The skin glands include three kinds of microscopic glands. They are the

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glands.

A. Astrocyte: This is the most abundant neuroglial cell in the central nervous system, characterized by its star-shaped morphology and perivascular feet. These cells are essential for maintaining the blood-brain barrier, regulating the chemical environment of the interstitial fluid, and providing structural support to neurons. Their primary role is homeostatic and metabolic.

B. Schwann Cells: Schwann cells are glial cells of the peripheral nervous system that form the myelin sheath around axons. This myelination increases the speed of electrical impulse conduction along the nerve fiber. Schwann cells also aid in the regeneration of damaged peripheral nerves by guiding axonal growth.

C. Microglial cell: This cell functions as the resident macrophage and primary immune defense within the central nervous system. These small, mobile cells constantly scavenge for plaque, damaged neurons, and infectious agents to maintain neural health through phagocytosis.

D. Ependymal cells: Ependymal cells line the ventricles of the brain and the central canal of the spinal cord. These ciliated epithelial-like cells are responsible for the production, circulation, and monitoring of cerebrospinal fluid (CSF), creating a permeable barrier between the CSF and the nervous tissue. Their specialization is related to fluid dynamics and ventricular lining.

E. Oligodendrocyte: This is a specialized glial cell that extends multiple cytoplasmic processes to wrap around axons in the central nervous system. These wraps form the myelin sheath, a lipid-rich insulating layer that significantly increases the velocity of action potential conduction through saltatory conduction.

A. Cardia: This anatomical region represents the junction where the esophagus enters the stomach, serving as the initial entry point for a bolus of food. It contains the lower esophageal sphincter, which is physiologically vital for preventing the reflux of acidic gastric contents back into the esophagus, thereby protecting the esophageal mucosa.

B. Fundus: This is the superior, dome-shaped portion of the stomach that typically sits tucked under the diaphragm and often contains gas or air swallowed during ingestion. It serves as a temporary storage area for undigested food and participates in receptive relaxation, allowing the stomach to expand without a significant increase in internal pressure.

C. Body/Corpus: The largest and most central region of the stomach, the body is where the majority of mechanical churning and chemical digestion occurs through the secretion of pepsinogen and hydrochloric acid. Its mucosal lining contains deep gastric pits and glands that are essential for breaking down complex proteins into smaller polypeptides.

D. Greater Curvature: This convex lateral border of the stomach provides a broad surface for the attachment of the greater omentum, a large, apron-like fold of peritoneum. The greater omentum is functionally significant as it contains adipose tissue and lymph nodes, helping to insulate the abdominal organs and localize infections within the peritoneal cavity.

E. Pyloric Sphincter: Located at the distal end of the stomach, this thick ring of smooth muscle regulates the rate of gastric emptying into the duodenum of the small intestine. By controlling the passage of chyme, it ensures that the neutralizing capacity of the duodenum is not overwhelmed by highly acidic gastric contents, optimizing the conditions for intestinal digestion.