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B2.3.9 (HL)—Cardiac and striated muscle

Cardiac and striated muscle cells are specialized with sarcomeres, mitochondria, branching, multinucleation, and intercalated discs for coordinated contraction and force.

Syllabus
First assessment 2025
Objective
B2.3.9
Level
HL

Exam analysis

Chance of appearing7%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper3
Typical marks1–3

Common command terms

  • Label
  • Describe
  • Identify
  • Outline
  • Explain

Scoring notes

Common mistake
Calling myogenic a structure when the row asks for structural features.

Recent exam appearances

May 2025Paper1A ["HL"] · TZ315[ 1 ]B2.3.9 (HL)—Cardiac and striated muscle
May 2023Paper1 ["HL"] · TZ138[ 1 ]B2.3.9 (HL)—Cardiac and striated muscle
May 2021Paper1 ["HL"] · TZ22[ 1 ]B2.3.9 (HL)—Cardiac and striated muscle
November 2019Paper2 ["HL"] · TZ05(a)(iii)[ 1 ]B2.3.9 (HL)—Cardiac and striated muscle
November 2019Paper2 ["HL"] · TZ05(a)(ii)[ 1 ]B2.3.9 (HL)—Cardiac and striated muscle
Practice this objective

Coverage 2017–2025 · Updated 15 Jul 2026

Concept essentials

  • Cardiac muscle cells are branched and connected by intercalated discs.
  • Gap junctions in intercalated discs support rapid impulse spread and coordinated contraction.
  • Skeletal muscle fibres are long, striated, and multinucleate.
  • Sarcomeres, myosin filaments, and mitochondria support muscle contraction.
ConceptIB Biology HL