Brainscape's Knowledge GenomeTM

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


See full index

GI > Oesophagus and its disorders > Flashcards

Oesophagus and its disorders Flashcards

1
Q

What is the oesophagus?

A
  • Fibromuscular tube (25cm) of striated squamous epithelium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where does the oesophagus lie?

A
  • Lies posterior to the trachea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where does the oesophagus begin and join the stomach?

A
  • Begins at end of laryngopharynx and joins stomach a few cm from diaphragm (at the cardiac orifice)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the oesophagus wall composed of?

A
  • The oesophagus wall is composed of striated muscle in the upper part, smooth muscle in the lower part, and a mixture of the two in the middle.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What coexists at the LOS?

A
  • At the LOS both squamous and columnar epithelium may coexist.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the functions of the oesophagus?

A
  • Transports food to stomach (eating gullet)

* Secretes mucus

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

What promotes the transport of ingested food into the stomach?

A

– Relaxation of the sphincters (UOS and LOS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does relaxation of the sphincters involve?

A

involves contraction and relaxation of the oesophagus which transports the food through the GIT

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

Steps that occur down the oesophagus

A

it moves from the mouth to the throat (pharynx; 1). Just as the food approaches the upper oesophageal sphincter, it opens (2) so that food/bolus can enter the oesophagus. Then rhythmic waves of muscular contractions and relaxations, called peristalsis, propel the food downward (3). The food/bolus then passes through the lower oesophageal sphincter (4) and finally into the stomach (reservoir; 5)

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

What muscles surrond the oesophagus?

A

Skeletal and smooth muscle

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

Where does the skeletal muscle surround the oesophagus from?

A

• Skeletal muscles surround the oesophagus below the pharynx (the upper third)

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

Where does the skeletal muscle surround the oesophagus from?

A

• Smooth muscles surround the lower two thirds

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

How many sphincters does the oesophagus have?

A

2

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

What are the 2 sphincters known as?

A
  • Upper oesophageal sphincter (UOS)

* Lower oesophageal sphincter (LOS)

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

What type of muscle is the UOS?

A

Striated muscle

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

What type of structure is the UOS?

A

• Musculo-cartilaginous structure

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

Why is the UOS constricited?

A

• Constricted to avoid air entering the oesophagus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What type of muscle is the LOS?

A

Smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the LOS?

A

area of high pressure zone where the oesophagus merges with the stomach

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What type of components does the LOS has?

A

• LOS has intrinsic and extrinsic components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the intrinsic component of the LOS and where is it located?

A

• Intrinsic component: oesophageal muscles; under neurohormonal influence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the extrinsic component of the LOS?

A

diaphragm muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What can the Malfunction of intrinsic and extrinsic components of LOS ?

A

Leads to GORD(oesophageal reflux disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What layers does the intrinsic components of LOS have?

A
  1. Thick circular smooth muscle layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What fibres are located on the right hand side of the intrinsic component of the LOS?

A
  1. Clasp-like semicircular smooth muscle fibres on the right side
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What type of activity does the intrinsic components of LOS have, and what is it less responsive of?

A

– Myogenic activity (some resting tone), but less ACh-responsive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What fibres are located on the left hand side of the intrinsic component of the LOS?

A

– Sling-like oblique gastric (angle of His) muscle fibres on the left side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How does the intrinsic components of LOS helps to prevent regurgitation?

A

Intrinsic components of LOS Work in concert with the clasp like-semicircular smooth muscle fibres, help to prevent regurgitation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Why is reflux common in infants?

A

– Angle of His is poorly developed in infants as it makes a vertical junction with stomach, hence why reflux is common in infants

30
Q

What is the angle of His?

A
  • Angle of His (oblique angle) is the acute angle created between the entrance to the stomach (cardia), and the oesophagus
31
Q

What does the angle of His form and what can it cause?

A

It forms a valve, preventing reflux of duodenal bile, enzymes and gastric acid from entering the oesophagus, where they can cause irritation of the oesophageal lining, inflammation and in extreme cases Barrett’s oesophagus

32
Q

What encircles the LOS and what does it form?

A

• Crural diaphragm encircles the LOS

– Forms channel through which oesophagus enters the abdomen

33
Q

What do fibers of the crural portion of the diaphragm posess?

A

• Fibres of the crural portion of the diaphragm possess a “pinchcock-like” action

34
Q

What does the anti-reflux barrier include and what are they known as?

A
  • The anti-reflux barriers include two sphincters: LOS and the diaphragmatic sphincter
35
Q

What does the extrinsic component of LOS consist of?

A

consists of the diaphragm muscle

36
Q

What does the the diaphragm muscle function as?

A

functions as an adjunctive external sphincter that raises the pressure in the terminal oesophagus related to the movements of respiration.

37
Q

What does the crural diaphragm form?

A
  • Crural diaphragm forms the oesophageal hiatus
38
Q

What does the oesophageal hiatus encircle?

A

it encircles the proximal 2-4 cm of the LOS

39
Q

What does the oesophageal hiatus determine?

A

determines the inspiratory-spike-like increase in LOS pressure

40
Q

What are involved in the control of tone of the lower oesophageal sphincter?

A

Involvement of cholinergic (i.e. via ACh) and non-cholinergic, NANC innervation in the control of tone of the lower oesophageal sphincter

41
Q

What is involved in the neural control of the oesophageal sphincter?

A
  • Acetylcholine, SP: contraction of intrinsic sphincters
  • NO and VIP: relax the intrinsic sphincters
  • Extrinsic and intrinsic sphincters work in concert to push the food into the stomach
42
Q

How does NO cause relaxation of smooth muscle cells?

A
  • NO interacts with AC which converts GTP to cGMP; cGMP activates PKG which acts on myosin phosphatase on smooth muscle cells and causes smooth muscle relaxation
  • Myosin phosphatase is an enzyme which dephosphorylates the regulatory chain of myosin II. The dephosphorylation reaction occurs in smooth muscles which initiates the relaxation of smooth muscles. Thus, myosin phosphatase undoes the muscle contraction process initiated by initiated by myosin light-chain kinase
43
Q

What type of muscle is the upper part of the oesophagus?

A

Striated muscles

44
Q

What is the upper part of the oesophagus supplied by?

A

supplied by somatic motor neurons of vagus nerve without interruption

45
Q

What type of muscle is the lower part of the oesophagus?

A

Smooth muscles

46
Q

What is the lower part of the oesophagus innervated by?

A

– Innervated by visceral motor neurons of vagus nerve with interruptions

47
Q

The oesophagus is encircled by nerves of what?

A

Oesophagus is also encircled by nerves of the oesophageal plexus

48
Q

What is the dorsal vagal nucleus?

A
  • Dorsal vagal nucleus (of the vagus nerve or posterior motor nucleus of vagus) is a cranial nerve nucleus for the vagus nerve in the medulla
49
Q

Where does the dorsal vagal nucleus lie?

A

It lies under the floor of the 4th ventricle and mostly serves parasympathetic vagal functions in the GIT, lungs and other thoracic and abdominal vagal innervations.

50
Q

What resides in the nucleus ambiguus?

A
  • The cell bodies for the preganglionic parasympathetic vagal neurons that innervate the heart reside in the nucleus ambiguus
51
Q

What is the phrenice nerve?

A

nerve that originates in the neck (C3-C5) and passes down between the lung and heart before it reaches the diaphragm

52
Q

What is the phrenice nerve important for?

A

Important for breathing

53
Q

What does the phrenice nerve innervate?

A

innervates the external; and internal intercostal muscles and the diaphragm; it passes motor information to the diaphragm and receives sensory information from it.

54
Q

How many phrenic nerves are there?

A

2 phrenic nerves

Left and right

55
Q

Where does the phrenic nerve originate mainly from but where does it also receive contributions from?

A
  • The phrenic nerve originates mainly from the 4th cervical nerve, but also receives contributions from the 5th and 3rd cervical nerves (C3-C5) in humans
56
Q

What fibres does the phrenic nerve contain?

A
  • The phrenic nerves contain motor, sensory, and sympathetic nerve fibres
57
Q

What is the only motor supply to the diaphragm as well as sensation to the central tendon?

A

Phrenic nerves?

58
Q

What does each phrenic nerve supply in the thorax?

A

In the thorax, each phrenic nerve supplies the mediastinal pleura and pericardium.

59
Q

What does the swallow reflex lead to?

A

Excitation of receptors in pharynx (oesophageal peristalsis and relaxation)

60
Q

Name some postganglionic transmitters

A

NO, VIP

61
Q

What is contraction of the crural diaphragm controlled by?

A
  • Contraction of the crural diaphragm is controlled by the inspiratory centre in the brainstem and the nucleus of the phrenic nerve
62
Q

What is the crural diaphragm innervated by?

A

The crural diaphragm is innervated by right and left phrenic nerves through ACh

63
Q

What is the striated muscle of the upper oesophagus innervated by?

A

The striated muscle of the upper oesophagus is innervated directly by the somatic efferent cholinergic fibres of the vagus nerve originating from the nucleus ambiguus

64
Q

What is the smooth muscle of the distal oesophagus innervated by?

A
  • Smooth muscle of the distal oesophagus is innervated by the preganglionic vagus nerve fibres from the dorsal motor nucleus
65
Q

What two types of neruons does ACh affect?

A

ACh affects two types of post-ganglionic neurons in the myenteric plexus: excitatory cholinergic neurons and inhibitory nitrinergic neurons via NO, VIP

66
Q

What triggers swallowing?

A

• Swallowing is triggered by afferent impulses in the trigeminal, glossopharyngeal and vagus nerves

67
Q

What initiats swallowing?

A
  1. Voluntary action – collect material on tongue and push it backwards into pharynx (skeletal muscle, mucus membrane)
  2. Waves of involuntary contractions push the material into oesophagus
68
Q

What happens in the inhibition of respiration?

A

nasopharynx is closed off

69
Q

What closes the glottis?

A

• Closure of glottis (around the vocal cords) by epiglottis

70
Q

What does closure of glottis prevent?

A

– Prevents food from entering the trachea

71
Q

What moves food towards the stomach?

A

• Ring of peristaltic waves (4cm/sec) behind the material move it towards the stomach

GI (7 decks)

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