Congenital Langerhans-Cell Histiocytosis
A female infant delivered at term by cesarean section had a “blueberry muffin” rash at birth. On physical examination, multiple purple, papulonodular lesions measuring 5 to 10 mm in diameter were seen on her trunk, arms and legs, palms and soles, oral mucosa, and palpebral conjunctiva. There was no lymphadenopathy or hepatosplenomegaly, and the results of funduscopy were normal. The results of initial laboratory tests, including a complete blood count, a peripheral-blood smear, a reticulocyte count, a metabolic panel, and a coagulation test, were normal. A chest radiograph was normal, as were the results of ultrasonography of the head and abdomen. Neither rubella nor cytomegalovirus IgM or IgG was detected in the mother or the infant. A biopsy specimen of the skin obtained from the right thigh showed a dense infiltrate of histiocytes with grooved, kidney-shaped nuclei. Immunohistochemical staining of the specimen was positive for S100+ CD1a+ and negative for CD43 and myeloperoxidase, findings that confirmed a diagnosis of skin-limited congenital Langerhans-cell histiocytosis. Because of the lack of extracutaneous involvement, the lesions were expected to resolve without treatment. At follow-up 6 weeks after delivery, the skin lesions had resolved. The infant continues to be followed for signs of recurrence.
Stomach
Foot X-ray AnatomyAnatomy of liverAbdominal aortic aneurysmImage of trachea blocked by chewing gum### Anatomy of the Heart: Summary The heart is a muscular organ responsible for pumping blood throughout the body, supplying oxygen and nutrients while removing waste products. It is located in the thoracic cavity, between the lungs, and is roughly the size of a fist. #### 1. **Structure:** - **Chambers:** The heart has four chambers: - **Right Atrium:** Receives deoxygenated blood from the body via the superior and inferior vena cavae. - **Right Ventricle:** Pumps deoxygenated blood to the lungs through the pulmonary arteries. - **Left Atrium:** Receives oxygenated blood from the lungs via the pulmonary veins. - **Left Ventricle:** Pumps oxygenated blood to the rest of the body through the aorta. - **Valves:** The heart contains four main valves that ensure unidirectional blood flow: - **Tricuspid Valve:** Located between the right atrium and right ventricle. - **Pulmonary Valve:** Located between the right ventricle and pulmonary arteries. - **Mitral (Bicuspid) Valve:** Located between the left atrium and left ventricle. - **Aortic Valve:** Located between the left ventricle and the aorta. #### 2. **Wall Layers:** - **Epicardium:** The outer layer, also known as the visceral pericardium. - **Myocardium:** The thick, muscular middle layer responsible for contraction. - **Endocardium:** The inner layer that lines the chambers and valves. #### 3. **Blood Supply:** - The heart receives its blood supply from the coronary arteries, which branch off the aorta. The **right coronary artery** supplies the right side of the heart, while the **left coronary artery** branches into the left anterior descending and circumflex arteries, supplying the left side. #### 4. **Electrical System:** - The heart's rhythmic contractions are controlled by its electrical conduction system, which includes: - **Sinoatrial (SA) Node:** The natural pacemaker located in the right atrium. - **Atrioventricular (AV) Node:** Receives impulses from the SA node and transmits them to the ventricles. - **Bundle of His and Purkinje Fibers:** Distribute the electrical impulse throughout the ventricles, leading to contraction. #### 5. **Function:** - The heart functions in two primary circulatory loops: - **Pulmonary Circulation:** Moves deoxygenated blood from the right side of the heart to the lungs for oxygenation. - **Systemic Circulation:** Distributes oxygenated blood from the left side of the heart to the rest of the body. The anatomy of the heart is crucial for its role in maintaining effective circulation and overall cardiovascular health. Understanding its structure helps in diagnosing and treating various heart conditions.