ISSA PT chapter 3

What are the 3 primary organ systems responsible for human movement?

• Nervous System (Command center / dictates movement)

• Muscular System (Generates force / creates movement)

• Skeletal System (Provides physical support and leverage)

What are the 3 main parts of a neuron and their functions?

• Cell Body (Soma): Core structure containing the nucleus; provides energy.

• Axon: Tail-like structure that conducts outgoing nerve impulses away from the cell body.

• Dendrites: Rootlike structures that receive incoming signals from other neurons.

What is the difference between Afferent and Efferent neurons?

• Afferent (Sensory) Neurons: Carry sensory signals Arriving at the Central Nervous System (CNS).

• Efferent (Motor) Neurons: Carry motor commands Exiting the CNS toward muscles and glands.

What is Decussation, and where does it occur?

• Decussation is the "crossover" of neural tracts where the left brain controls the right side of the body and vice versa.

• It occurs at the junction between the medulla oblongata and the spinal cord.

Match each brain lobe with its primary function: Frontal, Parietal, Temporal, Occipital.

• Frontal Lobe: Motor control, movement planning, emotion, language.

• Parietal Lobe: Sensory processing (touch, pain, temperature).

• Temporal Lobe: Hearing, memory, emotion.

• Occipital Lobe: Visual processing.

How many pairs of spinal nerves are in each section of the spine?

• Cervical: 8 pairs

• Thoracic: 12 pairs

• Lumbar: 5 pairs

• Sacral: 5 pairs

• Coccyx: 1 pair

What are the two divisions of the Autonomic Nervous System?

• Sympathetic Division: "Fight-or-Flight" (elevates heart rate and energy expenditure during stress/exercise).

• Parasympathetic Division: "Rest and Digest" (lowers heart rate and promotes digestion during rest).

What are the 3 types of Mechanoreceptors and what do they sense?

• Tactile Receptors: Sense of touch.

• Proprioceptors: Sense of body position and movement in space (Proprioception).

• Baroreceptors: Changes in blood pressure.

What is a Motor Unit and an Alpha Motor Neuron?

• Motor Unit: A single motor neuron and all the standard muscle fibers (extrafusal fibers) it innervates.

• Alpha Motor Neuron: The specific motor neuron originating in the spinal cord/brain stem that initiates muscle contraction.

What is the All-or-None Principle in nerve transmission?

• The strength of a nerve's action potential is independent of stimulus size—a nerve or motor unit either fires completely or not at all.

• To lift heavier loads, the body recruits more motor units rather than increasing the signal strength of individual neurons.