I/GCSE Biology - Heart

In this post, we'll talk about heart in I/GCSE Biology. Let's get started! 😆

• The HEART ➡️ a muscular organ in the circulatory system.
• It beats automatically, pumping blood around the body to provide cells with oxygen and dissolved food for RESPIRATION.
• The blood removes carbon dioxide and water as waste products.
• The muscle cells in the heart need a constant supply of oxygen and nutrients, and for their waste products to be removed.
• So the heart requires its own blood supply in order to keep beating

In I/GCSE Biology, it's important to know the blood flow in heart!!!

Blood flow:

1. Blood from the rest of the body enters the RIGHT ATRIUM of the heart.
2. It then moves into the RIGHT VENTRICLE before being pumped to the lungs.
3. When the oxygenated blood returns to the heart, it enters the LEFT ATRIUM.
4. It then moves into the LEFT VENTRICLE before being pumped to the rest of the body.

The heart is a DOUBLE PUMP in the circulatory system because blood returns twice.

Look at the diagram below to have a clear concept!

Do you remember the 3 types of blood vessels in I/GCSE Biology?

Let me remind you in the following!!!

Make sure you memorize these in the exam~

• The heart rate can be measured by taking the pulse.
• If it is too fast or too slow, then it could indicate problems.

Another, more accurate way of checking how hard your heart is working is through measuring BLOOD PRESSURE. This records the pressure of the blood on the walls of the artery and it results from two forces:

• SYSTOLIC pressure from the heart as it contracts and pumps blood into the arteries and through the circulatory system (HIGHER VALUE)
• DIASTOLIC pressure from the force of the arteries as they resist the flow when the heart relaxes (LOWER VALUE)

• High blood pressure is the biggest concern as it increases the risk of a heart attack- but low blood pressure can be dangerous too.
• However ‘NORMAL’ measurements for factors such as heart rate and blood pressure are always given as ranges because individuals vary.
• Blood vessels called the CORONARY ARTERIES supply blood to the heart muscles. If they become blocked, a HEART ATTACK can happen

A heart attack can happen because:

• Fatty deposits build up in the coronary arteries
• A blood clot can form on a fatty deposit
• The blood clot can block a coronary artery
• Some heart muscle cells do not get the oxygen and nutrients the need
• These cells start to die

And we're done with this topic! Well Done!

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Drafted by Alyssa (Biology)

References:

1. "Heart". Photo from the internet.
2. "Blood flow". Photo from the internet.
3. "Blood vessel". Photo from the internet.
4. "Systolic vs. Diastolic Blood Pressure", https://lifesourcecanada.com/wp-content/uploads/2020/07/SYS-DIA-illustration.png
5. "High Blood Pressure", https://post.healthline.com/wp-content/uploads/2020/09/1193-High_Blood_Pressure_Home_Remedies-732x549-thumbnail-1-732x549.jpg
6. "Heart Attack", https://images.medicinenet.com/images/illustrations/heart_attack.jpg