Anatomy Final

2 Types of Digestion

1. Mechanical Digestion

2. Chemical Digestion

Mechanical Digestion

physically breaking large pieces of food into smaller pieces (increases SA of food particles)

Chemical Digestion

breaking bonds between building blocks of complex molecules

• protein to amino acids (small enough to be absorbed) not the protein itself

How many subdivisions of the digestive system and what are they

2 groups of organs

1. GI tract

2. Accessory of digestive organs

GI tract, alimentary canal

continuous tube from mouth to anus

Accessory digestive organs do what. Name them

aid in mechanical and chemical digestion

• Ex: teeth, sublingual salivary gland, gallbladder, liver, pancreas, parotid gland, submandibular gland

4 major layers of the GI tract (inner to outer)

1. Mucosa

2. Submucosa

3. Muscularis

4. Serosa

Subdivisions of Submucosa in Gi tract?

• epithelium

• lamina propia

• muscularis mucosae

Mucosa of GI tract Epithelium types?

• different based on location

1. nonkeritnized stratified squamous: mouth, pharynx, esophagus, and anal canal (protective)

2. simple columnar: stomach and intestines (absorption and secretion)

How often are epithelial cells renewed in GI tract epithelium?

5-7 days

What is lamina propia part of mucosa made of up and do in GI tract?

• areolar CT

• carries blood and lymph vessels, supports and binds epithelial tissue

What does lamina propia part of mucosa of GI tract contain and what it does

Mucosa associated lymphatic tissue (MALT): immune response throughout GI tract (1st line of defense against pathogens moving from GI tract to deeper tissues)

What is muscularis mucosae part of mucosa in GI tract made of and what it does

• smooth muscle

• produces small folds in mucosa increasing surface area

  • folds cause more SA = better absorption

What is the submucosa of Gi tract made of?

areolar CT with collagenous fibers, nerves, blood vessels

What does the submucosa of GI tract have?

Submucosal plexus (plexus of Mesiner)

• collection of nervous tissue

• part of enteric nervous system (gut)

• sensory and motor fibers spread to mucosa to inntervate muscularis mucoase

• EX: are wall strecthing? sent through submucosal plexus for processing influences eneteric NS tells GI tract what to do

What is muscularis of GI tract made up of?

layers of muscle

What three things does muscularis of GI tract contain

1. skeletal muscle

2. smooth muscle (2 subdivisions)

3. Myenteric Plexus

Types of muscle in muscularis of GI tract

1. skeletal muscle

2. smooth muscle

skeletal muscle of GI tract in muscularis includes what things

mouth, pharynx, upper 2/3 of esophagus

Smooth muscle of GI tract in muscularis contain and subdivisions

remainder of GI tract

1. inner sheet: circular - wrap around GI tract: narrow and constrict

2. outer sheet: longitudinal - shorten and widen

What action do inner sheet and outer sheet of muscularis of Gi tract do together?

propel food from 1 place to the next

What does the myenteric plexus of muscularis GI tract other name and what it does?

Auerbach plexus controls movement between the inner and outer muscle layers of the GI tract.

What does the serosa layer of GI tract cover?

organs in abdominal cavity

What special thing does the serosa layer of GI tract have and what its made of and does

serous membrane

• visceral peritoneum

• areolar CT (binds membrane to muscularis) and simple squamous epithelium (smooth surface serous fluid slides easily no friction)

largest serous membrane in the body

peritoneum

how many divisions of peritoneum

1. parietal peritoneum

2. visceral peritoneum

What does parietal peritoneum cover?

abdominal wall

What does visceral peritoneum cover?

covers organs

are all structures covered by peritonuem

no

• some structures covered by 1 side of peritoneum

what does it mean when a organ is retroperioneal

not covered by peritoneum

where are retorperitoneal organs found

posterior abdominal wall

what organs is peritoneum on anterior surface only

ascending and descending colon, duodenum, pancreas

what organs have no peritoneum

kidneys and adrenal gland

how many folds in peritoneum

6

name fold in perioteum

1. greater omentum

2. falciform ligament

3. lesser omentum

4. mesentery

5. and 6. meseocolon

what does greater omentum attactch to

greater curve of stomach

what does greter omentum do

drapes down over intestines returns to attach to transverse colon

what things can greater omentum cause and prtect from

• adipose tissue can expand = beer belly

• protection aagainst hernia if defect in AAW

where is falciform ligament?

between 2 lobes of liver

what does the falciform ligament do

anchors liver in position and to diagrphram

what is the falciform ligament a reminant of

umblicial vein along path to inferior vena cava

• when born umblical shrivel but doesnt go away

lesser omentum located

stretches between lesser curve of stomach and liver

what does lesser omentum connect stomach from lesser curve to

duodenum and liver

what does lesser omentum contain

hepatic portal vein, common hepatic artery, and common bile duct

what does mesentary bind

jejunim and ileum to posterior adbominal wall

what is the mesentary assocaited with

small intestine

what function does mesentary have

wraps around small intestine loosly like a sling so doesnt drop out of position

what problem can mesentary cause

more visceral adipose = negative consequences (obesity)

how many folds in mesecolon

2

what fold is mesecolon similar to

mesentary

what organ does mesecolon keep in position

large intestine

what does the first fold of mesecolon do

binds transverse colon to posterior abdominal wall

what does the second fold of mesocolon do

binds sigmoid coon to posterior abdominal wall

• sigmoid colon can twist causing intetsinal blocking could be fatal (doberman)

does the colon holds large intestine tightly in place?

no

hold loosly can still move j so it doesnt drop out of position

esophagus layers

1. mucosa

2. submucosa

3. muscularis

4. adventitia

esophagues mucosa epithelium made up of? what glands does it have whats the purpose?

nonkerintized stratified squamous epithelium (protect)

mucous glands near opening of stomach secrete alkaline mucous incase acid rises

what is submucosa layer in esophagus made of

areolar CT

what are the three subdivisions of muscalaris layers of esophagus made up of

upper 1/3 - skeletal muscle

middle 1/3 - skeletal and smooth muscle

lower 1/3 - smooth muscle

what is adventitia layer of esophagus made up and what does it do

areolar CT

holds esophagus in place

what makes the layers of esophagues and GI tract different

instead of serous membrane has adventitia

what is the esophagus function

transports food

what does the upper esophageal sphincter regulate

entry and exit of material of Esophagus

what is upper esophageal sphincter made of

skeletal muscle attached to cricoid cartilage

is upper esophageal sphincter constricted

yes and needs to be relaxed to open

how does food have to do with upper esophageal sphincter

swallowing larynx elevates causes UES to relax and open and epiglottis closes airways so food has to eneter esophagus

which way does upper esophageal sphincter propel food

downward

what function does upper esophageal sphincter have to move food through esophagues

peristalsis

how does peristalis move food through esophagues

involuntary coordinated contraction and relaxation of smooth muscle layers to move food until gets into the stomach

• circular and logitudinal layers (constrict above opening below)

what type of sphincter is lower esophageal sphincter

physiological sphincter - no circular band of muscle but always constricted and relax to open still behnaves like sphincter

what does LES do to food

relaxes to allow bolus into stomach

what does LES prevent

backflow of material from stomach bc its acidic

what cause acid reflux

• smoking cigs and alcohol cause LES to relax increase acid reflex

• pregnancy bc pressure on stomach distort LES increas acid reflex

Subdivisons of stomach to 4 regions

1. cardia

2. fundus

3. body

4. pyloric region

what does cardia do in stomach

recieves whatever ingested in stomach

what does fundus look like in stomach

dom like shape

what is body in stomach

middle section

regions of pyloric region in stomach

subdivided into 3 regions

1. pyloric antrum

2. pyloric canal

3. pyloric spincter

pyloric antrum of pyloric region

enterence into pyloris

pyloric sphincter of pyloric region

regulates passage of material from stomach into small intestine

rugae of stomach

• textured

• gives more places products can be secreted

• flatten when lots of stuff in stomach

how many curvatures in stomach

2 lesser and greater

• greater omentum attatch to greater curvature vise versa

stomach layers

1. mucosa

2. submucosa

3. muscularis

4. serosa

which layers of stomach are unique

mucosa and muscularis

stomach mucosa contains big indents called what and what do they have

gastric pit

contains gastric gland

what are gastric glands in mucosa layer of stomach

inward folds of epithelium containing cells (can secrete different products)

two types of cells in mucosa of stomach layer

endocrine and exocrine

What do exocrine cells do

secrete product to outside of body into lumen of stomach

What do endocrine cells do

secrete product into blood

which cells are exocrine cells in mucosa layer of stomach

surfcae mucous cells

mucous neck cells

parietal cells

cheif cells

which cells are enteroendocrine cells in mucosa layer of stomach

G cells

gastric gland cells outer to inner

1. surface mucous cells

2. mucous neck cell

3. parietal cell

4. chief cell

5. g cell

what do surface mucous cells secrete

mucous (protects cells below)

what do mucous neck cells secrete

mucous (protects cell from harsh enviorment)

what do parietal cells secrete

1. hydorchloric acid (lower pH of stomach bc it’s acidic)

2. Intrinsic factor (increase absoprtion of vitamin B12 to produce RBC)

what do cheif cells secrete

1. pepsinogen (inactive enzyme of pepsin that breaks down proteins)

2. gatsric lipase (enzyme secreted by stomach breaks down lipids)

what do exocrine gastric cells secretion make

gastric juice

how much gastric juice produced per day

2-3 liters

What hormone do g cells secrete?

gastrine

what does gastrine do in g cells

increase secretion (stomach to make more acid and increase digestion activity)

what are g cells senstive to

products of digestion

• if detect free amino acid exocrine cells secrete more to digest