SB8 Flashcards
What is SA:V
The ratio between an organisms surface area and volume (SA/V)
What happens to the SA:V ratio as an organisms size increases
Ratio decreases
Why can’t large organisms rely on diffusion for all of their exchanges
- Their SA:V ratio is too low so diffusion is much slower
- They use specialised exchange surfaces and transport systems
What system are the lungs part of
Breathing system
How do the lungs take in oxygen
- Breathe in air through nose/mouth
- Trachea
- Bronchi
- Brochioles
- Alveoli
What is the function of the lungs
- Transfer oxygen to the blood
- Remove waste carbon dioxide from blood
How are alveoli adapted to their function
- A LOT of them = increased surface
- Alveoli are close to a capillary
- One layer thin walls = short diffusion pathway
- Moist lining = gases dissolve increasing RoD
- Constant blood flow = maintain high concentration gradient
Breathing rate equation
number of breaths/minutes
What factors is the rate of diffusion dependent on
- High surface area
- Short diffusion pathway
- Maintenance of a high concentration gradient
What does Fick’s Law state
The rate of diffusion is proportional to the (Surface area * Concentration difference)/thickness of membrane
What is blood
A tissue
What is bloods function
-To act as a huge transport system
- To transport oxygen across the body
What is blood made of
- Red blood cells
- White blood cells
- Plasma
- Platlets
What is the function of the red blood cell
- Carry oxygen from lungs to around the body
What adaptations do RBC have
- Haemoglobin binds to oxygen
- No nucleus - increase space for haemoglobin
- Large surface
- Biconcave disc shape
What are the different types of white blood cells
- Lymphocytes
- Phagocytes
- Anti-toxins
What is the role of a lymphocyte
- Create antibodies that bind to the pathogens antigens
What is the role of a phagocyte
- Engulf pathogens
What is the role of anti-toxins
- Neutralise any toxins
What is plasma
Straw coloured liquid
What is the function of plasma
- Carries RBC, WBC, platelets, urea, glucose, amino acids, carbon dioxide, hormones
How much of our blood is:
- WBC
- RBC
- Plasma
- 1>%
- 45%
- 55%
What is artificial blood
- Salt water
What is the purpose of artificial blood
- Substitute real blood
- Adds volume to blood to keep heart pumping and blood vessels full
What are the drawbacks of artificial blood
- Can only replace 2/3 of blood
What is an alternative to artificial blood
- Blood transfusions from blood donors
Describe the features of arteries
- Carry blood away from heart to the body
- Carries high pressure blood
- Thick wall of muscle and elastic fibres
- Small lumen
Describe the features of veins
- Carry blood back to the heart
- Carries low pressure blood
- Large lumen
- Thin wall of smooth muscle and elastic fibres
- Have valves to prevent backflow
Describe the features of capillaries
- Used for gas and nutrient exchange
- Carries low pressure blood (more time for exchange)
- Extremely small
- Close contact to all cells (short diffusion pathway)
- Permeable single cell thick wall made of endothelial cells
- Total cross sectional area is really high
Equation for rate of blood flow
Volume of blood flowed/mins
What is the purpose of the circulatory system
Transport oxygen and nutrients around the body
What is the system between the heart and lungs called
The pulmonary system
What is the system between the heart and body called
The circulatory system
Describe how the heart pumps blood
1) Deoxygenated blood enters the right atrium via the vena cava
2) Blood flows to the right ventricle as the AV valve opens due to muscles contracting
3) Blood is pumped from the pulmonary artery to the lungs as the semilunar valve opens due to muscles contracting
4) Oxygenated blood from the lungs enters the left atrium via the pulmonary veins
5) Blood flows to the left ventricle as the AV valve opens due to muscles contracting
6) Blood is pumped from the aorta to the rest of the body as the semilunar valve opens due to muscle contractions
Which ventricle has a thicker wall and why
- Left ventricle
- Has to pump high pressure blood
What are pacemaker cells
- Found in the right atrium
- Keeps heartbeat steady by producing small electrical impulse
- Causes heart muscles to contract
What happens if the pacemaker cells are faulty
- An artificial pacemaker is implanted near the collarbone
- A wire is guided through to the heart
- Sends electrical impulses
What is the purpose of the coronary arteries
- Provide heart with necessary glucose and oxygen
- On the surface of the heart
Name structures found in the heart
- Superior/ Inferior vena cava
- Right/ Left atrium
- AV/ Semilunar valves
- Right/ Left ventricles
- Pulmonary artery/ vein
- Aorta
- Septum
What is the purpose of the septum
- Separates the sides of the heart
What is the purpose of the tendons
To stop the valves from turning inside out
What is the purpose of cellular respiration
- Release energy as it is an exothermic reaction
What is energy needed for in the human body
- Making larger molecules
- Muscle contractions
- Maintaining body temperature
Define metabolism
All chemical processes that occur in a living organism in order to maintain life
Describe the features of aerobic respiration
- Occurs in the mitochondria
- Occurs when there is enough oxygen
- Most efficient way of releasing energy
What is the word equation for aerobic respiration
glucose + oxygen -> carbon dioxide + water + energy
Describe the features of anaerobic respiration
- Occurs when there is not enough oxygen
- Creates lactic acid (poisonous)
What is the word equation for anaerobic respiration
glucose -> lactic acid
What are the negatives of anaerobic respiration
- Creates an oxygen debt due to an incomplete reaction
- Lactic acid is poisonous
What is the word equation for anerobic respiration in plants
glucose -> ethanol + carbon dioxide
What is anerobic respiration called in yeast
Fermentation
Explain how lactic acid is oxidised
1) Lactic acid in muscles is transferred to the liver via blood
2) Reacts with oxygen in liver to form glucose
Describe how to investigate respiration (practical R)
1) Put soda lime granules into two tubes
2) Add cotton wool and woodlice into one tube, glass beads in the other
3) Set up respirometer
4) Set liquid in respirometer to a known volume using syringe
5) Put apparatus into water bath at 15C
6) When woodlice respire it decreases pressure as there is less air
7) Distance moved by liquid/time = respiration rate
8) Repeat 1-7 with water bath at different temps
What are control variables in practical R
- Mass of woodlice/glass beads
- Time
- Mass of soda lime granules
What is the independent variable in practical R
- Temperature of water bath
List the equipment needed in practical R
- Soda lime granules (absorb carbon dioxide)
- Two test tubes
- Cotton wool
- Woodlice
- Glass beads
- Syringe
- Respirometer,
