Animal Bio: Circulatory System

Question 1

What are the four components of blood?

Answer 1

Plasma, red blood cells, white blood cells, platelets

Question 2

What is plasma rich in? What is suspended in it? (9)

Answer 2

Rich in protein.

Blood cells, platelets, O2, proteins, glucose, vitamins, minerals, CO2, cellular respiration waste products are suspended in it

Question 3

Fibrinogen is a blood ______.

What is the role of fibrinogen?

Answer 3

Blood protein.

Blood clotting: fibrinogen activates when platelets have clotted a blood vessel and forms a mesh to capture more platelets. This lets the injured site fully heal

Question 4

The red blood cells have a _______ shape. What is the purpose of this?

Answer 4

biconcave shape

to increase S.A. for gas exchange

Question 5

What protein do red blood cells contain? What is its main purpose?

Answer 5

hemoglobin

main purpose is to carry O2 and CO2 to and from the lungs

Question 6

What is the main function of white blood cells?

Answer 6

To defend against harmful bacteria and viruses

Question 7

Explain the process of phagocytosis.

Answer 7

• Leukocyte engulfs bacteria
• Leukocyte releases enzymes to destroy the bacteria and the leukocyte itself
• The remnants produce pus

Question 8

What are platelets? What are they essential for?

Answer 8

Cell fragments

Essential for blood clotting

Question 9

Explain the process of blood clotting.

Answer 9

Platelets stick to collagen fibres in the blood vessel wall.

As more platelets stick, the hole in the blood vessel in sealed

Then, fibrinogen in plasma is activated. It forms long fibrin strands which become a mesh that captures more platelets. This allows the injured site to fully heal.

Once the blood vessel is fully healed, the clot is absorbed by the body.

Question 10

What happens in the tissues when a person is active?

Answer 10

Cellular respiration increases: more oxygen is used to make energy. As such there is an oxygen deficiency in these tissues.

The partial pressure of O2 falls in the tissue cells, letting oxygen from hemoglobin (higher P.P.) diffuse into the cells.

At the same time, PP for CO2 in the tissue cells is now higher than in capillaries. Hemoglobin binds with the CO2.

This is taken back to the heart through red blood cells via the venous system

Question 11

Explain the flow of blood around the circulatory system, starting with the right atrium of the heart.

Answer 11

Deoxygenated blood arrives in the right atrium via the superior and inferior vena cava.

The right atrium contracts, opening the tricuspid valve and pumping blood into the right ventricle.

When the right ventricle is full, it contracts to push blood out the pulmonary artery to the lungs.

Gas exchange happens in the lungs.

The now oxygenated blood returns to the heart through the pulmonary vein and enters the left atrium.

The left atrium contracts, opening the bicuspid valve and pumping blood into the left ventricle.

The left ventricle contracts to push blood out into the ascending aorta. From there, it is distributed throughout the body.