Exchange and transport in Animals Flashcards
What is the need for an exchange surface in single-celled organisms?
Gases & dissolved substances can diffuse directly into (or out of) the cell across the cell membrane. + It’s because they have a large surface area compared to their volume. + So enough substances can be exchanged across the membrane to supply the volume of the cell. +They have less distance to travel.
What three things does the rate of diffusion depend on?
+Distance +Concentration difference (gradient) +Surface area
What is the function of the lungs?
To transfer oxygen (O2) to the blood and to remove waste carbon dioxide (CO2) from it.
How does the lungs execute it function?
The lungs contain millions of little air sacs called alveoli where gas exchange takes place.
How does the alveoli execute its function?
Blood arriving at the alveoli has returned to the lungs from the rest of the body - contains lots of CO2. +Maximises concentration gradient for the diffusion of both gases. +O2 diffuses out of the air in the alveoli (where concentration of O2 is high) and into the blood (where the concentration of O2 is low). +Co2 diffuses in the opposite direction to be breathed out.
How are the alveoli adapted to maximise diffusion?
+They have a moist lining for dissolving gases +A good blood supply to maintain the concentration gradients of O2 and CO2. +Very thin walls - minimising the distance that gases have to move. +An large surface area (75 m2 in humans)
What is gas exchange?
The process of oxygen and carbon dioxide moving between the lungs and the blood.
What is Fick’s Law?
The relationship between the rate of diffusion and the factors that affect it. +Rate of diffusion DOUBLES if: +The surface area/difference in concentration DOUBLES +The thickness of the membrane HALVES
What are red blood cells?
Cells found in the blood that carry oxygen from the lungs to all cells in the body. +Has a biconcave disc disc shape - gives a large surface area for absorbing oxygen. +Has no nucleus - allows more room to carry oxygen. +Contain a red pigment (haemoglobin) - contains iron +In the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin. +In body tissues (reverse happens) - oxyhaemoglobin splits up into haemoglobin and oxygen. to release oxygen to the cells.
What are white blood cells
Cells that defend against infection. +Contains a nucleus +When an infection occurs, your white blood cells multiply to fight it off. +A blood test will show a high white blood cell count.
What are Phagocytes?
White blood cells that can change shape to engulf unwelcome organisms (phagocytosis)
What are Lymphocytes?
White blood cells that produce antibodies against microorganisms. +Some also produce antitoxins to neutralise any toxins produces by the microorganisms.
What is Plasma?
The pale straw coloured liquid that carries everything in the blood. They carry: +Red & White blood cells +Glucose & Amino acids +Carbon dioxide +Urea +Hormones +Proteins +Antibodies & Antitoxins (produced by white blood cells)
What are blood vessels?
Vessels designed to carry blood
What are arteries?
+Blood vessels that carry blood away from the heart +Heart pumps blood out at high pressure - artery walls are thick, strong & elastic +Contain layers of muscle to make them strong +Elastic fibres allow them to stretch and spring back.
What are Capillaries?
Blood vessels branched from arteries - allows exchange of materials. +Really tiny, narrow, (can squeeze into gaps between cells) - means they can carry blood really close to every cell in body to exchange substances. +Have permeable walls - substances can diffuse in and out. +Supply food & oxygen & take away waste like CO2. +Walls usually one cell thick - increases rate of diffusion by decreasing distance over which it occurs.
What are veins?
Blood vessels that take blood back to the heart +Capillaries join up to form veins. +Blood is at lower pressure in veins - walls don’t need to be as thick as artery walls +Has a bigger lumen than arteries - helps blood flow despite lower pressure. +Has valves - keep blood flowing in the right direction
What is a double circulatory system? (In mammals)
Heart pumps blood around body in two circuits: 1)+ Heart pumps deoxygenated blood to lungs to take in oxygen. +Oxygenated blood returns to heart 2)+ Heart pumps oxygenated blood around all other organs of the body to deliver oxygen to body cells. +Deoxygenated blood returns to heart
What is a single circulatory system? (In non-mammals[i.e fish])
+Deoxygenated blood from the fish’s body travels to heart +Heart pumps it right round body again in a single circuit (via gills where it picks up oxygen)
How does the heart pump blood?
Through blood vessels
What is the right atrium?
Receives deoxygenated blood from body (via the vena cava)
What is the right ventricle?
Receives deoxygenated blood from right atrium +Pumps it to the lungs (via pulmonary artery)
What is the left atrium?
Receives oxygenated blood from lungs (via pulmonary vein)
What is the left ventricle?
Receives oxygenated blood from left ventricle +Pumps it out round the whole body (via aorta)
Why does the left ventricle have a much thicker wall?
It needs more muscle because it has to pump blood around the whole body at high pressure. +The right ventricle only has to pump it to the lungs.
What are valves
Prevent backflow of blood in the heart
What is the cardiac output?
The total volume of blood pumped by a ventricle every minute.
What is respiration?
The process of transferring energy from the breakdown of organic compounds (usually glucose)
What are organic compounds?
These include: +Carbohydrates +Proteins +Lipids
What is energy used for?
+Metabolic processes +Contracting muscles +Maintaining a steady body temperature
What is aerobic respiration?
Respiration with oxygen involved +Most efficient way to transfer energy from glucose
What is anaerobic respiration?
Respiration without oxygen involved. +Transfers much less energy than aerobic respiration - less efficient +Glucose is only partially broken down - lactic acid is also produced
What does lactic acid do?
Builds up in muscles - gets painful & leads to cramp
Diagram of the alveoli
What i the expression for Fick’s Law?
Diagram of the artery
Diagram of the capillary
Diagram of the vein
Diagram of the circulatory system
Diagram of the heart
What is the equation for cardiac output?
Triangle for cardiac output
What is the equation for aerobic respiration?
What is the formula for anaerobic respiration?
What is the equation for anaerbic respiration in plants?
What are the lungs?
The organs of ventilation
What happens when you breathe in?
- Ribs move up - diapragm contracts
- Large volume created inside the lungs
- Creates a lower pressure (lower concentration of gas molecules in the lungs)
- Air is forced into the lungs by atmospheric pressure
What happens when you breathe out?
- Ribs move down
- Diaphragm relaxes
- Creates a higher pressure due to the decrease in volume
- Air is forced out of the lungs
What is breathing
When your muscles change the size of your lungs
What is ventilation?
The movement of air into and out of your lungs
