1.1 the cardiovascular system

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  • Created by: parker123
  • Created on: 06-11-18 17:35
  • Cardiovascular system is the body's transport system. 
  • it includes the heart and the blood vessels. 
  • during exercise efficient cardiovascular system is important as the heart works to pump blood through the various blood vessels to deliever oxygen to working muscles & waster products. 
  • it transports heat to the skin so you can cool down. 

THE HEART

THE STRUCTURE OF TH HEART

  • Chambes of the heart-  its divided into 2 parts by muscular wall called the septum.
    • Atria are smaller than ventricles as they push blood down into ventricles. artia have thinner muscular walls 
    • ventricles have much thincker muscular walls as they need to contact with greater force to push blood out of the heart.
    • left side is large as pumps blood al the way around the body. right side pumps deoxygenated blood to the lungs. 
  • Blood vessels of the heart- blood vessels attached to the heart;
    • Vena cava- brings deoxygenated blood back to the rught atrium 
    • pulmonary vein- delivers oxgyenated blood to the left atrium 
    • pulmonary artery- leaves right ventricle with deoxygenated blood to go to the lungs.
    • Aorta- leaves left ventricle with oxygenated blood leading to the body. 
  • Valves of the heart- 4 main vavles regualte blood flow ensuring its moving in 1 direction.
    • they open to allow blood through & close to prevent backflow.
    • Tricuspid valve- located between right atrium & reight ventricle
    • Bicuspid valve- between left atrium & left ventricle
    • Semi-lunar valves- between right & left ventricle, & pulmonary artery & aorta.

CARDIAC CONDUCTION SYSTEM- is group of specialised cells located in the wall of heart which send electrical impulses tothe cardiac muscle, causinf it to contact. then heart beats blood needs to flow through in controlled manner; in atria & out ventricles. 

  •  heart muscle is myogenic as the beat starts in the heart muscle itself with an electrical signal in the sinoatrial node (SAN).
  • this impulse then spreads through the heart, by waves.  
  • from SAN the electrical imulse spreads through the walls of the artria causing them to contract & forcing blood into the ventricles. 
  • impulses then passes through the atrioventricular node (AVN) found in atrioventricular septum. AVN delays transmission of cardiac impulse for 0.1s to ebale atria to fully contract before ventricular systole begins.
  • electrical impulse then asses down through specialised fibres which form bundle of his, located in the septum (seperating ventricles).
  • bundle of his branches out int smaller bundles calles purkinje fibres which spread thoughout the ventricles causing themto contact. 

factors affecting the change in rate of the conduction system- it ensures heart rate increases during exercise. done by:

  • NEURAL CONTROL MECHIANISM-  involves the sympathetic nervous system, which stimulate heat to beat faster & parasympathetic system which returns heart to resting level.
  • nervous system is made up of two parts 
    • central nervous sytem (CNS)- is the brain & spinal cord
    • peripheral nervous system- is the nerve cells that transmit info to & from the CNS.
  • these 2 system are co-ordinated by cardiac control centre (CCC) located in medulla oblongata in brain. 
  • sympathetic

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