transport in animals

• • fetal haemoglobin
  • adult haemoglobin

  
• what is required to produce energy in aerobic respiration

  oxygen and glucose
• how do small organisms obtain oxygen and glucose for aerobic respiration


  diffusion
• Multicellular organisms have a large diffusion distance so can't obtain substances simple from diffusion as t would be too slow to reach the cells in the centre of their body. What do they have to instead?

  mass transport system
• Mass transport system

  A system (e.g. the circulatory system) that carries substances to and from individual cells
• example of a mass transport system

  circulatory system

  - delivers oxygen and glucose to all body cells

  - removes waste products such as CO2 and water
• 4 types of circulatory systems

  - Open circulatory system

  - closed circulatory system

  - single circulation

  - double circulation
• open circulatory system

  - not enclosed in blood vessels

  - in insects
• explain open circulatory system in insects

  - blood flows out the heart and into the body cavity

  - blood flows around the insect's organs and back to the heart through a series of valves
• closed circulatory system


  - blood enclosed inside blood vessels

  - all vertebrates (eg. mammals and fish)
• Explain a closed circulatory system in vertebrates

  - arteries take blood away from the heart and towards organs

  - substances move between the bloodstream and tissues at the capillaries

  - veins take blood from tissues back to the heart
• single circulation


  - blood travels in one loops

  - passes through the heart once foreach complete circuit of the body

  - in fish
• explain single circulation in fish

  - heart pumps blood to the gills straight to the body tissues before returning back to the heart
• double circulation

  - blood travels in two loops (pulmonary system and systemic system )

  - in mammals
• explain double circulation in mammals

  - blood flows from the heart to the lungs for gas exchange

  - back to the heart

  - pumped around the whole body
• pulmonary system

  blood circulates from the heart to the lungs and back
• systemic system

  oxygenated blood is pumped from the heart to the rest of the body and back
• 5 blood vessels

  - arteries

  - arterioles

  - capillaries

  - venules

  - veins
• arteries

  - carries blood away form the heart to various organs

  - thick muscular walls

  - lost of elastic tissue

  - lined with endothelium

  - small lumen
• Why do arteries have a small lumen

  to maintain high blood pressure
• Why are arteries lined with endothelium cells

  allows them to expand (elastic recoil) also helps withstand high pressure
• Why do arteries have thick walls and a lot of elastic tissue?

  cope with high pressure generated from the heart forcing out blood with each heart beat
• veins

  - carry blood from the organ back to the heart

  - larger lumen

  - thinner walls

  - valves
• Why do viens have very large lumen and less elastic fibres


  blood is flowing at much lower pressure
• Why do veins have valves?

  prevent back flow of blood
• What helps blood flow through veins?

  Contraction of muscles surrounding them
• Capillaries

  - connects arteries and veins

  - substances move out of the blood to the body tissues and vice versa

  - small holes

  - walls one cell thick
• Why do capillaries have pores?

  to enable exchange of substances
• Why are capillaries wall one cell thick?

  to reduce diffusion distance for these substances
• tissue fluid

  The fluid surrounding the cells and tissues
• what is tissue fluid made of

  Small molecules that leave the blood plasma and waste products

  - Oxygen, water, glucose and mineral ions

  - CO2, water and urea
• Formation of tissue fluid

  arteriole end of the capillary

  > hydrostatic pressure in capillary exceeds that of tissue fluid

  > forces fluid and dissolved substances out of the capillary > down the pressure gradient

  > into space around the cells

  
  

  venule end of the capillary

  > less water

  > lower water potential inside capillary compared to te tissue fluid

  > water back into capillary by osmosis > down water potential gradient

  
  

  > excess tissue fluid drains into the lymphatic system > eventually returns fluid back into the bloodstream
• what are the 4 cambers of the heart

  - right atrium

  - left atrium

  
  

  - right ventricle

  - left ventricle
• why are the walls on the left side of the heart thicker

  it has to power blood through the entire body whereas the right side only has to push blood to the lungs
• What side of the heart has oxygenated blood?

  left side
• what chambers receives blood from the veins suppling the heart

  atria
• atrioventricular valves


  Valves located between the atrial and ventricular chambers

  
  

  > prevents backflow into the atria when the ventricles are contracting
• Semi-lunar valves


  Valves in either side of the heart that controls exit from the ventricles
• aorta


  main artery that takes oxygenated blood from the left side to the rest of the body
• pulmonary artery


  delivers deoxygenated blood from the right side of the heart and lungs