Nervous System...Responses to Exercise - Part 2

The differences between Afferent and Efferent neurons

Definition

Afferent: Afferent neurons are the neurons that carry sensory impulses towards the CNS.

Efferent: Efferent neurons are the neurons that carry motor impulses away from the CNS.

Known as

Afferent: Afferent neurons are also known as sensory neurons.

Efferent: Efferent neurons are also known as motor neurons.

Function

Afferent: Afferent neurons carry signals from sensory organs to the CNS.

Efferent: Efferent neurons carry signals from the CNS to effector organs and tissues.

Axon

Afferent: Afferent neurons consist of a short axon.

Efferent: Efferent neurons consist of a long axon.

Receptor

Afferent: Afferent neurons consist of a receptor.

Efferent: Efferent neurons lack a receptor.

Cell Body

Afferent: The cell body of the afferent neuron is situated in the dorsal root ganglion of the spinal cord, and no dendrites are found in it.

Efferent: The cell body of the efferent neuron is situated in the ventral root ganglion of the spinal cord and consists of dendrites.

Dendrons

Afferent: Afferent neuron consists of one long dendron.

Efferent: Efferent neuron consists of many short dendrons.

Function

Afferent: Afferent neurons carry signals from the outer part of the body into the central nervous system.

Efferent: Efferent neurons carry signals from the central nervous system to the outer parts of the body.

Multipolar / Unipolar

Afferent: Afferent neurons are unipolar.

Efferent: Efferent neurons are multipolar.

Found in

Afferent: Afferent neurons are found in skin, eyes, ears, tongue and nose.

Efferent: Efferent neurons are mainly found in muscles and glands.

Motor Units

Muscles are made up of bundles of muscle fibres, which are arranged in groups called motor units. A motor unit comprises 10 to 1000 muscle fibres and the motor neuron that innervates or supplies it. The number of fibres present in a motor unit depends on its location and function. Still, regardless of where it is located, all muscle fibres within the motor unit are activated by the same single motor neuron.

All muscle fibres innervated by the motor neuron will either work together simultaneously or not at all. This is commonly referred to as the all-or-nothing law.

Once the sufficient stimulus is received from the motor neuron, all muscle fibres within the motor unit will contract at 100% of their contractile capacity or not at all.

Muscles contain many motor units. The larger the muscle, the more motor units are likely to be present. The more motor units are innervated at once, the more force will be produced.

If a lot of force is required, i.e. lifting a large weight, a large number of motor units will work together. If a smaller amount of force is required, fewer motor units will be fired. Under no circumstances are the mechanical units operated at anything less than 100% of their contractile capacity. Force variation results from the recruitment of more or fewer motor units.

If a muscle task takes a long time, the motor units are recruited sequentially, in other words, one after the other. That way, as one motor unit tires, another will take over.

In examples of very low-intensity activity, e.g. walking, this sequential recruitment can be almost endless. Still, in more intense workouts, e.g. a set of presses, the job ends when all motor units are exhausted.

The number of motor units that can be innervated or activated simultaneously varies from person to person and is a trainable characteristic. A beginner may only be able to innervate 50% of their total motor units, while a more advanced practitioner may be able to innervate 70% or more. This helps explain why two people with the same amount of muscle can have such different levels of strength.

Beginner exercisers often experience rapid increases in strength not because their muscles grow but simply because their nervous system becomes more adept at innervating a more significant number of motor units at once.

While exercise “teaches” the nervous system to work more efficiently so that more motor units can be innervated to protect bones, muscles and connective tissue from injury, it is impossible to recruit all motor units simultaneously. The Golgi tendon organ controls this restriction.

Responses Of The Neuromuscular System To Exercise

Responses of the neuromuscular system to exercise!

Exercise profoundly affects all body systems, especially the neuromuscular system. Changes can be acute or short-term (i.e. during training) or chronic or long-term (i.e. as a result of several weeks or months of training).

Immediate Changes

During a workout, the following can happen:

• Vasodilation of blood vessels and capillaries to facilitate increased blood flow

• Blood was diverted from non-essential organs to working muscles

• Increased temperature

• Reduced neural inhibition

Annual Changes

The changes experienced by the neuromuscular system depend on several factors such as:

• Frequency of exercise

• Duration of exercise

• Exercise volume

• Exercise intensity

• Method of exercise

Finally

The organism perceives and reacts accordingly to changes in the environment. The information about these changes is collected by the receptors and transmitted to the central nervous system.

After processing the information, the central nervous system gives the appropriate commands to the muscles and glands. In this way, the organism can adapt its functions according to the changes in the environment, a necessary condition for its survival.

The organs of the nervous system are the brain and spinal cord, which make up the Central Nervous System, and the nerves, which make up the Peripheral Nervous System.

Resistance training can directly affect the functioning of our nervous system with the corresponding choice of load, and it can play a decisive role in neuromuscular adaptations.

Studies have shown that training with high loads affects and affects the nervous system. It has been shown that strength development through resistance training is always accompanied by neural adaptations, whether or not hypertrophy is present.

On the other hand, a higher rep program with lower loads may also promote muscle growth differently. The result has to do with the contribution of neural adaptations.

In short, strength needs high loads, muscular endurance, and lower loads explosiveness. This is generally because combinations also work depending on the design, muscle body type, muscle recovery and, above all, the corresponding diet.