Indirectly Assessed Flashcards
Why do organisms need to transport substances in and out?
To get rid of waste products
What substances are transported around the body?
Oxygen, CO2, water, dissolved food molecules, mineral ions, urea
What are platelets and what do they do?
Small fragments of cells with no nucleus that help blood to clot at a wound
What is plasma and what does it carry?
Pale straw-coloured liquid which carries:
- red/white blood cells
- nutrients like glucose
- CO2
- urea
- hormones
- proteins
- antibodies and anititoxins
What do phagocytes do?
White blood cell that’s engulf unwelcome microorganisms
What do lymphocytes do?
White blood cells that produce antibodies against microorganisms
How are red blood cells specialised?
- biconcave disc shape = large SA
- no nucleus = more space to carry O2
- haemoglobin = contains iron
How does haemoglobin help to carry O2 in red blood cells?
Haemoglobin binds to oxygen to become oxyhemoglobin
What do arteries, capillaries and veins do?
Arteries = carry blood away from heart Capillaries = involved in exchange of materials at tissue Veins = carry blood to the heart
How are arteries specialised?
- strong and elastic walls to cope with high pressure
- thick walls
- thick muscle and elastic fibres allows them to stretch
How are capillaries specialised?
- narrow so can reach every cell
- permeable walls for diffusion
- supply food and oxygen and waste
- wall = 1 cell thick = decreases distance
How are veins specialised?
- low blood pressure so thin ish walls
- bigger lumen to help blood flow
- valves to push blood in the right direction
How does blood flow in the heart?
- r.atrium receives deoxygenated blood from body via vena cava
- deoxygenated blood moves through to r.ventricle which pumps it to the lungs
- via pulmonary artery
- l.atrium receives oxygenated blood from the lungs
- via pulmonary vein
- oxygenated blood moves through to the l.ventricle and pumps it to body
- via the aorta
Why does the left ventricle have a thicker wall than the right?
Needs more muscle to pump blood at a higher pressure to the whole body, not just to the lungs
Why does the heart have valves?
To prevent back flow of the blood in the heart
