Week 8 - Study Guide Flashcards
Digestive System
Where does CHO digestion begin?
Oral cavity
Lipase - breaks down lipids in saliva
Where is the majority of protein digestion?
stomach
What functions as endocrine and exocrine?
pancreas
WHAT PRODUCES BILE?
liver
Where is bile stored?
in gallbladder
Where is everything digested and aborbed?
small intestine
CHO, lipid, protein
Basic processes of the GI (alimentary canal)
- ingestion
- movement (skeletal muscle)
- mechanical digestion (muscles contracting and propels)
- chemical digestion (enzymes, pH regulators)
- absorption (in small intestine mostly, some in large intestine)
- defecation
How long is GI tract
30 feet
What are the 4 tissue layers of the GI tract?
- Tunica mucosa
- Tunica submucosa
- Tunica muscularis
- Tunica serosa
Characteristics & function of the tunica mucosa
- inner most layer
- Protects and absorbs
- epithelium & connective tissue
Characteristics & function of the tunica submucosa
- Dense CT - provides strength holding tube together
- Binds tube together
Characteristics & function of the tunica muscularis
- double layer
- inner circular muscle and outer longitudinal (propels) muscle
- skeletal muscle in mouth, pharynx, upper esophagus, & anal sphincter
- smooth muscle - everywhere else
Characteristics & function of the tunica serosa
- outside of the tube
- CT
- single layer of epithelium → visceral peritoneum
Put the tunicas in order from innermost to outside layers
- tunica mucosa
- tunica submucosa
- tunica muscularis
- tunica serosa
If you add a strong acid (HCL) to a solution, which of the following molecules would make an effective buffer for this acid?
- NaH2PO4
- H2CO3
- NH2-protein-COO-
- NH3+-protein-COOH
- NH2-protein-COO-
What makes an acid or base strong?
Tendency to dissociate fully and therefore change pH substantially
What does a buffer contain to balance a strong base, or a strong acid?
Weak acid or base to bind or release the appropriate substance
What is the serous membrane of the abdominal cavity?
Peritoneum
What are the two categories of the peritoneum?
Visceral peritoneum
Parietal peritoneum
Which layer of the peritoneum is on the digestive organs surface?
Visceral peritoneum
Which layer of the peritoneum is lining the abdominal wall (exterior surface)
Parietal peritoneum
What is the space that is in between the two peritoneum layers?
Peritoneal Cavity
What is the job of the peritoneal cavity?
The fluid lubricates the mobile organs allowing movement without friction damage
What is the double layer of folded peritoneum that wraps around the intestines?
Mesentry
What routes for blood vessels, lymphatics, and nerves?
Mesentry
What holds organs in place and stores fat?
Mesentry
Can the mesentry move or change its organization?
yes - some flexibility
full bladder or not,
preganacy
tight clothes
What forms the greater curvature of the stomach?
Greater Omentum
What forms the lesser curvature of the stomach?
Lesser Omentum
What hangs over the intestines and is not attached?
Greater omentum
Which omentum connects stomach up to the bottom of the liver?
lesser omentum
What is the biological function of the omentums?
- Fat storage
(long-term storage for metabolism)
(moves fat through the digestion vis lymphatic system) - Immune regulation
(milky spots are clusters of immune cells important for defense)
What are the immune regulations that the omentums perform?
- Adheres to the site of inflammation
- Absorbs bacteria & contaminants
- Provides leukocytes for immune response
Oral Cavity - opens to:
oropharynx through fauces:
- nasopharynx - at the top
- oropharynx - back of oral cavity
- laryngopharynx - as heads down towards larynx region
Composition of the oral cavity includes:
- HCO3-
- Salivary amylase
- lingual lipase (initiates)
- Mucin - mucus, lysozyme & defensins fight bacteria, IgA antibodies
Another name for chewing
Mastication
Teeth that are for the ages (6-24 months)
deciduous teeth (20)
Teeth that come in from ages 6-17 years
permanent teeth (32)
Characteristics and differences of the Deciduous teeth
- Thinner enamel (appears whiter)
- More uniform enamel depth
- Dentin layer is thinner
- Pulp layer is thicker
Mechanical break down of food and act of swallowing turns food into
bolus
Another name for gums
gingiva
What is the exposed, hard surface of the tooth called
Crown
What is the crown made of
enamel
What part of the tooth is embedded in the jaw bone?
root
Protein-rich bonelike material = bulk of tooth, more flexible than enamel
Dentin
Part of the tooth that contains blood vessels, CT, nerves
Pulp
What nerve serves the teeth
Trigeminal nerve
What have a Synarthrotic joint and is fibrous
Gomphoses
What is the acidic bacterial secretions that etch enamel or dentin?
Caries
What is inflammation & degeneration of gingivae & may extend to the resorption of bone?
Periodontal disease
What is the pathway for food to the stomach?
esophagus
What is the swallowing of a bolus?
deglutition
What moves the bolus to the stomach?
Peristolasis
smooth muscle waves
What is another name for the gastroesophageal sphincter?
cardiac
region where it is located
What is the name of the sphincter that makes sure that the stomach contents do not come back up into the esophagus?
Gastroesophageal sphincter
(Cardiac)
If you have a dysfunction of the gastroesophageal sphincter what can happen?
heartburn or acid reflux
How is GI smooth muscle contraction similar to skeletal muscle?
- Actin & Myosin (sliding filament model)
- Trigger for contraction is Ca2+ influx
- ATP energizes the sliding process
How is GI smooth muscle contraction different than skeletal muscle?
- Ca2+ is bound by calmodulin (CaM)
- Calmodulin interacts with myosin light chain kinase (MLCK) which phosphorylates myosin
Relaxation of the GI muscles includes:
- Ca2+ unbinds CaM
- Ca2+ transports to SR & ECF
- Dephosphorylation of myosin
Esophagus connects to the stomach –
Cardiac orifice → pyloric sphincter
Beginning of stomach —> end of stomach
What is the dome-shaped top of the stomach?
Fundus
Which omentum is superior?
Lesser omentum (curvature)
Which omentum is inferior?
Greater omentum (curvature)
hangs down over the intestines
What are the folds of the stomach lining that flatten when filling (distended)?
Rugae
How much is the max amount the stomach can hold?
one gallon. (4L)
Imagine eating popcorn. Brief explanation of process or structures:
Deglutition
swallowing popcorn that formed into a bolus
Imagine eating popcorn. Brief explanation of process or structures:
Pyloric sphincter
end of stomach
Imagine eating popcorn. Brief explanation of process or structures:
Peristalsis
smooth wave contraction moving bolus
Imagine eating popcorn. Brief explanation of process or structures:
Salivary amylase
Enzyme that initiates digestion of CHO and lipids
Imagine eating popcorn. Brief explanation of process or structures:
Gomphoses
socket joint for teeth
Imagine eating popcorn. Brief explanation of process or structures:
Cardiac sphincter
where popcorn leaves esophagus and meets the stomach
The beginning of the stomach
(gastroesophageal sphincter)
Imagine eating popcorn. Brief explanation of process or structures:
Bolus
Popcorn being chewed
Imagine eating popcorn. Brief explanation of process or structures:
Rugae
Will begin to stretch out when popcorn (BOLUS) begin to fill the stomach
Imagine eating popcorn. Brief explanation of process or structures:
Enamel
Hard tough chewing surface for mastication
Imagine eating popcorn. Brief explanation of process or structures:
Lingual lipase
Initiates enymes
Imagine eating popcorn. Brief explanation of process or structures:
Mastication
Chewing of the popcorn
Mucosa - gastric glands have 4 types of cells:
- mucous cells
- parietal cells
- zymogenic (chief) cells
- enteroendocrine cells (gut-endocrine)
What produces the mucus that aids in protective layer and makes sure the acidic pH. of the stomach does not damage our sensitive tissue cells?
Mucous cells
What produces the ingredients needed for other aspects of digestion and are up high on the outside?
Parietal cells
What two things do the parietal cells produce?
- Intrinsic factor (protein)
- HCl
What protein is required for the absorption of Vitamin B12?
Intrinsic factor
Which cells have the biggest impact on pH?
Parietal cells
What do parietal cells make that activates enzymes?
HCL
Parietal
HCL
pH
Lowers pH in stomach allowing specific enzyme to take action
What vitamin can we NOT live without?
B12
Which cells secrete pepsinogen?
zymogenic (chief) cells
What is a precursor molecule to pepsin and lipase?
pepsinogen
What acid interacts with pepsinogen and converts it to pepsin?
HCl
What breaks down protein?
pepsin
Enteroendocrine cells release hormone-substance -
Gastrin
Cholecystokinin
What increases HCl secretion from parietal cells and stimulates muscle contraction and gastric emptying?
gastrin
90% of ulcers are due to:
H. Pylori
which is the strongest risk factor for gastric cancer
What are the two controls of gastric secretions?
Neural
Hormonal
Where is neural referring to
in your head
What phase where thinking, seeing, hearing, smelling, or tasting food initiates gastric secretions?
External Stimuli
Cephalic Phase
What is the phase called where your stomach is readying for digestion?
Cephalic phase
Pavlov’s dog
What nerve initiates gastric secretions?
Vagus Nerve
Where is hormonal control of gastric secretions?
Local control
What is the phase referred to that is under hormonal control?
Internal Stimuli
Gastric phase
What stimulates the gastric glands?
Gastrin
What does gastrin do?
relaxes pyloric sphincter & increases stomach motility → emptying
allows the small intestine to keep up
do not want a loss of nutrient absorption if stomach emptying is too fast
Which has a larger diameter, stomach or small intestine?
stomach
When chyme has reached the duodenum - this phase is called
Intestinal phase
What is the enterogastric reflex?
tightens the pyloric sphincter & delays the emptying of the stomach into the small intestine
Secretin is responsible for
pH balance
Secretin stimulates the pancreas to release
HCO3-
What increases the pancreatic enzyme secretion?
Cholecystokinin (CCK)
= digestive process
What loosens the hepatopancreatic sphincter for flow into the duodenum?
Cholecystokinin (CCK)
What are the intestinal phase hormones?
- Secretin
- CCK
- VIP
What hormone in the intestinal phase increases blood flow through the intestinal capillaries?
VIP
What is VIP all about?
Absorption
What is CCK all about?
digestive process
What is secretin all about?
pH balance
The order of the GI structures:
- Pharynx
- Esophagus
- Gastroesophageal sphincter (cardiac)
- Stomach
- Pyloric sphincter
- Duodenum
- Jejunum
- Ileum
- Cecum
- Appendix
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon
- Rectum
- Anus
Which sphincter is at the beginning of the small intestine?
Pyloric sphincter
Which sphincter is in between the small and large intestine?
ileocecal valve
What are the three subsections of the small intestine?
- Duodenum (1st foot)
- Jejunum (8 feet)
- ileum (12 feet)
What is the unsung sphincter in the intestines?
ileocecal valve
What are the three small intestine modifications?
- villi
- intestinal glands
- microvilli
What increases mucosal surface area of the small intestine?
villi
larger folds
What pits in mucosa between villi and produces intestinal juices?
Intestinal glands
What cells are deep in the intestinal glands and produce defensins and lysozyme that kill bacteria?
Paneth cells
Where are Paneth cells located?
small intestine
What two antimicrobial agents (chemicals) do paneth cells produce?
defensins & lysozyme
Which contain proteases & disaccharides in the membrane of the small intestine?
microvilli
What comes from the intestinal crypts of the small intestines?
intestinal juice
which is mostly isotonic fluid with mucus and some lysozyme
What is Pancreatic juices =
enzymes and NaHCO3-
What 4 items are part of the pancreatic juices?
- Amylase (CHO)
- Lipase (fats)
- Trypsin, chymotrypsin, carboxypeptidase (proteins) - inactive form and become active once arrive in the intestines
- Bile - emulsifies
What are the accessory organs?
- Liver
- Gallbladder
- Pancreas
- Salivary glands
What does not have any direct contact with ingested material?
Accessory organs
What organ that has the greatest internal surface area?
Liver
The liver receives blood from two sources:
- Hepatic artery
- Hepatic-portal vein
How does the blood exit from the liver?
through the hepatic vein
What blood does the hepatic artery deliver?
oxygenated blood from the aorta
What blood does the hepatic-portal vein deliver?
venous blood from the digestive system
Compartments in the liver are called
lobules
What cells line the liver and help screen blood?
hepatocytes
What two fx of liver
Detoxifies
stores (nutrients or toxins - including glucose
Where is bile stored?
gallbladder
What duct from the gallbladder joins the hepatic duct forming the common bile duct?
cystic duct
Back up in the gallbladder means you get
jaundice
What color is bilirubin
Yellow
Bile consists of
- pigments (bilirubin from heme groups on RBCs being broken down)
- Salts
Bacteria metabolize bilirubin to →
urobilinogen that causes the feces to be brown
Without bile…feces would be
- gray-white in color
- contain undigested fat
Liver actions
- production of heparin and plasma proteins
- Storage
- Breakdown of nitrogenous wastes and alcohol by using alcohol dehydrogenase
What role does the liver play in NFP?
Albumin production
Albumin is the driving force of osmotic pressure
Since liver produces bile, why do we need lipase?
Bile is the emulsifier - does not break up fats - just puts them in smaller globules
Lipase - digestion of the fats
Why would hemolytic anemia lead to jaundice?
- Breakdown of RBCs is happening too fast
- Puts stress on the liver
- There is a build-up of pigmentation in the soft tissues
The pancreas is a gland that has three functions:
- endocrine function into the bloodstream
- exocrine function in the small intestine
- pancreatic secretion
What of the pancreas secretes insulin and glucagon?
islets of Langerhans
Balances out the blood glucose
What tissue of the exocrine function of the pancreas secretes pancreatic juices that help balance out pH (enzymes and NaHCO3).
Acinar tissue
What of the pancreas is regulated by secretin, CCK, and VIP?
Pancreatic secretion
What does secretin do in the pancreas?
Increases pancreatic HCO3- and bile
What does CCK do in the pancreas?
Increases pancreatic [enzyme]
stimulates to release the pancreatic enzyme
What does VIP do in the pancreas?
It increases blood flow and pancreatic action
blood supply to help absorption
What three things slow the emptying of the stomach by slowing the motility?
- Secretin
- CCK
- VIP
Tightens up the pyloric sphincter - so nutrients do not leave the stomach to quickly
How long is the large intestine?
1.5 meters
What are the three sections of the large intestine?
- cecum
- colon
- rectum
What is the entryway into the large intestine?
cecum
What prevents the bacteria from breaching the wall of the large intestine and generates memory lymphocytes?
Cecum
What attaches to the cecum and is all about bacteria refuge and MALT immunity?
appendix
What are the 4 regions of the colon?
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon (s-shaped)
What sphincter is in between the ileum and cecum?
ileocecal valve
The rectum has two sphincters:
- Internal sphincter
- External sphincter
Which rectum sphincter is under voluntary control?
external sphincter
Which rectum sphincter is under involuntary control via spinal reflex arc?
internal sphincter
What is the reflex that begins with the movement of feces into sigmoidal colon and rectum?
Defecation Reflex
What manuever aids in defecation?
Valsalva’s maneuver
Pressure - don’t strain - caution at the gym