Topic 8 - Exchange and transport in animals Flashcards
What are the names of substances that need to transported into and out of the body
water, urea, oxygen
how does urea form and leave the body
waste product of proteins, diffuses from cells to blood plasma for removal from body by the kidneys
How is water taken into the body
cells take up by osmosis. along with dissolved food molecules and mineral ions.
How do oxygen and carbon dioxide enter and leave the body
through diffusion
How easy an organism can exchange substances with its environment depends on its:
surface area to volume ratio
larger the animal- the smaller the S.A to volume ratio
How do single celled organisms exchanged substances with their environment
because they have a large surface area to volume ration, it allows substances to diffuse directly into and out of them across their membrane which is much quicker
How do multicellular organisms exchanged substances with their environment
more difficult to exchange substances over entire body so they have transport systems to move substances from exchange surface to rest of body due to smaller surface area to volume ratio.
What does the rate of diffusion depend on
Distance/thickness of membrane
concentration difference- faster if big difference
surface area- larger =faster more surface to diffuse across
Describe how gas exchange in mammals occurs
lots of alveoli in the lungs
- blood arrives at alveoli for gas exchange which contains lots of CO2 and no much O2.
- O2 diffuses out of air and into alveoli where O2 concentration is high and into blood where O2 concentration is low.
- CO2 diffuses in opposite direction so is breathed out
How are alveoli adapted for gas exchange
- moist lining for dissolving gases
- good blood supply to maintain the concentration gradients of O2 and CO2
- very thin walls
- very large surface area
whats ficks law
rate of diffusion = surface area x concentration difference
What is the function of red blood cells
and how are they adapted for this
to carry oxygen around the body
- bioconcave disc for large surface area to absorb oxygen
- no nucleus
- haemoglobin (contains iron) which binds to oxygen to become oxyhaemoglobin which is then reversed to release oxygen to cells
What is the function white blood cells
name the 2 types
to defend against infection
- phagocytes are white blood cells which can change shape to engulf unwelcome microorganisms through phagocytosis
- Lymphocytes -produce antibodies against microoragnisms. Some may produce antitoxins to neutralise any toxins produced by microoragnisms
Why you have an infection, how will the number of white blood cells change in a blood cell count
they will multiply to fight off infection
What do Platelets do and what are they
- help blood clot
- small fragments of cells clot round wound to stop blood getting out and microorganisms getting in
- without them we would have excessive bleeding and bruising
What is plasma
Plasma is the liquid that carries everything in the blood such as: red, white blood cells and platelets carbon dioxide urea from liver to kidney hormones proteins antibodies and antitoxins
What are the 3 blood vessels
arteries, capillaries, veins
How are arteries adapted for their function
- carry blood under high pressure away from the heart so have strong, elastic walls
- walls are thick compared to lumen.
How are Capillaries adapted for their function
- branch off arteries
- narrow to squeeze between gaps between cells
- one cell thick cell walls so substances can diffuse
- supply food and oxygen + take away CO2
- exchange substances with cells
- large lumen
How are Veins adapted for their functions
Capillaries join up to form veins,
- lower pressure than arteries so walls arent as thick but still elastic
- bigger lumen for increase flow
- valves to keep blood flow in one direction
What kind of circulatory do mammals have
Double circulatory, means heart pumps blood in two circuits
-deoxygenated blood goes to lungs to get oxygen
oxiginated blood goes to heart.
-second circuit takes ooxygenated blood from heart to the body for cells then returns to heart
name an animal with a single circulatory system and how it works
Fish- deoxygenated blood from fish body goes to heart which pumps around again via gills which pick up
oxygen.
-heart only has 2 chambers
How is deoxygenated blood carried around heart
- through the vena cava
- to right atrium
- through tricuspid valve, through right ventricle
- through semi lunar valve
- to lungs through pulmonary artery
How is oxygenated blood carried around heart
- through the pulmonary vein to left atrium
- through bicuspid valve,
- to left ventricle
- through semi-lunar valve
- through aorta to the body
