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Animal Circulation. The Cardiovascular System. Coordinated activities such as growth and homeostasis depend on: transfer of ions, waste products, signaling molecules, transport proteins, and other substances within the body
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The Cardiovascular System • Coordinated activities such as growth and homeostasis depend on: • transfer of ions, waste products, signaling molecules, transport proteins, and other substances within the body • The circulatory system is a internal transport system consisting of: • blood vessels, a muscular heart, and fluids
Cellular Respiration • One very important process that takes place in all of your cells is cellular respiration. • How all of your cells get energy from food • How do all of our cells get O2 and glucose to them? • What about getting rid of CO2? Respiratory and Circulatory systems!
Blood ContainsMany Different Cell Types • Blood plasma is the fluid portion of blood and is 92 percent water; it contains dissolved gases, ions, and molecules • Red blood cells contain oxygen-binding proteins called hemoglobin for transporting oxygen throughout the body • White blood cells are involved with fighting foreign substances
Blood ContainsMany Different Cell Types • Platelets are fragments of larger cells that clump together to help staunch the loss of blood if a vessel is damaged
Hemoglobin • Iron containing protein that transports O2 and CO2. • Makes up approximately 97% of the red blood cells' dry content in mammals Iron containing heme groups are in green
The Human Heart Pumps Bloodto the Body through Two Circuits • The systemic circuit flows between the heart and the body • O2rich blood to all body cells and removes wastes • The pulmonary circuit flows between the heart and the lungs • deO2 to lungs to pick up oxygen and unload CO2
The Human Heart • The human heart is divided into four chambers that create two physically independent pumping units
The Human Heart • The chambers on the right and left sides of the heart are separated by a thick wall of tissue called the septum • The upper chambers: atria • The lower, larger chambers are called the ventricles
The Human Heart • The chambers on the left side of the heart receive oxygenated blood returning from the lungs and pump it through the systemic circuit • The two chambers on the right side of the heart receive blood returning from the systemic circuit that is low in oxygen and laden with CO2 and pump it through the pulmonary circuit
The Human Heart • The atria contract simultaneously and move blood to the ventricles • The ventricles have large, muscular walls, which are required for moving blood out of the heart
The Human Heart • The atria and ventricles are separated by valves that allow blood to flow in only one direction
Measuring the Heart • The heart rate is the number of times the heart beat per minute and can be measured as the pulse rate • Blood pressure measures the pressure in the arteries leading to the body from the left ventricle • The beating of the heart is part of the cardiac cycle, which is made up of a relaxation phase and a contraction phase
The Cardiac Cycle: Heartbeat • The cardiac cycle is made up of a relaxation phase and a contraction phase • Diastole: relaxation phase of the cardiac cycle
The Cardiac Cycle: Heartbeat • Systole is the pumping phase, during which blood is pumped • first from the atria to the ventricles • then from the ventricles to the lungs • Then to the rest of the body
The Cardiac Cycle: Heartbeat • The signal to contract is delivered to the heart muscle by a group of specialized cells in a region of the heart called the sinoatrial (SA) node • The signals from the SA node are relayed to the atrioventricular (AV) node
The Cardiac Cycle: Heartbeat • If the SA node is not working correctly an artificial pacemaker is sometimes implanted
Blood Pressure • Written as a ratio of systolic to diastolic pressure • for example: 120/80 mmHg • Systolic pressure represents the higher value in a blood pressure reading and diastolic pressure is the lower value
Blood Vessels • Arteries branch many timesto form a network of arterioles that carry blood from the heart for distribution to the body and control the flow of blood to the capillaries • Arteries have highly elastic walls that enable them to stretch when a heart contraction increases the blood pressure • All blood flowing away from the heart is in arteries
Blood Vessels • Capillaries allow the exchange of materials between the blood and the surrounding interstitial fluid and cells Capillary bed of the thyroid gland
Blood Vessels • Capillaries have extremely thin, porous walls across which materials diffuse easily • The large surface area of capillaries ensures efficient exchange of gases, nutrients, and other materials with the surrounding interstitial fluid, and in turn with respiring cells
Blood Vessels • Veinsbring deoxygenated blood back to the heart via a network of increasingly larger vessels • All blood flowing towards the heart is in venules or veins
Blood Vessels • Veins have specialized one-way valves to keep blood flowing toward the heart against gravity • Yes, exercising keeps your blood flowing!!
The Cardiovascular System and Homeostasis • The heart can be influenced by the nervous system and signaling molecules • Norepinephrine is a neurotransmitter that causes the cells of the SA node to signal the heart to beat faster and more forcefully under stressful situations • Changes in body temperature and exercise can also affect the heart rate of an individual