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Circulatory Systems

Multicellular organisms contain systems of organs that carry out specialised functions that enable them to survive and reproduce.

LG1: Circulatory System
BIO_Circulatory System.png

The Human Circulatory System

Outline the role of the circulatory system in supporting life processes.

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ACTIVITY 1: Colour, Symbol Image​

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CSI: Circulatory System - Visible Thinking Routine
(Printable Template)

The circulatory system, composed of the heart, blood vessels, and blood, plays a vital role in supporting life processes by transporting oxygen, nutrients, hormones, and waste products throughout the body.

By the end of this section, you should be able to:
 

  • LG1 - Outline the role of the circulatory system in supporting life processes.
     

  • LG2 - Describe the role of blood and its components.
     

  • LG3 - Describe the role of blood vessels and explain the different types.
     

  • LG4 - Describe the structure and function of the heart.
     

  • LG5 - Describe the flow of blood through the body including the heart.
     

  • LG6 - Compare the circulatory system of humans with different organisms.
     

  • LG7 - Consider how advances in technology, combined with scientific understanding of the functioning of body systems, has enabled medical science to replace or repair organs.
     

  • Review & Consolidation

"Your body is a marvel, a mechanism of action and reaction more intricate than the most complex machine. Treat it with the respect it deserves." - Adelle Davis

LG2: Blood

Blood & its components 

Describe the role of blood and its components.

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Blood plays a crucial role in the human body, serving as a complex and dynamic fluid that performs various vital functions. Comprising approximately 8% of the total body weight, blood consists of a liquid component called plasma and cellular components, including red blood cells, white blood cells, and platelets.

 

Blood Components
Blood Plasma

  • Plasma is a yellowish fluid that makes up about 55% of blood.

  • It carries nutrients, hormones, and waste products throughout the body.

  • Plasma also helps maintain the body's pH balance and regulates temperature.

 

Red Blood Cells (Erythrocytes)

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  • Red blood cells make up about 45% of blood. 

  • They are responsible for transporting oxygen from the lungs to the body's tissues and bringing carbon dioxide back to the lungs for exhalation. 

  • These cells contain hemoglobin, a protein that binds with oxygen and gives blood its red colour.

 

White Blood Cells (Leukocytes)
 

  • White blood cells make up left than 1% of blood.

  • They are a crucial part of the immune system, defending the body against infections and foreign invaders.

  • They can move out of the bloodstream to reach infected tissues and destroy pathogens.

  • There are several types of white blood cells, each with specific functions in the immune response.
     

Platelets (Thrombocytes)
 

  • Platelets make up left than 1% of blood.

  • They are involved in blood clotting and play a crucial role in preventing excessive bleeding when there is damage to blood vessels.

  • They help form blood clots by adhering to the site of injury and releasing substances that stimulate clotting.

BIO [8-9]_Blood (IMAGE).png

DEMO: Modelling Blood​

BIO [8-9]_Modelling Blood (IMAGE-PA)_edi

​Use items (such as beads) to model the components of blood.

ACTIVITY 2: Observing Blood Smears​

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Observing Blood Smears
(Printable Worksheet)

Analysing Irregular Blood Smears
(Thinking Exercise)

To complete this activity, you will need a microscope, pre-made blood smears and the worksheet & PDF below.​

LG3: Blood Vessels

Blood Vessels

Describe the role of blood vessels and explain the different types.

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Blood vessels (arteries, veins, and capillaries) form a network to facilitate the flow of blood. There are three main types of blood vessels: arteries, veins, and capillaries. 

The interaction between these three types of blood vessels forms a closed circulatory system. Arteries branch into smaller arterioles, which then lead to networks of capillaries in tissues and organs. After exchanging nutrients and oxygen for waste products in the capillaries, blood is collected by venules, which merge into larger veins that return the blood to the heart.

BIO [8-9]_Blood Vessels (DIAGRAM).PNG

ACTIVITY 3: Concept Attainment

Concept Attainment
(Teacher Led)

Complete this activity as an introduction to the content.

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  • PART 1 - Complete the teacher lead concept attainment thinking activity. ​
     

  • PART 2 - use learning and discussions from the concept attainment task to complete 2x Frayer Model graphic organisers on: 

    • Arteries 

    • Veins

Frayer Model
(Printable)

Blood Vessels in Detail: 
 

Arteries:

  • Arteries carry blood away from the heart to the rest of the body.

  • The largest artery is the aorta, which branches into smaller arteries that further divide into arterioles.

  • Arteries have thick and elastic walls that help them withstand the high pressure generated by the pumping action of the heart.

  • The elastic nature of arterial walls allows them to expand and contract, helping to propel blood forward and maintain a steady flow.
     

Veins:

  • Veins transport blood from the body back to the heart.

  • The largest vein is the vena cava, which brings blood from the body's upper and lower halves back to the right atrium of the heart.

  • Veins have thinner walls compared to arteries and are less elastic. They also have valves to prevent the backflow of blood and ensure it moves towards the heart despite lower pressure.
     

Capillaries:

  • Capillaries are tiny, thin-walled vessels that connect arteries and veins.

  • They facilitate the exchange of oxygen, nutrients, and waste products between the blood and surrounding tissues at the cellular level.

  • Capillary walls are so thin that substances like oxygen and nutrients can diffuse through them.

BIO [8-9]_Blood Vessels (SUMMARY).PNG
LG4: Th Heart

The Heart

Describe the structure and function of the heart.

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Structure: The heart has four chambers - two atria and two ventricles. It is a muscular organ that contracts to pump blood throughout the body.
 

Function: The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs for oxygenation.

BIO [8-9]_Heart (DIAGRAM).png

ACTIVITY 4: Heart Dissection

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Heart Dissection
Visual Guide

Heart Dissection

Printable Worksheet

FORMATIVE ASSESSMENT 1: Circulatory System

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Circulatory System

(Formative Assessment)

Circulatory System

(Answer Key)

LG5: Blood Flow

Blood Flow

Describe the flow of blood through the body including the heart.

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Blood flows in the the human circulatory system in one continuous loop. This is known as a closed system. Oxygenated blood flows from the left ventricle to the body through arteries, returns as deoxygenated blood through veins to the right atrium, then pumped to the lungs by the right ventricle for oxygenation before returning to the left atrium. This cycle repeats, and the heart continuously pumps blood throughout the body, ensuring that organs and tissues receive the oxygen and nutrients they need while removing waste products.

BIO [8-9]_Blood Flow (DIAGRAM).PNG

ACTIVITY 5: Role Play​

Set up a circuit on the ground using masking tape or chalk that mirrors the layout of the flow of blood through the heart and body. Label the circuit with significant system parts. Have students play the role of RBCs and walk the circuit, currying “oxygen” balls (red) and “carbon dioxide” balls (blue) in the appropriate locations throughout the circuit.

LG6: Other circulatory systems

Other Circulatory Systems

Compare the circulatory system of humans with different organisms.

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Until now, you've focused on understanding the human circulatory system; however, it's important to note that circulatory systems across animals exhibit diversity. While the fundamental function of these systems remains consistent across different organisms, variations exist in their structure and components. To illustrate this, let's delve into a comparison between the circulatory systems of humans and two other organisms: fish and insects.​

Human vs. Fish vs. Insect Comparison

ACTIVITY 6: Comparing Circulatory Systems​

  1. Students will select and then research the circulatory system of an animal from one of the following categories: insects, birds, amphibians, or fish.
     

  2. Students need to present their research in a form of their choosing (see attached document). 
     

  3. Students will swap-and-share their findings with their peers in triad-group presentations.
     

  4. Students will provide peer constructive feedback during the sharing process. 

Comparing Circulatory Systems

(Research Task)

Peer Feedback

(Template)

BIO [8-9]_Fish Circulatory System (DIAGRAM).png
BIO [8-9]_Insect Circulatory System (DIAGRAM).PNG
LG7: Organ Transplants

Heart Transplants & Organ Donation (SHE)

Consider how advances in technology, combined with scientific understanding of the functioning of body systems, has enabled medical science to replace or repair organs.

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Heart transplants involve replacing a diseased or damaged heart with a healthy donor heart.

Several ethical issues surround organ transplantation, including:
 

  1. Organ Shortage: The demand for organs far exceeds the available supply, leading to ethical dilemmas in organ allocation.
     

  2. Fair Distribution: Ensuring equitable distribution of organs and preventing discrimination in the selection process.
     

  3. Informed Consent: Ensuring that donors and recipients fully understand the risks and benefits of organ transplantation.
     

  4. Organ Trafficking: The illegal trade of organs raises serious ethical concerns.
     

  5. End-of-life Issues: Deciding when and how to approach potential donors, especially in cases where the donor is deceased.

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Alternatives to Human Organ Transplants:
 

  1. Xenotransplantation: This involves the transplantation of organs or tissues from animals (usually pigs) into humans. Challenges include immune rejection and the risk of transmitting animal viruses to humans.
     

  2. Lab-Grown Organs: Scientists are exploring the possibility of growing organs in the laboratory using a patient's own cells. This could potentially eliminate issues of organ rejection.
     

  3. Artificial Organs: Some medical devices, such as artificial hearts or assist devices, can temporarily take over the function of a failing organ while awaiting transplantation or as a long-term solution

ACTIVITY 7: Silent Debate

Silent Debate
(Part 1)

​​Students will debate a topic related to organ transplants (see list of suggested topics) using the silent debate routine.
 

  • PART 1 - Allocation of topic and position followed by individual preparation and research.  ​
     

  • PART 2 - Student pair up with their opposing partner and silently engage in a written debate on their topic. 

Silent Debate
(Part 2)

Suggested
Debate Topics

Review & Consolidatin

Review & Consolidation

Reflect on your achievement of the learning goals. 
 

LG1 - Outline the role of the circulatory system in supporting life processes.
 

LG2 - Describe the role of blood and its components.
 

LG3 - Describe the role of blood vessels and explain the different types.
 

LG4 - Describe the structure and function of the heart.
 

LG5 - Describe the flow of blood through the body including the heart.
 

LG6 - Compare the circulatory system of humans with different organisms.
 

LG7 - Consider how advances in technology, combined with scientific understanding of the functioning of body systems, has enabled medical science to replace or repair organs

ACTIVITY 8: Review & Consolidation​

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Circulatory System - Visual Summary (Printable)

FORMATIVE ASSESSMENT 2:
Review Circulatory System

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Circulatory System

(Formative Assessment)

Circulatory System 
(Answer Key)

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