Biology 101: Circulatory, Respiratory, and Lymphatic Systems Study Guide and Review

In this quick and easy study guide, we share our notes and review the circulatory, respiratory, and lymphatic systems in the following 3 sections. From the anatomy of the heart and blood flow in the circulatory system to the breaths we take traveling through the lung and lymphatic flow.


The purpose of the circulatory system is to deliver oxygen and nutrients to all the cells in your body.

Using the diagram of the heart, write the letters of the structures and their name in the order blood goes through the heart:

Anatomy of the Circulatory System

Anatomy of the Heart and Circulatory System

I and Lvena cava (inferior & superior)
Jrt. atrium
Htricuspid valve
Grt. ventricle
Bpulmonary artery
Clt. atrium
Ebicuspid valve (mitral valve)
Flt. ventricle

The interventricular septum separates the right and left ventricle.  All blood entering the right side of the heart is oxygen-poor because it comes from the body.  All blood entering the left side of the heart is oxygen-rich because it is returning from the lungs.

To circulate blood through the body, arteries always carry blood AWAY from the heart and veins always carry blood TO the heart.  Because they go from and to the body, the vena cava is the largest vein and the aorta is the largest artery.  The term “pulmonary” indicates that blood is going to or from the lungs

Although the heart is constantly pumping blood, the blood moves through with so much pressure and so quickly that it cannot pick up the oxygen it needs.  Therefore, the coronary artery supplies the heart itself with blood.

Fetal Circulation

Circulation is different in a fetus from an adult because the fetus gets its oxygen and nutrients through the umbilical vein from the mom.  All wastes are sent to the mom through the umbilical artery.  Because it is not necessary for all blood to go to the lungs the fetal heart has a couple of ways to allow blood to bypass the lungs, the ductus arteriosis (between the pulmonary artery and aorta) and the foramen ovale (between the left and right atria).  These openings usually close upon birth.

Circulatory Health

atherosclerosisbuild-up of fatty tissue in the arteries  
high blood pressureStress, genetics, high-sodium intake, obesity smoking
heart attackblockage of the coronary artery  
strokeblockage of an artery leading to the brain  


Blood is responsible for collecting nutrients from villi in the small intestine, oxygen from alveoli in the lungs, and waste products from tissues.  However, blood is made of several components:

PlasmaMade of water, salts, nutrient, enzymes, hormones, waste, proteins; proteins transport substances, regulate blood volume, help fight viral and bacterial infections
Red Blood CellsTransports oxygen  
White Blood CellsFights foreign substances or organisms  
PlateletsProteins and cell fragments that help blood to clot  

Both red blood cells and white blood cells are produced in red bone marrow.  Besides differences in their function, one difference between red and white blood cells is that red blood cells do not have a nucleus because they contain hemoglobin instead, an iron-containing protein that helps bind oxygen.


The purpose of the respiratory system is to bring in oxygen for your body and remove carbon dioxide.

Anatomy of the Respiratory System
  1. Air enters through your mouth and nose.  When the diaphragm muscle contracts and pulls down, you inhale.  When it relaxes you exhale.  This muscle is structure C
  • Air then goes through structure G, the pharynx.  Structure F, the epiglottis, makes sure air goes to the lungs instead of the stomach.  Next air will pass through the larynx, which is the voicebox and enables you to talk and sing.
  • To get to the lungs, air must go through the trachea, structure E.  The passageway branches off into smaller and smaller vessels called bronchiole, structure B.
  • Finally, gas exchanges occurs in structure A.  Oxygen passes through the thin membrane of the alveoli and gets carried to the rest of the body by red blood cells and carbon dioxide is dropped off and exhaled by the lungs.

Breathing is controlled by the medulla oblongata located on the brain stem.  As carbon dioxide levels rise, nerve impulses cause the diaphragm to contract, bringing air into the lungs.

Pneumothorax is also known as a collapsed lung.

Respiratory Health

The respiratory system is coated with a thin layer of mucus to help trap inhaled particles, and cilia (tiny hairs) help move anything trapped out of the respiratory system.  Smoking can affect the respiratory system in many different ways.  Complete the following chart on the effects of smoking:

Contains carbon monoxideBlocks transport of oxygen by hemoglobin; deprives tissues of oxygen
Contains tarCan cause cancer
Causes paralysis of ciliaMucus accumulates, causes smoker’s cough
Leads to emphysemaLoss of elasticity of lung tissues; difficult to get oxygen
Can cause chronic bronchitisConstriction of bronchi; difficult to get oxygen

Respiratory System Questions and Answers:

  1. Why are chest wounds so serious? You no longer have the sealed cavity needed to create a partial vacuum – there will be no difference in atmospheric pressure and therefore the contraction of the diaphragm will not draw air into the lungs.
  1. What is asthma?  Constriction of the alveoli and bronchi; less air flows to lung tissue
  1. What is the danger of being in very high altitudes? Lower levels of oxygen but no more carbon dioxide in blood than usual so body may not recognize that it’s starving for oxygen (remember breathing is controlled by levels of carbon dioxide)

The Lymphatic System

The lymphatic system interacts closely with several other systems.  Explain the role the lymphatic system has in each of the following systems:

CirculatoryReturns fluid lost by blood into the circulatory system
ImmuneLymph nodes trap bacteria, matures specialized white blood cells (lymphocytes)
DigestiveAbsorb fat and fat-soluble vitamins from digestive tract, carry to blood

Lymphatic System Questions and Answers:

  1. What signals your heart to beat? Sinoatrial node (pacemaker) sends impulse to atria (atria contracts) and is picked up by the atrioventricular node and is carried to the ventricles (ventricles contract).
  • Explain the function of a heart valve.  To prevent blood from flowing backward (ex. when rt.ventricle contracts blood cannot flow into the rt. atria, must flow to pulmonary artery)
  • Explain why your heart rate increases while exercising.  Exercise increases body’s need for oxygen to keep up production of ATP, heart must beat faster to keep up supply of oxygen to body through blood flow.
  • Compare and contrast the structure and function of arteries and veins.  Arteries carry blood away from the heart and therefore have a thick wall of muscle to help withstand the pressure from the contraction of the heart and the flow of blood.  Veins carry blood to the heart and therefore have valves to prevent blood from flowing backward because most veins are directing blood against the force of gravity.
  • What protein-iron compound is carried by red blood cells?  What is its function?  Hemoglobin.  It’s job is to bind to oxygen.
  • When red blood cells die, how are they filtered from the blood?  The spleen destroys old blood cells.
  • Describe three functions of the lymphatic system.  To return lost fluids to the blood, to trap bacteria in lymph nodes and mature white blood cells, to absorb lipids and fat-soluble vitamins from the digestive system.
  • List at least three other body systems that interact with the circulatory system and describe how they interact.  Digestive system – capillaries surround villi in small intestine and pick up nutrients to send to cells in the body.  Respiratory system – capillaries surround alveoli in lungs and pick up oxygen to be circulated through body while dropping of carbon dioxide to be exhaled.  Excretory system – blood carries nitrogenous wastes from cells to the kidneys where they filter out wastes and control how much water is returned to the blood (also controlling blood volume).  Endocrine system – plasma carries hormones to where they are needed by the body.  Immune and lymphatic system – blood carries white blood cells to where they are needed and the lymphatic system returns lost fluid to the blood.

Woohoo! You’re here! Hope you enjoyed the study guide and review!

Click and check out these articles for more information: 🙂

Circulatory System: Blood Flow Pathway Through the Heart

Circulatory System: Heart Structures and Functions

Ductus Arteriosus Vs Ductus Venosus Vs Foramen Ovale: Fetal Heart Circulation

Cardiac Arrhythmias: Definition, Types, Symptoms, and Prevention

Upper Vs Lower Respiratory System: Upper vs Lower Respiratory Tract Infections

Seven General Functions of the Respiratory System

Digestive System Anatomy: Diagram, Organs, Structures, and Functions

Kidney Embryology & Development: Easy Lesson

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