review of integrated meal response

chewing

mechanical digestion

fletcher

chew more= more nutrients

saliva

produced by exocrine glands

fluoride, HCO3-, lysozyme

salivary amylase (Carbs)

swallowing

bolus

sphincters

aid but not controlled by gravity

bolus

food and saliva

upper esophagus sphincter

skeletal muscle (voluntary)

Lower esophagus sphincter

smooth (involuntary)

achalasia

high pressure above bolus

lower esophagus sphincter opened

GERD

when lower esophagus sphincter pressure less, stomach acid will come back up

small intestine anatomy

duodenum

jejunum

ileum

vilii

lacteal

duodenum

mixing and digestion

jejunum and ileum

absorption

villi

muscular mucosa layer

receptive relaxation

trigger by food in esophagus

pre emptive

adaptive relaxation

food in stomach

peristalsis (gastric motility)

more in distal stomach

pyloric sphincter is closed

allows for stretching regulated by mechanical stimuli (stretch) and chemical stimuli (digestive product, protein)

proximal portion of stomach

fundus, cardia, body

distal portion of stomach

antrum and pyloric sphincter

proximal stomach function

reservoir

distal stomach function

pumping

very active motility

oblique layer of muscle

rugae

ridges tract stretch on stomach lining

parasympathetic innervation

Ach stimulates secretion of HCl

colonic phase consists of what body parts

large intestine

cecum

colon (ascending, descending, transverse, and sigmoid)

rectum

haustra sacs causes sacs by muscle contraction

mass movements

regulated by meals and circadian rhythm

defeceation reflex

stretch receptors signal smooth muscle contraction

internal anal sphincter

smooth muscle

external anal sphincter

skeletal muscle

dumping syndrome

loss of feedback control

interferes with nutrient digestion

gastric emptying

moving food down from stomach to duodenum

increased tone of gastric reservoir

open/ relax pyloric sphincter (PS)

nervous system innervation needed for this (VIP relaxes PS)

enterogasterones

CCK (fats)

GIP (carbs) > triggers insulin release

secretin (acidity) > brings HCO3- in

when small intestine is active then

pyloric sphincter remains closed

small intestine motility

segmentation > proximal and distal contraction

slow propulsions

infrequent peristalsis

MMC

stimulated by motilin (fasting)

stomach growling

gastric absorption

very little absorption here

alcohol + absorption absorption

restricted by mucus

forms a barrier

chemotherapy targets rapidly dividing cells, including mucosal cells

gastric secretions

LES + pyloric sphincter

mucous + HCO3-

create buffer to protect other tissues

gastric pits

secretory cells are located here

parietal cells

secrete HCl + intrinsic factor for B12 absorption

regulated by protein pump H/K/ ATPase

G cells

secrete gastrin (GQ coupled)

stimulate ECL + parietal cells

ECL cells

secrete histamine (Gs coupled)

stimulates parietal cells

D cells

secrete somatostatin (Gi coupled)

inhibits parietal cells

activated by decrease in pH

chief cells

secrete pepsinogen (inactive)

becomes pepsin when with HCl

G cell activation picture

pancreas exocrine (acinar)

enzymes: amylase, HCO3-, tripisinogen

resulted by enterogasterones

pancreas endocrine

hormones: insulin and glucagon

secretions at duct

acidity stimulates secretin

secretions at acinus

fatty acids

secretions into small intestine

stimulate enzyme release

vagus nerve control

pancreatitis

autodigestion of tissues

liver and gallbladder

produce bile, while stored in gallbladder

made of hepatocytes (liver)

system of ducts connect the two

CCK stimulates bile release from gallbladder

no insulin

hypoglycemic

fasting

post absorptive state

insulin

hyperglycemia

fed

absorptive state

hepatocyte no insulin

glucoginolyis

hexokinase (enzyme)

gluconeogenesis > make new glucose from something else

increase glucose

skeletal muscle/ adipocytes no insulin

glycogenolysis

• no glucose 6 phosphate

• lipolysis

heptaocyte insulin present

glycogen synthesis

decrease gluconeogensis

decrease glucose

skeletal muscle/ adipocytes insulin

glut 4 at membrane

glycogen synthesis

lipogenesis