Circulatory System Blood Flow Summary Blood Vessels The Blood The Heart

The Circulatory System You Gotta Have Heart The Circulatory System

Circulatory System Consists of… Blood Vessels Blood Heart

Overview The Heart pumps blood through the body through blood vessels (arteries, capillaries and veins) Arteries take blood away from the heart, veins return blood to the heart Blood carries O2 (food) towards and CO2 (waste) away from tissues The lungs are not part of the circulatory system!!

Circulatory System BLOOD VESSELS

Two Pathways Pulmonary Circulation Systemic Circulation Carries blood to lungs and back Systemic Circulation Carries blood to body and back

Your Blood Vessels: Pathway of Circulation 3 types of vessels Arteries (mostly shown as Red because blood has O2) Capillaries (Red and Blue because some O2 lost to tissues) Veins (mostly shown as Blue because O2 lost to tissues)

Red Blood and Blue Blood Blood is never blue!!!!!!!!!!!!!!!!!! Oxygenated blood is bright red and deoxygenated blood is dark red Veins appear blue because of the way light reflects off the blood vessel We don’t see arteries because they are too deep. We draw them blue to distinguish them on diagrams and simplify things

Arteries vs. Veins What you need to know about the STRUCTURAL differences between Arteries and Veins: Artery walls are much thicker, are very elastic and have more muscle Veins are thin walled and contain valves to push the blood along

Arteries vs. Veins Why are arteries and veins the way they are? Blood is under very high pressure when it leaves the heart and enters the arteries Therefore, arteries need to be strong!! Once it has left the tissues and enters the veins, the blood is under a very low pressure Therefore, veins are weak

Arteries: Carry blood Away from heart Large Thick-walled, Muscular Elastic Oxygenated blood Exception Pulmonary Artery Carried under great pressure Steady pulsating (used to measure pulse) Arterioles: smaller vessels, enter tissue

Capillaries Smallest vessel Microscopic Walls one cell thick Located at the tissue Nutrients and gases (O2, CO2) diffuse here

Veins: Carry blood to the heart Carries blood that contains waste and CO2 Exception pulmonary vein Blood under low pressure Valves to prevent back flow due to gravity Venules: small veins, larger than capillaries Mechanism of Vein and Varicose Veins Videos

Animation of blood flow Blood Vessels Animation of blood flow

The Aorta – The largest blood vessel Blood Vessel Animation

Blood Vessels Blood flow is like a round trip to grandma’s house - You leave your home (The Heart) You jump on the Highway (Arteries) You get off at grandma’s street (Arterioles) You pull in to grandma’s driveway (capillaries) You go inside her house (The Cell) and give her a kiss (Glucose and Oxygen) You leave with leftovers (CO2) Get back into your car and exit driveway (capillaries) You drive back along her street (Venuoles) You get back on the highway (Veins) Arrive back at home (The Heart)

End of Day 1

Circulatory System BLOOD

The Blood Body contains 4-6 L Consists of Water Red Blood Cells Plasma White blood cells and platelets

Your Blood: Fluid Transport Liquid Portion Carries Blood cells (made in bone marrow) Erythrocytes (RBC - red blood cells) Leucocytes (WBC - white blood cells) Platelets (fragments of the cells in bone marrow – no nucleus) Proteins Nutrients - Digestive System Gases - Respiratory System

Oxygen in the Blood O2 O2 O2 O2 Hemoglobin, iron containing molecule – found in RBC Loosely picks up oxygen in the lungs Releases oxygen in areas low in oxygen – body tissues O2 O2 O2 O2

Carbon Dioxide in the Blood Hemoglobin also carries CO2 CO2 is a waste product of cellular respiration Travels to the lungs to be exhaled

What does blood contain? 50% Water 45% Erythrocytes (RBC) 4% Plasma with Substances 1% Leukocytes (WBC) + Platelets

Erythrocytes (RBC) Transporters of Oxygen Carbon Dioxide RBC Lack a nucleus Contain hemoglobin Disk-shaped RBC are produced in the bone marrow Lives for ~120 days Old RBC are destroyed in liver and spleen

Leukocytes (WBC) WBC fight infection Less abundant Attack foreign substances Less abundant Created in the bone marrow Some live for months Most just a few days Several types ALL contain nuclei

Platelets PLATELETS are for CLOTTING blood Cell fragments Produced in bone marrow Short life span (1 week) Form a web trapping blood cells

Blood Clotting Break in Capillary Wall Blood vessels injured. Clumping of Platelets Platelets clump at the site and release a protein Clot Forms Protein creates a net creating a clot. The clot prevents further loss of blood.

How does Blood Clot?

End of Day 2

Circulatory System HEART Heart Anatomy

Your Heart Pumps blood around your body to keep you alive! If your heart stops you will die!

Heart: Structure and Function Keeps blood moving Large organ composed of cardiac muscle rich in mitochondria

The Structures of the Heart Gets Oxygen-Rich blood from the Lungs Aorta – Artery that supplies the body with Oxygen-Rich Blood Vena Cava Vein that brings oxygen-poor blood from the body to the heart Pulmonary Arteries Sends Oxygen-Poor blood to the Lungs Pulmonary Veins Bring oxygen-rich blood from the lungs to the left atrium Pulmonary Arteries Bring oxygen-poor blood to the lungs Receives Oxygen-Poor blood from the body Sends Oxygen-Rich blood to the body Sends Oxygen-Poor blood to the lungs

Structure of Heart (cont) Four chambers Two upper (Atria) Walls thinner Less muscular Two lower (Ventricles) Walls thicker More muscular Do more work Heart Structure Animation

Blood Flow Through the Heart

Bloods Path Through the Heart Both Atria fill at same time Right atrium receives oxygen POOR blood from body from vena cavas Left atrium receives oxygen RICH blood from lungs through four pulmonary veins After filled with blood atria contract, pushing blood into ventricle

Both ventricles contract Right ventricle contracts and pushes oxygen-poor blood toward lungs through the pulmonary arteries

Bloods Path Through the Heart Left ventricle contracts and forces oxygen rich blood out of heart Through the aorta (largest vessel)

Animation of blood flow The cardiac cycle Animation of blood flow

Control of the Heart The Heart is controlled by nerves and hormones: Its own nerves  pacemaker which keeps a constant beat Heart will beat even if it is disconnected from the brain Can be substituted by an artificial pacemaker - The Brain  can speed-up (exercise) or slow down the heart (sleep) if needed

Heart Rate Animation ECG and (Defibrillation) Paddles discussion

Control of the Heart Hormones: Certain hormones such as epinephrine (adrenalin) impact how the heart operates Heart Beat

Control of Heart Rate – Class Demonstration Resting Heart Rate (beats per min.) Heart Rate during exercise

Your Heart: The Vital Pump At REST, the heart beats about 60-80 times per minute (~4.7L) During EXTREME EXERTION (exercise) it can beat between 150-200 times per minute (~38L)

Heart Rate Discussion Why?? Brain sends a signal to increase HR Adrenal Gland secretes epinephrine Both work together to increase blood flow around the body Increased blood flow = Increase O2/glucose delivery to cells and CO2 removal

DISORDERS Coronary Artery Disease Your heart needs Oxygen too! Is supplied with Oxygen by coronary arteries Coronary arteries can become partially blocked by plaque (fat and cholesterol mainly) Causes by lifestyle choice and genetics This block limits the amount of oxygen delivered to the heart Can cause  tiredness, dizziness and pain

Coronary Artery Disease Can be diagnosed with an angiogram whereby a fluorescent dye is injected into the bloodstream. This dye shows up on an x-ray and shows where flow is disrupted

Heart Attack 1 Heart Attack 2 Disorders (cont) Heart Attack Coronary Artery(ies) become completely blocked No Oxygen can reach the heart muscle Heart muscle begins to die and eventually stops beating Symptoms Nausea, Shortness of breath, Severe chest pain, sweating, dizziness, fatigue IMMEDIATE MEDICAL ATTENTION NECESSARY Heart Attack 1 Heart Attack 2

Disorders (cont) Stroke Heart attack for the brain Blood cannot reach the brain due to a blockage in its blood vessels or severe brain bleed. Brain cells die due to lack of oxygen Can lead to paralysis, loss of ability to speak death Causes a Stroke?

Current PREVENTION Recommendations Regular exercise Weight control Well balanced diet Do not smoke Diet low in saturated fat

Bill Nye – Blood and Circulation Video Download the Blood and Circulation Worksheet