Grade 10 Bio Unit 1 The Human Circulatory system

Where are nutrients transported from and to by the circulatory system?

Nutrients are transported from the small intestine to the liver.

Where is carbon dioxide transported from and to by the circulatory system?

Carbon dioxide is transported from all cells to the lungs.

Where is ammonia transported from and to by the circulatory system?

Ammonia is transported from all cells (where it breaks down to Urea) to the liver.

Where is urea transported from and to by the circulatory system?

Urea (made from ammonia) is transported from the liver to the kidneys (where it is used to produce urine).

Where are hormones transported from and to by the circulatory system?

Hormones are transported from endocrine glands to target cells.

Where is heat transported from and to by the circulatory system?

Heat is transported from more active tissues to less active tissues.

What is required for all living cells and made from food and oxygen?

Respiration.

What type of system do larger organisms require to supply oxygen, glucose, and other substances throughout the body?

A mass flow system.

What are the four parts of a mass flow system?

A Medium (fluid/blood); A system of tubes (arteries and capillaries); A pump (the heart); Sites of exchange (capillaries).

What is the average volume of blood in an adult?

The average adult has 5dm^3 of blood.

Where are blood cells first formed?

Blood cells are first formed in the bone marrow of long bones like the femur.

What is the function of red blood cells (erythrocytes)?

They transport oxygen from the lungs to all respiring cells and prepare carbon dioxide from all respiring tissues to the lungs.

How is the structure of red blood cells suited to their function (oxygen transport)?

They contain haemoglobin, an iron-containing pigment that picks up oxygen in the lungs and drops it off in the tissues. They have no nucleus, creating more space for haemoglobin, and are extremely small to easily pass through capillaries.

What is the function of white blood cells (phagocytes)?

They remove microorganisms that may cause disease and infection in the body by engulfing them.

How is the structure of white blood cells (phagocytes) suited to their function?

An irregularly shaped nucleus allows them to squeeze through gaps in capillary walls. Enzymes in the cytoplasm digest engulfed microorganisms. A sensitive cell surface membrane can detect microorganisms.

What is the function of white blood cells (lymphocytes)?

They produce antibody-protein to help defend against disease.

How is the structure of white blood cells (lymphocytes) suited to their function?

They have a large nucleus containing many copies of genes for the control of antibody proteins.

What is the function of platelets?

Platelets are responsible for blood clotting.

What is the function of arteries?

To transport blood at high pressure from the heart to the tissues of the body and lungs.

Describe the structure of arteries.

Arteries have a narrow lumen for maintaining high blood pressure and a thick, elastic wall of muscles that prevents rupturing under high blood pressure and allows elastic recoil.

What is the function of veins?

To carry (collect) blood from tissues at low blood pressure back to the heart.

Describe the structure of veins.

Veins have a wide/large lumen, which helps in returning blood to the heart, contain fewer muscles and elastic fibers (for slower blood flow), and contain valves which prevent backflow.

Why are valves important in veins?

Valves prevent the backflow of blood, especially when blood is moving slowly against gravity, ensuring it continues towards the heart.

Describe the structure of capillaries.

Capillaries are extremely small, allowing only one red blood cell at a time. They are made of a single layer of cells to minimize the distance of diffusion.

What is the function of capillaries?

To exchange materials between cells in tissues and blood, traveling at low pressure. They are where arteries branch, causing blood to move slowly so all cells are near a blood supply. After material exchange, capillaries pool into small veins, which join into larger veins to return blood to the heart.

How many chambers does the human heart have?

The human heart is a 4-chambered organ, made up of 2 atria and 2 ventricles.

What is the function of the atria in the heart?

The atria act as reservoirs, collecting blood entering the heart in veins and where oxygenated blood flows around the body.

What is the function of the ventricles in the heart?

The ventricles act as pumps, expelling (pushing) deoxygenated blood from the heart at high pressure in the arteries.

what is the function of the circulatory system?

to transport materials/nutrients in the blood around the body