The Transport System Topic 6.2

Transport Song

Transport Every minute or two, one red blood cell makes a complete circuit through the transport system. Every minute or two, one red blood cell makes a complete circuit through the transport system.

The Heart’s Job The heart’s job is to collect blood in it’s atriums, pump the blood to the ventricles, then from the ventricles pump it to the pulmonary or systemic circuits. The heart’s job is to collect blood in it’s atriums, pump the blood to the ventricles, then from the ventricles pump it to the pulmonary or systemic circuits. Along the way, it must open or close its valves. Along the way, it must open or close its valves.

VAlves Right and left atrioventricular valve between atrium and ventricle Right and left atrioventricular valve between atrium and ventricle Right and left semilunar valve upon exiting each ventricle. Right and left semilunar valve upon exiting each ventricle. Valves prevent backflow of blood into the wrong chamber. Valves prevent backflow of blood into the wrong chamber. fVDGu82FeQ

A RBC Journey A RBC first arrives through the vena cava at the right atrium, where it must wait for others to arrive. A RBC first arrives through the vena cava at the right atrium, where it must wait for others to arrive. Then the atrium contracts and it gets pushed through the right atrioventricular valve into the right ventricle. Then the atrium contracts and it gets pushed through the right atrioventricular valve into the right ventricle.

A RBC Journey Finally the right ventricle contracts and it is pushed passed the semilunar valve into the pulmonary artery. Finally the right ventricle contracts and it is pushed passed the semilunar valve into the pulmonary artery.

Destination: Gas Exchange The pulmonary artery connects it to a lung. The pulmonary artery connects it to a lung. There it gets rid of his CO 2 and collects fresh O 2 There it gets rid of his CO 2 and collects fresh O 2 Afterwards, it heads back to the heart via a pulmonary vein Afterwards, it heads back to the heart via a pulmonary vein

A RBC Journey It is dropped off in the left atrium, and again has to wait. It is dropped off in the left atrium, and again has to wait. Finally it is pushed through the open atrioventricular valve into the left ventricle. Finally it is pushed through the open atrioventricular valve into the left ventricle.

A RBC Journey When the left ventricle contracts he is propelled through the semilunar valve into the aorta When the left ventricle contracts he is propelled through the semilunar valve into the aorta From the aorta he heads throughout the rest of the body, delivering O 2 From the aorta he heads throughout the rest of the body, delivering O 2

Heart Animations hhw_pumping.htmlhttp:// hhw_pumping.htmlhttp:// hhw_pumping.htmlhttp:// hhw_pumping.html

Control of the heart Most of the heart is made of cardiac muscle. Most of the heart is made of cardiac muscle. Myogenic muscle contraction : Cardiac muscle contracts and relaxes without the control of the nervous system.Myogenic muscle contraction : Cardiac muscle contracts and relaxes without the control of the nervous system. Myogenic activity is controlled by the sinoatrial (SA) node. Myogenic activity is controlled by the sinoatrial (SA) node.

Sinoatrial Node Known as the “pacemaker” of the heart Known as the “pacemaker” of the heart This is a mass of tissue on the right atrium that sends out an “electrical” signal telling the atrium to contract This is a mass of tissue on the right atrium that sends out an “electrical” signal telling the atrium to contract It also sends a signal to the atrioventricular (AV) node It also sends a signal to the atrioventricular (AV) node The AV node delays 0.1 seconds, then signals for the ventricles to contract The AV node delays 0.1 seconds, then signals for the ventricles to contract

Watch it work! hhw_electrical.htmlhttp:// hhw_electrical.htmlhttp:// hhw_electrical.htmlhttp:// hhw_electrical.html

Heart Rate (pulse) “Resting heart rate” = approx 60 – 100 beats per minute. “Resting heart rate” = approx 60 – 100 beats per minute. Pulse is lower for well trained athletes Pulse is lower for well trained athletes If your heart beats 72 times per minute, your SA node sends a signal about every 0.8 seconds If your heart beats 72 times per minute, your SA node sends a signal about every 0.8 seconds

Listening to Your Heartbeat Use the stethoscope, listen to your heartbeat several times. The “lub-dub” sound comes from the closing of the heart valves. Use the stethoscope, listen to your heartbeat several times. The “lub-dub” sound comes from the closing of the heart valves. “Lub” = closing of atrioventricular valves “Lub” = closing of atrioventricular valves “Dub” closing of semilunar valves “Dub” closing of semilunar valves

Check your pulse Hold your first and second fingers (not your thumb) under your jaw and once you can feel your pulse, start timing for 60 seconds, counting how many times your heart beats. Hold your first and second fingers (not your thumb) under your jaw and once you can feel your pulse, start timing for 60 seconds, counting how many times your heart beats.

Increasing Activity Why might you need to raise your heart rate? Why might you need to raise your heart rate? The medulla (in your brainstem) sends a signal through the cardiac nerve to the SA node to increase the heart rate as needed. The medulla (in your brainstem) sends a signal through the cardiac nerve to the SA node to increase the heart rate as needed. This doesn’t change HOW the heart beats, rather, it changes when. This doesn’t change HOW the heart beats, rather, it changes when. After exercise, the medulla sends a signal through the vagus nerve, which tells the SA node to take control again. After exercise, the medulla sends a signal through the vagus nerve, which tells the SA node to take control again. Adrenaline hormone also tells the SA node to signal more quickly Adrenaline hormone also tells the SA node to signal more quickly

The Systemic Circuit After leaving the aorta, RBCs make a path through the systemic circuit, delivering O 2 to the rest of the body. After leaving the aorta, RBCs make a path through the systemic circuit, delivering O 2 to the rest of the body.

RBC’s Systemic Circuit Blood goes through: Blood goes through: A large artery A large artery Smaller artery branches Smaller artery branches An arteriole (smallest artery) An arteriole (smallest artery) A capillary bed A capillary bed A venule (smallest vein) A venule (smallest vein) Larger veins Larger veins A large vein taking the blood back to the heart A large vein taking the blood back to the heart

Arteries Arteries always takes blood away from the heart before it reaches a capillary. Arteries always takes blood away from the heart before it reaches a capillary. Thick, smooth, and their diameter can be controlled (this is how blood pressure changes) Thick, smooth, and their diameter can be controlled (this is how blood pressure changes) Blood is at a high pressure since it is being pumped by the heart Blood is at a high pressure since it is being pumped by the heart They become smaller until they become arterioles, then blood reaches a capillary. They become smaller until they become arterioles, then blood reaches a capillary.

Coronary Artery The coronary artery branches from the aorta to the heart itself, supplying cardiac muscle with oxygen & nutrients. The coronary artery branches from the aorta to the heart itself, supplying cardiac muscle with oxygen & nutrients. When it is blocked with plaque, heart attacks occur. When it is blocked with plaque, heart attacks occur.

Capillary A capillary is so small that only ONE blood cell can fit through at a time. A capillary is so small that only ONE blood cell can fit through at a time. Their walls are thin – only one cell thick. Their walls are thin – only one cell thick. This is where all exchanges take place: This is where all exchanges take place: Gas (O 2, CO 2 ) Gas (O 2, CO 2 ) Nutrients (often in the villi) Nutrients (often in the villi) Blood loses its pressure since it has to squeeze through one at a time. Blood loses its pressure since it has to squeeze through one at a time.

Vein Veins always takes blood towards the heart after it has been through a capillary. Veins always takes blood towards the heart after it has been through a capillary. Thin walled since the blood is at a low pressure. Thin walled since the blood is at a low pressure. Veins have internal valves to help prevent backflow as blood must often move against gravity. Veins have internal valves to help prevent backflow as blood must often move against gravity.

Varicose Veins

Comparison Chart ArteryCapillaryVein Thick walledWall is 1 cell thickThin walled Narrow lumen (inside channel) Lumen allows only one cell through Wide lumen NO exchangesALL exchanges occur NO exchange No internal valves Have internal valves Internal pressure high Internal pressure low

BLOOD Components Plasma: liquid portion of blood Plasma: liquid portion of blood CO 2 is dissolved in the plasma CO 2 is dissolved in the plasma Erythrocytes: Red blood cells (carry O 2 ) Erythrocytes: Red blood cells (carry O 2 )

BLOOD Components Leucocytes: White blood cells (phagocytes & lymphocytes) Leucocytes: White blood cells (phagocytes & lymphocytes) Platelets: Cell fragments that are involved in blood clotting Platelets: Cell fragments that are involved in blood clotting

Blood Transport What is Transported Details NutrientsGlucose, amino acids, etc. (NOT Lipids – these are transported by lymph) OxygenReactant needed for aerobic cell respiration Carbon Dioxide Waste product of aerobic cell respiration HormonesTransported from the gland that secreted them to the target cell where they signal something to change AntibodiesProteins involved in immunity (disease prevention & control) UreaNitrogenous waste (filtered by kidneys and excreted in urine) HeatSkin arterioles change diameter in order to gain or lose heat

Blood Transport 2.2.A3 Methods of transport of glucose, amino acids, cholesterol, fats, oxygen and sodium chloride in blood in relation to their solubility in water.