Cardiovascular System Flashcards
(8 cards)
STRUCTURE OF THE HEART
(Diagram on Phone)
Right Atrium (deoxygenated blood enters)
Right Ventricle (oxygenated blood leaves)
Left Atrium (blood enters)
Left Ventricle (blood leaves)
Aorta (oxygenated to the body from LV)
Septum (separates left and right)
Aortic Valve (back-flow from LV & Aorta)
Pulmonary Vein (oxygenated from lungs to LA)
Pulmonary Artery (deoxygenated from RV to lungs)
Pulmonary Valve (back-flow from RV & PA)
Tricuspid Vein (back-flow from RV & RA)
Biscuipid Valve (back-flow from LV & LA)
Superior Vena Cava (deoxygenated from UB for RA)
Inferior Vena Cava (deoxygenated from LB for RA
STRUCTURE OF THE BLOOD VESSELS
Arteries always carry blood away from the heart. always carry oxygenated blood, with the exception of the pulmonary artery, which takes deoxygenated blood away from the heart to the lungs. are elastic, so they can accommodate changing volumes of blood passing through them. have muscular walls that can contract to maintain blood pressure when there is a reduction in blood flow. Arteries have two major properties: elasticity and contractility. This contactility of the arteries helps to maintain blood pressure in relation to changes in blood flow. The arteries are mostly located deep within the body they have small lumen and branch out into smaller arterioles that deliver blood to the capillaries.
Arterioles link arteries with capillaries.
They have similar properties and functions to arteries. However, they have thinner muscular walls as blood is not at such a high pressure as they are further from the force of contraction of the heart.
Their muscular walls allow the arteriole to control blood flow into the capillary, vasodilating to increase blood flow during exercise and vasoconstricting to reduce blood flow when resting.
Capillaries connect arteries and veins by uniting arteroioles and venules. They are the smallest of blood vessels narrow and thin. They form an essential part of the cardiovascular system as they allow diffusion of oxygen and nutrients required by the bodys cells to produce energy. The walls of capillaries are only one cell thick allowing nutrients, oxygen and waste products to pass through. They also have a very small lumen which only allows blood to pass through one cell at a time and the pressure of blood btween the capillaries is higher than the veins but lower than the arteries.
Veins facilate the retrun of deoxygenated blood to the heart. They have thinner walls than arteries and relatively large lumen they carry blood at low pressure. Contracting muscles push the thin walls of the veins inwards to help squeeze the blood back towards the heart. Valves in the veins help to prevent the backflow when the muscles relax. Veins branch into smaller vessels called Venules which extend to the capillary network.
Venuoles although small, these are larger than capillaries. They carry deoxygenated blood and take the carbon dioxide from the capillary and transport it to the veins.
COMPOSITION OF THE BLOOD
The average human has 4-5 litres of blood. There are four main structures: Plasma- liquid which carries blood cells. Red blood cells- carry oxygen. White blood cells- fight infection and disease. Platelets- allows blood to clot.
Plasma- made up of 90% water - its job is to carry blood cells, nutrients, gases and waste products.
Red blood cells- haemoglobin in red blood cells carries oxygen. Transports oxygen to muscle and waste products to lungs. Red blood cells have a large surface area.
White blood cells- (leucocytes) fight infection and disease. They identify, destroy and remove pathogens such as bacteria and viruses. They come from the bone marrow.
Platelets- prevent blood loss and allow our blood to clot stimulate fibrin. Produced in the bone marrow.
FUNCTION OF THE CARDIOVASCULAR SYSTEM
The delivery and removal of nutrients and waste- Haemoglobin and plasma deliver oxygen, nutrients to our working muscles and remove waste products away from the working muscles. During exercise we need more of these as our cardiovascular system has to respond to ensure it delivers more. During exercise we produce more carbon dioxide and lactic acid so it is essential these are removed for exercise to continue. Removed by either the liver turned to CO2 to glucose. If they are not removed muscle fatigue will occur and you are more likely to suffer DOMS 24 or 48 hours after exercise.
Thermoregulation- Cardiovascular system is responsible for distribution and redistribution of heat to maintain thermal balance of 37°C during exercise. There are two ways Vasodilation (open) and Vasoconstriction (close). Vasodilation this occur in the blood vessels inside the working muscles The diameter of the blood vessels increases this decrease resistance to the blood. The vessels come towards the surface of the skin which results in a decrease in body temperature. Vasoconstriction blood vessels can also temporarily limit blood flow to the tissues. The diameter of the blood vessels decreases. They move away from the surface of the skin and heat loss is reduced. More friction between the blood cells- therefore heat is produced.
Fighting Infection- White blood cells are responsible for fighting illness and disease they do this by consuming pathogens these are substances that cause illness. They then produce antibodies that will destroy pathogens. Produce antitoxins which
Clotting of the blood- Platelets are found in white blood cells they form solid clots in the blood to stop us bleeding out. Injury triggers a reaction within blood vessels activating platelets which form a plug where the injury is. Fibrin factors then stick to the plug to strengthen it they are found in the plasma.
SHORT TERM EFFECTS OF EXERCISE ON THE CARDIOVASCULAR SYSTEM (responses)
Changes in heart rate when exercising- Anticipatory rise - an increase in heart rate just before the start of physical activity. It is caused by the release of adrenalin into the blood. Increased heart rate - to speed up oxygen delivery and carbon dioxide removal during exercise.
Increased blood pressure- Blood will be flowing at a faster rate due to the increase in heart rate. Also, the heart will contract more forcibly to squeeze more blood out. This will cause a temporary increase in systolic blood pressure.
Increased cardiac output- Cardiac output is the amount of blood leaving the heart per minute. It is calculated by multiplying heart rate by stroke volume.
Stroke volume is the amount of blood leaving the heart per beat. If either heart rate or stroke volume increase, cardiac output will increase.
Redirection of blood flow- When we exercise we need more oxygen for greater energy production. This increase in energy production increases waste products that need removing from the body. The body satisfies these demands by: increasing cardiac output and redirecting blood flow so that the majority of the circulating blood goes to the areas of the body that need it most. This is achieved through vasodilation of arterioles supplying active areas and vasoconstriction of arterioles supplying inactive areas.
LONG TERM EFFECTS OF EXERCISE ON THE CARDIOVASCULAR SYSTEM (ADAPTIONS)
Cardiac hypertrophy- Hypertrophy means muscle cell enlargement, the increase is taking place in the heart muscle specifically the left ventricle wall.
Stroke volume increases- Stroke volume increases as the muscular walls of the heart undergo cardiac hypertrophy. Therefore, more blood can be ejected from the heart per beat. This is true at rest and during exercise.
Resting heart rate decreases- If we increase our resting stroke volume, we do not need the heart to beat as often to achieve the required cardiac output at rest.
Decreased heart rate recovery time- Heart rate remains elevated after exercise to aid recovery. However, due to an increased stroke volume, a high level of blood can still be circulated without the need for a very high heart rate. Therefore, heart rate will return to resting levels sooner.
Capillarisation- This is the development of the capillary network in the body. Capillary density is increased in skeletal muscle and around the alveoli in the lungs. The increase in capillary density means that a greater volume of blood can flow through the body, ensuring a good supply of oxygen and nutrients to the tissues, and removal of carbon dioxide.
Reduction in resting blood pressure- By dropping resting blood pressure, we reduce the risk of heart-related ill health. Several factors contribute to a drop in resting blood pressure such as cardiac hypertrophy, increased nitric oxide release, which vasodilates the blood vessels and an increase in plasma volume.
Increase in blood volume- Blood volume is a measure of the amount of plasma and red blood cells circulating around the body. Initial increases in blood volume are due to an increase in plasma, although maintenance of training can also result in an increase in red blood cells. The increase in blood volume improves oxygen delivery and temperature regulation.
The viscosity of the blood will not increase; it may even reduce. If blood viscosity does reduce it will decrease its resistance to blood flow, therefore contributing to a reduction in resting blood pressure.
CARDIOVASCULAR SYSTEM ISSUES
Sudden arrhythmic death syndrome (SADS)
SADS results in sudden death, normally in people under the age of 35. It is caused by cardiac arrhythmia. Cardiac arrhythmia is a condition caused by an irregular heartbeat, it means that the normal rhythm of the heart is altered causing cardiac arrest. Most cases of cardiac arrhythmia do not result in sudden death. However, as there are often no clear symptoms of SADS, people are likely to have the condition and not know. When these people participate in strenuous exercise, even though they appear fit and healthy, they can die due to SADS.
Blood pressure
As blood passes through the blood vessels it exerts a pressure against the walls of the blood vessel.
The amount of pressure exerted will vary depending on: the rate of blood flow and the size of the internal diameter of the blood vessel.
normal blood pressure - 120/80 mmHg
high blood pressure (hypertension) -
140/90 mmHg
low blood pressure (hypotension) -
90/60 mmHg.
Hyperthermia- Hyperthermia is an increase in core body temperature. It can lead to heat cramps, heat exhaustion or heat stroke. When we exercise, we generate heat, which we can normally lose through thermoregulation. However, if we are in a hot environment this becomes more difficult, although appropriate clothing can help.
Hypothermia- Hypothermia is a drop in core body temperature below 35°C. It can occur when exposed to cold, or cold and wet conditions for long periods of time without adequate clothing. In these conditions performers will lose their ability to make decisions or move quickly.
NERVOUS CONTROL OF THE CARDIAC CYCLE
Blood movement through the heart-
The atria contract, forcing blood through the bicuspid and tricuspid valves, into the ventricles, which are relaxing so they can fill with blood. This is diastole.(relaxing)
The atria relax, the bicuspid and tricuspid valves close, the ventricles contract, forcing blood through the semi-lunar valves, out of the heart into the main arteries (the pulmonary artery or aorta). During this time the atria are refilling with blood for the next cardiac cycle. This is systole.(contracting)
The sympathetic nervous system causes the heart rate to increase during exercise; after exercise the heart rate slows down due to the parasympathetic nervous system.
Control of the cardiac cycle- The sinoatrial node acts as a pacemaker; it initiates the heartbeat. It transmits electrical impulses causing the atria to contract. Each electrical impulse is detected by the atrioventricular node and passed to specialised cardiac muscle fibres called the bundle of His.
These muscle fibres conduct the impulse throughout the muscular walls of the ventricles. The Purkinje fibres receive these electrical impulses and signal both ventricles to contract.
