Physiology module 2 Sync session B

These flashcards cover key concepts from the physiology lecture on muscle contraction, action potentials, and cellular transport mechanisms.

What is the primary requirement for a pump in cellular transport?

A pump requires ATP and works against a concentration gradient, indicating active transport.

Define passive transport in the context of cellular activity.

Passive transport is the movement of substances across cell membranes without the need for energy input, typically along a concentration gradient.

What happens to a cell placed in a solution with lower osmolarity than its internal environment?

The cell will increase in volume as water enters due to osmosis.

During an action potential, what is the role of sodium ions?

Sodium ions rush into the cell, causing depolarization when the membrane reaches a threshold.

Why is the sodium-potassium pump important for cellular function?

It maintains the concentration gradient of sodium and potassium across the cell membrane, which is necessary for action potentials.

What neurotransmitter is released at the neuromuscular junction to trigger muscle contraction?

Acetylcholine is released, which binds to receptors on the muscle cell to initiate contraction.

Describe the significance of calcium ions in muscle contraction.

Calcium ions facilitate the contraction process by binding to troponin, which then causes tropomyosin to expose binding sites for myosin on actin filaments.

What is rigor mortis and how is it related to ATP?

Rigor mortis is the stiffness of muscles after death due to a lack of ATP, preventing myosin heads from releasing actin.

Explain the term 'refractory period' in relation to action potentials.

The refractory period is the time during which a new action potential cannot be initiated because the membrane is either depolarized or briefly hyperpolarized.

How do nerve impulses trigger muscle contractions?

Nerve impulses reach the neuromuscular junction, leading to the release of neurotransmitters, which bind to receptors on muscle cells and initiate an action potential that results in contraction.