2 Functions of the Circulatory System Transports oxygen, nutrients, and other substances throughout the body and removes wastes from tissueWe have a closed circulatory system made up of:HeartBlood VesselsBlood
3 The HeartHollow organ about the size of a clenched fist made almost entirely of musclePowerful contractions of the myocardium muscle pump blood through the circulatory systemOn average, an adults heart beats 72 times a minute and can go as high as 200 beats per minute!
4 The HeartDivided into 4 chambers separated by the septum (separates right and left parts)Right & Left Atrium: receive blood from the bodyRight & Left Ventricle: pumps blood to the body
5 The Heart Blood travels in this manner: right atrium right ventricle lungs left atrium left ventricle bodyValves 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 HeartHow does the heart get the nutrients it needs? Coronary arteriesIf they are blocked, muscle cells run out of oxygen and die – heart attack
7 The HeartPulmonary circulation: right side of the heart pumps deoxygenated blood from the heart to the lungsSystem circulation: left side of the heart pumps oxygenated blood to the rest of the body
8 The HeartThe 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 contractHeart rate varies depending on your body’s need to take in oxygen and release carbon dioxide
9 Blood VesselsAs blood flowers through the circulatory system, it moves 3 types of blood vessels:Arteries: large vessels that carry blood from the heart to the tissuesExcept for the pulmonary artery, all arteries carry oxygenated bloodCapillaries: smallest vessels that drop off oxygen & nutrients and pick up wasteVeins: small vessels the return deoxygenated blood to the heart to re- oxygenate
10 Blood PressureWhen the heart contracts, it produces a wave of fluid in the arteries – blood pressureTypical blood pressure reading is 120/80If pressure is too high – can pop the arteries / veinsIf pressure is too low – blood is not pumped throughout the body (fainting)
11 33.2 Blood Functions of blood: Transport oxygen & nutrients Regulate body temperatureFight infectionsProduce clots
12 33.2 BloodYour 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 BloodThe most numerous cells in blood are red blood cells (erythrocytes): they transport oxygen on a protein that binds it – hemoglobin, and turns redRBC’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 bacteriaIf your WBC’s count rises, you’re probably fighting an infectionAlso made in the bone marrow, but can live for years and outnumber RBC’sPlatelets contain proteins that help in blood clottingWhen they come in contact with a broken blood vessel, they become sticky and cluster around the wound
15 33.2 Circulatory Diseases3 common and serious diseases of the circulatory system are heart disease, stroke, and high blood pressureIf you have high blood pressure, you’re at greater risk for the other twoHeart disease is the leading cause of death in the U.S.
16 33.2 Circulatory DiseasesHeart Disease occurs when blood flow through the coronary vessels is obstructedCan be due to atherosclerosis – fatty deposits causing plaqueCauses: High fat/cholesterol diet, genetics, drug usage & smokingSymptoms: angina (chest pain), nausea, shortness of breath, and pain in the neck, jaw, or left arm
17 33.2 Circulatory DiseasesStroke is the sudden death of brain cells when blood supply is interruptedCauses: blocked blood vessels in the brain or bleeding in the brainSymptoms: severe headache, numbness, dizziness, confusion, trouble seeing/speakingOutcomes: Paralysis, loss of speech, or death
18 33.2 Circulatory DiseasesHigh blood pressure (hypertension) is when your reading is higher than 140/90Causes: High fat/cholesterol diet, geneticsCan cause small tears in blood vessels and lead to heart attack, stroke, and kidney damage
19 33.2 Circulatory DiseasesCholesterol is a lipid that can cause disease. There are 2 types:LDL: Becomes part of plaque – the bad oneHDL: removes excess cholesterol from tissue and arteries to the liver for removal – the good oneWe 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 usedSome people carry defective LDL receptors which prevent the liver from removing cholesterol and stop making their own – leads to high cholesterol levelsThis is the genetic part
21 33.2 Circulatory DiseasesIt is much easier to PREVENT heart disease than cure it, so…Eat rightGet 30 minutes of exercise every dayGet 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