Science - Chapter 4: Grade 7

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**Name four things the cardiovascular system does.**

1. Delivers needed substances to cells

2. Carries wastes away from cells

3. Helps regulate body temperature

4. Blood contains cells that fight disease

How does blood travel through the body?

In the first loop, blood travels from the heart to the lungs and then back to the heart. In the second loop, blood travels from the heart throughout the body, and then back to the heart.

The differences between arteries and veins.

Arteries are thick-walled muscular vessels that carry blood away from the heart to the body cells. Veins are large vessels with walls thinner than artery walls that carry blood from the blood cells back to the heart.

What are the four components of blood and what does each one do?

1. Plasma: The liquid part of blood. Water makes up 90 percent of plasma. The other 10 percent is dissolved materials. It carries nutrients and carries away most of the carbon dioxide and many other wastes cell processes produce. Appears yellow because of protein molecules.

2. Red Blood Cells: Take up oxygen in the lungs and deliver it to cells throughout the body. They are produce in bone marrow, and is made out of hemoglobin. They have no nuclei, so they cannot repair or reproduce itself. It is red and resembles a cough drop

3. White Blood Cells: The body’s disease fighters. Some of them recognize disease-causing organisms, such as bacteria, and alerts the body to the invasion. Others produce chemicals to fight the invaders. Still others can still surround and kill the organism. Is produced in the bone marrow. It looks white and spiky.

4. Platelets: Are cell fragments that help form blood clots. When a blood vessel is cut, platelets collect and stick to the vessel at the site of the wound. Platelets release chemicals that release a protein called fibrin. It looks tiny pink raisins.

What are some ways to maintain cardiovascular health?

By exercising regularly, eating a balanced diet that is low in saturated fats, trans fats, cholesterol, and sodium; and avoid smoking

Which blood is compatible with each specific blood type?

Blood type O is compatible with O, blood type A is compatible with A and o, blood type B is compatible with b and O, blood type A B is compatible with Ab a b, and O

Cardiovascular system  

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Made up of the heart, blood vessels, and blood.

Atrium

An upper chamber that receives blood that comes into the heart.

Ventricle

A lower chamber that pumps blood out of the heart.

Coronary arteries

The first branches off the aorta called _____, carry blood to the heart itself.

Valve

A flap of tissue that prevents blood from flowing backward. It separates the ventricles and the large blood vessels that carry blood away from the heart.

Aorta

Blood in the left ventricle is pumped into this. It is the largest artery in the body.

Diffusion

When molecules move from an area of higher concentration to an area of lower concentration.

Blood pressure

A force that blood exerts against the walls of blood vessels.

Plasma

The liquid part of the blood. 

Hemoglobin

Red blood cells are made mostly of this. It is a protein that contains iron and binds chemically to oxygen molecules.

Platelet

Cell fragments that help form Blood clots

Lymphatic system

The body’s drainage system. A network of veinlike vessels that returns fluid to the bloodstream. Carries excess fluid away

Lymph node

Filters lymph, trapping bacteria and other disease-causing microorganisms in the fluid

Atherosclerosis

A condition in which an artery wall thickens as a result of the buildup of fatty materials.

Heart attack

Occurs when blood flow to part of the heart muscle is blocked, causing cells to dies

Hypertension

High blood pressure. A disease in which a person’s blood pressure is consistently higher that normal --- usually defined as greater than 140/90. It causes the heart to work harder.