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%