chapter 9 transport in humans Flashcards
what makes up plasma (4)
- 90% water = acts as a solvent to soluble proteins like fibrinogen, prothrombin and antibodies
- Dissolved mineral salts
- Food substances like glucose, amino acids, fats and vitamins
- Excretory products like urea, uric acid, creatinine, carbon dioxide (present as hydrogencarbonate ions)
function of red blood cells
- contains haemoglobin: combines reversibly with oxygen
- To transport oxygen from lungs to all cells to the body
adaptations of RBCs
- Has a circular biconcave shape: increase SAVR = contains more haemoglobin = higher rate of absorption and release of oxygen
- Does not have a nucleus: increase in space = carry more haemoglobin
- Elastic and bellshaped: can squeeze through blood vessels smaller than itself
what are white blood cells (feature + types)
feature: able to change its shape and squeeze through the walls of thin blood capillaries into spaces among tissue cells = mobile to fight bacteria
types:
1. lymphocytes: produce antibodies = protect body from disease causing microorganisms
2. phagocytes: able to ingest foreign particles like bacteria
how does agglutination happen
happens when plasma contains antibody (in plasma) and antigen (on surface of RBC) of same letter:
antibody a binds to antigen A,
antibody b binds to antigen B
donation: involves only blood (only antigens) - if agglutination occurs it is due to plasma in recipient
features of blood type A
- can receive A and O
- plasma/serum has antibody b
- RBC has antigen A
features of blood group B
- can receive B and O
- Plasma has antibody a
- RBC has antigen B
features of blood group AB
- can receive A, B, AB and O (universal acceptor)
- Plasma has no antibody
- RBC has antigen A and B
features of blood group O
- can receive O (universal donor)
- Plasma has antibody a and b
- RBC has no antigen
how does blood clotting occur when there is an open wound (4 steps)
- Damaged blood vessels release enzyme thrombokinase
- stimulates conversion of protein prothrombin into thrombin in presence of calcium ions
- Thrombin catalyses conversion of soluble protein fibrinogen to insoluble fibrin threads (will not dissolve in water present in plasma)
- Fibrin threads form mesh which trap blood cells and seals wound = microorganisms like bacteria cannot enter
what is phagocytosis
definition: process of engulfing/ingesting foreign particles by white blood cells (phagocytes)
process: Phagocyte engulfs bacteria by flowing over them and enclosing them = digests ingested bacteria
how do lymphocytes protect our body (3)
- Destroying bacteria: attaches to them, causing bacterial surface membrane to rupture
- Causing bacteria to clump together = easily ingested by phagocytes
- Neutralising harmful substances produced by bacteria
how to reduce risk of rejection in a transplant
- Tissue match = must be genetically close to the recipient as possible (either from same person or family member)
- Use immunosuppressive drugs: inhibit responses of recipient’s immune system = antibodies will not be produced and attack the tissue
what are arteries (function, structure, blood pressure, speed of blood flow)
function: Transports blood away from the heart→ carry oxygenated blood (except pulmonary artery)
structure: Thick muscular walls, Small lumen, no valves
BP: high = more blood flowing per unit time in a smaller space
speed of blood flow: fast
adaptations of arteries
- Thick muscular walls = withstand immense pressure of blood forced out from the heart
- Walls with much elastic tissue: able to stretch and recoil under high pressure to push blood along the artery
what are veins (function, structure, blood pressure, speed of blood flow)
function: Transport blood towards heart → carry deoxygenated blood (except pulmonary veins)
structure: Large lumen, Thin muscular walls with less elastic tissue, Has semi-lunar valves (open to let blood flow, close to prevent from back flow = usually close after blood has flown so that there will be no backflow)
BP: Low = lumen is larger, more blood flows per unit time in one space
speed: Very slow
adaptations of vein
- Thin muscular walls: Veins transport blood back to the heart = lower blood pressure = walls do not have to withstand the low BP = walls are not so thick and elastic
- Valves are present to prevent backflow of blood = blood can flow in one direction (as blood in vein has lower BP, there is less pressure to keep them continuously flowing forward, so it may backflow)
- Large lumen provides lower resistance = blood flows back smoothly to heart
what are capillaries (function, structure, blood pressure, speed of blood flow)
function: Involved in exchange of substances
structure: One cell thick wall, no muscular or elastic tissue, Large lumen
BP: low
speed: slow
adaptations of capillaries (one capillary and capillarIES)
One capillary:
1. one-cell thick wall = shorter diffusion distance which increases rate of diffusion;
2. large lumen relative to diameter = reduce pressure of blood flowing from arteriole end to venule end = allow more time for exchange of materials;
Capillaries
3. extensive network = to increase (cross-sectional) surface area = increased exchange of materials (more blood flows through more capillaries)
how does exchange of substances occur in capillaries (5 steps)
- happens between blood capillary, tissue fluid (carries substances in solution between tissue cells and blood capillaries) and tissue cells
- blood flow towards right: oxygen gets released from oxyhaemoglobin, dissolved food substances diffuse out of RBC - out of blood capillary - into tissue fluid - into cells
- RBCs may become bell shaped: increase surface area to speed up absorption/release of oxygen
- rate of blood flow decreases = more time for exchange of materials between blood and tissue cells
- waste products diffuse out of cells = into tissue fluid = diffuse through capillary walls into RBCs
what happens during atrial diastole (relaxation)
- deoxy blood flows into right atrium (RA) via vena cava
- oxy blood flows into left atrium (LA) via pulmonary vein (PA)
- pressure in atria increases but does not exceed pressure in ventricles
- valves are still closed due to pressure
- ventricles start to contract
what happens during atrial systole (contraction)
- pressure in atria increases, exceeds pressure in ventricles
- bicuspid and tricuspid valves open
- deoxy blood flows from RA through tricuspid valve (TV) into right ventricle (RV)
- oxy blood flows from LA through bicuspid valve (BV) into left ventricle (LV)
what happens during ventricular systole
- pressure in ventricles increases, exceeds pressure in aorta and pulmonary artery (PA)
- semi lunar valves (SLV) open
- deoxy blood flows out of RV through SLV into PA
- oxy blood flows out of LV through SLV into aorta
- pressure in ventricles exceeds pressure in atria
- BV and TV close before blood starts to flow into aorta/PA (shld close before blood starts to flow, to prevent backflow back from ventricles into atria)
what happens during ventricular diastole
- pressure of ventricles decrease
- semi lunar valves close after all blood in ventricles have been emptied out (now all valves are closed)
- artrial diastole starts
how is the lub sound produced
when pressure in ventricles exceeds pressure in atria, and BV/TV close
how is dub sound produced
when pressure in aorta/PA exceeds pressure in ventricles and semi lunar valves close (ventricular diastole)
why do left and right atria have the lowest thickness
left and right atria have the lowest thickness: only force blood a short distance to the ventricles = does not need to withstand high pressure
why is left ventricle the thickest
→Left ventricle has a thicker muscular wall compared to right ventricle: LV pumps blood around the body = has to withstand higher pressure than that in right ventricle
→ LV is thicker than RV: more force is exerted when thicker wall of LV contracts to force blood out = higher BP in LV
why is right ventricle not as thick as left ventricle
→ Right ventricle has a thinner muscular wall to LV: need to withstand lower pressure than that in LV = only needs to pump blood a short distance = to lungs located close to the heart
what does coronary heart disease affect
→affects coronary arteries: lie on outside of heart and carry blood to muscles in the walls of heart
what does coronary heart disease cause (cause + effect on cells)
causes atherosclerosis: fats and cholesterol deposits on inner wall of arteries harden to form a plaque = narrows lumen of artery = affected artery develops rough inner surface = increases the risk of a blood clot being trapped in artery = cuts off supply of blood and oxygen to the heart muscles
effect: cells/part of heart tissue within the affected part die/get damaged = heart cannot function anymore = heart attack
how can coronary heart disease be prevented (3)
- Stop smoking: reduces the intake on nicotine and carbon monoxide = decreases risk of deposition of fats on inner lining of arteries;
- Regular physical exercise: strengthens the heart and maintains elasticity of the arterial walls
- Substituting animal fats in diet with polyunsaturated plants fats: these fats do not stick to the inner surface of arteries
