8. Exchange and Transport in Animals: Circulatory System

Question 1

What is Blood?

Answer 1

Blood is a tissue and acts as a huge transport system

Question 2

What is purpose and characteristics of Red Blood Cells?

Answer 2

• Red blood cells are erythrocytes
• Carry Oxygen from lungs to all cells in body
• Biconcave disc shape - large surface area to absorb oxygen
• No nucleus - more room for oxygen
• Red pigment - Haemoglobin - contains iron - bind to oxygen in lungs -> Oxyhaemoglobin
• In body tissues oxyhaemoglobin splits oxygen and haemoglobin to release oxygen to cells

Question 3

What do White Blood cells do? What are the different types?

Answer 3

• Defend against infection - white blood cells multiply to fight off - blood test shows high white blood cell count
• Phagocytes - white blood cells change shape to engulf unwelcome microorganisms - phagocytosis
• Lymphocytes - white blood cells - produce antibodies to defend against microorganisms - some produce antitoxins to neutralise toxins from microorganisms

Question 4

What are Platelets?

Answer 4

• Help blood clot at a wound - stops blood pouring out and microorganisms from getting in
• Small fragment of cells - No Nucleus
• Lack of platelets causes excessive bleeding

Question 5

What is Plasma?

Answer 5

• Pale straw colour - Liquid that carries everything in the blood
• > platelets, red and white blood cells
• > nutrients like glucose and amino acids which are digested and absorbed in the gut
• > Carbon Dioxide from organs to the lungs
• > Urea from liver to kidneys
• > Hormones
• > Proteins
• > Antibodies and antitoxins

Question 6

What are the 3 types of Blood Vessel?

Answer 6

• Arteries - blood away from heart
• Capillaries - exchange of materials at the tissues
• Veins - blood to the heart

Question 7

What do Arteries do?

Answer 7

• Pumps blood at high pressure so artery walls thick, strong and elastic
• Hole in middle is the lumen
• Contain thick muscle

Question 8

What are Capillaries and what do they do?

Answer 8

• They are really small - squeeze into gaps between cells - carries blood to every cell and exchanges substances
• Arteries branch into capillaries
• Permeable walls - one cell thick - substances diffuse in and out
• Supply food and oxygen
• Remove waste e.g. co2

Question 9

What are Veins and what do they do?

Answer 9

• Take blood back to heart
• Capilleries join up to veins
• Blood at low pressure so not as thick as arteries
• larger lumen vs arteries to help blood flow despite low pressure
• Valves - keeps blood flowing the right direction

Question 10

What is the Heart?

Answer 10

• Heart pushes blood around the body

Question 11

What circulatory system do Mammals have?

Answer 11

Double circulatory system

Question 12

What is a Double Circulatory System?

Answer 12

• Heart pumps blood around body in two circuits
• First circuit - deoxygenated blood to lungs - lungs take in oxygen - Oxygenated blood to the heart
• Second circuit - Pumps oxygenated blood around to other organs - deoxygenated blood return to heart

Question 13

What are the 4 Chambers and 4 major blood vessels in the heart?

Answer 13

• Right atrium - receives deoxygenated blood from body - through the vena cava
• Right ventricle - deoxygenated blood pumped to the lungs via the pulmonary artery
• Left atrium - receives oxygenated blood from the lungs - pulmonary vein
• Left ventricle - thicker wall than right ventricle because oxygenated blood pumped around the whole body at high pressure (right ventricle only has to pump to the lungs) via the aorta
• Valves prevent back flow to the heart

Question 14

What is the equation to calculate how much blood is pumped every minute?

Answer 14

• Cardiac output = total volume of blood pumped by a ventricle every minute
• Cardiac output ( cm3 min-1 ) = heart rate ( beats per min) x stroke volume (cm3)
• Heart rate - number of beats per minute
• Stroke volume - volume of blood pumped by one ventricle each time contracted

Question 15

What is heart rate of person with average stroke volume of 72cm3 and cardiac output of 5420 cm3 min-1?

Answer 15

• Heart rate = cardiac output / stroke volume

- 5420 / 72 = 75.2777 = 75 bpm

Question 16

What is Cellular Respiration?

Answer 16

• Releases energy
• Goes on in every cell continuously for all living organisms
• Transferring energy from breakdown organic compounds (usually glucose)
• Energy is transferred into the environment - Respiration is exothermic reaction - some of the energy is transferred by heat
• Two types - AEROBIC and ANEROBIC

Question 17

What is the Energy from Respiration used for?

Answer 17

• Used for :
• Metabolic processes e.g. making larger molecules from smaller ones (proteins from amino acids)
• Contracting muscles (in animals)
• Maintaining steady body temp (mammals and birds)

Question 18

What is Anaerobic Respiration?

Answer 18

• Doesn’t use oxygen
• When doing vigorous exercise, body can’t supply enough oxygen to muscles for aerobic respiration - Despite breathing and heart rate increasing - Muscles have to start using Anaerobic respiration
• Transfers less oxygen than Aerobic - Less efficient - Glucose only partially broken down and produces lactic acid
• Lactic acid builds up in muscles - Causes cramps and pains
• Glucose —> Lactic Acid

Question 19

What is the equation for Anaerobic Respiration?

Answer 19

• Glucose —> Lactic Acid - (animals)
• Anaerobic respiration in plants is different - Glucose —> ethanol + Carbon Dioxide
• plants can respire without oxygen but they produce ethanol and CO2 instead of Lactic Acid

Question 20

What is Aerobic Respiration?

Answer 20

• Means ‘with oxygen’
• Plenty of oxygen is available - most efficient way transferring energy from glucose
• Happens all the time in plants and animals

Question 21

What is the equation for Aerobic Respiration?

Answer 21

Glucose + Oxygen —> Carbon Dioxide + Water

Question 22

How is Anaerobic Respiration in plants different?

Answer 22

• Glucose goes to ethanol and carbon dioxide instead of going to lactic acid

Question 23

What is the equation for Anaerobic Respiration in plants?

Answer 23

Glucose -> ethanol + carbon dioxide

Question 24

What is a Respirometer?

Answer 24

Device used to measure the Rate of Respiration

Question 25

After 5 minutes of intense sprinting, a student got cramp in his leg. Explain what caused this.

Answer 25

The student only used up partial amount of the glucose and produce lactic acid as a result of Anaerobic respiration - the lactic acid then caused the cramp

Question 26

How can you measure the Rate of Respiration?

Answer 26

• Aerobic Respiration - measure amount of oxygen consumed by organisms in a given time = rate of respiration
• Experiment:
• Soda Lime in 2 test tubes - absorbs CO2 produced by respiring wood lice
• Ball of cotton wool placed above soda lime - wood lice on top of cotton wool in 1 tube
• Glass beads - same mass as woodlice used in the control tube
• Respirometer set up - ADD DIAGRAM
• Syringe used to set fluid in manometer to known level
• Leave apparatus for set period of time in bath water set to 15 degrees C
• Decrease in volume of air in test tube containing woodlice which use up oxygen as respire - CO2 produced absorbed by soda lime
• Decrease in volume reduces pressure in tube causing coloured liquid in manometer to move towards test tube containing woodlice
• Distance of liquid moved over time is measured - use value to calculate volume of oxygen taken in by woodlice per minute = rate of respiration cm3 min-1
• Repeat with bath water at different temperatures - to see impact on RoR