What are the main differences between the jejunum and ileum?

Key differences include wall thickness (jejunum is thicker and more vascular, ileum thinner and less vascular), lumen size (jejunum is wider at ~4 cm, ileum narrower at ~3.5 cm), plicae circulares (larger and more numerous in jejunum), Peyer’s patches (few in jejunum, numerous in distal ileum), and arterial arcades (jejunum has 1–2 with long vasa recta, ileum has 4–5 with short vasa recta).

What is the arterial supply to the small intestine?

The jejunum and ileum are supplied by 12–15 jejunal and ileal branches of the superior mesenteric artery (SMA), forming arterial arcades, with the terminal ileum also supplied by ileal branches of the ileocolic artery.

What are Peyer’s patches and where are they located?

Peyer’s patches are aggregated lymphatic follicles located mainly in the distal ileum along the antimesenteric border, involved in immune function.

How does the nerve supply to the small intestine work?

The nerve supply involves sympathetic fibers from T10–T11 spinal segments via splanchnic nerves (pain referred to umbilicus) and parasympathetic fibers from the vagus nerve (stimulates peristalsis and inhibits sphincters).

What is the mesentery of the small intestine?

The mesentery is a fan-shaped peritoneal fold suspending the jejunum and ileum from the posterior abdominal wall, with a ~15 cm root and ~6 m free border.

What clinical conditions are associated with the small intestine?

Clinical conditions include typhoid ulcers (vertical oval ulcers in Peyer’s patches), tubercular ulcers (circular ulcers causing obstruction), and Meckel’s diverticulum (a remnant causing bleeding or mimicking appendicitis).

How does lymphatic drainage occur in the small intestine?

Lymph drains through mesenteric nodes to superior mesenteric nodes at the root of the SMA, with a circular lymphatic course explaining circular tubercular ulcers.

Jejunum vs Ileum – Key Differences & Blood Supply

❓ Frequently Asked Questions