Cardiovascular & Respiratory Physiology

Key Terms - Cardiovascular system - Heart + blood vessels that move blood through the body. - Circulatory system - The fluid-transport network (cardiovascular + lymphatic systems). - Systemic (greater) circulation - Loop supplying tissues: left ventricle → body capillaries → right atrium. - Pulmonary (lesser) circulation - Loop for gas exchange: right ventricle → lungs → left atrium. - Arterial system - Vessels that carry blood away from the heart (to tissues). - Venous system - Vessels that carry blood back to the heart (from tissues). - Capillaries - Small vessels where exchange happens between blood and tissues. - Pulmonary veins - Veins that carry oxygenated blood from lungs to the left atrium.

Active Recall - Cardiovascular system - ________________________________________________ ______________________________________________ - Circulatory system - ______________________________________________ ______________________________________________ - Systemic (greater) circulation - ______________________________________________ ______________________________________________ - Pulmonary (lesser) circulation - ______________________________________________ ______________________________________________ - Arterial system - ______________________________________________ ______________________________________________ - Venous system - ______________________________________________ ______________________________________________ - Capillaries - ______________________________________________ ______________________________________________ - Pulmonary veins - ______________________________________________ ________________________________________________

Worked Examples

Example 1 (straightforward): Identify the “loop” 1. Blood is pumped from the left ventricle. 2. It goes to tissues via arteries and exchanges at capillaries. 3. After exchange, it returns via veins to the right atrium. Answer: This is systemic (greater) circulation.

Now you try: A blood sample is found in systemic capillaries during tissue exchange. Where should it end up next? ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

Example 2 (oxygen logic): Which circulation to lungs? 1. Blood starts in the right ventricle. 2. It goes to the lungs using the pulmonary artery. 3. Gas exchange happens in lung alveoli; oxygenated blood returns via pulmonary veins to the left atrium. Answer: This is pulmonary (lesser) circulation.

Now you try: Deoxygenated blood is leaving the heart to reach the alveoli. Name the chamber and vessel it travels through first. ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

Example 3 (combined pathway): Trace one full circuit segment 1. Left ventricle → systemic arteries → capillaries (tissue exchange). 2. Capillaries drain into systemic veins → right atrium. 3. From right atrium → right ventricle → pulmonary artery → lungs for re-oxygenation. Answer: Systemic loop completes at right atrium, then pulmonary loop begins.

Now you try: Write the sequence of major vessels/chambers for: lungs → oxygenated blood return → left atrium. ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

Practice Questions 1. (Easy) Define systemic (greater) circulation in one sentence. ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

2. (Easy) In systemic circulation, where does exchange between blood and tissues occur? ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

3. (Medium) Trace the pathway of blood from the right ventricle to the left atrium (include the key vessel names). ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

4. (Medium) Compare oxygenated vs deoxygenated flow: which circulation supplies oxygenated blood to body tissues, and where does that oxygenated blood come from? ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

5.

(Hard) In systemic circulation, state the “left side supply” and “right side return” pattern using chambers (left ventricle/right atrium) plus at least two vessel types. ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

6. (Hard) A patient has impaired gas exchange in the lungs. Which circulation is directly affected first, and what downstream effect would you expect on systemic oxygen delivery? ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

7. (Hard) A blood vessel obstruction blocks flow from the right ventricle to the lungs. Predict what happens to oxygenated blood reaching the left atrium. ________________________________________________ ______________________________________________ ______________________________________________ ________________________________________________

Answer Key 1. Systemic circulation is the pathway that carries blood from the heart to body tissues and back again. 2. Exchange occurs at the capillaries with the tissues. 3. Right ventricle → pulmonary artery → lungs → pulmonary veins → left atrium. 4. Systemic (greater) circulation supplies oxygenated blood to body tissues; oxygenated blood comes from the lungs (pulmonary veins → left atrium → left ventricle). 5. Oxygenated blood goes out from left ventricle through systemic arteries to capillaries; venous blood returns via systemic veins to right atrium. 6. Pulmonary (lesser) circulation is affected first; less oxygenated blood returns to the left atrium, so systemic oxygen delivery drops. 7. Oxygenated blood production/return to the left atrium falls, so blood reaching the left atrium becomes inadequate (leading to reduced oxygenated systemic supply).

Exam Tips & Common Mistakes - Mixing up systemic vs pulmonary: systemic = body tissues; pulmonary = lungs. Anchor it with “systemic = greater, body; pulmonary = lesser, lungs.” - Forgetting the capillary exchange step: examiners expect “capillaries are where exchange happens” for both loops (tissues in systemic; alveoli in pulmonary). - Saying “right ventricle sends blood to systemic circulation”: wrong. Right ventricle sends blood to lungs via pulmonary artery. - Not using vessel names: if you only mention chambers, you lose marks. Add at least one vessel per step (systemic arteries/systemic veins; pulmonary artery/pulmonary veins). - For pathway questions, don’t jump: write the sequence like a chain (ventricle → artery → capillaries → vein → atrium).

Exam-focused phrasing: - For 8-mark/12-mark answers, include (1) pathway, (2) exchange site, (3) oxygenated vs deoxygenated direction.

Quick Reference **Rules / “must-know

End of chapter one. 4 more chapters in the full book.