the circulatory system (5th Yr)

• Veins are blood vessels that carry deoxygenated blood back to the heart.
• The heart has four chambers - two atria (upper) and two ventricles (lower).
• Deoxygenated blood enters the right side of the heart from the body and is pumped to the lungs to get oxygenated. Oxygenated blood returns from the lungs to the left side of the heart and is pumped out to the body.
• The heart acts as a pump to circulate blood through the body.
• Arteries are blood vessels that carry oxygen-rich blood away from the heart.
• Capillaries are tiny, thin-walled blood vessels where exchange between tissues and blood occurs.
• Blood pressure refers to the force exerted by blood against the walls of arteries as it flows through them.
• Systolic pressure is the highest point during contraction, while diastolic pressure is the lowest point during relaxation.
• Plasma


  Liquid portion of blood, contains nutrients, waste products, and proteins
• What substances does blood carry?

  Carbon dioxide, oxygen, nutrients, waste products, heat, and hormones
• What is the difference between open and closed circulatory systems?


  • Open circulatory system: blood flows out of vessels and around tissue cells.
  • Closed circulatory system: blood is contained within vessels at all times.
• Which organisms typically have an open circulatory system?


  Invertebrates, such as insects
• How does blood return to the heart in an open circulatory system?


  Through small pores called ostia
• What are the components of the human circulatory system?


  Blood vessels, heart, and blood
• What is one advantage of a closed circulatory system?


  Blood can be pumped faster, allowing for quicker nutrient delivery
• How does blood flow rate change in a closed circulatory system?


  It can be increased to specific organs, like leg muscles during running
• Describe the process of a single circulatory system.

  1. Blood travels from the heart to the gills.
  2. Oxygen is absorbed and carbon dioxide is released.
  3. Blood flows to the organs and tissues.
  4. Blood returns to the heart.
• Describe the process of a double circulatory system in mammals.


  1. Blood goes from the heart to the lungs for oxygenation.
  2. Blood returns to the heart.
  3. Blood is pumped to the body organs and tissues.
  4. Blood returns to the heart again.
• How many chambers does a two-chambered heart have?


  Two chambers
• What type of heart is associated with a double circulatory system?


  A four-chambered heart
• What is the role of the right side of the heart in a double circulatory system?


  To move deoxygenated blood to the lungs
• What is the role of the left side of the heart in a double circulatory system?


  To move oxygenated blood to the body
• How does blood pressure in a double circulatory system compare to a single circulatory system?


  Blood is under higher pressure in a double circulatory system
• What are the main components of arteries, veins, and capillaries?

  • Arteries: Thick, elastic walls; carry oxygenated blood.
  • Veins: Thin walls; carry deoxygenated blood; contain valves.
  • Capillaries: Thin walls; connect arteries and veins.
• What color is oxygenated blood typically?


  Bright red
• What color is deoxygenated blood typically?


  Deep purple-red
• What prevents backflow of blood in veins?

  Valves
• How is blood moved back to the heart from veins?

  By the action of skeletal muscles
• What is the function of capillaries?


  To link arteries and veins
• What is the structure of the heart made of?

  Cardiac muscle
• What surrounds the heart?

  A double membrane called the pericardium
• How many times does the heart contract in a day?


  100,000 times
• What is the range of blood pumped by the heart per minute?


  1. 20 litres
• Describe the structure of the heart.

  • Divided by septum into two sides.
  • Four chambers: 2 atria and 2 ventricles.
  • Valves separate atria from ventricles.
  • Valves held by tendons and papillary muscles.
• What is the name of the valve on the right side of the heart?

  Tricuspid valve
• What is the name of the valve on the left side of the heart?

  Bicuspid valve
• What do semilunar valves do?


  Prevent blood from returning to the heart
• Describe the steps of blood flow through the heart.

  1. Deoxygenated blood enters the right atrium.
  2. Blood moves to the right ventricle.
  3. Oxygenated blood enters the left atrium.
  4. Blood moves to the left ventricle.
  5. Blood is pumped to the body and lungs.
• What is the pulmonary circuit?


  The circuit that pumps deoxygenated blood to the lungs
• What is the systemic circuit?


  The circuit that pumps oxygenated blood to the body