Ward Gastric Physiology of digestion

Question 1

(blank) are secreted from the mouth to the terminal regions of the intestine.

Answer 1

digestive enzymes

Question 2

(blank) is secreted throughout the GI tract by glands to provide lubrication and protection of the epithelial lining.

Answer 2

mucus

Question 3

What are the two primary types of secretion?

Answer 3

digestive enzymes

mucus

Question 4

What are the four types of glands associated with secretion?

Answer 4

single cell mucous glands
crypts of Leberkuhn
Tubular glands
Salivary glands, pancreas and liver

Question 5

What is this:
(mucous cells/goblet cells) Are located in the epithelium and are found in most parts of the GI tract and respond to local stimulation of the epithelium by extruding their mucus onto the epithelial surface to act as a lubricant and to protect the epithelial surface.

Answer 5

Single cell mucous glands

Question 6

What is this:
These are in the small intestine and are invaginations of epithelium into the submucosa. These are usually deep and contain specialized secretory cells.

Answer 6

Crypts of Leiberkuhn

Question 7

What is this:
Located in the stomach and upper duodenum are large numbers of deep tubular glands which often secrete acid and pepsinogen.

Answer 7

Tubular glands

Question 8

What is this:
More complex glands with a primary function to provide secretions for digestion and emulsification of food. Two of these glands are compound acinus (containing many acinar cells) glands that lie outside the wall of the GI tract and are connected via ducts that empty into the GI tract itself.

Answer 8

Salivary glands, pancreas and liver

Question 9

The (blank) and (blank) are compound acinus (containing many acinar cells) glands that lie outside the wall of the GI tract and are connected via ducts that empty into the GI tract itself.

Answer 9

salivary and pancreatic glands

Question 10

Transportation of nutrient material needed for the formation of the secretory material must diffuse or be transported into the base of the glandular cell from (blank)

Answer 10

capillaries

Question 11

Synthesis of the secretory substance occurs in the (blank) and (blank)

Answer 11

ER and golgi complex

Question 12

The secretory substance is transported through the ER, passing into the (blank)

Answer 12

golgi complex

Question 13

In the golgi, secretory substances are modified, concentrated and discharged into the cytoplasm in the form of (blank)

Answer 13

secretory vesicles

Question 14

Secretory vesicles are normally stored in the (blank) ends of the cell until (blank) cause them to empty their contents through the cell’s surface.

Answer 14

apical ends

neural or hormonal signals

Question 15

The mechanism by which the secretory vesicle fuses to the plasma membrane (exocytosis) is usually (blank) dependent.

Answer 15

calcium

Question 16

The neural or hormonal substance causes an increase in (blank), which leads to a fusion of the secretory vesicle with the apical membrane.

Answer 16

intracellular calcium

Question 17

Sufficient water and electrolytes need to be secreted along with (blank).

Answer 17

organic substances

Question 18

Nerve stimulation has a specific effect on the (blank) portion of the cell membrane, causing (blank) transport of (blank) ions into the cell.

Answer 18

basal
active
Cl-

Question 19

When you have nerve stimulation that causes active tranport of Cl- into the cell you have a resultant (blank) charge inside the cell which causes (blank) to move into the cell.

Answer 19

negative charge

Na+

Question 20

When nerve stimulation causes Cl- to enter the cell and as a result, Na+ into the cell, the excess of both these ions inside the cell creates a (blank) condition within the cell and a force that does what?

Answer 20

hyperosmotic

OSMOTIC force -> pulls water into the cell increasing the hydrostatic pressure

Question 21

The increase in hydrostatic pressure resulting from nerve stimulation and the subsequent increase in Na+ and Cl- ions into the cell causes (blank) of the secretory border. Release of water through these openings results in the flushing of (blank) and (blank) out of the apical end of the cell and into the lumen of the gland

Answer 21

minute rupturing

electrolytes and organic substances

Question 22

The increase in hydrostatic pressure resulting from nerve stimulation and the subsequent increase in Na+ and Cl- ions into the cell causes minute rupturing of the secretory border. Release of water through these openings results in the flushing of electrolytes and organic substances out of the (blank) end of the cell and into the lumen of the gland

Answer 22

apical

Question 23

The presence of (blank) in a particular segment of the GI tract causes glands, in that region and often in adjacent regions to secrete digestive juices.

Answer 23

food

Question 24

What are the two types of local stimulation of the GI tract glands?

Answer 24

direct contact-> of food with glands

epithelial stimulation-> neural activity causes secretion

Question 25

What kind of GI stimulation is this: activates the autonomic nervous system via tactile, chemical and distension mechanisms. The increase in neural activity causes mucus glands and deeper glands in the mucosa to increase secretion.

Answer 25

Epithelial stimulation of GI tract glands

Question 26

What is the parasympathetic stimulation of secretion?

Answer 26

increase rate of glandular secretion - > upper portion of GI tract (Vagus) - >distal portion of large intestine (Pelvic Parasympathetics)

Question 27

What are the components of the upper GI tract that the parasympathetics increase stimulation of secretion in? What are these innervated by?

Answer 27

``` salivary glands esophageal glands gastric glands pancreas brunner's glands in Innervated by the vagus! ```

Question 28

What parasympathetics innervate the distal portion of the large intestine?

Answer 28

the pelvic parasympathetics

Question 29

Secretion in the remainder of the small and large intestine not innervated by parasympathetics is controlled how?

Answer 29

by local neural and hormonal stimuli in each segment of the gut

Question 30

What is the sympathetic stimulation of secretion?

Answer 30

causes slight/moderate increase in secretion | constriction of blood vessels

Question 31

When will sympathetic stimulation cause an increase in secretion?

Answer 31

if parasympathetic nerve stimulation of salivary glands is low. If parasympathetic stimulation of salivary glands is high,then sympathetic stimulation will result in a reduction in secretion.

Question 32

Summarize the hormonal stimulation of secretion:

Answer 32

GI hormones (polypeptides) from stomach and intestines are liberated from mucosa in response to food. They are absorbed into circulatory system and carried to particular gland to stimulate secretion

Question 33

What is saliva necessary for and what is it dependent on?

Answer 33

Speech and mucus

Question 34

What are the 6 constituents of saliva?

Answer 34

``` serous secretion mucus secretion lactoferrin proteolytic enzymes thiocyanate ions binding glycoprotein for IgA ```

Question 35

(blank) an enzyme for digesting starches.

Answer 35

Ptyalin (alpha-amylase) | ph of saliva is optimal for this

Question 36

(blank) Chelates iron and inhibits the growth of organisms that require it for growth.

Answer 36

lactoferrin

Question 37

(blank) attack bacterial cell walls

Answer 37

proteolytic enzymes (lyzozomes)

Question 38

(blank) With IgA forms secretory IgA that is immunologically active against viruses and bacteria.

Answer 38

Binding glycoprotein for IgA

Question 39

What is Composed of electrolytes, glycoproteins and water. Composition varies in the GI tract, but is an excellent lubricant and protectant.

Answer 39

saliva

Question 40

(blank) properties of mucus allow it to tightly bind to food and spread a thin film over the surface of particles.

Answer 40

adherent

Question 41

What are the functions of mucus

Answer 41

binds to food acts as a barrier to mucosa binds fecal material can buffer (amphoteric properties)

Question 42

(blank) allows for the easy passage of food along the GI tract and also prevents abrasions or chemical damage to the epithelium.

Answer 42

mucus

Question 43

What are the three majory salivary glands and what are they all drained by?

Answer 43

parotid, sublingual, submandibular | a single major excretory duct

Question 44

What is a minor salivary gland consisting of many single packages and are polystomatic.

Answer 44

buccal

Question 45

In (blank) glands, sexual dimorphosism often exists

Answer 45

mandibular

Question 46

(Blank) lie outside the wall of the GI tract and are connected via ducts that empty into the GI tract itself.

Answer 46

acinus glands

Question 47

(blank) are involved with directing fluids into the oral cavity.

Answer 47

ductal cells

Question 48

(blank) are contractile and are involved in helping move serous and mucous secretions into ducts.

Answer 48

myoepithelial cells

Question 49

(blank) are Secretions of ptyalin (-amylase) and/or mucin from acinar cells in a solution of ions similar to that found in extracellular fluid.

Answer 49

primary secretions

Question 50

Explain the intracellular mechanism for the movement of ions in salivary glands

Answer 50

Na+ ions are reabsorbed, K+ ions are secreted. This leads to a membrane potential of -70mV. This allows for passive reabsorption of Cl- ions. Cl- and Na+ ions are now at a low level in the ducts. Ca ions and bicarb are secreted by the ductal epithelial by an exchange of bicarb for chloride (actively)

Question 51

What is the net result o the intracellular movements of ions in the duct?

Answer 51

Na+ and Cl- ions are low (10% of plasma) K+ ions are higher Bicarb ions are higher

Question 52

During (blank) of the salivary glands, Na+ and Cl- ion concentration approaches levels found in plasma. In the presence of excess (blank) secretion, Na+ and Cl- ion absoprtion and K+ ion secretion is greatly increased!

Answer 52

maximal secretion | aldosterone

Question 53

Conditioned reflexes, smell, taste, pressure, and nausea do what to the salivary nucleus of the medulla?

Answer 53

activate it

Question 54

Fatigue, sleep, fear, and dehydration do what to the salivary nucleus of the medulla?

Answer 54

suppress it

Question 55

What is the primary regulator of the salivary glands?

Answer 55

parasympathetic nerves

Question 56

What parasympathetic nerves stimulate the release of aCH thus increasing salivary secretion, vasodilation, myoepithelial contraction, metabolism and growth?

Answer 56

CN IX and X

Question 57

What sympathetics effect secretion and through which ganglion?

Answer 57

T1-3 through the superior cervical ganglion

Question 58

(blank) nerve stimulation to the salivary glands begins and maintains salivary secretion.

Answer 58

parasympathetic

Question 59

Increased secretion is enhanced by (blank) which are also innervated by the parasympathetic system.

Answer 59

Myoepithelial cell contractions,

Question 60

Increased cellular activity in response to parasympathetic stimulation causes a release of (blank) resulting in the production of (blank) potent vasodilator) and also growth of the salivary glands.

Answer 60

Kallikrein | Bradykinin

Question 61

(blank) is Associated with chronic ulcerations of the buccal mucosa and with dental caries.

Answer 61

xerostomia (dry mouth)

Question 62

(blank) is the absence of saliva

Answer 62

congenital xerostomia

Question 63

(blank) is the Atrophy of the glands and decreased saliva production. In cystic fibrosis, salivary sodium, calcium and protein are elevated. Digitalis drugs cause increased calcium and potassium concentrations in saliva.

Answer 63

sjorgren's syndrome

Question 64

(blank) is when sodium concentrations are increased.

Answer 64

addison's disease

Question 65

(blank) can create Excessive salivation

Answer 65

tumors or parkinsons's disease

Question 66

(blank) activity aids digestion.

Answer 66

gastric motor activity

Question 67

What are four constituents of gastric juice that have physiologic functions?

Answer 67

intrinsic factors hydrogen ions pesin mucus

Question 68

What is required for the absorption of vitamin B12 by the ileal mucosa (released from parietal cells)

Answer 68

intrinsic factors

Question 69

What is necessary for the conversion of pepsinogen to pepsin. Also kills bacterial

Answer 69

hydrogen ions

Question 70

What, along with acid, begins to breakdown protein and is released from chief cells

Answer 70

pepsin

Question 71

What protects the mucosa lining of the stomach, lubricates and neutralizes a small amount of acid (released from goblet/mucus cells)

Answer 71

mucus

Question 72

What are the 2 gland areas of the gastric mucous?

Answer 72

oxyntic and pyloric

Question 73

What does this: | secretes acid, pepsinogen, mucus and intrinsic factor and is located on the proximal 80% of the stomach.

Answer 73

oxyntic gland area

Question 74

What does this: | The distal 20% (antrum) synthesizes and secretes the hormone gastrin and mucus.

Answer 74

pyloric gland area

Question 75

The line of demarcation between the oxyntic and pyloric gland mucosa is in the region of the (blank) on the lesser curvature.

Answer 75

incisura or angulus

Question 76

The (blank) lie deep in the stomach wall and receive a rich blood supply and autonomic innervation.

Answer 76

gastric glands

Question 77

(blank) Contain the acid-producing parietal cells and the peptic or chief cells, which secrete the enzyme precursor pepsinogen.

Answer 77

oxyntic glands

Question 78

(blank) are Present where the glands open into the pits. These cells divide and the daughter cells migrate to the surface where they become mature mucous cells and down into the glands where they become parietal cells in the oxyntic gland area or G cells in the region of the pyloric gland mucosa.

Answer 78

mucous neck cells

Question 79

(blank) are capable of mitosis, but they can also arise from mucus neck cells during the repair of damage to the mucosa.

Answer 79

peptic cells

Question 80

To generate the massive concentration of H ions brought to us by the 3 billion parietal cells that secrete HCL at a conc. of 150-160 mMolar, how many calories/L of gastric juice is required?

Answer 80

1500

Question 81

Between meals the cytoplasm of the parietal cell is dominated by numerous (blank) and intracellular (blank) that is continuous with the lumen of the oxyntic gland. During acid secretion, what happens to the tubulovesicles?

Answer 81

tubulovesicles. canaliculus they become microvilli and project into the canaliculus (which expand)

Question 82

What enzymes are located in the microvilli of the parietal cells during acid secretion?

Answer 82

carbonic anhydrase, ATPase enzymes

Question 83

What is the mechanism of HCL acid secretion by parietal cells?

Answer 83

in apical membrane active H+/K+ATPase pumps H+ ions out of cell (from dissociated water) and pumps K in (from acid secretion). Basolateral membrane has a Cl/HCO3 exchanger that brings cl into the lumen and HCO3 into the blood.

Question 84

To obtain the H needed in the HCL secretion of parietal cells, what do we need? How do we replenish this?

Answer 84

we need to breakdown water | To replenish water we need carbonic acid which is made from OH and CO2 (provided by metabolic sources in cell)

Question 85

To get the H secretion from the parietal cell you need an abundance of H (given by water) and an increased K conductance, where does this increase in K come from?

Answer 85

from active acid secretion

Question 86

Because of the HCO3- that is secreted into the blood stream during active acid secretion into the lumen of the oxyntic gland, the blood is quite alkaline, a phenomenon known as the (blank). Water is also drawn into the lumen, maintaining the iso-osmolallity of acid secretion.

Answer 86

ALKALINE TIDE.

Question 87

astric juice has high concentration of what 2 ions and a low concentration of what 2 ions?

Answer 87

Cl-, H+ | K+, Na+