Chapter 6: Transport in humans Flashcards
What is the yellowish liquid in blood?
Plasma
What does plasma contain?
Mainly water, blood cells, excretory products, nutrients, hormones
What is the primary function of red blood cells (RBC)?
To transport oxygen from the lungs to other parts of the body
What does RBC consist mostly of?
Haemoglobin with reversibly combines with oxygen to oxyhaemoglobin
What are the 3 characteristics of the RBC?
Biconcave shapes, no nucleus and flexible
Why does the RBC have a biconcave shape?
To increase the surface area to volume ratio , increasing the rate of diffusion of oxygen in and out of the cell
Why does the RBC have no nucleus?
For more space available for haemoglobin (increasing the amount of oxygen transported)
Why are RBC flexible?
So it can move easily through narrow capillaries
What are the 2 types of white blood cell (WBC)?
Phagocyte and Lymphocyte
What does the phagocytes do?
engulf and destroy pathogens (phagocytosis)
What does the lymphocytes do?
produce antibodies (destroy pathogens, clump pathogens up, neutralise toxins produces by bacteria)
What do platelets do?
Contains an enzyme that catalyses the conversion of fibrinogen to fibrin threads, which then entangles with RBC to form clot, stopping the bleeding
What are the adaptations of arteries?
- Thick and muscular walls to withstand the high pressure of blood flowing within
- elasticity to help stretch and recoil
- contraction and relaxation to divert blood to other organs
What are the adaptations of veins?
- Transport blood back to the heart
- walls are thinner than veins as blood flow is slower
- valves present to prevent backflow of blood
What are the adaptations of capillaries?
- large surface area
- short diffusion distance
- steep concentration gradient
Explain the process of blood flow in the heart. (Based on the common graph tested)
- Increase in ventricular pressure due to the contraction of the left atrial muscles, forcing blood into the ventricle
- Ventricular muscles begin to contract (bicuspid valve closes)
- Ventricular muscles continue to contract, without change in volume of blood (pressure continues to rise)
- Pressure in ventricle is higher than in aorta, so aortic valve (SL valve) opens, the pressure decreases as blood is forced into the aorta
- Ventricular muscles relax without change in volume of blood
- Bicuspid valve opens when the pressure in the ventricle is lower than in the atrium
- Pressure in ventricle rises as blood enters ventricle from atrium
What causes coronary heart disease?
Fatty deposits in the coronary arteries. (restricting blood flow)
