular in shape. (T/F)

False, white blood cells are irregular in shape

What are platelets?

Platelets are fragements of cytoplasm

What do platelets contain?

They contain an enzyme that catalyses the conversion of fibronogen to fibrin threads

What do fibrin threads form?

Fibrin threads form a network that entangles red blood cells to form a clot, preventing excessive blood loss and entry of harmful organisms into the bloodstream

How does blood clot?

Blood exposed to air will soon clot. Platelets are involved in converting the soluble protein, fibronogen into insoluble threads of fibrin, sealing the wound, which prevents excessive blood loss and foreign particles from entering the bloodstream

What happens to people who have haemophilia who are injured?

People suffering from a hereditary disease called haemophilia, the normal blood-clotting mechanism is greatly impaired, so if they are not treated immediately, they might bleed to death of die from internal bleeding

What is organ transplant?

When a person’s tissue or organ is damaged or diseased, it can be replaced with healthy tissue or organ from a donor

What is tissue rejection?

A foreign tissue may be recognised by the white blood cells, which may repond by producing antibodies to destroy the foreign tissue

How to prevent tissue rejection?

Take skin from the same person

Find a tissue match, which is as genetically similar to the recipient’s tissue

Use drugs to inhibit the recipient’s immune system

What are antigens?

Special proteins found on the surface of all your red blood cells

Blood plasma contains antibodies. which are produced by …

the white blood cells, and are always present in the blood

Natural antibodies may not react to antigens in your blood, …

but they may react to antigens in other people’s blood, causing the clumping of red blood cells

What are the different types of blood groups?

A, B, AB and O

Antigens are presented using …

capital letters like A or B

Antibodies against antigens A or B are represented using …

small letters a and b

Antibody a reacts with antigen A. (T/F)

True