Skip to content
Dabour HubLEARN · PRACTICE · EXPLORESign inStudent

1.2.2Unit 1: Lifestyle, Transport, Genes and Health

Blood Vessels: Structure and Function — IAL Edexcel Linear Revision Notes & Topical Questions

5 min read 4 parts Lesson 14 of 29 Unit quiz

📚 IAL Edexcel Linear Hub / Topical Revision
🩺
100% Curriculum Specification Match Lesson Doctor Verified
The only platform with 100% curriculum specification match and verified interactive question banks.
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
0%read

Part 1 of 4Arteries and Arterioles

Function
  • Function Arteries carry blood away from the heart under high pressure, and branch into smaller arterioles that deliver blood to capillary beds.
Thick wall
  • Thick wall The wall contains a thick layer of elastic fibres and smooth muscle that withstands high pressure without bursting.
Elastic recoil
  • Elastic recoil Elastic tissue stretches as the heart pumps and recoils afterwards, smoothing out surges so that blood flows more evenly.
Narrow lumen
  • Narrow lumen A narrow lumen helps to maintain high pressure, and arterioles can constrict or dilate to control how much blood reaches a tissue.

Part 2 of 4Veins and Venules

Veins and Venules
Function
  • Function Veins carry blood back to the heart at low pressure, and are fed by venules that collect blood from the capillaries.
Thin wall
  • Thin wall There is little elastic tissue or muscle, since the pressure is low and there is no need for the wall to stretch and recoil.
Wide lumen
  • Wide lumen A wide lumen offers little resistance to flow, helping blood to return to the heart.
Valves
  • Valves Pocket valves prevent backflow, and the squeezing action of skeletal muscles pushes blood towards the heart.

Part 3 of 4Capillaries

1
Capillaries form dense networks, called capillary beds, that run very close to almost every cell in the body.
2
Their walls consist of a single layer of flattened endothelial cells, which provides an extremely short diffusion distance.
3
The lumen is so narrow that red blood cells pass through in single file, which slows blood flow and gives more time for exchange.
4
Gaps between the endothelial cells allow fluid to leave the blood, forming tissue fluid that bathes the cells.
5
Oxygen, glucose and other substances diffuse from the blood to cells, while carbon dioxide and wastes diffuse in the opposite direction.
VesselWallLumenValves
ArteryThick, elastic and muscularNarrowNo
VeinThinWideYes
CapillaryOne cell thickVery narrowNo

Part 4 of 4Exam Checklist & Tips

1.2.2 – Key Points for the Exam

  • Artery A vessel carrying blood away from the heart at high pressure.
  • Vein A vessel returning blood to the heart at low pressure.
  • Capillary A very thin, narrow vessel where exchange between blood and tissues takes place.
  • Lumen The central space of a blood vessel through which the blood flows.
  • Tissue fluid Fluid that leaks from capillaries and bathes cells.

Common Mistakes

  • Writing that arteries always carry oxygenated blood, ignoring the pulmonary artery.
  • Saying that veins have thicker walls than arteries; their walls are thinner.
  • Stating that capillaries have valves, when it is veins that contain valves.
  • Explaining pulse as blood flowing faster, instead of the elastic wall stretching and recoiling with each beat.

Last updated:

\n