B3.2 Transport SL Flashcards
Arteries
Transport blood away from the heart under high pressure. Their walls are thick and elastic to accommodate and regulate blood pressure.
Capillaries
Small, thin-walled blood vessels for substance exchange between blood and tissues. Their walls are one cell thick for efficient diffusion.
Veins
Return blood to the heart. Have thinner walls and larger lumens than arteries, with valves to prevent backflow of blood.
Measuring Pulse Rate - Manual Method
Feel the radial or carotid artery, count pulses for 15 seconds, and multiply by four for beats per minute.
Measuring Pulse Rate - Digital Method
Use devices like heart rate monitors or smartphone apps for more accurate and reliable readings.
Occlusion of Coronary Arteries
Blockage leading to coronary heart disease, caused by plaque buildup, narrowing arteries, and reducing blood flow to the heart.
Consequences of Artery Occlusion
Can cause myocardial infarction (heart attack), tissue damage, or death due to restricted blood flow and oxygen supply to heart muscles.
Adaptation of Blood Vessels
Arteries, veins, and capillaries are uniquely structured for their specific roles in blood transport, exchange, and return.
What is the primary role of xylem in plants?
The xylem’s primary role is to transport water and dissolved minerals from the roots to all other parts of the plant
How does transpiration drive water transport in plants?
Transpiration creates a negative pressure potential in leaves, pulling water up from the roots through the xylem.
What are the adaptations of xylem vessels for efficient water transport?
Xylem vessels are strengthened with lignin for rigidity and waterproofing, and contain pits for lateral water movement.
What is capillary action in the context of xylem?
Capillary action in xylem is the movement of water against gravity, facilitated by cohesive and adhesive forces in water molecules.
How do root hairs aid in water absorption?
Root hairs increase the surface area of roots, enhancing their ability to absorb water and minerals.
Describe the distribution of xylem in the stem of dicotyledonous plants.
In dicotyledonous plant stems, xylem is located closer to the inside of the stem, forming part of the vascular bundles.
What is the significance of lignin in xylem vessels?
Lignin provides strength and rigidity to xylem vessels, allowing plants to withstand mechanical stress and maintain water impermeability.
