Mammalian Transport System

• Out blood system transports what?

  nutrients and oxygen
• what needs to be disposed?

  waste products such as carbon dioxide
• How do single-celled organisms such as Paramecium and cnidarians meet their requirements for the supply of nutrients and oxygen and removal of waste products?

  They don't have a pump, they simply do it by the means of diffusion.
• What are 2 things that contribute to easy diffusion in paramecium and cnidarians?

  1) large surface area, there is relatively large area of membrane across which gases can diffuse in and out of their bodies.

  2) not very active organisms, so their cells do not have large requirements for glucose or oxygen, nor do they produce large amounts of waste products.
• how do organisms other than paramecium and cnidarians transport nutrients and oxygen and remove waste products and why do can't they use diffusion?

  They have transport systems with pumps to keep fluid moving through them. They can't use diffusion because they are more active so they need large amounts of nutrients and oxygen and therefore more waste products.
• The main transport system of mammals:

  blood system / cardiovascular system
• what is the cardiovascular system made of?

  blood, pump (heart), and blood vessels
• What kind of a system is the cardiovascular system?

  It is a closed system because blood always remains within the vessels.
• Trace the journey of the blood.

  Left ventricle

  all parts of body except lungs

  venacava (right side of heart)

  Right ventricle

  pulmonary arteries

  lungs

  pulmonary veins

  left atrium
• double circulatory system


  The combination of pulmonary circulation and systematic circulation.
• pulmonary circulation


  circulation of blood between the heart and the lungs
• systematic circulation


  flow of blood from the heart through the body back to the heart
• 2) How does circulatory system of a fish differ from that of a mammal?

  The fish has a single circulatory system, whereas the mammal has a double circulatory system. In the fish, blood leaves the heart and travels to the gills, where it picks up oxygen, before continuing around the body. in the mammal, the blood returns to the heart after picking up oxygen at the lungs, and is then pumped around the body.
• 2) Suggest the possible advantages of the design of the mammalian circulatory over that of a fish.

  Oxygenated blood can be pumped around the body at a a higher pressure, and therefore faster, in a mammal than in a fish, because pressure is lost in the capillaries in the gills. This can provide a more efficient oxygen supply to mammalian cells than to fish cells.
• arteries


  vessels carrying blood away from the heart
• veins


  vessels carrying blood towards the heart
• capillaries


  tiny vessels that link arteries and veins and take blood close to almost every cell in the body
• Where is large amounts of elastic fibres and why?

  in the tunica media of the arteries near the heart because of high blood pressure
• The function of arteries

  To transport blood, swiftly and at high pressure, to the tissues.
• how many layers do walls of arteries and veins contain?

  3
• Name and describe the 3 layers of arteries.

  1) an inner endothelium(lining tissue), made up of a layer of flat cells fitting together like jigsaw pieces (squamous epithelium): this layer is very smooth, minimizing friction with the moving blood and rest on elastic fibers;

  2) middle layer called the tunica media, containing smooth muscle, collagen and elastic fibres (tunica intima)

  3) an outer layer called the tunica externa, containing elastic fibres and collagen fibres.
• The distinctive characteristic of an artery wall

  strength
• blood pressure in the human aorta may be around

  120 mm Hg, or 16 kPa
• what has the htickest walls of any blood vessel?

  artieries
• largest artery


  aorta
• diameter aorta and thickness

  2.5 cm, 2mm
• thickest part of arterial wall

  tunica media
• arterioles


  small vessels that receive blood from the arteries
• Effects of elasticity in arteries

  stretch as pulse of blood surge through at high blood pressure

  reducing the likelihood of bursting

  "even out" blood flow

  gives lower blood pressure blood a little push
• how are arterioles different from arteries

  they are smaller and have less elastic fibres and more smooth muscle because of low blood pressure
• 3) Suggest why arteries close to the heart have more elastic fibres in thier walls than artieries further away from the heart.

  Elastic fibres allow the artery to stretch and recoil as blood pulses through. Nearer the heart, the pressure changes between systole and diastole will be greater, and the maximum systolic pressure greater, than anywhere else in the circulatory system. Thus more elastic fibres are needed to cope with these large pressures and pressure changes.
• 4) Suggest why there aere no blood caplillaries in the cornea of the eye. How might the cornea by supplied with it requirements?

  Blood cells, and haemoglobin in red blood cells, would cause scattering and absorption of light before it reached the retina. The aqueous humour supplies the cornea with its requirements.
• function of capillaries


  to take blood as close as possible to all cells, allowing rapid transfer of substances between cells and blood.
• capillaries form a network throughout every tissue in the body except ___ and ___

  cornea and cartilage
• capillary beds


  networks of capillaries that infiltrate every organ and tissue in the body
• capillary in diameter


  7 micro meter diameter, about same size as a red blood cell
• capillary walls are made of


  single layer of endothelial cells, very thin
• what happens to blood as it reaches the capillaries


  it losses a great deal of pressure
• venules


  small vessels that gather blood from the capillaries into the veins
• function of veins


  to return blood to the heart