1Describe how the structures of capillaries are adapted to capillary function. Include lumen diameter, branching, wall thickness, and fenestrations.
Lumen diameter: Narrow, allowing close proximity of red blood cells to the walls for efficient diffusion.
Branching: Extensive network increases surface area for exchange.
Wall thickness: One cell thick to minimize diffusion distance.
Fenestrations: Small pores in the wall allow exchange of molecules like oxygen and nutrients.
2Compare the diameter, relative wall thickness, lumen size, number of wall layers, abundance of muscle and elastic fibers and presence of valves in arteries and veins.
Arteries:
- Thick walls with three layers (tunica intima, media, adventitia).
- Narrow lumen to maintain high pressure.
- Abundant elastic fibers and smooth muscle.No valves.
Veins:
- Thinner walls, wider lumen for low-pressure flow.
- Fewer elastic fibers and smooth muscle.
- Valves prevent backflow.
3Given a micrograph, identify a blood vessel as an artery or vein.
Arteries: Thick wall, narrow lumen, no valves.
Veins: Thin wall, wide lumen, visible valves.
4State the function of arteries.
Transport blood away from the heart under high pressure to tissues.
5Describe the structures and functions of the three layers of the artery wall.
Tunica intima: Smooth endothelium reduces friction.
Tunica media: Elastic fibers allow stretching, and smooth muscle regulates diameter.
Tunica adventitia: Tough outer layer provides structural support.
6Discuss how the wall thickness, lumen size, and muscle and elastic allow arteries to withstand and maintain high blood pressures.
thick walls prevent rupture.
Narrow lumen maintains high pressure.
Elastic fibers stretch and recoil to absorb pressure fluctuations.
7State the unit of measurement of the pulse rate
Beats per minute (bpm).
8Outline two methods for determining heart rate.
Counting beats manually on the wrist or neck over a set time.
Using a heart rate monitor or pulse oximeter.
9State the function of veins.
Transport blood back to the heart at low pressure.
10Discuss how pocket valves, thin walls and skeletal muscles maintain the flow of blood through a vein.
Pocket valves: Prevent backflow.
Thin walls: Allow compression by surrounding muscles.
Skeletal muscles: Contract to push blood forward.
11State the function of the coronary arteries.
Supply oxygenated blood to the heart muscle.
12Outline the cause and consequence of a coronary occlusion.
Cause: Build-up of fatty deposits (atherosclerosis) in coronary arteries.
Consequence: Reduced oxygen to heart tissue, potentially leading to a heart attack.
13Evaluate correlations between diet and lifestyle variables and risk of coronary heart disease.
Diet: High intake of saturated fats, trans fats, and cholesterol increases LDL cholesterol levels, contributing to atherosclerosis and CHD risk. Diets rich in fruits, vegetables, and unsaturated fats are protective.
Lifestyle Variables: Sedentary lifestyle, smoking, and excessive alcohol consumption are strongly linked to higher CHD risk. Regular exercise, avoiding smoking, and moderate alcohol intake reduce risk.
Evaluation: While correlations exist, individual risk is multifactorial, influenced by genetics, preexisting conditions, and environmental factors. Lifestyle modifications are highly effective in reducing overall risk.
14List factors that are correlated with an increased risk of coronary occlusion and heart attack.
- High cholesterol,
- smoking,
- obesity,
- lack of exercise,
- high blood pressure,
- stress,
- genetic predisposition.
15State that xylem tissue is used to transport water from roots to leaves in plants.
Xylem
16Outline the role of cellulose in the transport of water via capillary action.
Cellulose in xylem walls attracts water, aiding upward movement through capillary action.
17Describe the cause and consequence of transpiration pull.
Cause: Transpiration pull is caused by the evaporation of water from stomata in leaves, creating a negative pressure in the xylem.
Consequence: This negative pressure draws water upward from the roots through the xylem in a continuous column, enabling the transport of nutrients and maintaining plant hydration.
18State why transport of water relies on cohesion between water molecules.
Cohesion between water molecules allows them to stick together, forming a continuous column in the xylem, which facilitates the upward movement of water during transpiration pull.
19State that transpiration is a passive process.
passive (relies on evaporation and cohesion, no energy input)
20Describe how the structure of xylem vessels are adapted for the transport of water under low pressure.
Hollow tubes with no end walls.
Thick lignified walls provide structural support.
Narrow diameter facilitates capillary action.
21Outline how xylem is able to maintain rigidity even under low pressure or mechanical disturbance.
Thickened cell walls: Xylem walls are reinforced with lignin, providing structural support.
Continuous tubes: Form a rigid, continuous column of cells for efficient water transport.
Dead cells: The hollow, non-living structure ensures that the xylem is mechanically strong
.
Lignification patterns: Spiral or ring-like lignin patterns add flexibility and durability under stress.
22Draw a plan diagram to show the distribution of tissues in a stem, including vascular bundles, xylem, phloem, cambium, cortex, pith and epidermis.
see slide 14
23Outline the function of tissues in a stem, including vascular bundles, xylem, phloem, cambium, cortex, pith and epidermis.
Xylem: Transports water.
Phloem: Transports sugars.
Cambium: Produces new xylem and phloem.
Cortex and pith: Support and storage.
Epidermis: Protects stem.
24state two ways xylem and phloem can be differentiated in cross sections of stem.
Xylem: Located closer to the center of the vascular bundle, towards the inside of the stem.
Phloem: Positioned on the outer side of the vascular bundle, closer to the epidermis.
25Draw a plan diagram to show the distribution of tissues in a root, including vascular bundles, xylem, phloem, cortex and epidermis.
Slide 15
26Outline the function of tissues in a root, including vascular bundles, xylem, phloem, cortex and epidermis.
Xylem: Transports water and minerals.
Phloem: Transports sugars.
Cortex: Storage and transport.
Epidermis: Absorbs water and nutrients.
27State two ways xylem and phloem can be differentiated in cross sections of root.
Xylem: Located in the center, typically star-shaped or arranged in a cross pattern.
Phloem: Found between the arms of the xylem, forming small clusters or rings around it.