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Nervous pathway to the Neuromuscular (NMJ)

By: HWC, Views: 8292

• A nervous impulse, also called an action potential, starts from the brain or spinal cord to signal skeletal muscle cell contraction. Action potentials continue along a motor neuron to the muscle cell. • The signal to contract must cross a synapse - the neuromuscular junction (NMJ) - betwe...

Muscle Fatigue and Recovery

By: HWC, Views: 7522

• After prolonged activity, muscle contraction weakens, and the muscle enters a state of fatigue. • Fatigue results from in muscle cells, such as: • Inadequate release of calcium ions • Depletion of energy sources • Lack of oxygen • Build up of lactic acid other metabolic w...

Depolarization of the SA node, Action potentials of the myocardium & ANS effects

By: HWC, Views: 7638

• A typical contractile cell in the myocardium has a resting membrane potential. • The resting membrane potential of cells in the SA node is not fixed, and is known as the pacemaker potential. • The action potential of a healthy SA nodal cell has three parts: • Pacemaker potential: ...

Structures that affect circulation - kidneys, blood volume and venous tone

By: HWC, Views: 7707

• Kidneys regulate blood volume and blood osmolarity via salt and water reabsorption. • Increased reabsorption increases blood volume and venous return (and CO). • Decreased reabsorption increases urine production, which decreases blood volume and venous return (and CO). • Systemi...

Blood Flow through the Human Heart

By: HWC, Views: 7512

The heart is the pump of the human circulatory system. The left side of the heart has two connected chambers, the left atrium and the left ventricle. The right side of the heart also has two connected chambers, the right atrium and the right ventricle. These two sides, or pumps, of the heart are ...

ATPase function - membrane transport, contractile proteins and synthesis

By: HWC, Views: 8111

• Energy from ATP is used to move ions across the cell membrane during active transport. • This membrane protein transports sodium out of the cell and potassium into the cell. As such, it is called a sodium-potassium pump. • Because this pump also acts as an enzyme to hydrolyze ATP it i...

Status Epilepticus

By: Administrator, Views: 10729

Status epilepticus (SE) is a single epileptic seizure lasting more than five minutes or two or more seizures within a five-minute period without the person returning to normal between them. Previous definitions used a 30-minute time limit. The seizures can be of the tonic–clonic type, with a re...

Mechanisms for chromosome movement Animation

By: HWC, Views: 4743

At mitotic metaphase, the fully-formed spindle is composed of many microtubules that extend from the poles. Some of these, the kinetochore microtubules, are attached to the kinetochores of each chromosome. Kinetochores are located at the centromeres. At anaphase, sister chromatids separate and...

Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 7897

Once the muscle cell has been excited it will contract. • A muscle action potential will trigger the release Of Ca2+ ions into the sarcoplasm. • The Ca2+ ions bind to the regulatory proteins and trigger contraction. • Within skeletal muscle cells are structures that provide the ability...