S1 L1 General overview of GI tract function and basic anatomy Flashcards
- *Purpose of the gut**
- List 3
- Adaptations of the ‘tube’ to make it more functional?
- Food ingestion, digestion, absorption and egestion
- Food must be digested into monoschharides, small peptides, fatty acids etc, in order to be absorbed and used
- In addition, the gut must be a storage (e.g. stomach) of food, kill pathogens, move food along the tract via peristalsis
- *Alimentary canal**
- order food passes
Role of the following:
- Mouth
- Oesophagus
- Stomach
- Duodenum (SI)
- Jejunum (SI)
- Ileum (SI)
- Ascending colon (LI)
- Transverse colon (LI)
- Descending colon (LI)
- Sigmoid colon (LI)
- *Alimentary canal**
- Role of each ‘portion’
- *Alimentary canal**
- Transport in the oesophagus is called _______
- Small intestine, can also be called______
- Brief role of bile
- Where is the cecum?
- How is chyme neutralised in the duodenum?
- Meaning of colon acting as a temporary ‘food’ store?
- Which part of the AC has lots of bacteria?
- Diagram of AC
- Transport in the oesophagus is called _______
Peristalsis - Small intestine, can also be called______
Small bowel - Brief role of bile
Breakdown fats - Where is the cecum?
Connection between the terminal ileum and ascending colon - How is chyme neutralised in the duodenum?
Through HCO3 rich secretions - Meaning of colon acting as a temporary ‘food’ store?
(otherwise constantly going for a poo)
- Which part of the AC has lots of bacteria?
Large intestine! (massive microbioma compared to small intestine)
- *Peritoneal Cavity**
- What is this space?
- What are the two ‘layers’
- Are organs enveloped or like a ‘bag’?
- Cell type of the ‘layers’
- What does it mean if organs are retroperitoneal?
- Which organs are retroperitoneal?
- Which organs are intraperitoneal?
- What are mesentry’s?
- What is this space?
The space between the parietal and visceral peritoneal membranes
- What are the two ‘layers’
Parietal and visceral layers
- Are organs enveloped or like a ‘bag’?
Membranes are continuous - those layers touching the organs are viseceral and those touching the abdominal walls are parietal
- Cell type of the ‘layers’
Mesothelium (simple squamous epithelium), secrete serous fluid
- What does it mean if organs are retroperitoneal?
Organs that lie behind the peritoneal cavity, only their anterior surface touches the cavity
- Which organs are retroperitoneal?
kidneys, oesophagus, pancreas
- Which organs are intraperitoneal?
stomach, liver, spleen
- What are mesentry’s?
Double folds of peritoneum, allows passage of blood vessels, lymphatic. Connects retroperitoneal space to an intra-peritoneal ogans.
Types of cavities in the body
- *Control of the Gut**
- 3 main types list
Neural control (Sympathetic and Parasympathetic NS)
Enteric nervous system
Hormones
- *Control of the gut:**
- Neural control (2 branches)
ANS!
- *Control of the gut:**
- Enteric nervous system
- *Control of the gut:**
- Produced by what type of cells?
- Hormones
- 3 types of hormones
- 4 examples
- Which family are they in?
- How do they increase in quantity?
Gastrin (gastrin family), cholecystokinin (gastrin family), secretion (secretion family) - all endocrine
Gastric inhibitory polypeptide (secretion family) - neurocrine
How do they increase in quantity?
Response of food intake and stretch
- *Layers in the gut**
- How many layers?
- Name them?
- 1st layer, split into 3, name these
- Explain what each layer contains and role of it
- *Layers in the gut:**
- Two plexus in the enteric nervous system, found in which layers of the gut?
- Name of these plexus
- Submucosa: Submucosal plexus (meisseners)
- External muscle layer: Myenteric plexus (Auerbach’s)
Clinical correlates:
Coeliac disease
- Damage to which layer of the gut?
- Unable to tolerate what?
- This causes what?
- Damage to which layer of the gut?
Mucosa
- Unable to tolerate what?
Gluten
- This causes what?
Malabsorption (damage to the mucosa layer)
Abdominal wall
- layers
(state superficial to deep)
- *Abdominal wall muscles** (1/2)
- 4 of them in total, state 2
- Role of 2
- Don’t worry too much about origin or insertion
- Nerve
Nerve: Anterior rami T7-T7 (Internal oblique and transversus abdominus also supplied by L1)
INTERNAL OBLIQUE - Ipsilateral contraction (contraction of the right side, turn to the right)
EXTERNAL OBLIQUE - Contralateral contraction (contraction of the right side, turn to the left) hands in pockets - makes sense as forms the inguinal ligament
- *Abdominal wall muscles (2/2)**
- 4 of them in total, state the other 2
- Role of these 2
- Don’t worry too much about origin or insertion
- Nerve
- *Aponeurosis**
- What is this?
- Which muscles make up the rectus sheath?
- What is the rectus sheath
- What is the arcuate line? Significance of it?
- Anatomically, where is the arcuate line found?
- What are the two layers posterior to the RA muscle, below the arcuate line?
- What is this?
Flattened tendons
- Which muscles make up the rectus sheath?
Produced from 3 anterolateral muscles (external oblique, internal oblique, transverse abdominus
- What is the rectus sheath?
Aponeurosis of the 3 muscles listed above, these aponeurosis surrond the rectus abdominal muscle
- Anatomically, where is the arcuate line found?
Arcuate line is found halfway between the umbilicus and the pubic symphysis
- What is the arcuate line? Significance of it?
see pic —- blue lines are the 3 anterolateral muscles
Below the arcuate line - all aponeuorsis are anterior to the rectus abdominus muscle (don’t have aponeurosis posteriorly)
- Anatomically, where is the arcuate line found?
Arcuate line is found halfway between the umbilicus and the pubic symphysis
- What are the two layers posterior to the RA muscle, below the arcuate line?
Transversalis fascia and parietal peritoneum
- *Epithelial of the gut (1/8)**
- Types of epithelial cells in the gut (list at different places and state why)
Epithelial of the gut (2/8)
Stomach:
- Type of epithelium
- What do these cells secrete?
- Describe more details of the epithelium…. g____ p_____
- What are g____ p______ attached to?
- Why are mucus cells important?
Surface mucous cells
• Line gastric mucosa/gastric pits
• Secrete mucus/HCO3 that forms barrier to stomach acid
• Exocytosis of mucin
Epithelial of the gut (3/8)
Small intestine:
- Site of what?
- Type of cell?
- Describe small intestine epithelium
- Features of this epithelium
Epithelial of the gut (4/8)
Intestines:
- Major important cell (g____ c___)
- What does it produce?
- The three roles of mucus
- Where do you find crypts in the gut?
- Where do you find crypts in the gut?
In both small and large intestine
Epithelial of the gut (5/8)
Crypts
- Where?
- Secrete which hormones?
- Structure of the crypts
Epithelial of the gut (6/8)
Specialised gland in the duodenum
- Name of it
- Where is it located?
- What does it do?
Epithelial of the gut (7/8)
Where do different food groups go in SI?
- Once nutrients and water are absorbed across the enterocyte, where do they go?
- Where do proteins go?
- Where do fats go?
Epithelial of the gut (8/8)
Colon
- Explain and describe the colon’s epithelium
- How does water move out of the colon
Water moves out of the colon:
Na+ moves along the epithelial layers, water follows
Active fluid transport in lateral intracellular spaces
To clear up:
- What are messenteries
- What is the peritoneal ligament
- Messenteries - Double fold of peritoneum, connects visceria to posterior abdominal wall (usually posterior)
- Peritoneal ligament - Connects 2 viscera (like in MSK, ligament connects bone to bone)
Sections of the abdomen
- pain in each region, list what structures could be ‘unwell’
Epigastric region - referred pain from foregut
Umbilical region - referred pain from midgut
Pubic region - referred pain from hindgut
