1. The Circulatory System
Ms. Luaces
Honors biology

2. Functions of the Circulatory System
Transports oxygen, nutrients, and other substances throughout the body and removes wastes from tissue
We have a closed circulatory system made up of:
Heart
Blood Vessels
Blood

3. The Heart
Hollow organ about the size of a clenched fist made almost entirely of muscle
Powerful contractions of the myocardium muscle pump blood through the circulatory system
On average, an adults heart beats 72 times a minute and can go as high as 200 beats per minute!

4. The Heart
Divided into 4 chambers separated by the septum (separates right and left parts)
Right & Left Atrium: receive blood from the body
Right & Left Ventricle: pumps blood to the body

5. The Heart Blood travels in this manner:
right atrium  right ventricle  lungs  left atrium  left ventricle  body
Valves located between the atria and ventricles open and contract to allow blood through and make sure oxygen & deoxygenated blood don’t get mixed up

6. The Heart
How does the heart get the nutrients it needs? Coronary arteries
If they are blocked, muscle cells run out of oxygen and die – heart attack

7. The Heart
Pulmonary circulation: right side of the heart pumps deoxygenated blood from the heart to the lungs
System circulation: left side of the heart pumps oxygenated blood to the rest of the body

8. The Heart
The heart must beat in a coordinated way: the SA node sets the pace (pacemaker) while the AV node picks up the pace and continues it to the ventricles to contract
Heart rate varies depending on your body’s need to take in oxygen and release carbon dioxide

9. Blood Vessels
As blood flowers through the circulatory system, it moves 3 types of blood vessels:
Arteries: large vessels that carry blood from the heart to the tissues
Except for the pulmonary artery, all arteries carry oxygenated blood
Capillaries: smallest vessels that drop off oxygen & nutrients and pick up waste
Veins: small vessels the return deoxygenated blood to the heart to re- oxygenate

10. Blood Pressure
When the heart contracts, it produces a wave of fluid in the arteries – blood pressure
Typical blood pressure reading is 120/80
If pressure is too high – can pop the arteries / veins
If pressure is too low – blood is not pumped throughout the body (fainting)

11. 33.2 Blood Functions of blood: Transport oxygen & nutrients
Regulate body temperature
Fight infections
Produce clots

12. 33.2 Blood
Your body contains about 4-6 liters of blood, of which 55% is plasma. Plasma is 90% water & 10% dissolved gases, nutrients, hormones, etc.
Helps to control body temperature

13. 33.2 Blood
The most numerous cells in blood are red blood cells (erythrocytes): they transport oxygen on a protein that binds it – hemoglobin, and turns red
RBC’s are produced in the bone marrow & circulate approximately 120 days before dying

14. 33.2 Blood Blood also contains white blood cells & platelets
White blood cells guard against infection, fight parasites and attack bacteria
If your WBC’s count rises, you’re probably fighting an infection
Also made in the bone marrow, but can live for years and outnumber RBC’s
Platelets contain proteins that help in blood clotting
When they come in contact with a broken blood vessel, they become sticky and cluster around the wound

15. 33.2 Circulatory Diseases
3 common and serious diseases of the circulatory system are heart disease, stroke, and high blood pressure
If you have high blood pressure, you’re at greater risk for the other two
Heart disease is the leading cause of death in the U.S.

16. 33.2 Circulatory Diseases
Heart Disease occurs when blood flow through the coronary vessels is obstructed
Can be due to atherosclerosis – fatty deposits causing plaque
Causes: High fat/cholesterol diet, genetics, drug usage & smoking
Symptoms: angina (chest pain), nausea, shortness of breath, and pain in the neck, jaw, or left arm

17. 33.2 Circulatory Diseases
Stroke is the sudden death of brain cells when blood supply is interrupted
Causes: blocked blood vessels in the brain or bleeding in the brain
Symptoms: severe headache, numbness, dizziness, confusion, trouble seeing/speaking
Outcomes: Paralysis, loss of speech, or death

18. 33.2 Circulatory Diseases
High blood pressure (hypertension) is when your reading is higher than 140/90
Causes: High fat/cholesterol diet, genetics
Can cause small tears in blood vessels and lead to heart attack, stroke, and kidney damage

19. 33.2 Circulatory Diseases
Cholesterol is a lipid that can cause disease. There are 2 types:
LDL: Becomes part of plaque – the bad one
HDL: removes excess cholesterol from tissue and arteries to the liver for removal – the good one
We get cholesterol from meat, eggs, dairy products, fried foods, and our own body (in the liver)

20. 33.2 Circulatory Diseases How does cholesterol work in the body?
LDL binds to receptors, is taken into the cell, cholesterol is broken down and then stored or used
Some people carry defective LDL receptors which prevent the liver from removing cholesterol and stop making their own – leads to high cholesterol levels
This is the genetic part

21. 33.2 Circulatory Diseases
It is much easier to PREVENT heart disease than cure it, so…
Eat right
Get 30 minutes of exercise every day
Get checked at the doctor every year – blood work!

22. Let’s Practice! Study Workbook A – Pg. 437 – 439
Work with a buddy – 1 sheet of paper, Q&A