Digestive system intro and overview

Question 1

function of the digestive system

Answer 1

mechanical and chemical breakdown of food

Question 2

Accessory digestive organs includes

Answer 2

salivary glands, liver, gallbladder, pancreas

Question 3

liver producing bile in gall bladder helps with digesting ___ (detergent)

Answer 3

fat

Question 4

pancreas producing juice with digestive enzymes can break down all nutrients. It also contains ____ which neutralizes the acid coming from the stomach into the duodenum

Answer 4

bicarbonate

Question 5

___ ___ performs most of the work, and is the main site of digestion and absorption

Answer 5

small intestine

Question 6

Four basic digestive process of the digestive system are:

Answer 6

motility
secretion
digestion
absorption

Question 7

Digestion can be mechanical or chemical:
____ is accomplished by physical means, such as chewing, mushing, mixing, mashing action of digestive tubes

____ - Involves chemical operation of the food with the help of digestive enzyme and bile juices produced by the liver

Answer 7

mechanical

chemical

Question 8

contractions of smooth muscle in the wall of the tube that crush, mix and propel its contents is called ____

Answer 8

Motility

Question 9

delivery of enzymes, mucus, ions, water into the lumen, and (specialized endocrine cells) hormones into the blood is called ___

Answer 9

Secretion

Question 10

food is broken down into smaller molecules suitable for absorption (chemical and mechanical). this process is called ___

Answer 10

digestion

Question 11

the transport of water, ions and nutrients from the lumen, across the epithelium and into the blood is called

Answer 11

absorption

Question 12

The digestive tract wall has four layers:

Answer 12

mucosa, submucosa, muscularis externa, serosa

Question 13

The ___ layer covers the digestive tube, and provides a protective barrier

Answer 13

epithelial

Question 14

inner most layer highly folded mucous membrane, exocrine, endocrine gland cells and epithelial cells specialized for absorption.

Answer 14

Mucosa

Question 15

thick layer of connective tissue

gives digestive tube elasticity

Answer 15

Submucosa

Question 16

inner circular and outer longitudinal smooth muscle layers

Answer 16

Muscularis externa

Question 17

In the muscularis externa, when circular muscle contract we ___ the diameter of digestive tube, when longitudinal contracts, the digestive tube ____

Answer 17

decrease

shortens

Question 18

Between the submucosa and muscularis externa theres a network of nerves called___ ____ – together the submucosal and the myenteric plexus make up the enteric (intrinsic) nervous system

Answer 18

myenteric plexuses

Question 19

outer connective tissue, secretes serous fluid to lubricate and prevent friction

Answer 19

Serosa

Question 20

secrete water slippery fluid in the digestive organ and surroundings to lubricate and prevent friction. Throughout the digestive tract, its continuous with mesentery which suspends the digestive tract organ from the abdominal wall

Answer 20

Serosa cells

Question 21

True or false? The contents of the stomach lumen are outside the body

Answer 21

True

Question 22

Substances inside the lumen of Digestive Tube are considered inside the body and are part of internal body environment only after they have been absorbed by the intestinal ____ cells

Answer 22

epithelial

Question 23

Conditions essential for digestion can be tolerated ___ the body but not ___ the body within the bodies internal environment

Answer 23

outside

inside

Question 24

existence of microbes in our colon, in lumen they are not harmful but beneficial, however, if bacteria gets in the internal environment, they become ___

Answer 24

harmful

Question 25

Content of ___ in Digestive Tube are part of external environment and are outside body

Answer 25

lumen

Question 26

Ist layer of cells which encounter any nutrients in digestive tube is the ____ layer, and are arranged in invaginations called ___ and finger-like projection called ___ —- this arrange helps increase absorptive surface area.

Answer 26

epithelial
crypt
vilus

Question 27

Most epithelial are ___, tight junctions —essential for absorption of nutrients. It also provides the barrier that prevents harmful substance from getting in from the outside

Answer 27

columnar

Question 28

Together, the absorption by the epithelial of nutrients and the barrier preventing harmful substance from entering is called “____ ____” — tight junction plays important role. Another important component is the ___ layer secreted by the specialized cells.

Answer 28

gastrointestinal barrier

mucus

Question 29

Efficient transport of nutrients across the epithelium while passage of harmful molecules and organisms is rigorously excluded

Answer 29

gastrointestinal barrier

Question 30

___ ___ also divide the membranes into two separate compartment with specific function (apical and basolateral membrane)

Answer 30

Tight junctions

Question 31

The gastrointestinal epithelial is a ___ epithelia

Answer 31

polarized

Question 32

Transport from the lumen to extracellular fluid (ECF) - ___. Transport from ECF to lumen - ___

Answer 32

absorption

secretion

Question 33

___ epithelia have different transport proteins on apical and basolateral membranes allowing selective directional transport across the epithelium

Answer 33

Polarized

Question 34

Epithelial cells arise from stem cells that are located at the base of ___ in the intestine and in the middle of gastric glands in the stomach. The cell travels from the crypt to the tip of the villus takes ~___ days
the lining of the digestive tube is completely replaced

Answer 34

crypts

3 days

Question 35

we have the speciaized stem cells that constantly divide and diff and travel from bottom of the crypt to the tip of villus where they undergo cell death, or ___. They then shed into ____ to be replace by newly diff epithelial cells. — lining of the digestive tube is completely replaced

Answer 35

apoptosis

lumen

Question 36

GIT its highly populated with macrophages, lymphoctyes etc, invloved in the ___ response.

Answer 36

immune

Question 37

GIT is the ____ organ. The ____ tissue associated with the GIT is call the GUT-associated lymphoid tissue (GALT), which its said to contain as many lymphocytes as our spleen

Answer 37

lymphoid
lymphoid
GUT-associated lymphoid tissue (GALT)

Question 38

the lymphocytes in our GIT are divided into three major population depending on location

Answer 38

Peyer’s Patches
Lamina propria lymphocytes
Intraepithelial lymphocytes

Question 39

peyer’s patches are ____ follicals

Answer 39

lymphoid

Question 40

peyer’s patch are ___ cells (M cells) on epithelial layer that sample different antigens from the lumen. Via endocytosis it engulfs them and transfers them to the macrophages and dendritic cells instead of digesting them. Macrophages and Dendritic cells present them to ___ and this results in appearance of plasma cells that secrete ___ into the lumen and help prevents the colonization of pathogens and bacteria in lumen. In addition the ___ cells they sample antigens in lumen

Answer 40

microfold
tcells
IgA
dendritic

Question 41

In the post-prandial period (after a meal) blood is diverted from the skeletal muscles and other body systems. The blood volume in the GIT increases up to __ folds

Answer 41

5

Question 42

Enteric nervous system consist of two neural plexus:

Answer 42

myenteric and submucosal plexus

Question 43

The autonomic nervous branches controls the enteric nervous system (sympathetic and parasympathic nervous system), however some reflexes are integrated within the ENS not requiring ANS or CNS action at all, because the ENS can serve as its own information processing center. “consider GIT ___ ___”

Answer 43

little brain

Question 44

The ____ plexus is mainly involved with control of gut motility

Answer 44

myenteric

Question 45

The ___ plexus coordinates intestinal absorption and secretion

Answer 45

submucosal

Question 46

What kind of adverse gastrointestinal effect will most likely develop as a result of prolonged treatment with anticholinergic drugs?

Answer 46

constipation

Question 47

____ is the primary neurotransmitter involved in the stimulation of secretion and motility in GIT.

Answer 47

Acetylcholine

Question 48

__ and __ function as inhibitory neurotransmitters.

Answer 48

ATP

NO

Question 49

___ neurotransmitters, e.g. vasoactive intestinal polypeptide (VIP), stimulates intestinal fluid and electrolyte secretion but inhibits motility.

Answer 49

Peptide

Question 50

___ is active in emergency situations. In general it decrease all aspect of digestive function.
___ dominates in quiet situations, when the digestion can reach its optimum, that is why it stimulates all aspect of the digestive function

Answer 50

Sympathetic

Parasympathetic

Question 51

In the digestive tract wall, there are 3 types of receptors:

Answer 51

chemoreceptors
mechanoreceptor
osmoreceptors

Question 52

___ are activated by various chemicals present in lumen, ____ are stimulated by the stretch and distension of the digestive wall , ___ stimulated by different osmolarity of the lumen content

Answer 52

chemoreceptors
mechanoreceptor
osmoreceptors

Question 53

Stimulation of chemoreceptors, mechanoreceptor, &b osmo-receptors receptors can stimulate or inhibit the___ nervous system: the neurons of the submucosa plexus, myenteric plexus, change activity of autonomic nervous fibers and change secretion of gastrointestinal hormones.

Answer 53

intrinsic

Question 54

All processes in digestive system are under physiological control under three types of mechanisms:

Answer 54

neural
endocrine
paracrine

Question 55

involves regulation of the intrinsic nervous system, the submucosal nervous system, and myenteric plexus and by fibers of autonomic nervous system

Answer 55

Neural regulation

Question 56

refers to the presence of highly specialized entero-endocrine cells that secrete various hormones into the blood circulation, and then the gastrointestinal hormones can reach the distant sites in the digestive tube and change their function

Answer 56

Endocrine regulation

Question 57

There are more than 13 different hormones secreted in the GI tract; it is considered one of the largest ____ organ in our bodies

Answer 57

endocrine

Question 58

Some agent and substances are not stable enough to persist in the blood circulation, instead when they are released they change the function of the neighboring cell– this is called the ___ ___

Answer 58

the paracrine regulation

Question 59

A good example of paracrine regulation would be the release of ___ by the stomach cells, in which they stimulate the neighboring parietal cells in the stomach to secrete the gastric acid

Answer 59

histamine

Question 60

the smooth muscle cells allow the digestive tube to perform two major patterns of motility:

Answer 60

propulsive movements

mixing movements

Question 61

____ moves content so that the digest tube move forward.
Mixing movement have two purposes: 1st they have to mix the content with the digestive juices and they have digestion but also they have to expose all parts of the lumenal content to the absorptive surface of the small intestine so they also facilitate absorption

Answer 61

Propulsive movements

Question 62

So the major type of the propulsive movements, which is seen particularly well in the esophagus and the small intestine is called ____

Answer 62

peristalsis

Question 63

refers to the ring-like contraction of the circular smooth muscle cells that move progressively forward and push bolus in the relax area ahead of contraction

Answer 63

Peristalsis

Question 64

segmental ringlike contractions with mixing movement that chop and mix the food

Answer 64

Segmentation

Question 65

Electrical activity of smooth muscle cell in GIT activity is induced by pace-maker cells called interstitial cells of

Answer 65

Cajal

Question 66

the __ junctions serve the main purpose of cell cell communication. In particular, the charged ions can freely pass, which means the electrical activity initiated by the pacemaker cells by the interstitial cells of cajal can be easily passed to the smooth muscle cells

Answer 66

gap

Question 67

When partially digested food enter small intestine we have a stretch and distention of the intestinal wall which in turn activates the ____ within the gut wall
This causes release of excitatory neurotransmitters, which leads to membrane potential becoming more depolarized, followed by muscle contractions. The contraction moves around and along through the ___ junctions
If inhibitory neurons are released, the opposite will occur

Answer 67

mechanoreceptors

gap

Question 68

Saliva is produces by three major salivary glands:

Answer 68

parotid glands, submandibular gland, and sublingual gland

Question 69

The saliva help to start the digestion of complex carbohydrate bc it contains the enzyme called ___ ___

Answer 69

salivary amylase

Question 70

the saliva is very important for oral hygiene bc it contains the ___ which helps kill the majority of microorganisms that enter the oral cavity

it also facilitates the movement of lips and tongue

Answer 70

lysozyme

Question 71

Both parasympathetic and sympathetic induce salivary secretion, however the amount is very different. The ___ produces a lot more saliva, the ___ generates smaller volumes of viscous saliva which is reached in mucous.

Answer 71

parasympathetic

sympathetic

Question 72

Food goes from the oral cavity (bolus) into the ___ (the throat). The throat/pharynx participates in the swallowing reflex. ___ can be voluntary, but once it is initiated it cannot be stopped.

Answer 72

pharynx

Swallowing

Question 73

The ___ elevates closing the nasal passages, then the ___ is pushed down closing respiratory airways. With them closed, the pharyngeal muscles contract and pushes bolus into esophagus.

Answer 73

uvula

epiglottis

Question 74

we don’t perform strong respiratory activity during swallowing bc the swallowing center in ___ of brain stem temporarily inhibits nearby ligated respiratory centers

Answer 74

medulla

Question 75

Esophagus contains ___ muscle in addition to circular and longitudinal muscle like the rest of the digestive tract.

Answer 75

skeletal

Question 76

___ ____ deals with skeletal muscle fatigue. One of the common symptoms is difficulty swallowing

Answer 76

Myasthenia gravis

Question 77

The esophagus is guarded by sphincters on both ends, ____ sphincter and the ____ sphincter—- these sphincters are closed most off the time except during swallowing.
___ is closed to prevent large amount of air getting into the digestive tube and accumulation of gas. The ___ sphincter is always closed to prevent the high acidic gastric content from getting into the esophagus and damaging wall

Answer 77

pharyngoesophageal sphincter
gastroesophageal sphincter
pharyngoesophageal
gastroesophageal

Question 78

The ___ nerve ending release acetylcholine which can act on the excitatory or inhibitory neurons of the myenteric plexus

Answer 78

vagus

Question 79

The excitatory neurons of the myenteric plexus release mainly ___ and _____

Answer 79

substance P

acetylcholine

Question 80

a neurotransmitter that modulates the pain perception. It also acts as an important peptide neurotransmitter in the digestive tract

Answer 80

SUB P

Question 81

The inhibitory neurons of the myenteric plexus that release nitric oxide and vasoactive peptide causes smooth muscle ___.

Answer 81

relaxation

Question 82

Acid from the stomach in the esophagus cause

Answer 82

GERDs

Question 83

symptoms of GERDs

Answer 83

regurgitation, burning chest pain(heart burn)

Question 84

Minor symptoms of GERDs are

Answer 84

dysphagia (difficulty swallowing), non-burning chest pain

Question 85

Atypical extra-esophageal symptoms of GERDs include

Answer 85

sore throat, coughing, increased salivation shortness of breath

Question 86

refers to the presence of inflammatory cells within the esophageal mucosa.

Answer 86

Esophagitis

Question 87

major complications of GERDs

Answer 87

esophagitis
Esophageal stricture
Barret’s esophagus

Question 88

– inflammation of esophageal wall and the presence of various types of pro-inflammatory and infiltration of immune cells in the esophageal epithelial

Answer 88

esophagitis

Question 89

– where the lumen of the esophagus becomes abnormally narrow, due to the thickening of the esophageal wall – which happens bc of the persistant inflammatory process—- main cause is GERD, and is responsilbe of 70% of all cases

Answer 89

Esophageal stricture

Question 90

esophageal stricture can interphere with the normal passages of food bolus across esophagus
and causes the ____ (difficulty swallowing)

Answer 90

dysphagia

Question 91

Treated by dilation using endoscopically inserted balloons. Its also important to manage GERD in order to heal esophageal wall and prevent stricture from return again.

Answer 91

Esophageal stricture

Question 92

The esophageal wall contains same epithelial as the oral cavity and skin called ___ epithelial

The stomach and rest of digestive tube are covered with ___ epithelium.

Between stomach and esophagus there’s a demarcation line called ____ columnar junction. The ___ epithelium appears whitish pink and the ___ appears reddish salmon pink.

Answer 92

squamous
columnar
squamous
squamous
columnar

Question 93

The abnormal healing of the erosions where the normal squamous becomes columnar epithelium which is normally present in the stomach and father in the digestive tube
—–at higher risk 10X esophageal cancer
This is called

Answer 93

Barret’s esophagus

Question 94

achalasia

Answer 94

Another disorder associated with the dysfunction of the lower esophageal sphincter

Question 95

is translated as failure to relax. Theres a constant contract of the lower esophageal sphincter. If constantly closed the food cant pass normally in the esophagus to stomach.

Answer 95

achalasia

Question 96

the main symptom of achalasia is

Answer 96

dysphagia

Question 97

undigested food in the esophagus can result in pulmonary ___

Answer 97

aspiration

Question 98

studies show that in achalasia patients there’s a degeneration loss of neurons of ___ plexus which regulate the contraction of smooth muscle lower esophageal sphincter

Answer 98

myenteric

Question 99

the smooth muscle of the lower esophageal sphincter contains the presence of the myenteric plexus with excitatory neurons that release __ that stimulate smooth muscle contraction and inhibitory neuron which release ___, a major inhibitory neuron found in GI system

Answer 99

Ach

nitric oxide

Question 100

measures the pressure as the swallowing proceeds, so it increases as we swallow, but then at the level of lower esophageal sphincter (LES), the pressure drops as the sphincter relaxes and opens to let the food into the stomach

Answer 100

manometry

Question 101

Patients with Achalasia, theres a loss and degeneration mainly of the neurons that release inhibitory neuron transmitter ___. In this case the Lower Esophageal Sphincter fails to relax resulting in difficulty swallowing

Answer 101

nitric oxide

Question 102

if there’s no presence of excitatory or inhibitory neurons due to major loss of mysenteric neurons, this leads to ___

Answer 102

dysphagia/diff swallowing

Question 103

achalasia is managed with balloon, which is inserted with endoscope, allowing the sphincter to stay constantly open. This however results in ___. Because ___ is easily manageable with medications — it’s a reasonable tradeoff.

Answer 103

GERDs

GERDs

Question 104

the injection on ___ __ has also been tested to treat achalasia.

Answer 104

botulin toxin

Question 105

inhibits Ach release so without Ach the smooth muscle is not contracting so strong, allowing swallowing to proceed normally by relaxing the sphincter.

Answer 105

Botulin toxin