Pathophysiology of Anosmia: Anosmia is the complete loss of the sense of smell. It may be temporary or permanent and can occur because of obstruction of the nasal passages, damage to the olfactory receptors, injury to the olfactory nerve, or disorders affecting the brain’s olfactory pathways. The sense of smell is important not only for…
Pathophysiology of Vertigo: Vertigo is a false sensation of movement, usually described as spinning, turning, tilting, or the surroundings moving when they are actually stationary. It is not a disease itself but a symptom caused by dysfunction of the vestibular system or its connections with the brain. The vestibular system helps the body maintain balance,…
Pathophysiology of Otitis Media: Otitis media (OM) is an inflammatory disorder of the middle ear cavity that commonly develops following Eustachian tube dysfunction, often in association with an upper respiratory tract infection. It may involve accumulation of fluid, inflammation, and infection within the middle ear. The condition is particularly common in children because their Eustachian…
Pathophysiology of Otitis Externa: Otitis externa is an inflammatory or infectious condition of the external auditory canal, commonly known as “swimmer’s ear.” It occurs when the protective mechanisms of the ear canal are disrupted, allowing microorganisms to multiply and cause inflammation. The most common bacterial cause is Pseudomonas aeruginosa, although other bacteria and fungi may…
Pathophysiology of Myopia: Myopia (short-sightedness) is a refractive error in which a person can see nearby objects clearly, but distant objects appear blurred. In myopia, light rays from a distant object are focused in front of the retina rather than directly on the retina. Step 1: Normal Refraction of Light Normally, light entering the eye…
Pathophysiology of Cataract: Cataract is a condition in which the normally transparent crystalline lens of the eye becomes progressively opaque, resulting in reduced transmission of light to the retina and causing blurred or decreased vision. Cataract develops because of structural and biochemical changes in lens proteins, particularly crystallins, along with oxidative stress, disruption of lens…
Pathophysiology of Glaucoma: Glaucoma is a group of progressive eye disorders characterized by damage to the optic nerve, particularly the retinal ganglion cell axons, leading to characteristic visual field loss. The major risk factor is often increased intraocular pressure (IOP), although glaucoma can also develop with IOP within the statistically normal range. The disease is…
The Peripheral Nervous System (PNS) is the part of the nervous system that lies outside the brain and spinal cord. It forms an important communication network between the central nervous system (CNS) and the rest of the body. The PNS carries sensory information from receptors in the body to the CNS and transmits motor commands…
Pathophysiology of Iron Deficiency Anemia: Iron deficiency anemia (IDA) is the most common nutritional deficiency disorder and one of the most common causes of anemia worldwide. It develops when the body’s iron requirement exceeds iron availability for a prolonged period, resulting in depletion of iron stores, impaired hemoglobin synthesis, reduced red blood cell production, and…
Diseases of Bones and Joints: Bones and joints are essential components of the musculoskeletal system that provide support, protection, movement, and stability to the human body. Healthy bones maintain body structure, while joints allow smooth and coordinated movement. Various diseases can affect bones and joints due to aging, infections, nutritional deficiencies, autoimmune disorders, metabolic abnormalities,…