Circulatory System 1 - Heart

This lesson covers:

  1. How the heart, blood vessels, and blood, make up the circulatory system 
  2. What we mean by 'single circulatory system' and 'double circulatory system'
  3. The structure of the heart 
  4. The route of blood flow through the heart
  5. The role of the coronary arteries 

Fish have a single circulatory system


In single circulatory systems the blood travels in a single loop, passing through the heart once for each complete circuit of the body.

Diagram showing the single circulatory system in fish with deoxygenated blood passing through the gills and oxygenated blood flowing to the body.

Fish have single circulatory systems:

  1. Deoxygenated blood from the body travels to the fish's two-chambered heart.
  2. The heart pumps the blood through the gills, where the blood is oxygenated.
  3. The oxygenated blood continues circulating throughout the body in a single circuit, releasing oxygen to the body cells before travelling back to the heart.

Mammals have a double circulatory system


In double circulatory systems, the blood travels around two separate loops per complete circuit.

Diagram showing the double circulatory system with two loops, one passing through the lungs and heart, and the other through the heart and body.

Mammals have a double circulatory system:

  1. A loop connecting the heart and lungs - in order to oxygenate the blood.
  2. A loop connecting the heart to the rest of the body - in order to deliver the oxygenated blood to the body's cells. 

Advantages of double circulation


  1. In double circulatory systems, oxygenated blood is pumped to the body tissues at a higher blood pressure. 
  2. This faster blood flow ensures more oxygen is delivered to the body cells.
  3. This is vital to warm-bodied, complex organisms with higher metabolic rates.

The three parts of the circulatory system are the b, the b v, and the h.

lood
lood
essels
eart

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Our double circulatory system has two loops:

Diagram showing the double circulatory system with lungs, heart, and body, illustrating the movement of blood.

Which letters represent the movement of deoxygenated blood?

(Select all that apply)

A

B

C

D

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Diagram of the heart with a chamber labelled A.

Name the chamber labelled 'A' on the diagram above.

Right atrium

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On each side of the heart, the atrium and ventricle are separated by a , which prevents the blood from flowing b.

valve
ackwards

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Diagram of the heart showing the chamber labelled A.

What is the name of the chamber labelled 'A' on the diagram above?

Right atrium

Right ventricle

Left atrium

Left ventricle

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The _______ ventricle has thicker walls because it has to pump blood all the way around the body.

right

left

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Which blood vessel carries deoxygenated blood from the heart to the lungs?

Vena cava

Aorta

Pulmonary artery

Pulmonary vein

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The journey of blood around the body


left ventricle / pulmonary artery / right atrium / pulmonary vein


Body tissues ➔ vena cava ➔  ➔ right ventricle ➔  ➔ lungs ➔  ➔ left atrium ➔  ➔ aorta ➔ body tissues

right atrium
pulmonary artery
pulmonary vein
left ventricle

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Which blood vessel carries oxygenated blood from the heart to the body?

Pulmonary Artery

Aorta

Pulmonary Vein

Vena cava

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The movement of blood between the ventricles and atria: 


contract / relax / ventricles / atria / aorta


  1. The walls of the atria , pushing blood into the relaxed ventricles.
  2. The walls of the contract, pushing blood out of the heart. At the same time, more blood will enter the now-relaxed .
  3. The cycle repeats.
contract
ventricles
atria

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Pacemaker cells are found in which chamber of the heart?

Right atrium

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Which statement is always true regarding arteries?

They carry blood towards the heart

They carry oxygenated blood

They carry blood away from the heart

They carry deoxygenated blood

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Which statements is always true for veins?

They carry blood away from the heart

They usually carry deoxygenated blood

They carry blood towards the heart

They usually carry oxygenated blood

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The c arteries supply the heart muscle with oxygen and nutrients.

oronary

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