Title: Anatomy / 8 Digestive system

Q: parts
of the digestive tract, border
A: Parts:
1. Upper digestive tract:
- Oral cavity,
- Pharynx;
2. Lower digestive tract:
- Esophagus,
- Stomach,
- Small intestine,
- Large intestine,
- Digestive glands;
Border: Transverse Colon;

Q: oral
cavity: borders
A: It’s formed by the facial skeleton & muscle tissues:
- Palate (superior)
- Floor of mouth (inferior)
- Cheeks (lateral)

Q: oral cavity: Mucosa
& salivary glands
A: - Mucosa: The cavity is lined with a specialized protective membrane
- Salivary glands: Exocrine glands that secrete substance through ducts directly into the oral cavity.
- Major glands: Parotid, sublingual, submandibular

Structures
in the oral cavity

Q: Tongue
A: Musculature: striated muscle fibers in all directions;
Papilla: For taste, pain, …

Q: Teeth
A: Structures & Layers
Arches: Upper (Maxillary) & Lower (Mandibular)
Types:
- Primary (Milk): 20 Teeth (2 incisors, 1 canine, 2 molars per quadrant)
- Secondary (Permanent): 32 Teeth (2 incisors, 1 canine, 2 permolars 3 molars per quadrant)

Q: swallowing
A: Includes both a voluntary and involuntary (automatic) reflex phase
Airway Protection: The larynx and epiglottis protect the lower airways during the process

layers
of intestinal tube wall

Q: esophagus:
characteristics, constrictions
A: Characteristics:
- Length: Approximately 25 cm.
- Structure: A muscular tube with a star-shaped lumen.
- Parts: Divided into a thoracic and an abdominal part.
- Musculature: The cranial portion consists of striated muscle, while the caudal portion consists of smooth muscle.
- Wall Structure: Cranial to the diaphragm, it has no serosa (peritoneum).
- Attachment: It is attached to the pharynx at the esophageal opening.
- Constrictions:

Q: abdominal
cavity: boundaries
A: The abdominal cavity is the largest body cavity, containing most of the digestive & urinary organs.
Boundaries:
- Diaphragm (superior);
- Pelvic floor (inferior);
- Abdominal wall (anterior/lateral);

Q: abdominal
cavity: regions
A: - Epigastric region: upper central;
- Hypogastric region: lower central;

Q: abdominal cavity: Peritoneum
& Mesentry
A: - Visceral peritoneum: The layer covering the organs.
- Parietal peritoneum: The layer lining the abdominal wall.
- Mesentery: The structure connecting the organs to the body wall

Q: abdominal cavity: Definition of organ locations
A: Organs are classified by how they are covered by the peritoneum:
- Intraperitoneal: Organs with a peritoneal covering, lying inside the peritoneal sac.
- Extraperitoneal: Organs with only partial or no peritoneal covering, lying outside the sac.
  - Subperitoneal: Located caudal (below) the peritoneum.
  - Retroperitoneal: Located dorsal (behind) the peritoneum.
    - Primary retroperitoneal: Organs located behind the peritoneum from the start of development.
    - Secondary retroperitoneal: Organs that develop intraperitoneally but move to a retroperitoneal position during development.

Q: stomach: position & parts
A: Position: intraperitoneal (= within the peritoneal)
Parts:
- Cardia: The entrance where the esophagus meets the stomach.
- Fundus: The upper, dome-shaped part.
- Corpus: The main body of the stomach.
- Antrum: The lower section before the exit.
- Pylorus: The sphincter muscle at the exit leading to the duodenum.

Q: stomach: curvatures
A: - Major curvature: long, convex outer edge
- Minor curvature: shorter, concave inner edge

Q: stomach: Mucosa, gastric pits, important cell types
A: Mucosa: Characterized by mucous folds that form the gastric canal
Gastric pits: These serve as the outlets for the stomach glands located deeper in the wall
Important cell types:
- Mucous cells: Produce mucus for protection.
- Principal cells: Produce pepsinogen (precursor for protein digestion).
- Parietal cells: Produce hydrochloric acid (HCl) and intrinsic factor

Q: small
bowels: parts, characteristics, position, tasks, surface area enlargement
A: Dimensions: 3–5 m long.
Position: Starts after the pylorus of the stomach and ends at the caecum of the colon.
Parts:
- Duodenum (red): Shortest part; secondary retroperitoneal.
- Jejunum (green): Intraperitoneal.
- Ileum (blue): Intraperitoneal.
Tasks:
- Main site for nutrient absorption.
- Duodenum contains orifices for the bile duct and pancreatic duct.
Surface area enlargement:
- Kerkring folds
- Villi and crypts.
- Microvilli

Q: large
bowels: parts, characteristics (including features), position
A: Parts:
- Caecum with the vermiform appendix.
- Colon: Ascending, transverse, descending, and sigmoid colon.
- Rectum and Anus.
Characteristics:
- 1.5 – 1.8 m long.
- Contains two flexures (right and left)
Features:
- Haustrae
- Taeniae
- Semilunar plicae
- Epiploic appendices
Position (Peritoneal Status):
- Intraperitoneal: Cecum/appendix, transverse colon, and sigmoid colon.
- Secondary retroperitoneal (no mesentery): Ascending and descending colon.
- Intra- / subperitoneal: Rectum.

Q: rectum
/ anus
A: Position: Located intra- / subperitoneal.
Characteristics of the Rectum:
- Parts: Features the rectal ampulla.
- Folds: Contains Kohlrausch's fold.
Characteristics of the Anus:
- Consists of the anal canal.
Sphincters (=Schließmuskels):
- Internal sphincter: Involuntary.
- External sphincter: Voluntary.

Q: Pancreas
A: - Position: Located (secondary) retroperitoneal.
- Dimensions: Approximately 15 cm long and weighs about 90 g.
- Parts: Divided into the head, corpus (body), and cauda (tail).
- Types of Glands: Functions as both an exocrine and endocrine gland.
- Pancreatic Duct: Leads into the major duodenal papilla.
- Islets: Contains the islets of Langerhans, which produces insulin and glucagon

Q: Liver
A: The liver is the largest gland of the human body, weigthing approximately 1.5 kg.
Position: Located intraperitoneally
Parts: Divided into 4 lobes:
- Right lobe.
- Left lobe.
- Caudate lobe.
- Quadrate lobe.
Ligaments:
- Falciform hepatis ligament.
- Teres hepatis ligament.
Duct: The hepatic duct (carries bile).
Circulations: The liver has a dual blood supply:
- Functional circulation: brings nutrient-rich blood from abdominal organs;
- Nutritional circulation: Supplies the liver tissue itself with oxygenated blood.

Q: gall bladder (position, task)
A: - Position: Located intraperitoneally.
- Task: Storage and concentration of bile with a holding capacity of approximately 30 ml.