GIM Flashcards
What is the superior abdominal boundary
Diaphragm
What is the inferior abdominal boundary
Pelvic inlet (continuous with the pelvis)
What is the anterolateral abdominal boundary
Musculo-aponeurotic abdominal wall
What is the posterior abdominal boundary
Lumbar vertebrae
What are the planes of the quadrants of the abdomen
Median plane (vertical) and transumbilical plane (horizontal)
4 quadrants of the abdomen
RUQ, LUQ, RLQ, LLQ
Clinical significance of the quadrants
Locate abdominal organs
Locate sites of pain
Allow accurate history to be taken
What are the horizontal planes of the regions of the abdomen
Transtubercular plane
Subcostal plane
What is the transtubercular plane
Iliac tubercles and body of L5
What is the subcostal Plane
Inferior border of the 10th cc and body of L3
What are the vertical planes (regions)
Midclavicular planes (halfway along clavicle and mid inguinal point)
What are the 9 regions of the abdomen
Right hypochondriac, epigastric, left hypochondriac, right lumbar (lateral), umbilical, left lumbar (lateral), right inguinal, hypogastric, left inguinal
What lymph nodes are superior to umbilicus
Axillary lymph nodes
What lymph nodes are inferior to umbilicus
Superficial inguinal lymph nodes
Clinical significance of lymphatic drainage
Diagnosis, prognosis and treatment of cancer
Where are melanomas in men
Most often thorax, abdomen or back
Where are melanomas in women
Most often lower legs
What dermatome supplies skin superior to umbilicus
T7-9
What dermatome supplies umbilicus
T10
What dermatome supplies iliohypogastric (L1) and ilioinguinal (L1) supply skin below umbilicus
T11-12
What dermatome supplies suprapubic region
L1
Clinical significance of dermatome
Referred pain
Dermatome using sensory testing if spinal nerve / cord functioning normally
What is the peritoneum
Smooth transparent serous membrane
What is the importance of the peritoneum
Holds organs within cavity
Reduce friction to allow organs to slide against each other during movement (esp in a very active GI tract)
What does serous mean
Fluid secreting
What are the layers of the peritoneum
Parietal peritoneum - covers body wall
Visceral peritoneum - covers organs (continuous)
What is the peritoneal cavity
Potential space with small amount of peritoneal fluid (no organs)
What is peritoneal fluid
Water, electrolytes, leukocytes and antibodies
Importance of peritoneal fluid
Lubrication
Free movement of abdominal viscera
Immunity
What are the intraperitoneal organs
Stomach (covered with visceral peritoneum)
What are the retroperitoneal organs
Kidneys (behind peritoneum)
What is peritonitis
Inflammation of peritoneum
Eg by trauma, penetration
Release of serum / pus into cavity -> pain, tenderness, nausea
What is ascites
Accumulation of fluid in peritoneal cavity
What viscera is in the right hypochondriac region
Pylorus of stomach, part of right lobe of liver, gall bladder, right kidney
What viscera is in the epigastric region
Liver, stomach, duodenum, pancreas
What viscera is in the left hypochondriac region
Stomach, left kidney, spleen
What viscera is in the right lumbar (lateral) region
Ascending Colon, small intestines
What viscera is in the umbilical region
Small intestines
What viscera is in the left lumbar (lateral) region
Descending colon, small intestines
What viscera is in the right inguinal (groin) region
Caecum, appendix
What viscera is in the hypogastric (pubic) region
Sigmoid colon
What viscera is in the left inguinal (groin) region
Descending colon
2 subdivisions of the peritoneal cavity
Greater sac Lesser sac (omental bursa)
Where is the lesser sac
Posterior to the stomach and lesser omentum
Where is the communication between the greater and lesser sac
Epiploic (omental) foramen of Winslow
Where is the greater omentum
4 layers of visceral peritoneum
Connects the stomach and proximal part of the duodenum to the transverse colon
What are omenta
Sheets of visceral peritoneum which extend from the stomach and the proximal part of the duodenum to other abdominal organs
What are the parts of the greater omentum
Gastrophrenic ligament ( greater curvature of stomach) Gastrosplenic ligament (side of stomach near spleen) Gastrocolic ligament ( on the sheet of the omenta)
What is the lesser omentum
Double layer of visceral peritoneum
Connects lesser curvature of the stomach and proximal duodenum to the liver
2 parts of the lesser omentum
Hepatogastric ligament
Hepatoduodenal ligament
What is a mesentery
Double layer of peritoneum b/c invagination of peritoneum by organ eg small intestine mesentery
What is the peritoneal ligament
Double layer of peritoneum that connects an organ with another organ to the abdominal wall
What is the falciform ligament
Attaches liver to anterior abdominal wall
Where is the linea alba
Runs from xiphoid process to pubic symphysis
What is the supracolic compartment
Above transverse mesocolon stomach, liver, spleen
What is the infracolic compartment
Below transverse mesocolon small intestine, ascending and descending colon
What are the paracolic gutters
Space between the ascending and descending colon and the posterolateral abdominal wall
What is gastrulation
Formation of 3 germ laters (ectoderm, mesoderm, endoderm) week 3
What is embryonic folding
Converting a flat germ disc into a 3D structure (parts of yolk sac become incorporated into embryo) week 4
Which germ layer is the GI tract derived from
Endoderm
What is gut tube formation
Midline fusion transforms flat endoderm into a gut tube
What is fore, mid and hind gut formation
- cranial and caudal blind ended tubes (foregut and hindgut)
Midgut remains temporarily open to the yolk sac
What GI tract organs are derived from the foregut
Oesophagus
Stomach
Duodenum - whole of the superior part and upper half of descending part
- liver and extra hepatic biliary system
- pancreas
What GI tract organs are derived from the midgut
Duodenum- descending distal to major papilla, horizontal and ascending parts
- jejunum
- ileum
- caecum and appendix
- ascending colon
- proximal 2/3 of transverse colon
What GI tract organs are derived from the hindgut
Distal 1/3 of the transverse colon
Descending colon
Sigmoid colon - rectum
Upper part of anal canal
What is the blood supply of the foregut
Coeliac trunk
Where is the blood supply of the midgut from
Superior mesenteric aa
What is the blood supply of the hindgut
Inferior mesenteric aa
Explain stomach rotation and growth in an embryo
Begins to form in week 4 (fusiform shape)
Rotates 90 clockwise along longitudinal axis
Rotates on AP axis, pylorus moves up, duodenum becomes c shaped
What happens to the vagus nerve in the abdomen
Left vagus -> anterior a gal trunk
Right vagus -> posterior vagal trunk
B/c stomach rotation
Examples of congenital abnormalities of the GI tract
Atresias and stenosis
Abnormal rotations
Anterior abdominal wall defects
How does the omental bursa form
Rapid expansion of the liver forms a sac region behind the stomach
Why do the greater and lesser curvatures of the stomach form
Because the walls grow at different rates
What is the midgut
Suspended from the dorsal abdominal wall
Communicates with yolk sac by vitelline duct
Rapid elongation forms primary intestinal loop
What is the rotation fo the midgut
270 anticlockwise rotation around the superior mesenteric aa
Elongation of small intestine loop = jejunum and ileum coiled loops
Where can atresis and stenosis occur
Anywhere along the developing intestinal loop
What is an atresia
Complete absence of a lumen
What is a stenosis
Narrowing of the lumen
Define nutrition
The provision of nourishment to cells, tissues, organs, systems and the body as a whole = how food influences out body function and health
What is clinical nutrition
Feeding patients
Dietetics - diet as therapy / prevention of disease
What are the core concepts of nutrition
- nutrient balance
- nutrient turnover
- nutrient flux
- metabolic pools
- adaptation to altered nutrient supply
What is nutrient balance
Intake - output = change in body stores -> buffering effect of body stores
What is nutrient turnover
Metabolic substrates are continually being utilised and replaced. Allows for rapid adjustments to changes in metabolic state
Potential for dysfunction if rates of utilisation and synthesis are mismatched
What is nutrient flux
A measure of the activity of the pathway
Not necessarily related to the size of the metabolic pool
What is a functional pool
Direct involvement in body functions
What is a storage pool
Provides buffering effect ie can be made available to the functional pool when and as
What is a precursor pool
Provides the substrate for nutrient / metabolite synthesis
What is adaptation to altered nutrient supply
Minimises the consequences of such alterations
The greater the capacity to respond to adverse nutritional states the greater the capacity to survive those states
Role of GI tract
Ingest food, break it down mechanically and enzymatically into molecules that can be absorbed into the blood and taken to the liver to be used to synthesise proteins, carbohydrates and lipids needed for cellular functions
Layers of the GI tract
1) mucosa (inner lining)
2) submucosa (support)
3) muscularis externa / propria (muscle)
4) serosa / adventitia (outer wrapping)
What makes up mucosa
Epithelium - changes throughout the tube in relation to function
Basement membrane
Lamina propria - supports the epithelium (structurally and nutritionally)
Muscularis mucosa - causes the lining to be visibly folded
What makes up submucosa
Connective tissue, blood vessels, lymphatics and nerves
Some of the glands
What is the submucosal plexus
Supplies glands and muscularis mucosa
What makes up muscularis externa/ propria
Smooth muscle: inner circular and outer longitudinal. Responsible for peristalsis
What is myenteric (auerbach’s) plexus
Between muscle layers
Modulates peristalsis
Modulated by autonomic nervous system
What is peristalsis
The involuntary constriction and relaxation of the muscles of the intestine or another canal, creating wavelike movements that push the contents of the canal forward
What is the adventitia
The outer wall of the gut tube
Thin later of connective tissue
What is the serosa
Where covered by a serous membrane
Serous membrane = squamous epithelial cells secreting a small amount of fluid to allow the organs to glide over each other (peritoneum in the abdomen) = visceral peritoneum
What is protective epithelium
Stratified squamous non keratinising
Where would you need protective (stratified squamous) epithelium
Oesophagus, anal canal, oral cavity, pharynx
What is secretory / absorptive epithelium
Columnar (microvilli)