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The human circulatory system has two circuits - Leaving Cert Biology - Question 13 - 2009
Question 13
The human circulatory system has two circuits. (i) Give the name of each of these circuits. (ii) Which of these circuits involves the pumping of blood by the left ve... show full transcript
Worked Solution & Example Answer:The human circulatory system has two circuits - Leaving Cert Biology - Question 13 - 2009
Step 1
Give the name of each of these circuits.
Answer
The two circuits of the human circulatory system are:
- Pulmonary Circuit - responsible for carrying deoxygenated blood from the heart to the lungs to pick up oxygen.
- Systemic Circuit - responsible for carrying oxygenated blood from the heart to the rest of the body.
Step 2
Step 3
Write a short note on each of the following: Pulse.
Answer
The pulse is the rhythmic expansion and contraction of arteries as blood is pumped through them by the heart, specifically during the ventricular contraction (systole) and relaxation (diastole). It can be felt at various points on the body, such as the wrist or the neck, where an artery is close to the surface.
Step 4
Write a short note on each of the following: Blood pressure.
Answer
Blood pressure is the force exerted by circulating blood on the walls of blood vessels, measured in millimeters of mercury (mmHg). It is typically expressed with two numbers: systolic pressure (during heartbeats) over diastolic pressure (between heartbeats). It is vital for ensuring adequate blood flow to organs and tissues.
Step 5
Comment on the effect of each of the following on the circulatory system: Diet.
Answer
Diet plays a crucial role in the circulatory system. A balanced diet rich in fruits, vegetables, whole grains, and lean proteins can contribute to heart health, reduce cholesterol, and maintain healthy blood pressure levels. Conversely, a diet high in saturated fats, trans fats, and sugars can lead to obesity, hypertension, and cardiovascular diseases.
Step 6
Comment on the effect of each of the following on the circulatory system: Exercise.
Answer
Regular exercise strengthens the heart muscle, improves circulation, and helps maintain healthy blood pressure and cholesterol levels. It enhances overall cardiovascular efficiency, reduces the risk of chronic diseases such as heart disease, and contributes to weight management and improved mental health.
Step 7
Give two ways, other than colour, in which a red blood cell differs in structure or composition from a typical body cell such as one in the cheek lining.
Answer
- Nucleus: Red blood cells do not contain a nucleus, while typical body cells, such as cheek cells, do have a nucleus containing genetic material.
- Shape: Red blood cells are biconcave discs which allow for increased surface area for gas exchange, whereas typical body cells have a variety of shapes depending on their function.
Step 8
What is the role of the SA (sinoatrial) and AV (atrioventricular) nodes in the heart?
Answer
The SA node, located in the right atrium, acts as the heart's natural pacemaker, initiating the electrical impulses that trigger heartbeats. The AV node, located between the atria and ventricles, receives impulses from the SA node and delays them slightly before transmitting them to the ventricles, ensuring coordinated contraction of the heart chambers.
Step 9
Give the precise locations of both the SA and the AV nodes in the heart.
Answer
The SA node is located in the upper wall of the right atrium, near the entrance of the superior vena cava. The AV node is located at the junction of the right atrium and the right ventricle, specifically in the interatrial septum near the opening of the coronary sinus.