Transport in Humans

• Blood clotting: Platelets bind together and stick to form a scab. This stops infection.
• Plasma is 55% of the blood. The other 45% is blood cells.
• More blood cells in the plasma means more white blood cells fighting odd a virus or illness.
• What is the process which separates a sample of blood into 2 layers?

  Centrifuge
• Red blood cells : erythrocytes are made in the bone marrow to carry oxygen around the body
• oxygen + haemoglobin = oxyhemoglobin
• What is the shape of red blood cells?

  Biconcave
• RBC have a biconcave disc shape which gives them a large surface area -> this is so oxygen can get to the centre of the cell by diffusion.
• What is the function of white blood cells?

  to protect our body against disease
• Neutrophils are phagocytic cells which are the first line of defence of the immune system.
• White blood cells are around 70% phagocytes and around 30% lymphocytes.
• The B Lymphocyte cells produce antibodies which cling on to the antigen.

  
• Antibodies stopping pathogens:

  • they cause the bacteria to burst
  • they cause bacteria to stick together
  • they neutralise toxins produced by pathogens
• Phagocytosis: an immune cell which surrounds and kills bacteria. They ingest foreign material and remove dead cells.
• Plasma is 90% water. More accurately 92%.
• Plasma transports:

  • glucose
  • cholesterol
  • amino acids
  • urea
  • hormones
  • carbon dioxide
  • antibodies

  + heat (keeps us warm)
• The heart is made from cardiac muscle.
• The function of the heart is to pump blood.
• The heart has valves to ensure blood flows in one direction only. Prevents back flow.
• Chambers in the top of the heart are atriums and on the bottom are ventricles.
• Cardiac output = volume of blood pumped per minute
• Ventricles contract which forces the bicuspid and tricuspid valves to close.

  Blood cannot return to the atria.

  As the ventricles diastole (relax) the semi-lunar valves close.
• Tricuspid valve is on the right and bicuspid valve is on the left.
• The atria fills up with blood as the cycle restarts. The atria contracts and the blood is pumped into the ventricles.
• Which side of the heart is the deoxygenated blood?

  Right

  
• Heart dissection:

  1. Peel off the membrane and remove the fat with scissors or a scalpel.
  2. Identify the right side and perform a cross section with a scalpel.
  3. Cut from the right atrium to the right ventricle to the left ventricle to the left atrium.
  4. Create a butterfly shape and identify the valves and arteries.
• Analysis of heart dissection:

  The muscle was heart to cut as it is constantly in use and we had blunt instruments. The aorta was also hard to cut as it had thick walls. We observed the valves and they were still intact. No anomalies were found as the heart was made for human consumption.
• When respiration increases, heart rate increases to supply to muscles with enough oxygen.
• Sensors in the aorta and carotid artery detect increased carbon dioxide levels in the blood and send this information to the medulla in the brain.
• The coronary arteries run along the coronary sulcus of the myocardium of the heart. Their main function is to supply blood to the heart.

  
• The muscle wall is thicker in the ventricles than the atria because the ventricles have to pump blood against gravity.
• Explain why the muscle wall is thicker in the left ventricle than the right.

  The right ventricle only pumps deoxygenated blood to the lungs whereas the left ventricle pumps blood into the aorta (the biggest artery) which supplies blood to the whole body. The blood is pumped with great pressure into the aorta.
• Explain why the heart has valves between the chambers.

  Valves are located on each end of the ventricles (lower chambers) and prevent back flow of blood making sure it flows in the right/one direction.
• Explain the difference between a human and frog heart?

  One difference is that human hearts are four chambered whereas frog hearts are three chambered.

  Frogs have two atrial chambers and one ventricle.

  Because they are significantly smaller than humans, they don't need as much blood and oxygen pumped around the body therefore only one ventricle is needed.
• Definition of plasma

  The clear yellowish liquid which transports blood cells around the body. It is the liquid component of the blood.
• Red blood cells, white blood cells and platelets float around in the plasma.
• What are the functions of plasma?

  1. Transport nutrients, hormones and proteins to the part of the body that need them
  2. Remove waste products
  3. Redistributing water
  4. Supports blood vessels from collapsing or clotting
• Experiencing a lot of diseases and infections makes your immune system stronger.
• Name the valves that separate the atria from the ventricles in the heart


  atrio-ventricular (av valves)
• What substance found in fats is thought to contribute to heart disease?

  Cholesterol