Types of Muscle

• What is the composition of smooth muscle fibers?

  Small bundles of actin and myosin
• How does smooth muscle contract compared to other muscle types?

  Smooth muscle has slow contraction but tires slowly
• How many nuclei do smooth muscle cells have?

  Single nucleus
• What is the shape of smooth muscle cells?

  Spindle shaped
• Where is smooth muscle found in the body?

  Walls of the intestine, iris of the eye, wall of arteries and arterioles, cervix of uterus
• What type of muscle is cardiac muscle?

  Cardiac (myogenic)
• What are myofibrils made of in skeletal muscle?

  Myofibrils are made of actin and myosin
• What neurotransmitter is involved in neuromuscular transmission?

  Acetylcholine
• What is the structure of cardiac muscle cells?

  Branched with intercalated discs
• What is the number of mitochondria in skeletal muscle?

  Many mitochondria
• What are the components of skeletal muscle cells?

  Sarcolemma, sarcoplasm, sarcoplasmic reticulum
• What happens at the presynaptic membrane during neuromuscular transmission?

  Acetylcholine is released
• What is the role of the synaptic cleft in neuromuscular transmission?

  It allows diffusion of acetylcholine
• How many nuclei do smooth muscle cells have?

  Single nucleus
• How does skeletal muscle contract compared to other muscle types?

  Skeletal muscle contracts quickly and powerfully but tires quickly
• What are the structural components of smooth muscle?

  Small bundles of actin and myosin
• What is the process of neuromuscular transmission?

  1. Action potential travels down the axon
  2. Acetylcholine is released at the presynaptic membrane
  3. Acetylcholine diffuses across the synaptic cleft
  4. Binds to receptors on the sarcolemma (postsynaptic membrane)
  5. Depolarization occurs
  6. T-tubules transmit the signal
  7. Sarcoplasmic reticulum releases Ca⁺⁺
• What happens during depolarization in muscle cells?

  It leads to the release of Ca⁺⁺ from the sarcoplasmic reticulum
• What is the structure of cardiac muscle cells?

  Branched
• How does calcium ion diffusion affect muscle contraction?

  It triggers the contraction of muscle fibers
• What type of muscle is smooth muscle?

  Smooth/involuntary (neurogenic)
• How does smooth muscle contract compared to skeletal muscle?

  Smooth muscle contracts slowly but tires slowly
• Where is smooth muscle found in the body?

  Walls of the intestine, iris of the eye, wall of arteries and arterioles, cervix of uterus
• What are intercalated discs in cardiac muscle?

  Cell membranes fused so gap junctions allow free diffusion of ions and conduction of action potentials
• How do voluntary muscles contract compared to smooth muscles?

  Voluntary muscles contract quickly and powerfully but tire quickly
• What type of muscle is cardiac muscle?

  Cardiac (myogenic)
• How do cardiac muscle contractions compare to skeletal muscle contractions?

  Cardiac muscle contracts similarly to skeletal muscle but lasts longer and does not fatigue
• What are the main components of skeletal muscle cells?

  Sarcolemma, sarcoplasm, sarcoplasmic reticulum, myofibrils made of actin and myosin
• What is the function of T-tubules in muscle cells?

  They transmit the action potential into the muscle cell
• What is the shape of smooth muscle cells?

  Spindle shaped
• What type of muscle is voluntary muscle?

  Voluntary/striated/skeletal
• How many nuclei do skeletal muscle cells have?

  Multiple nuclei (multinucleate)
• What does the sarcoplasmic reticulum do in muscle cells?

  It releases Ca⁺⁺ during muscle contraction