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High school biology
Course: High school biology > Unit 8
Lesson 2: The circulatory and respiratory systemsThe circulatory system review
Key terms
| Term | Meaning |
|---|---|
| Circulatory system | The body system responsible for carrying blood, nutrients, and waste throughout the body |
| Cardiac | Related to the heart |
| Pulmonary | Related to the lungs |
| Artery | Blood vessel that moves blood away from the heart |
| Vein | Blood vessel that moves blood toward the heart |
| Aorta | Major artery that carries blood to the systemic circulatory system |
| Capillary | Small blood vessel that allows nutrient exchange |
| Atrium | Upper chamber of the heart |
| Ventricle | Lower chamber of the heart |
The circulatory system
The circulatory system is a network consisting of blood, blood vessels, and the heart. This network supplies tissues in the body with oxygen and other nutrients, transports hormones, and removes unnecessary waste products.
The heart
The heart is made of specialized cardiac muscle tissue that allows it to act as a pump within the circulatory system.
The human heart is divided into four chambers. There are one atrium and one ventricle on each side of the heart. The atria receive blood and the ventricles pump blood.
The human circulatory system consists of several circuits:
- The pulmonary circuit provides blood flow between the heart and lungs.
- The systemic circuit allows blood to flow to and from the rest of the body.
- The coronary circuit strictly provides blood to the heart (not pictured in the figure below).
Blood and blood vessels
Blood from the heart is pumped throughout the body using blood vessels. Arteries carry blood away from the heart and into capillaries, providing oxygen (and other nutrients) to tissue and cells. Once oxygen is removed, the blood travels back to the lungs, where it is reoxygenated and returned by veins to the heart.
The main artery of the systemic circuit is the aorta which branches out into other arteries, carrying blood to different parts of the body.
Common mistakes and misconceptions
- Arteries usually carry oxygenated blood and veins usually carry deoxygenated blood. This is true most of the time. However, the pulmonary arteries and veins are an exception to this rule. Pulmonary veins carry oxygenated blood towards the heart and the pulmonary arteries carry deoxygenated blood away from the heart.
- Blood is always red. Veins can appear blue as we see them through our skin, leading some people to believe that deoxygenated blood is blue. However, this is not the case! Blood only appears blue because of the way tissues absorb light and our eyes see color. Although oxygen does have an effect on the brightness of the blood (more oxygen makes a brighter red, less makes it darker), blood is never actually blue.
Want to join the conversation?
how long does it take to do a full rotation through the full body(16 votes)
For the blood to circulate throughout the body and back to the heart, it takes about one minute.(26 votes)
why do we have a double circulatory system?(10 votes)
The two circulatory systems serve different purposes.(0 votes)
What kinds of diseases can the circulatory system get?(10 votes)
Hypertension
Heart Attacks
Strokes
Heart murmurs
There are many more and you can learn about them through this link:
https://www.khanacademy.org/science/health-and-medicine/circulatory-system-diseases
I hope this helps.(15 votes)
Why does oxygenated blood go to the heart and deoxygenated blood go away?(5 votes)
Blood in need of oxygen enters heart called deoxygenated passes from the right atrium to the right ventricle then send it to the lungs through the pulmonary valve into the pulmonary artery,Fresh blood full of oxygen leaves the lungs and comes back to the heart in the pulmonary veins. This oxygen-rich blood enters the left atrium — the top left chamber of the heart blood passes from left atrium to left ventricle
The left ventricle relaxes and fills up with blood before squeezing and pumping the oxygen-rich blood through the aortic valve into the aorta — the main artery that carries blood to your body. The muscle wall of the left ventricle is very thick because it has to pump blood around the whole body.
in short :
1/ the oxygenated blood enter the heart to pump through the aortic valve into the aorta to the rest of your body
2/ the deoxygenated blood need oxygen to get "pump" in the heart so the heart push it to the lungs to "oxygenate".(10 votes)
- blood on the right side vs. blood on the left side of the heart(5 votes)
Blood on the right is deoxygenated (on its way to the lungs through the pulmonary artery) whereas blood on the left is oxygenated (on its way to the rest of the body through the aorta).(7 votes)
What is a heart attack and what does it have to do with the circulatory system?(2 votes)- If oxygenated blood doesn't reach the heart due to blocks or clots in arteries, then the muscle cells of the heart weaken which leads to what we call the heart attack. Since it is in the circulatory system where the blockage takes place, it is linked to the causes for a heart attack.(7 votes)
- why do we have a double circulatory system?(4 votes)
If deoxygenated blood is not blue, than why do my science books show that? Is it just their artificial color so that you can see them, like they do for x-rays?(2 votes)
They mostly just picture deoxygenated blood as blue to make it easier to tell from the stuff that's oxygenated. If you can see veins (carrying deoxygenated blood) under your skin they look blue, though that's an illusion, but it's probably partially why they chose blue.(4 votes)
How much heart beat per minute(1 vote)
It varies from person to person; the average pulse rate for an adult is 60-100 beats per minute (bpm). Trained athletes usually have a higher resting rate of 80-120 bpm. Does this help?(6 votes)
- how fast is the heart blood flow(3 votes)
The heart can shoot blood from the heart down to the foot about (on average) 3-4 MPH, or about walking speed.(2 votes)
