Splanchnology: Exploring the World Inside the Body

Splanchnology: Exploring the World Inside the Body

Splanchnology is the branch of anatomy that studies the internal organs of the body, especially their location, structure, and function. To better understand splanchnology, we need to grasp some basic concepts:

1. Transverse Section:

When studying transverse sections, consider these rules:

• Observation: All sections are viewed from below, observed as if looking at the patient from the feet towards the head, with the patient lying on their back.

• Right and Left: Organs on the right side of the image will be on the left side of the body and vice versa.

• Anterior and Posterior: The anterior part of the body corresponds to the upper part of the image, and the posterior part corresponds to the lower part of the image.

2. What are Viscera?

Viscera are the organs located within the body cavities such as the mouth, nose, chest, abdomen, and pelvis.

3. Visceral Systems:

• Digestive System

• Respiratory System

• Genitourinary System

• Endocrine System

4. Connective Tissue:

Connective tissue plays a crucial role in the body:

• Support: Forms the internal framework of the body, providing strength and stability.

• Connection: Connects internal organs to the rest of the body.

• Position Maintenance: Maintains the relative position of internal organs.

• Pathway Provision: Provides paths for the distribution of blood vessels, lymphatic vessels, and nerves.

5. Mesenchyme:

Mesenchyme is loose connective tissue that differentiates into most of the connective tissues in the body. Fascia develops from mesenchyme.

6. Fascia:

• Function: Fascia is a layer or sheet of connective tissue visible during gross dissection (with the naked eye).

• Classification: Fascia is divided into 3 parts:

• Superficial Fascia (subcutaneous/hypodermis)

• Deep Fascia

• Subserous Fascia

• Role: Protects and connects structures within the body.

7. Potential Spaces:

Potential spaces are spaces between membranes that are closely apposed. These membranes are not physically attached, so under abnormal conditions, they can separate, creating a space that can contain fluid.

8. Membranes:

• Structure: Membranes consist of an epithelial sheet and a layer of connective tissue.

• Function: Enclose and protect structures and other tissues within the body.

• Classification: There are 4 types of membranes:

• Mucous membrane

• Serous membrane

• Cutaneous membrane (skin)

• Synovial membrane

9. Lamina Propria:

The lamina propria is the loose connective tissue layer of the mucous membrane.

10. Oral Mucosa:

The oral mucosa has stratified squamous epithelium.

11. Reticular Tissue:

Reticular tissue forms the supporting framework for fat masses and the tissues of most organs.

12. Superficial Fascia (Subcutaneous/Hypodermis):

• Structure: It is a layer of loose connective tissue that separates the skin from the organs underneath.

• Role:

• Separates the skin from the organs underneath.

• Provides a cushion that allows the skin and underlying organs to move independently of each other.

13. Deep Fascia:

• Structure: It is a dense, fat-free connective tissue layer that lies beneath the superficial fascia.

• Characteristics: The fibrous structures in deep fascia are arranged in layers. The fibers in each layer run in the same direction, but between different layers, the fibers are arranged in different directions. This arrangement strengthens the deep fascia in multiple directions.

• Role: Holds and connects structures.

14. Subserous Fascia:

• Structure: It is the fascia that lies between the deep fascia and the serous membrane, lining the body cavities.

• Role: Protects the lining (serous membrane, mucous membrane).

15. Transudate:

Transudate is fluid produced between the surfaces of serous membranes.

16. Serous Membranes:

• Classification: There are 3 types of serous membranes:

• Pleura

• Pericardium

• Peritoneum

• Function:

• Lines the anterior body cavities.

• Covers the surfaces of the organs located within the anterior body cavities.

• Structure: Serous membranes have two layers that are always in contact with each other: the parietal layer and the visceral layer.

17. Pelvic Cavity:

The pelvic cavity contains the rectum, bladder, urethra, and reproductive organs.

18. Abdominal Cavity:

The abdominal cavity contains most of the digestive organs, spleen, kidneys, and ureters.

19. Mediastinum:

The mediastinum is a compartment extending from the base of the neck to the diaphragm, including:

• Heart

• Major blood vessels

• Esophagus

• Trachea

• Thymus

20. Retroperitoneal Viscera (Retroperitoneal Organs):

Retroperitoneal viscera are organs that are covered by peritoneum only on the side opposite the peritoneal cavity. Retroperitoneal organs include:

• Kidneys

• Ureters

• Adrenal glands

• Most of the pancreas

• Abdominal portion of the aorta and inferior vena cava

21. Posterior Mesentery:

The intestines are suspended from the posterior abdominal wall by the posterior mesentery.

22. Mesocolon:

The posterior mesentery of the large intestine is called the mesocolon.

23. Lesser Omentum:

The lesser omentum is a peritoneal fold that extends from the lesser curvature of the stomach to the liver, containing:

• Blood vessels

• Nerves

• Ligaments

• Lymph nodes

• Lymphatic vessels

• Common bile duct

24. Anatomical Regions:

Right Hypochondriac Region:

• Right lobe of the liver

• Gallbladder

• Right adrenal gland

Left Hypochondriac Region:

• Body and fundus of the stomach

• Spleen

• Left colic flexure

• Upper 2/3 of the left kidney

• Tail of the pancreas

Epigastric Region:

• Left lobe and part of the right lobe of the liver

• Pylorus and lesser curvature of the stomach, first and second parts of the duodenum

• Body and upper part of the head of the pancreas

• Right and left adrenal glands

Umbilical Region:

• Middle part of the transverse colon

• (Part of) small intestine

• Bifurcation of the abdominal aorta and inferior vena cava

Hypogastric (Pubic) Region:

• Bladder (full)

• (Part of) small intestine

• (Part of) sigmoid colon

Right Lumbar Region:

• Ascending colon

• Right colic flexure

• Lower outer portion of the right kidney

• (Part of) small intestine

Left Lumbar Region:

• Descending colon

• Lower 1/3 of the left kidney

• (Part of) small intestine

Right Iliac (Inguinal) Region:

• Lower part of the ascending colon

• Appendix

• (Part of) small intestine

Left Iliac (Inguinal) Region:

• Junction of the left colon and sigmoid colon

• (Part of) small intestine

25. Regional Anatomy:

Regional anatomy is the study of the location of organs (Topography), including:

• Location in the region/body (Holotopy)

• Projection onto bones (Skeletotopy)

• Position relative to other organs (Syntopy)

26. Important Functions of Visceral Fascia:

• Protection: Protects viscera from trauma.

• Hemostasis: Controls bleeding in the viscera.

27. Mucous Membrane:

• Protective Function: Mucous membranes protect the internal tissues from the effects of the external environment.

• Structure:

• Outer: Muscle layer

• Middle: Connective tissue

• Inner: Epithelium

• Classification: Mucous membranes are divided into layers:

• Tunica mucosa

• Submucosa

• Muscularis: Circular, longitudinal, oblique layer

• Subserosa

• Tunica serosa

• Tunica externa: Fibrous connective tissue, in pharynx, esophagus, rectum

28. Comparing Mucous Membrane and Serous Membrane:

• Mucous Membrane: Contains columnar epithelium, with a lot of blood vessels underneath.

• Serous Membrane: Contains no columnar epithelium, few blood vessels.

29. Mesentery:

• Structure: Two layers of peritoneal membranes come together.

• Contents: Blood vessels, nerves, and lymphatic vessels going to and from the digestive tract.

• Function:

• Fixes the relative position of the organ.

• Prevents twisting of the intestines during digestive activity or sudden changes in body position.

30. Peritoneal Cavity:

The peritoneal cavity is present in the ovaries of females.

Note: The above article is a general overview of basic knowledge in splanchnology. To understand each organ in more detail, you should refer to more specialized materials.