Related Concept Videos

The Thyroid Gland01:23

The Thyroid Gland

The thyroid gland is a small, butterfly-shaped gland located in the neck and covers the anterior surface of the trachea. The gland has two lateral lobes connected by a thin tissue mass called the isthmus. Internally, each lobe comprises many small spherical structures known as thyroid follicles, surrounded by a network of blood vessels.
The follicles have a central cavity lined by simple cuboidal to squamous epithelial cells called follicular cells. These cells produce the glycoprotein...
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Chronic Pancreatitis I: Introduction01:24

Chronic Pancreatitis I: Introduction

The pancreas, an elongated and flat gland situated behind the stomach, serves a vital function in digesting food and managing blood sugar levels.
Pancreatitis is the inflammation of the pancreas, which occurs when the immune system becomes active and causes swelling, pain, and disruptions in organ function. Pancreatitis can manifest as either an acute or chronic condition.
Acute pancreatitis arises suddenly and lasts for a brief duration, while chronic pancreatitis is a long-term affliction...
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Accessory Structures of the Skin: Nails01:05

Accessory Structures of the Skin: Nails

Nails are one of the important accessory structures of the skin. They are hard, protective structures that cover the dorsal surface of the distal phalanges of fingers and toes. Nails are composed of specialized keratinized cells and serve various functions, including protection, sensation, and manual dexterity.
The main components of a nail include the following.
Nail Plate: The nail plate is the visible portion of the nail that extends beyond the fingertips or toes. It is a hard, translucent...
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Peripheral Arterial Disease II: Clinical Manifestations and Diagnostic Evaluation01:21

Peripheral Arterial Disease II: Clinical Manifestations and Diagnostic Evaluation

Clinical manifestationsPeripheral Arterial Disease (PAD) manifests through a range of symptoms, from the characteristic intermittent claudication to atypical presentations and severe complications in advanced stages. Intermittent claudication, a hallmark symptom of PAD, presents as exercise-induced muscle pain that typically resolves within minutes of rest. This pain is reproducible and stems from inadequate blood flow, leading to the accumulation of lactic acid produced during anaerobic...
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Blood and Nerve Supply to the Bones01:29

Blood and Nerve Supply to the Bones

Bones are dynamic organs that require a rich supply of oxygen and nutrients. Around 5% to 10% of the cardiac output supplies blood to the bones. A typical long bone has three main sources: the nutrient artery, the metaphyseal and epiphyseal arteries, and the periosteal arteries.
Nutrient Artery
The nutrient artery is the main blood vessel that enters the diaphysis via the nutrient foramen. While most long bones have only one nutrient foramen, large bones, such as the femur, may have two. This...
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Synthesis and Regulation of Thyroid Hormones01:20

Synthesis and Regulation of Thyroid Hormones

Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the thyrotropin-releasing hormone (TRH). TRH then reaches the pituitary gland and stimulates the release of thyroid-stimulating hormone(TSH) into the bloodstream.
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The...
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