B4 - (Part 1) Organising Animals Flashcards
What are the components of blood?
Platelets, plasma, red blood cells and white blood cells
How to differentiate between the different types of wbc under a microscope
Phagocytes have a lumpy nucleus
Lymphocytes have a very large nucleus
What is plasma and what is its function
- It is the liquid part of the blood
- Its function is to carry the blood cells, CO₂, nutrients, urea
Structure and adaptations of a red blood cell
- No nucleus to carry more haemoglobin + O₂
- Biconcave so large SA:V so quick O₂ diffusion
- Small to squeeze through capillaries
Function of red blood cells
- Carry oxygen due to haemoglobin which has iron which bind to O₂
Function of phagocytes and lymphocytes
- Phagocytes - Engulf pathogens through phagocytosis
- Lympocytes - produces antibodies which target pathogens
Structure and function of platelets
- Structure - small fragments of cells without a nucleus
- Function - help the blood to clot to stop blood loss
Structure of arteries and why
- Thick, strong outer wall and thick layer of fibres and muscle as blood is under high pressure
- Small lumen (gap) to maintain high pressure
Structure of veins and why
- Thin outer wall and thin layer of fibres and muscle to be squeezed by skeletal muscles
- Large lumen as blood is under low pressure
Function of valves and where they are found
- Valves stop the backflow of blood
- They are only found in the veins
Structure of capillaries and why
- Small lumen and wall made of a single layer of cells
- This allows there to be lots of capillaries
- It also allows substances to easily diffuse in and out of them
Explain the different parts of the double circulatory system
- The pulmonary system carries low pressure blood to and from the lungs
- The systemic system carries high pressure blood to and from the body
What causes the heart to pump blood?
- The pacemaker in the right atrium sends an electrical impulse atria and the ventricles which contract
How does the heart recieve its own blood supply?
Through the coronary artery, located on the surface of the heart which supplies oxygen and glucose and removes CO₂
What is coronary heart disease and how is it dangerous?
- Where the coronary artery gets clogged up with fatty deposit
- This reduces blood flow, O₂ supply to heart leading to less respiration, less heart muscle contraction
Ways to fix or prevent coronary heart disease
- Stents - mesh that keeps artery open
- Statins - drugs to lower cholestrol
- Bypass surgery
Complications with stents
- Wire mesh could be sharp + cut blood vessels
- Risk of infection
- Metal so could cause blood clots
What are artificial pacemakers used for
To correct irregularities in the heart rate if the pacemaker isn’t working
Consequences of faulty valves
- Breathless as not enough oxygenated blood going round
- Can be fatal
Different types of valve replacements
- Biological valves
- Mechanical valves
Advantage and disadvantage of mechincal valve replacements
- Last a lifetime
- Need to take anticoagulants
Advantages and disadvantages of biological valve replacements
- No need to take anticoagulants
- Don’t last for long
- Religious concerns
What is an artificial heart and its advantages
- A mechanical heart given whilst waiting for a permanent transplant
- Gives the heart a rest and time to recover
Disadvantages of artificial hearts
- Metal so risk of blood clotting
- Very costly
- Not a permanent replacement
Adaptions of the alveoli (3)
- Large surface area for more diffusion
- Good blood supply to manitain conc. gradient
- Thin walls for short diffusion distance
What happens in the gas exchange system when you breathe in
- Intercostal muscles contract moving ribs up and out
- Diaphragm contracts and moves down
- Pressure decreases inside chest so air rushes in
What happens in the gas exchange system when you breathe out
- Intercostal muscles relax moving ribs down and in
- Diaphragm relaxes and moves up
- Pressure increases inside chest so air rushes out
