Transport In Humans Flashcards
What is the blood made up of? (2)
Plasma
Blood cells
What 2 main things does the blood do?
Transports substances from one part of the body to another (oxygen, nutrients, urea, hormones)
Helps defend the body against disease
What is the function of plasma?
(Liquid) carries mineral ions, glucose, hormones, amino acids, CO2 and urea
Describe a RBC
Biconcave shape, no nucleus, contains haemoglobin
What’s the function of a RBC?
Contain haemoglobin which carries oxygen from lungs to organs
What are the 2 categories of white blood cells?
Lymphocytes and phagocytes
What is the function lymphocytes?
Produce antibodies
What is the function of phagocytes?
Engulf foreign bodies
Decide a platelet
Fragment of cells, no nucleus, small
What’s the function of a platelet?
To clot the blood
Why are RBCs biconcave?
For a larger surface area to volume ratio - 02 diffuses in and out quickly
What does haemoglobin contain?
Iron
What is a disease?
A condition that prevents the body or part of it working properly
What causes disease?
Other organisms entering the body and reproducing in it.
They may damage or poison it
What act as physical barriers to diseases?
Skin and membranes
What happens if physical barriers become damaged?
White blood cells take over defence
What can phagocytes do?
Change their shape and move from place to place
Move through walls of capillaries into the tissues
Always move to areas of infection
What do lymphocytes do to make sure our body from being infected by the same pathogen?
Produce memory cells and remain in circulatory system for a lifetime
What do memory cells do?
When the body encounters the same pathogen, react with it and produce antibodies much earlier
We are said to have gained immunity
How does vaccination work?
Body given a dose of the pathogen and is either the dead pathogen or parts of the pathogens cell surface
What do arteries do?
Take blood away from heart Quite large diameter Think muscular walls Small lumen High pressure to push blood along arteries
What are veins like and what is their function?
Take blood from tissues back to heart Large in diameter Thin walls Big lumen Low pressure
How does blood flow through veins?
Sandwiched between muscles
When muscles contract, veins are squashed forcing blood in them to move
Contain one way pocket valves to make sure they move in the correct direction
