2 Do NowWhy is it important for your heart to continue beating even when you’re sleeping?What does your body need?What are some wastes?
3 Circulation and Respiration Each breath brings oxygen rich air into your bodyYour cells need that oxygen to make ATPYour heart delivers oxygen to your cellsWorking together, your circulatory and respiratory systems supply cells throughout the body with the nutrients and oxygen that they need to stay alive!
4 Multicellular NeedsUnicellular organisms don’t need a circulatory system, because the cell is in direct contact with the environment and oxygen, nutrients and wastes can easily diffuse across the cell membrane by diffusion.Multicellular organisms need a circulatory system to transport substances made in one part of the body to sites where they are needed in another part of the body.
5 FunctionThe circulatory system transports substances including oxygen, nutrients and wastes to and from cellsUses diffusion (from high to low concentration along concentration gradient).
6 Structure Humans have a closed circulatory system. Blood is pumped through a system of vessels(In an open system, blood flows in vessels and sinuses/gills)Sometimes the circulatory system is also called the “cardiovascular system” because:Cardio = heartVascular = vesselsThe human circulatory system consists of:The heartA series of blood vesselsBlood that flows through them
7 The Heart Located near the center of your chest A hollow organ about the size of your fist composed of cardiac muscle.Contractions of the myocardium, a thick cardiac muscle, pump blood through the circulatory systemThe heart contracts about 72 times a minuteEach contraction pumps about 70 mL of blood
8 Heart valves divide each side into 2 chambers: totaling 4 chambers Upper chambers receive blood = atriumLower chambers pump blood out of heart = ventricle
9 Pulmonary Circulation The right side of the heart pumps blood from the heart to the lungsIn the lungs, carbon dioxide leaves the blood while oxygen is absorbed.The oxygen-rich blood goes into the left side of the heart
10 Blood Flow through the heart Blood leaves the heart in arteries, and blood returns to heart in veins.Oxygenated blood returns from the lungs to the left atrium and ventricle and out the aorta, the largest artery of your bodyThe aorta branches into various arteries pumping blood through your body where oxygen is usedDeoxygenated blood is pumped from the right atrium and ventricle and leaves the heart to go to the lungs to release the carbon dioxide and get more oxygenHeart circulation animation:
12 Blood vesselsBlood circulates in one direction and it is moved by the pumping of the heartAs blood flows through the circulatory system, it moves through three types of blood vessels:ArteriesCapillariesVeins
13 ArteriesLarge vessels that carry blood away from the heart to tissues of the bodyExcept for the pulmonary arteries, all arteries carry oxygen-rich blood.
14 CapillariesThe smallest of the blood vessels connecting arteries and veinsWalls are one cell thick allowing for easier diffusion of nutrients and oxygen from capillaries to body cells and wastes and carbon dioxide from body cells to capillaries
15 Veins Return blood to the heart Veins have walls of connective tissue and smooth muscleMany veins are located near skeletal muscles, so when the muscles contract, they help force blood through the veins, even against gravity
16 Blood Blood is composed of several parts: - plasma: (yellow liquid) - red blood cells: carry oxygen and remove wastecarbon dioxidewhite blood cells - fight germs and diseaseplatelets - stop bleeding/help blood clotsalt and nutrients
17 Red Blood Cells made in your bone marrow transport oxygen collected from alveoliRemove carbon dioxide waste from cells to the alveoliContain HEMOGLOBIN which is a protein that binds with oxygenBlood is RED because of hemoglobin
18 White Blood Cells made in your bond marrow fight off bacterial infections
19 Circulatory, Repsiratory, and Digestive Systems Each breath brings oxygen rich air into your bodyYour cells need that oxygen to make ATPYour heart delivers oxygen to your cellsWorking together, your circulatory and respiratory systems supply cells throughout the body with the nutrients and oxygen that they need to stay alive!Nutrients come from digested food from digestive system
20 Blood Pressure The heart produces pressure when it contracts. The force of blood on the arteries’ walls = blood pressureBlood pressure decreases when the heart relaxes, but there must always be some pressure to keep the blood flowingDoctors measure blood pressure with a sphygmomanometer recording two numbersSystolic pressure = force felt in arteries when ventricles contractDiastolic pressure = force of blood felt in arteries when ventricles relaxAverage adult’s blood pressure = 120/80
21 Regulating Blood Pressure With the nervous system:Sensory neurons at several places in the body detect blood pressure and send impulses to brain stem (medulla oblongata)When too high, the autonomic nervous system releases neurotransmitters that cause the smooth muscles around blood vessels to relax, lowering blood pressure.When too low, neurotransmitters are released that cause the smooth muscles to contract, elevating blood pressure.With the endocrine/excretory system:Hormones produced by the heart and other organs cause kidneys to remove more water from the blood when blood pressure is too high, reducing blood volume and lowering blood pressure
22 Disorders Disorders of the circulatory system are very common: High Blood PressureHeart AttackStrokeMost stem from atherosclerosis = fatty deposits (plaque) builds up on walls of arteries, obstructing blood flow, increasing blood pressure and risk of blood clots
23 High Blood Pressure Also known as Hypertension Forces heart to work harder, which may weaken or damage the heart muscle and vesselsMore likely to develop heart disease and increased risk of heart attack and stroke
24 Heart Attack A medical emergency Coronary arteries (supplying heart blood) bring oxygen and nutrients to the heart muscle itselfBlockage of coronary artery may damage or kill part of heart muscle (myocardium) due to lack of oxygen = heart attackSymptoms include: chest pain/pressure, feeling of heartburn/indigestion, sudden dizziness, or brief loss of consciousness
25 StrokeBlood clots may break free from vessels and get stuck in a blood vessel leading to a part of the brain = strokeBrain cells relying on that vessel may begin to die from lack of oxygen and brain function in that region may be lostStrokes can also occur when a weakened artery in the brain burst, flooding the area with blood
26 Prevention Cardiovascular diseases are easy to prevent: Exercise – increases respiratory system’s efficiencyWeight control – reduces body fat and stressSensible diet – low in saturated fat reduces risk of heart diseaseNot smoking – reduces risk of heart disease