stomach and spleen Flashcards
what important things do we need to know about organs ?
- size
- shape
- position
- relationship with organs organs
- their parts
- blood supply , venous + lymphatic drainage
where is the stomach found ?
- between the esophagus + small intestine
- part of the epigastric umbilical + left hypochondria regions
what happens if the stomach has to much tone ?
what is this known as ?
- stomach = shorter + flatter
- hypertonia
what happens if the stomach doesnt have enough tone ?
what is this known as ?
stomach sacks into abdominal cavity
hypotonia
what happens when there is a complete loss of tone ?
what is this known as ?
stomach sags into pelvis
atonia
what else determines stomach shape ?
body shape
what are the 5 regions of the stomach ?
- cardiac region
- fundus
- body
- antrum
- pylorus
where is the cardiac notch found ?
angle between cardia and fundus
where is the incisura angularis found ?
between the pyloric antrum + body of stomach
what is the main role of the cardia ?
increase mucus secretion
reduce reflux of acid in esophagus
what is an internal feature found in the cardia ?
- gastroesophageal junction
- where stratified squamous epithelium of esophagus turns into simple columnar of stomach
what is the purpose of the fundus ?
fills with air
what is the function of the body of the stomach ?
stores ingested food
what are the 5 cells type found on the stomach wall ?
what do they produce ?
- goblet cells = mucus
- parietal cells = gastric acid + IF
- chief cells = pepsinogen
- D cells = somatostin
- G cells = gastrin
what is the purpose of IF that paritetal cells secrete ?
absorbs vitamin B12
what is pernicious anemia ?
what is it caused by ?
- failure to produce / utilize iF
- patients cant acquire energy from proteins or fats
what is the average volume of the adult stomach ?
1000ml
what can the stomach wall absorb ?
- water
- electrolytes
- alcohol
- aspirin
what can absorbtion of asiprin cause ?
cause stomach wall to bleed + peptic ulcers
what makes up the pyloric region ?
- pyloric antrum
- pyloris
what happens in the antrum ?
lots of mixing + grinding of chyme
what pushes chyme towards the pyloris ?
peristaltic waves
what is the pyloric sphincter ?
where does it lead to ?
- ring of smooth muscle
- leads to pyloric canal
what does contraction of the pyloric sphincter cause ?
- closure of sphincter = no food into canal
how many layers is the wall of the stomach made up of ?
what are the layers ?
- 4
- mucosa
- sub-mucosa
- muscularis extrania
- adventitia / serosa
what makes up the mucosa ?
- gut epithelium
- lamina propria
- muscularis mucosa
what does the muscularis mucosa do ?
controls contractions of the mucosa
what glands are found in the mucosa ?
- ducts of the accessory glands e.g liver + pancreas
- mucosal glands
- sub-mucosal glands
what does the sub-mucosa layer contain ?
contains submucosal plexus controls secretions of glands within submucosa + mucosa
always controls contractions of the mucosa
what is the submucosal plexus part of ?
what can it be influenced by ?
- enteric nervous system
- parasympathetic nerves of the vagus or pelvic splanchnic nerves
what is found in the muscularis externa ?
- has 2 layers of muscle
inner circular layer
outer longitudinal layer - contains the Myentric plexus
what is the purpose of the muscularis externa ?
generates peristaltic contractions controlled by myentric plexus
what is the difference between adventitia / serosa ?
adventitia = retroperitoneal parts of the gut serosa = intraperitoneal parts of the gut
what plexus are sensory nerves found in ?
what do they respond to ?
- myenteric plexus
- ## responded to local factors in wall of gut
what layers of muscles make up the stomach ?
- inner oblique layer
- middle circular layer
- outer longitudinal layer
what happens to the circular layer at the pyloric sphincter ?
increases
to control contractions of chyme
what controls gastric secretions into the esophagus ?
muscle fibres of the diaphragm
angulation of cardia
what do folds of the stomachs longitudinal layer make ?
what is there purpose ?
rugae
allow stomach to stretch after eating
what is the key artery of the upper abdominal arteteries ?
where does it come from ?
- coeliac trunk
- aorta
what are the 3 large branches of the coeliac trunk ?
- common hepatic artery to the right for the liver
- splenic artery to the left for the spleen
- left gastric artery at the top for the stomach
what does the common hepatic artery give rise to ?
proper hepatic artery
divides into a right + left hepatic artery
what arteries supply the stomach ?
- left gastric which supplies the lesser curvature
- common hepatic = lower part
- right gastroepiploic = greater curvature
- splenic = upper part
what is the route of lymphatic drainage ?
- nodes drain into the coeliac nodes
- drain to para-aortic nodes
- then into thoracic duct
where does parasympathetic stimulation of the GI tract come from ?
- from vagus nerves
- from 10th cranial nerve
where does the esophageal plexus come from ?
what do they give rise to ?
- branches from left + right vagus nerves
- becomes twisted around lower esophagus = anterior + posterior vagal trunks
where does the coeliac + superior mesentry come from ?
fibres from the posterior vagal trunk
where does sympathetic stimulation come from ?
what do these nerves cause ?
- greater splanchnic nerves at T6 + T9
- distributed via coeliac plexus
- cause vasoconstriction
what is another feature of sympathetic nerves ?
- inhibitory to intrinsic plexuses
- inhibit peristalsis
how do sympathetic nerves reach the organs of the abdominal cavity ?
- preganglionic nerves synapse in ganglia at the root of the coeliac trunk
- postganglionic neurons travel with blood vessels to its intended organ
where is the spleen found ?
- in the upper left hypocchondrium
- lies along axis of 10th rib
- sit between 9-11th
what is the purpose of macrophages in the spleen ?
to destroy aging red blood cells
what does the spleen produce ?
- lymphocytes
- erythrocytes in infants
what happens if the spleen enlarges ?
greater number of platelets in the spleen = less in blood = excessive bleeding
what does the spleen respond to ?
- stimulation for sympathetic nerves
- adrenaline
what attaches the spleen to the stomach ?
where else is the spleen attached to ?
- gastrosplenic ligament
- to the posterior abdominal wall + left kidney by lienorenal ligament
what are the 2 boarders of the spleen ?
- notched one
- smooth one
what are the 2 forms of splenic pulp ?
- red pulp 75% = RBC + macrophages
- white pulp 25% = lymphocytes
what is the primary function of the red pulp ?
filter the blood
remove pathogens + old RBC
what is found within the red pulp ?
what is there purpose ?
venous sinuses
filters out healthy RBC from old ones
what is a splenomegarly ?
enlargement of the spleen
due to immune hyperplasia (increased immune response )
can also be due to anemia
