The Circulatory System

Chapter 38

• BEGIN labeling the heart using page 945 in your book.

Transport and Distribution

• Includes the lymphatic and cardiovascular systems.

• Acts as a highway, connecting the muscles and organs of the body.

A muscular pump• The human heart has two separate

circulatory loops, the right side of the heart is responsible for driving the pulmonary loop, which pumps oxygen-poor blood through the pulmonary arteries, to the lungs. In the lungs the blood gets oxygen and is returned to the left side of the heart by the pulmonary veins.

• The left side of the heart is responsible for driving the systemic loop, which pumps oxygen rich blood through the arteries to the tissues of the body. The oxygen poor blood is then returned to the right side of the heart through the veins.

5 Types of molecules that move through the cardiovascular system.

1. Nutrients from digested food.

2. Oxygen from the lungs, transported to all blood vessels.

3. Metabolic wastes (carbon dioxide)

4. Hormones

5. Distributes heat to maintain homeostasis.

Blood Vessels

Blood – tissue composed of fluid, cells and cell fragments

3 different types

1. Arteries

2. Capillaries

3. Veins

Arteries

• Carry blood AWAY from the heart

• Very forceful

• Walls made of elastic

Capillaries

• Very tiny – one cell thick

• Transfers gases, nutrients and hormones as well as carbon dioxide.

Veins

• Largest type of blood vessel

• Have valves to prevent backflow and allow blood to travel up hill.

• Carry blood TOWARD the heart

The Lymphatic System

• Collects and recycles fluids leaked from the cardiovascular system

• Helps fight infections

• Leaky fluid is called lymph

The Components of Blood: Plasma

• Makes up 60% of blood

• Made up of 90% water and 10% metabolites, wastes, salt and proteins.

• Fluid portion that suspends the blood cells.

Red Blood Cells

• Most numerous• Carry oxygen• Also called

erthrocytes• Packed with

hemoglobin• Produced in the

White Blood Cells

• Also called leukocytes

• Primary job is to

fight disease

• Large and have

a nucleus

Platelets

• Formed in bone marrow

• Help clot blood• People with

hemophilia lack platelets

Hemoglobin

• Iron containing proteins

• Found in RED BLOOD CELLS

• Binds oxygen in the lungs and transports it to the tissues

Blood Types

• A, B, AB, O

• Letter A and B stand for carbohydrates found on the surface of blood cells.

• Act as antigens

• Blood contains antigens and antibodies

Blood Types

O is the universal donor because it does not carry any antigensAB is the universal recipient because they do not have any antibodies

RH factor

• Antigen found on red blood cells

• Can cause problems in pregnancy

Circulation of blood

• Mammalian hearts have 4 chambers.• The two upper are called atria.• The two lower are called ventricles.• Each chamber is divided by a septum,

keeps oxygen poor blood from mixing with oxygen rich blood.

• The protective coat surrounding the heart is called the pericardium.

• Walls of the heart are made of a thick layer of muscle called the myocardium.

The Human Heart

Right atrium

• Contains cells that make up the sinoatrial node or “pacemaker”.

Blood Pressure

• Force exerted by blood as it moves through blood vessels.

• First number is systolic – pressure exerted when the heart contracts

• Second number is diastolic- when the heart relaxes

• Normal 120/80• Lower in veins than in arteries• Kidneys aid in regulating blood pressure• Too high - hypertension

Pulse

• Caused by contractions in the left ventricle.

• Indicator of heart rate

• Average is 70-90 beats per minute

Mapping Your Valves: Class Activity

• By applying pressure to your arm, you can locate the valves in the veins of your arm.

.

PROCEDURE:

1. Have a classmate make a fist and extend his or her arm, with the hand palm up and slightly below elbow level. Locate a prominent vein on the inside of the forearm. Using one finger, press down on the vein at a point near the wrist to block the blood flow.

2. Gently place a second finger along the vein about 5 cm from the first finger (toward the elbow). Release the second finger, but not the first. The vein should refill partway. Mark this point, which indicates the location of a valve, with the pen. You may have to try more than one vein to locate a valve.

Discussion Questions : Answer on your own sheet of paper.

1. IDENTIFY the direction blood flows in the vein you chose.

2. PROPOSE why the subject must make a fist and hold his arm slightly down.

3. INFER what effect standing in one place for long periods of time might have on the veins in the legs.

Directed Reading: The Heart

1.Describe the path blood follows through the pulmonary circulation loop.

Oxygen poor blood is pumped from the heart to the lungs through the pulmonary arteries. The blood gains oxygen in the lungs and is returned to the heart through the pulmonary veins.

2. Describe the path blood follows through the systemic circulation loop.

Oxygen rich blood is pumped from the heart to the lungs through the pulmonary arteries. Oxygen poor blood is then returned to the heart through the veins.

3. B

4. F

5. A

6. G

7. D

8. E

9. C

10.1

1,3,6,5,7,8,4,2

Vena cavae (vein) > rt. Atrium > rt.

Ventricle (low in oxygen) > pulmonary

Arteries (away) > lungs (get oxygen) >

Pulmonary veins > left atrium > left

Ventricle > aorta (artery – away) > body

Coronary arteries