Transport in Humans Flashcards
Why do large animals need a transport system?
They have a small surface area to volume ratio and large distances between organs, making diffusion too slow for oxygen and glucose to reach all cells efficiently.
What are the three main types of blood vessels?
Arteries, veins, and capillaries.
What are the structural adaptations of arteries? (3 points)
- Thick walls to withstand high pressure.
- Elastic fibers to stretch and recoil.
- Narrow lumen to maintain high pressure.
What are the structural adaptations of veins?
- Thin walls to be squeezed by skeletal muscles.
- Wide lumen to decrease resistance.
- Valves to prevent backflow of blood.
What are the structural adaptations of capillaries?
- Thin walls for a short diffusion distance.
- Pores between cells for rapid gas exchange.
Describe the pathway of blood circulation in the body.
Vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs → Pulmonary vein (oxygenated blood) → Left atrium → Left ventricle → Aorta → Body organs → Veins (deoxygenated blood) → Vena cava.
What are the two types of heart valves and their locations?
Atrioventricular valves (in heart chambers):
* Tricuspid valve: Between the right atrium and ventricle.
* Bicuspid valve: Between the left atrium and ventricle.
Semi-lunar valves: At the start of arteries.
What is the function of the septum?
It prevents the mixing of oxygenated and deoxygenated blood.
What happens if there is a hole in the septum?
Oxygenated and deoxygenated blood mix, decreasing oxygen levels, leading to less aerobic respiration and less energy production.
Why does the left ventricle have thicker walls than the right ventricle?
- The left ventricle pumps blood at high pressure to the whole body
- The right ventricle pumps at lower pressure to the lungs to prevent damage.
How does exercise affect heart rate? (4 points)
- During exercise, heart rate increases to pump more blood to muscles
- This blood carries oxygen and glucose for increased aerobic respiration
- This provides more energy for muscle contraction.
- To remove excess CO2 in blood quicker
How do you measure heart rate?
Press your middle and index fingers on an artery (e.g., wrist or neck), count beats for one second, multiply by 2, and take an average of multiple readings.
What happens in coronary heart disease? (4 points)
- Cholesterol builds up in coronary artery walls, reducing elasticity
- This leads to less oxygen reaching the heart muscle
- This increases anaerobic respiration and lactic acid buildup
- Leading to weaker pumping and potential heart attack
What are the risk factors for CHD?
- Smoking
- Stress
- Obesity
- Lack of exercise
- High consumption of animal fats in diet
What does plasma transport?
- Nutrient molecules from intestines to body cells.
- Hormones from glands to target organs.
- CO₂ from cells to lungs.
- Waste (urea) from liver to kidney.
What is the function and adaptations of red blood cells? (2 points)
Function:
* Transport oxygen.
Adaptations:
* Biconcave shape for larger surface area and faster diffusion.
* No nucleus to maximize space for hemoglobin.
What are the two types of white blood cells and their functions?
Phagocytes:
* Engulf and digest pathogens using enzymes (phagocytosis) and absorb their products.
Lymphocytes:
* Produce antibodies that bind to specific antigens.
* Label pathogens for phagocytosis.
* Form memory cells that recognize pathogens upon re-exposure and produce antibodies faster (second immune response).
How does vaccination work? (4 points)
- Injecting dead or weakened pathogens.
- Lymphocytes identify the pathogen
- Lymphocytes produce antibodies
- Lymphocytes create memory cells for more rapid and concentrated release of antibodies for future responses
What are the advantages of blood clotting?
- Prevents excessive bleeding.
- Prevents entry of pathogens.
What is the mechanism of blood clotting? (3 points)
- Platelets stick to the edges of the cut blood vessel.
- Platelets release enzymes that convert soluble fibrinogen into insoluble fibrin
- Forming a mesh that traps blood cells.
