Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology Exam 5 > 58 - GI Mouth and Esophagus > Flashcards

58 - GI Mouth and Esophagus Flashcards

1
Q

What are the two types of secretions from the salivary glands?

A
  • Serous secretions

- Mucinous secretions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe serous secretions from salivary glands

A

First is serous, which is watery and contains alpha amylase. Although insignificant in adults, it’s involved in carb digestion and is a marker of serous secretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe mucinous secretions

A

Second is mucinous secretion, which can be found throughout the GI tract

It’s a highly glycosylated protein that coats and protects things.

With respect to saliva – remember from cell bio that parotid is mostly serous, submandibular is a mix and sublingual is mostly mucinous (still technically a mix). Minor glands form mucous product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the mechanism by which water and salt is secreted into the lumen of the salivary gland

A

Two cell types play a role here - acinar cells and ductal cells

Ach stimulates acinar cells at muscarinic receptors to push Chloride out into the lumen. This active process ultimately results in water and Na following passively through the duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens to Na and Cl as they pass through the duct?

A

. As fluid progresses up the duct, Na and Cl are removed and “replaced “ by bicarb and K.

Bicarb keeps pH at around 8 during active secretion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does differential secretion affect the lumen of the salivary gland?

A

Na reabsorption is greater than K secretion. The net result of this differential of secretion is an increase in hypotonicity of the liquid as it rises – Chlorine and bicarb balance each other out because of the luminal side antiporter.

Na/K pump is used on the luminal side allows for the gradient to remain (– increase Na gradient outside means there is passive diffusion (via channel) back into the cell where it gets kicked into the interstitial space because of Na/K pump)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the components of saliva?

A 
1 - Alpha amylase
2 - IgA, lysozyme and lactoferrin
3 - Lingual lipase
4 - Mucin
5 - Water
6 - Electrolytes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the role of alpha amylase?

A

Alpha amylase is involved in starch digestion – less significant in adults due to development of the pancreas, therefore this may play a more significant role prior to the development of a fully functional pancreas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the role of IgA, lysozyme and lactoferrin

A

Antimicrobials to protect from bacterial and fungal growth. If you remember from pathology, the infections people with IgA deficiency were prone to

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the role of ligual lipase

A

Fat digestion. The expression is variable – also probably insignificant in adults, similar to alpha amylase. Pancreatic lipases take care of this function for adults.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the role of mucin

A

mucin is key in lubrication and protection of the mucosa.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of water?

A

Water – functions in taste, swallowing and speech.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the role of electrolytes?

A

Electrolytes – Key one to remember is bicarb. It functions to neutralize stomach acid that comes back up the esophageal tube – covers and coats to neutralize returning acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What would happen if you were lacking amylase and lipase?

A

Losing alpha amylase and lipase would probably be inconsequential as the pancreas takes care of this function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What would happen if you were lacking mucin and electrolytes?

A

Loss of mucin and electrolytes becomes problematic, mucin helps in protection from acid and probably abrasion as well (to some degree)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What would happen if you were lacking bicarb?

A

Loss of bicarb means you have stomach acidity problems.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the primary stimulus that increases salivary secretion

A

ACh

18
Q

Describe the basics of swallowing

A

Initiated voluntarily
Followed by reflex control
Respiration is inhibited, preventing food from entering trachea

19
Q

Three phases of esophageal motor activity

A

1 - Oral phase
2 - Pharyngeal phase
3 - Esophageal phase

20
Q

Describe the oral phase

A

This is a voluntary phase

  1. Tip of tongue separates
    a bolus of food by pressing against hard palate
  2. Bolus moves into the pharynx where the food stimulates touch receptors
  3. Swallowing reflex is initiated
21
Q

Describe the pharyngeal phase

A
  1. soft palate is pulled to prevent
    reflux into nasopharynx
  2. larynx & vocal cords pulled
    upward
  3. epiglottis swings downward
  4. UES relaxes
  5. pharynx muscles contract
  6. peristaltic wave initiates
    Important ***
    Primary and secondary peristaltic wave
22
Q

Describe the esophageal phase

A
  1. UES constricts
  2. peristaltic wave below UES (1º peristalsis)
  3. if insufficient to clear bolus, 2 º peristalsis begins at site of distension
23
Q

What is a main point about the initiation of peristalsis and GI motility

A

DISTENTION is key in starting these processes

24
Q

Describe GERD

A

Gastroesophageal reflux disease

  • Reflux of the gastric contents into esophagus
  • Can lead to inflammation of mucosal surface of esophagus (esophagitis)
  • Can eventually cause ulcer, edema, pre-cancerous lesion, bleeding

GERD can cause a motility issue or result from a motility issue

25
Q

Common causes of GERD

A
  • Weakened LES
  • Weak peristalsis
  • Hiatal hernia
  • Gastric ulcer
  • Delayed gastric emptying caused by a narrow pyloric region
26
Q

Barrett’s esophagus

A
  • Characterized by the replacement of squamous epithelial cells with columnar epithelial cells
  • Gives the epithelial surface a dark red appearance compared to light pink (normal)
  • Associated with an increased risk for the development of esophageal cancer
27
Q

Describe cystic fibrosis in relation to impaired salivary secretion

A
  • Cystic fibrosis leads to impared salivary secretion
  • CFTR (cystic fibrosis transmembrane conductance regulator) is a chloride ion channel that is regulated by cAMP and is dysfunctional in CF patients
  • CFTR is important for water and bicarb secretion into the lumen of salivary glands and causes ducts to clog, resulting in damage repaired by fibrosis
28
Q

Sjogren syndrome

A

Similar to CF in terms of salivation

  • Loss of function of CFTR due to autoimmune response
  • Result is having a dry mouth
29
Q

Dysphagia

A

Difficulty swallowing

- Can result from mechanical/functional impairments

30
Q

Describe mechanical reasons for dysphagia

A
  • Mechanical: tumors, stricture, herniation

- Can be caused by reflux disease, alcohol and tobacco use, viral infections from HPV

31
Q

Describe functional reasons for dysphagia

A
  • Functional: disruption of striated muscle, neuronal disorder
  • Can be caused by dermatomyositis, cerebrovascular accident, Parkinson’s disease, achalasia

Achalasia is a result of denervation of esophageal smooth muscle and impaired function of the LES

32
Q

Hiatal herniation

A

Hiatal hernias are diaphragmatic hernias which are caused by protrusion of the stomach through the diaphragm and into the thorax

33
Q

Sliding hernia

A
  • Most hiatal hernias are sliding hiatal hernias.
  • The stomach slides into the thoracic cavity through the esophageal hiatus.
  • Causes: coughing, bending, tight clothing, ascites, obesity, and pregnancy.
  • Symptoms: commonly observed as reflux of gastric contents into the esophagus
34
Q

Paraesophageal hernia

A
  • A less common herniation of the stomach
  • The greater curvature of the stomach protrudes through an opening or tear in the diaphragm
  • Often occurs in conjunction with reflux disease, ulcers, gallstones, pancreatitis, and inflammation of the gallbladder
  • The result of this hernia may be reflux esophagitis, vascular disruptions, or both
35
Q

What exacerbates symptoms of hiatal hernias?

A

Patients diagnosed with a hiatal hernia should avoid the flat supine position and exercises which increase intra-abdominal pressure, both will exacerbate symptoms of the hernia.

36
Q

On to case #2…

A

Go read case #2

37
Q

What is the pathogenic mechanism of her GI disorder?

A

LES relaxation, delayed gastric emptying, damage/scarring of tissue causing impaired relaxation, loss of secondary peristalsis, pressure/tone changes, excess NO production (this last one is unlikely).

38
Q

How may her lifestyle impact her symptoms?

A
  • Sleep after eating because gravity no longer helps in the digestive process
  • Smoking impacts the UES (skeletal muscle is innervated by NICOTINIC Ach receptor – probably also impacting esophageal motor activity – maybe inhibiting UES relaxation during pharyngeal phase of esophageal motor activity).
  • Benzodiazepines shown to induce smooth muscle relaxation (sphincter issue)
39
Q

What are some complications of chronic esophageal reflux disease?

A

Barrett’s is closer observed: cancer, lesion, obstruction, and dysphagia, incompetent LES.

40
Q

What therapeutic strategy would you use to address her condition?

A

Proton pump inhibitors

  • Decreases stomach acid very effectively
  • Example: Prilosec (omeprazole)

Physiology Exam 5 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions