Physiology Chapter: Nerves and Muscles

GALALA UNIVERSITY

• GALALA UNIVERSITY is a university.
• The university has a Faculty of Nursing.
• The university offers Physiology courses.
• A Physiology Course is offered by the Faculty of Medicine.

Physiology of Nerves and Muscles

• The course covers the functions of nerves and muscles.
• The slides include diagrams of nerve cells and muscles.
• The content describes the process of excitation-contraction coupling.

Learning Outcomes

• By the end of this lecture, students will be able to:
  • Identify excitable tissues.
  • Explain factors that cause resting membrane potential.
  • Identify the stages and propagation of the action potential.
  • Identify the structure of the neuromuscular junction.
  • Explain the link between excitation and contraction in skeletal muscles.

Excitable Tissues

• Excitable tissues are tissues capable of responding to stimuli.
• They have the ability to generate and propagate electrical or chemical or mechanical signals.
• These activities make excitable tissues important.

Resting Membrane Potential

• During rest, the outside of the cell membrane is positively charged and inside is negatively charged.
• The resting membrane potential (RMP) usually ranges from -60 to -90 mV.
• RMP is caused by selective permeability of the membrane, and activity of the sodium-potassium pumps.

Action Potential

• An action potential is a change in membrane potential in response to a stimulus.
• Stages include depolarization, repolarization, hyperpolarization.

Action Potential Propagation

• Action potentials can be propagated by two types:
  • Saltatory conduction: It occurs along myelinated axons. It is faster. It jumps between the nodes of Ranvier.
  • Continuous conduction: It occurs along unmyelinated axons. It is slower and involves each part of the membrane.

Neuromuscular Junction

• Neuromuscular junction is where a nerve meets a muscle.
• The neurotransmitter, acetylcholine (ACh), is involved in the process of excitation-contraction coupling.

Excitation-Contraction Coupling

• The process of excitation-contraction coupling links neural signal to muscle contraction.
• Calcium is a key ion in muscle contraction.
• The release of acetylcholine (ACh) leads to muscle contraction.
• The movement of Ca²⁺ triggers the sliding filament mechanism.

Sliding Filament Mechanism

• Myosin filament slides over the actin filament.
• ATP is required for this movement.
• The process continues until the nerve impulse stops.

The Sarcomere

• The sarcomere is a functional unit of a muscle.
• It includes actin and myosin filaments.
• Myosin filaments slide over actin filaments during muscle contraction.

This quiz covers the key concepts related to the physiology of nerves and muscles as part of the Physiology course offered by the Faculty of Medicine at Galala University. Students will explore various topics including excitable tissues, resting membrane potential, action potentials, and the neuromuscular junction. Test your understanding of how muscles contract and how nerves function.