Histology Quiz: Tissue Types and Action Potential

Histology

Tissue Types

• Epithelial tissue: forms the lining of organs, glands, and body surfaces; functions in absorption, secretion, and protection
• Connective tissue: provides support, structure, and connectivity to the body; includes bone, cartilage, fat, and blood
• Muscle tissue: responsible for movement, contraction, and relaxation
• Nervous tissue: specialized for transmitting and processing information

Action Potential

Definition

• A rapid, temporary change in the electrical potential of a neuron or muscle cell
• Generated by a rapid influx of sodium ions and a rapid efflux of potassium ions

Phases

1. Resting phase: the neuron is at rest, with a negative resting potential (approximately -70mV)
2. Depolarization: the membrane potential becomes less negative, reaching a threshold (approximately -55mV)
3. Action potential: the membrane potential rapidly becomes positive (approximately +30mV)
4. Repolarization: the membrane potential returns to its resting state
5. Refractory period: the neuron is unable to generate another action potential

Ion Channels

• Sodium channels: responsible for rapid depolarization
• Potassium channels: responsible for rapid repolarization
• Calcium channels: involved in neurotransmitter release

Types of Action Potentials

• Somatic action potentials: occur in skeletal muscle cells
• Autonomic action potentials: occur in smooth muscle cells and autonomic neurons
• Cerebellar action potentials: occur in cerebellar Purkinje cells

Histology

Tissue Types

• Epithelial tissue forms the lining of organs, glands, and body surfaces, functioning in absorption, secretion, and protection.
• Connective tissue provides support, structure, and connectivity to the body, including bone, cartilage, fat, and blood.
• Muscle tissue is responsible for movement, contraction, and relaxation.
• Nervous tissue is specialized for transmitting and processing information.

Action Potential

Definition

• A rapid, temporary change in the electrical potential of a neuron or muscle cell occurs due to rapid influx of sodium ions and rapid efflux of potassium ions.

Phases

• Resting phase: neuron at rest with negative resting potential (approx. -70mV).
• Depolarization: membrane potential becomes less negative, reaching a threshold (approx. -55mV).
• Action potential: membrane potential rapidly becomes positive (approx. +30mV).
• Repolarization: membrane potential returns to resting state.
• Refractory period: neuron unable to generate another action potential.

Ion Channels

• Sodium channels are responsible for rapid depolarization.
• Potassium channels are responsible for rapid repolarization.
• Calcium channels are involved in neurotransmitter release.

Types of Action Potentials

• Somatic action potentials occur in skeletal muscle cells.
• Autonomic action potentials occur in smooth muscle cells and autonomic neurons.
• Cerebellar action potentials occur in cerebellar Purkinje cells.

Test your knowledge of epithelial, connective, muscle, and nervous tissues, as well as the definition and process of action potential in the human body.