Nerve Plexuses In the context of Nerve Plexuses & Reflex Actions, a nerve plexus is a complex network of intersecting nerves that redistributes fibers from multiple spinal nerves, enabling shared sensory and motor functions. The four major nerve plexuses are: 1.Cervical Plexus (C1-C4): Located in the neck, supplies muscles and skin of the neck and … Read more
Origin of the Cranial Nerves Cranial nerves emerge directly from the brain or brainstem. There are 12 pairs of cranial nerves, each with a specific number and name based on its function and location. The numbering of cranial nerves is based on their position from anterior (front) to posterior (back): Cranial Nerves I and II: … Read more
Origin of the Spinal Nerves Spinal nerves originate from the spinal cord, specifically from the spinal segments. There are 31 pairs of spinal nerves, categorized based on the regions of the spine: 8 cervical nerves (C1-C8) 12 thoracic nerves (T1-T12) 5 lumbar nerves (L1-L5) 5 sacral nerves (S1-S5) 1 coccygeal nerve (Co1) Each spinal nerve … Read more
Structure of the Parasympathetic Nervous System (PNS) The parasympathetic nervous system (PNS) originates from the craniosacral region: it arises from the brainstem (cranial nerves) and sacral spinal cord (S2-S4). Cranial nerves involved include the vagus nerve (cranial nerve X), which innervates most thoracic and abdominal organs. Sacral nerves primarily innervate the pelvic organs. Preganglionic neurons: … Read more
Structure of the Sympathetic Nervous System (SNS) The sympathetic nervous system (SNS) originates from the thoracolumbar region of the spinal cord (T1-L2). Its nerve fibers arise from neurons in the lateral horn of the spinal cord. Preganglionic neurons: These are shorter neurons that exit the spinal cord and travel to a sympathetic ganglion (a cluster … Read more
Classification of the Peripheral Nervous System includes the somatic and autonomic systems, controlling voluntary and involuntary body functions. The Peripheral Nervous System (PNS) is one of the two major components of the nervous system, the other being the Central Nervous System (CNS). The PNS consists of all the nerves that lie outside the brain and … Read more
Nerve fibers are long extensions of neurons that transmit electrical signals throughout the nervous system. They consist of axons covered by a myelin sheath and are classified into three main types based on diameter, myelination, and conduction velocity: A, B, and C fibers. Types of Nerve Fibers: A Fibers: Myelinated with a large diameter (1-22 … Read more
Flow of fluids is the movement of a fluid (liquid or gas) from one location to another. It can be characterized based on various parameters such as velocity, pressure, and the type of fluid. Understanding fluid flow is essential in numerous engineering applications, including hydraulics, aerodynamics, and process engineering. Flow of fluids refers to the movement … Read more
A nerve impulse, also known as an action potential, is an electrical signal that travels along the nerve cells or neurons in the nervous system. It is the fundamental mechanism through which neurons communicate with each other and transmit information. Nerve impulses are crucial for processing sensory input, generating motor output, and enabling higher cognitive … Read more
The nervous system introduction is a complex network of nerves, neurons, and supporting cells that coordinate and transmit information throughout the body. It is responsible for sensing and responding to various internal and external stimuli, enabling organisms to interact with their environment and maintain homeostasis. The nervous system can be divided into two main parts: … Read more
