Biology 8 Lesson 18: Transporting blood through the vascular system and cleaning the circulatory system
1. Summary of theory
1.1. Transport of blood through the vascular system
– Blood is transported through the vascular system.
The force of the heart when the ventricles contract produces blood pressure and blood velocity.
Note: 1: Aorta, 2: Arteries, 3: Small arteries, 4: Capillaries, 5: Small veins, 6: Veins, 7: Venous veins
– Blood pressure gradually decreases throughout the length of the vascular system due to friction with the vessel wall and between blood molecules.
– The velocity of blood in the vessels decreases gradually from the arteries to the capillaries, then gradually increases in the veins.
+ The support of the circuit system
- Arteries: due to the dilation of arteries.
- Veins: thanks to the contraction of the muscles around the vessel walls, the suction of the thoracic cavity when inhaling and of the atria when dilated, the action of the one-way valve.
1.2. Cardiovascular hygiene
a. Need to protect the heart from harmful agents
– There are many causes for the heart to increase unwanted and harmful to the heart:
- Circulatory system defects: open or narrow heart valves, hardening of blood vessels.
- Bacteria, viruses: flu, typhoid, rheumatism…
- The body has some kind of shock: high fever, blood loss, shock…
- Use of stimulants: alcohol, tobacco, heroin.
- Negative emotions: anger, pain, fear, nervousness, etc.
- Food high in animal fat, too salty.
– For a healthy heart and vascular system, we need:
- Unwanted heart rate and blood pressure restriction.
- Do not use stimulants.
- Timely bandage the wound, do not let the body lose a lot of blood.
- Periodic medical examination and treatment for early detection and timely treatment of cardiovascular-related defects.
- Have a comfortable and happy mental life, away from negative emotions.
- Vaccination against diseases harmful to the heart: flu, typhoid..
- Limit the intake of foods that are harmful to the cardiovascular system.
b. Need to train the cardiovascular system
– It is necessary to do regular, regular and moderate cardiovascular exercise with daily exercise, moderate labor and massage.
2. Illustrated exercise
Where and how is the main thrust that helps to circulate blood continuously and in one direction in the vascular system?
The sample is transported vascularly by a force generated by the heart (ventricular contraction). This thrust creates a pressure in the blood vessels, called blood pressure (maximum pressure when the ventricles contract, diastolic pressure when the ventricles relax) and the velocity of blood in the vessels. This thrust (blood pressure) is gradually lost along the length of the vascular system due to friction with the vessel wall and between the blood particles, while the velocity of blood in the vessel decreases gradually from the artery to the capillary (0.5 m/s at arterial → 0.001 m/s in capillaries), then gradually increased in veins.
3.1. Essay exercises
Question 1: How is blood transported in the body?
Verse 2: Measures to prevent harmful agents for the heart are
Question 3: Athletes who practice for a long time often have a lower heart rate / minute than the average person. What is this metric and what does it mean? How can this be explained when the number of heartbeats / minute is less, but the body’s oxygen demand is still guaranteed?
3.2. Multiple choice exercises
Question 1: Blood is transported through the vascular system by:
A. The force of the heart when the heart contracts
B. Circuit support
C. Thanks to the valve system
D. Both A and B are correct
Verse 2: Arrange the velocity of blood flow in the vessel wall in the correct sequence
A. Arteries > veins > capillaries
B. Arteries > capillaries > veins
C. Veins > arteries > capillaries
D. Veins > capillaries > arteries
Question 3: In a normal person, on average, how long does the heart completely rest in each cycle?
A. 0.3 seconds
B. 0.4 seconds
C. 0.5 seconds
D. 0.1 seconds
Verse 4: In a normal person, how long does it take for blood to flow from the ventricles into the arteries?
A. 0.6 seconds
B. 0.4 seconds
C. 0.5 seconds
D. 0.3 seconds
Question 5: Diseases related to the circulatory system are:
B. Cerebrovascular accident
D. All of the above answers
After completing this lesson, you should be familiar with the following structures:
- Students understand the mechanism of blood transport through the vascular system.
- Students who know the harmful agents of the cardiovascular system take preventive measures and do cardiovascular exercise.