Brainscape's Knowledge GenomeTM

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


See full index

Semester 4: Nutrition and Metabolism > PBL Topic 4 Case 1 > Flashcards

PBL Topic 4 Case 1 Flashcards

1
Q

Identify four roles of the GI tract

A
  • Movement of food through the tract
  • Digestion, aided by secretion of digestive juices
  • Absorption of water, electrolytes and digestive products
  • Circulation of blood through to carry away the absorbed subsances
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Identify the five layers of the intestinal wall from the outer surface inward

A
  • Serosa
  • Outer longitudinal muscle layer
  • Inner circular smooth muscle layer
  • Submucosa
  • Mucosa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Outline the dimensions and arrangmeent of a smooth muscle fibre in the GI tract

A
  • 200 to 500 micrometres in length
  • 2 to 10 micrometres in diameter
  • Fibres are arranged as bundles in parallel fibres
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the role of gap junction between muscle fibres in each bundle?

A
  • Allow low-resistance movement of ions from one muscle cell to the next.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is the smooth muscle of the GI tract described as a syncytium?

A
  • Muscle fibre bundles fuse at various points

- Action potential travels in many directions as a result

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

What are slow waves?

A
  • Undulating changes in the resting potential of about 5 to 15 millivolts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the role of interstitial cells of Cajal and how are they arranged?

A
  • Electrical pacemakers of smooth muscle cells
  • Which interact with smooth muscle cells to excite the appearance of spike potentials
  • Form a network with each other and have synaptic-like connections with smooth muscle cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the frequencies of slow waves in the stomach, duodenum and ilium?

A
  • Stomach: 3 per minute
  • Duodenum: 12 per minute
  • Ilium: 9 per minute
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the resting membrane potential of GI smooth muscle cells?

A
  • -55 mV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When does a spike potential occur? (with reference to changes in membrane potentials)

A
  • When the resting membrane potential becomes more positive than -40 mV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Identify two ways in which the spike potential in a GI smooth muscle cell differs to that in a nerve fibre

A
  • Influx of calcium as well as sodium through calcium-sodium channels
  • Longer duration due to slow closure of calcium sodium channels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the frequency of spike potentials?

A
  • 1 to 10 per second
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How long does each spike potential last?

A
  • 10 to 20 milliseconds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Outline the process of smooth muscle contraction

A
  • Calcium binds to calmodulin
  • This complex activates myosin kinase
  • Myosin kinase phosphorylates regulatory chain on myosin head causing it to bend with actin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Why are slow waves not involved in smooth muscle contraction?

A
  • They do not cause calcium ions to enter the smooth muscle fibre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is meant by tonic contraction?

A
  • Continuous contraction not associated with basic electrical rhythm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Identify three causes of tonic contraction

A
  • Continuous repetitive spike potentials
  • Hormones that cause depolarisation of smooth muscle
  • Continuous entry of calcium ions into the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is meant by unitary smooth muscle? Identify three places in which it is found

A
  • Thousands of muscle fibres contract as a single unit

- GI tract, ureters, uterus, bile duct, blood vessels

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

What is the embryological origin of the enteric nervous system?

A
  • Neural crest cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How many neurones is the enteric nervous system composed of?

A
  • 100 million (same as spinal cord)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where is the myenteric plexus located and what does it control?

A
  • Between outer circular and inner longitudinal smooth muscle
  • Controls GI movements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where is the submucosal plexus located and what does it control?

A
  • Submucosa

- Controls GI secretion and blood flow

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

Identify three effects of stimulation of the myenteric plexus

A
  • Increased tonic contraction
  • Increased intensity of rhythmical contraction
  • Increased rate of rhythmical contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Describe the inhibitory functions of the myenteric plexus and its regulation

A
  • Inhibit of intestinal sphincter muscles

- Regulated by vasoactive intestinal polypeptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Identify three effects of stimulation of the submucosal plexus

A
  • Intestinal secretion
  • Local absorption
  • Local contraction of submucosa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the main excitatory and inhibitory neurotransmitters secreted by enteric neurons?

A
  • Excitatory: ACh

- Inhibitory: Noradrenaline, adrenaline

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

From which cranial nerves does the parasympathetic nervous system arise?

A
  • Vagus
  • Glossopharyngeal
  • Facial
  • Oculomotor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

From which spinal nerves does the parasympathetic nervous system arise?

A
  • S2
  • S3
  • Occasionally S1 and S4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

The majority of parasympathetic nerve fibres travel through which nerve?

A
  • Vagus nerve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Identify eight organs supplied by the vagus nerve

A
  • Oesophagus
  • Stomach
  • Small intestine
  • Proximal colon
  • Liver
  • Gallbladder
  • Kidneys
  • Upper portion of ureters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Identify four organs supplied by the sacral parasympathetic fibres

A
  • Descending colon
  • Rectum
  • Bladder
  • Lower portion of ureters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Which neurons in the parasympathetic nervous system are cholinergic? Where are the ganglia located?

A
  • Both preganglionic and postganglionic

- Distally close to effector organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How does glandular secretion in different parts of the GI differ in terms of innervation?

A
  • Glands in the upper GI tract are mainly controlled by parasympathetic fibres
  • Glands in the lower GI tract are controlled by local factors and enteric nervous system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Identify three ways that parasympathetic stimulation increases GI motility

A
  • Promoting peristalsis
  • Relaxing of sphincters
  • Increased glandular secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

From which spinal cord segments does the sympathetic innervation of the GI tract arise?

A
  • T5
  • L1
  • L2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How are the preganglionic neurons and ganglia of the sympathetic nervous system arranged?

A
  • Preganglionic neurons enter sympathetic chain

- To pass through ganglia which are located proximally, distant from the effector organ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Identify two sympathetic ganglia located in the GI tract

A
  • Celiac ganglion

- Mesenteric ganglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Which neurons in the sympathetic nervous system are cholinergic and which are adrenergic?

A
  • Preganglionic: Cholinergic

- Postganglionic: Adrenergic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Outline the effect of sympathetic stimulation on GI motility and identify two mechanisms that cause this effect

A
  • Reduces GI motility (inhibition of peristalsis and increases tone of sphincters)
  • Effect of noradrenaline on intestinal tract smooth muscle
  • Inhibitory effect of noradrenaline on neurons of the enteric nervous system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Identify three types of GI reflexes

A
  • Reflexes integrated within gut wall
  • Reflexes from gut to sympathetic ganglia and back to gut
  • Reflexes from gut to spinal cord or brainstem and back to gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is the gastrocolic reflex?

A
  • Signals from stomach to cause evacuation of colon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is enterogastric reflex?

A
  • Signals from colon and small intestine to inhibit stomach motility and secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is colonoileal reflex?

A
  • Signals from colon to inhibit emptying of ileal contents into colon
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Which cells secrete gastrin?

A
  • G-cells of antrum of stomach
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

When is gastrin released?

A
  • Distension of stomach
  • Products of proteins
  • Gastrin releasing peptide

(Following ingestion of a meal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the primary effects of gastrin?

A
  • Stimulation of gastric acid secretion

- Stimulation of growth of the gastric mucosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Which cells secreted cholecystokinin?

A
  • I cells of mucosa of duodenum and jejunum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

When is cholecystokinin released?

A
  • In response to digestive products of fat, fatty acids and monoglycerides
  • Which are present in the intestinal contents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Identify 3 effects of cholecystokinin

A
  • Contracts gallbladder which expels bile
  • Relaxation of sphincter of Oddi which allows bile to mix with and emulsify fatty substances
  • Inhibition of muscle contraction in stomach, producing time for fat digestion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Which cells secrete secretin?

A
  • S cells in mucosa of duodenum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

When is secretin released?

A
  • In response to gastric acid juice emptying into duodenum from pylorus of stomach
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are the primary effects of secretin?

A
  • Promotes pancreatic secretion which neutralises the acid in small intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Where is gastric inhibitory peptide secreted from?

A
  • Mucosa of upper small intestine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

When is gastric inhibitory peptide released?

A
  • In response to amino acids in the duodenum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What are the primary effects of gastric inhibitory peptide?

A
  • Decreasing motor activity of stomach

- Slowing emptying of gastric contents into duodenum when small intestine is overloaded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Where is motilin secreted from?

A
  • Upper duodenum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What are the primary effects of motilin?

A
  • Increases GI motility

- By stimulating waves of motility called inter digestive myoelectric complexes every 90 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Where is glucose dependent insulinotropic peptide released? When is it released and what are its primary effects?

A
  • Small intestine
  • In response to glucose
  • Stimulates insulin secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What is peristalsis?

A
  • Wave-like propulsive movements in GI tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Identify three stimuli of peristalsis

A
  • Parasympathetic signals
  • Distension of gut wall
  • Chemical or physical irritation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What is the effect of atropine on peristalsis?

A
  • Reduced peristalsis
  • Paralysis of cholinergic nerve terminals
  • Of myenteric plexus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Why does peristalsis die out in the orad direction?

A
  • Myenteric plexus is polarised in the anal direction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

How far can each contractile ring push intestinal contents?

A
  • 5 - 10 cm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is receptive relaxation?

A
  • Gut relaxes downstream towards anus

- Allowing food to be propelled more easily in this direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is meant by Starling’s law of the gut?

A
  • Refers to myenteric reflex / peristaltic reflex

- And movement in the anal direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Identify two causes of mixing movements in the GI tract

A
  • Peristalsis against a closed sphincter

- Local intermittent constrictive contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What does hunger determine?

A
  • The amount of food that a person ingests
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What does appetite determine?

A
  • The type of food to ingest
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What is meant by satiety?

A
  • Desire to limit food intake

- After ingesting a satisfying amount of food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Stimulation of which nuclei results in hyperphagia?

A
  • Lateral hypothalamic feeding centre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Stimulation of which nuclei results in aphagia?

A
  • Ventromedial hypothalamic satiety centre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is the role of serotonin in appetite regulation?

A
  • Inhibits the lateral hypothalamic feeding centre

- Which alters the appetite set point (baseline for caloric and nutrient intake)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

How do levels of serotonin differ in anorexics and bulimics differ?

A
  • Raised in anorexia

- Reduced in bulimia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Identify four signals that the hypothalamus receives from elsewhere in the body that influence feeding behaviour

A
  • Sensory information about stomach filling
  • Chemical signals from nutrients in blood
  • Hormones released by adipose tissue
  • Signals from cerebral cortex (sight, smell, taste)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What are orexinergic and anorexigenic substances in relation to feeding?

A
  • Orexigenic stimulates feeding

- Anorexigenic inhibits feeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Identify two anorexigenic neurons of the arcuate nuclei

A
  • POMC neurons (Pro-opiomelanocortin)

- CART neurons (cocaine- and amphetamine-related transcript)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Identify two orexigenic substances

A
  • Neuropeptide Y (NPY) acting on Y1 and Y2 receptors

- Agouti-related protein (AGRP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What do POMC neurons release and to which receptors does this chemical bind?

A
  • Alpha-Melanocyte Stimulating Hormone (a-MSH)

- Binds to MCR-3 and MCR-4 in paraventricular nuclei

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What are the biochemical and physiological effects of AGRP neurons?

A
  • Competitive inhibitor of a-MSH
  • As it binds to MCR-3 and MCR-4
  • Resulting in excessive feeding and obesity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What is the effect of cholecystokinin on feeding?

A
  • Activation of melanocortin pathway in hypothalamus
  • Causes release of a-MSH from POMC and CART neurons acting on MCR-3 and MCR-4 receptors of paraventricular nuclei
  • Resulting in reduced feeding
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Identify a hormone that stimulates AGRP neurons

A
  • Ghrelin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Identify 3 hormones that inhibit AGRP neurons / excite POMC/CART neurons

A
  • Insulin
  • Leptin
  • CCK
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Identify four glands that secrete saliva

A
  • Parotid glands
  • Submandibular glands
  • Sublingual glands
  • Small buccal glands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

How many mL of saliva is produced each day?

A
  • Between 800 and 1500 mL
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

Identify two major types of saliva secretion and what each type contains

A
  • Serous secretion containing ptyalin, an alpha amylase, for starch digestion
  • Mucus secretion containing mucin, a glycoprotein, for lubrication and protection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

How does secretion type vary between the salivary glands?

A
  • Parotid: mainly serous
  • Sublingual and submandibular: both types
  • Buccal glands: mainly mucus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

What is the pH of saliva?

A
  • Between 6.0 and 7.0
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Which ions are most prominent in saliva?

A
  • Potassium

- Bicarbonate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What occurs in the primary stage of salivary secretion?

A
  • Acini secrete ptyalin and/or mucin
  • Reabsorption of sodium from salivary ducts
  • Secretion of potassium ions in exchange for sodium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Why is chloride absorbed passively from the salivary ducts?

A
  • Excess sodium reabsorption over potassium secretion

- Creating an electrical negativity of -70 mV in the ducts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

What occurs in the secondary stage of salivary secretion?

A
  • Bicarbonate ions are secreted by ductal epithelium

- This is caused by passive exchange of bicarbonate ions for chloride ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What are the concentrations of sodium, chloride, potassium and bicarbonate in saliva?

A
  • Sodium: 15 mEq/L
  • Chloride: 15 mEq/L
  • Potassium: 30 mEq/L
  • Bicarbonate: 60 mEq/L
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Identify 4 ways that saliva helps to maintain healthy oral tissue

A
  • Flow of saliva washes away bacteria and food (removing bacterial support)
  • Lysosomes attack bacteria and digest food (removing metabolic support)
  • Thiocyanate ions are bactericidal
  • Secretory IgA can destroy bacteria
94
Q

Identify the role of saliva in digestion of carbohydrates

A
  • a-amylase hydrolyses 5% of starch into maltose
95
Q

Why is salivary starch activity blocked in the stomach?

A
  • Gastric acid secretions have a low pH

- Amylase becomes nonactive below a pH of 4.0

96
Q

Which division of the autonomic nervous system regulates salivary secretion?

A
  • Parasympathetic nervous system
97
Q

What is the role of the superior salivatory nuclei?

A
  • Innervates submandibular and sublingual glands

- Via the submandibular ganglion from the chorda tympani, a branch of the facial nerve

98
Q

What is the role of the inferior salivatory nuclei?

A
  • Innervates parotid gland

- Via the otic ganglion from the tympanic branch of the glossopharyngeal nerve

99
Q

Identify five factors that increase salivary secretion

A
  • Sour taste (acids)
  • Smooth objects
  • Pleasant smelling food (links to olfactory cortical areas)
  • Reflexes caused by Irritating foods (helps to dilute the substance)
  • Increased blood supply
100
Q

Outline the vasodilator effect of saliva on blood vessels

A
  • Salivary cells secrete kallikrein
  • Which splits a2-globulin to form bradykinin
  • Which is a strong vasodilator
101
Q

What is the character of oesophageal secretion?

A
  • Mucous which provides lubrication for swallowing
102
Q

Identify two types of glands in the oesophagus

A
  • Simple mucus glands superiorly prevent mucosal damage by food
  • Compound mucus glands inferiorly prevent damage by acidic gastric juice
103
Q

What is the importance of mastication in relation to fruits and raw vegetables?

A
  • Fruits and vegetables which have indigestible cellulose membranes
  • Which must be broken down before the food can be digested
104
Q

What is the importance of mastication in relation to digestive enzymes?

A
  • Digestive enzymes only work on the surface of food particles
  • Chewing food increases surface area for digestive enzymes
105
Q

What is the importance of mastication in relation to protection of the GI tract?

A
  • Chewing food breaks it down into a fine particulate consistency
  • Which prevents excoriation of the GI tract
  • And increases the ease with which food is emptied form the stomach into the small intestine
106
Q

What are the roles of incisors and molars? What are the relative forces each type of tooth can be closed by jaw muscles?

A
  • Incisors provide a strong cutting action, 25 KG

- Molars provide a grinding action, 90 KG

107
Q

Identify four muscles of mastication and the function of each

A
  • Masseter, elevation of mandible
  • Temporalis, elevation and retraction of mandible
  • Medial pterygoid, elevation and lateral movements of mandible
  • Lateral pterygoid, protrusion and lateral movements of mandible
108
Q

Identify the innervation of the muscles of mastication

A
  • Mandibular branch of trigeminal nerve
109
Q

What is the role of the buccinator muscle? What is its innervation?

A
  • Contraction presses the cheek against the teeth
  • Which keeps the cheek taut and aids in mastication
  • By preventing food from accumulating between the teeth and cheek.
  • Facial nerve
110
Q

Identify the three nuclei that receive sensory innervation during mastication and the type of information each recieves

A
  • Mesencephalic nucleus: proprioceptive from spindle-rich muscles of mastication
  • Chief nucleus: tactile information of food in mouth
  • Spinal nucleus: nociceptive information
111
Q

What is the jaw-closing reflex?

A
  • Contact of food with oral mucous membrane activates jaw-closing motor neurones so that the teeth are brought to occlusion
112
Q

What is the jaw-opening reflex?

A
  • Activation of stretch afferents due to dental occlusion

- Which inhibits closure motor neurons and activates jaw openers

113
Q

What is another term for swallowing?

A
  • Deglutition
114
Q

Identify the three stages of swallowing and a brief description of each

A
  • Voluntary stage, which initiates swallowing
  • Pharyngeal stage, involuntary stage which allows passage of food from pharynx into oesophagus
  • Oesophageal stage, involuntary stage which transports food from oesophagus to stomach
115
Q

Identify the muscles involved in the voluntary stage of swallowing and the role of each

A
  • Orbicularis oris: adducts the lips to form a tight seal

- Superior longitudinal muscles: elevates the tongue to make contact with hard palate to propel bolus posteriorly

116
Q

Where are epithelial swallowing receptors located and which nerve do they stimulate?

A
  • Tonsillar pillars

- Glossopharyngeal nerve

117
Q

How does stimulation of epithelial swallowing receptors result in contraction of muscles of the palate, pharynx and larynx?

A
  • Information is relayed via glossopharyngeal nerve to nucleus solitarius
  • Which relays information to nucleus ambiguus
  • Which contains motor neurons that innervate muscles of palate, pharynx and larynx
118
Q

What is the role of levator veli palatini in the pharyngeal stage of swallowing?

A
  • Elevates soft palate to close the posterior nares

- Which prevents food enter nasal cavities

119
Q

What is the role of the superior constrictor muscle in the pharyngeal stage of swallowing?

A
  • Adducts the palatopharyngeal folds
  • Forming a sagittal slit
  • Which allows food that is masticated enough to pass with ease
  • Impeded posterior movement of large objects
120
Q

What is the role of the lateral cricoarytenoids, oblique and transverse arytenoids during the pharyngeal stage of swallowing?

A
  • Adduction of vocal folds
  • Causing epiglottis to swing backward over laryngeal inlet
  • Which prevents passage of food into the trachea
121
Q

What is the role of the digastric and stylohyoid muscles during the pharyngeal stage of swallowing?

A
  • Elevates the hyoid bone
  • Which lifts the larynx upwards
  • Resulting in enlargement of the opening of the oesophagus
  • Also lifts the glottis out of the stream of food flow
122
Q

What is the role of the constrictor muscles during the pharyngeal stage of swallowing? When is this function performed?

A
  • Sequential contraction which propels food by peristalsis into oesophagus
  • Occurs once the larynx is raised AND upper oesophageal sphincter becomes relaxed
123
Q

What is the cricopharyngeus and when is it open?

A
  • Lowest part of the inferior constrictor

- Which only opens for the advancing bolus

124
Q

How long is the entire pharyngeal stage of swallowing?

A
  • Less than 6 seconds
125
Q

What are the two peristaltic movements that occur during the oesophageal stage of swallowing?

A
  • Primary peristalsis: simple continuation of peristaltic wave that begins in oesophagus
  • Second peristalsis: caused by distension of oesophagus when primary peristalsis fails
126
Q

What are the neural mechanisms involved in secondary peristalsis during the oesophageal phase of swallowing?

A
  • Intrinsic neural circuits in the myenteric nervous system
  • Reflexes that begin in pharynx that are transmitted via vagus nerve to medulla and back again to oesophagus via glossopharyngeal and vagus nerve
127
Q

How does innervation in the upper third of the oesophagus differ to that in the lower third?

A
  • Musculature in upper third is skeletal muscle and is innervated by skeletal nerve impulses from CN9 and CN10
  • Musculature in lower third is smooth muscle and is innervated by CN10 and also myenteric plexus
128
Q

Outline receptive relaxation in relation to the lower oesophageal sphincter and its regulation

A
  • Relaxation of LOS ahead of peristaltic wave
  • Which allows easy propulsion of swallowed food into stomach
  • Regulated by nitric oxide and serotonin
129
Q

Aside from regulation of food into the stomach identify another role of the lower oesophageal sphincter

A
  • Helps to prevent reflux of stomach contents into the oesophagus
130
Q

What is dysphagia?

A
  • Difficulty swallowing

- A sensation of obstruction during the passage of solid or liquid through the pharynx or oesophagus

131
Q

Identify a disease of the tongue or mouth that can result in dysphagia

A
  • Tonsilitis
132
Q

Identify two neuromuscular disorders that can result in dysphagia

A
  • Bulbar palsy

- Myasthenia gravis

133
Q

Identify three oesophageal motility disorders that can result in dysphagia

A
  • Achalasia
  • Scleroderma
  • Chagas’ disease
134
Q

Identify three causes of external pressure that can result in dysphagia

A
  • Goitre
  • Mediastinal glands
  • Enlarged left atrium
135
Q

Identify three intrinsic lesions that can result in dysphagia

A
  • Foreign body
  • Stricture
  • Rings and webs
136
Q

Identify three abnormalities that can occur when the swallowing mechanism is paralysed

A
  • Complete abrogation of swallowing so that swallowing cannot occur
  • Failure of the glottis to close to that food passes into the lungs instead of the oesophagus
  • Failure of the soft palate and uvula to close the posterior nares so that food refluxes into the nose
137
Q

Describe the negative effects of impairment of swallowing mechanism during anaesthesia

A
  • Unconscious patients often vomit
  • Vomit is sucked into trachea because anaesthesia has blocked swallowing mechanism
  • Patients either choke to death on their vomit or it results in aspiration pneumonia (Mendelson’s syndrome)
138
Q

A patient suffers from intermittent slow progression of dysphagia, with a history of heartburn, suggest the most likely diagnosis

A
  • Benign peptic stricture
139
Q

A patient suffers from relentless progression over a few weeks, suggest the most likely diagnosis

A
  • Malignant stricture (carcinoma)
140
Q

A patient suffers from slow onset of dysphagia for solids and liquids at the same time, suggest the most likely diagnosis

A
  • Achalasia
141
Q

What is the investigation of choice for swallowing difficulties?

A
  • Endoscopy
142
Q

Which investigations may be carried out if no abnormality is found using endoscopy?

A
  • Barium swallow with video fluoroscopic swallowing assessment
  • Oesophageal manometry where a catheter is inserted through nose into oesophagus and the pressure generated within the oesophagus is measured
143
Q

How do the symptoms of oropharyngeal and oesophageal dysphagia differ?

A

Oropharyngeal dysphagia: difficulty initiating swallowing, chocking + aspiration

  • Oesophageal: food sticking after swallowing + regurgitation
144
Q

Outline the pathology of achalasia

A
  • Damage to myenteric plexus in lower third of oesophagus resulting in reduction of ganglion cell numbers
  • LOS remains spastically contracted
  • So food cannot enter stomach for many hours
  • Oesophagus becomes enlarged and becomes infected during long periods of stasis
145
Q

Outline the epidemiology of achalasia

A
  • 1:100,000
  • Equal in males and females
  • Occurs at all ages but rare in childhood
146
Q

Outline the clinical features of achalasia

A
  • Intermittent dysphagia for solids and liquids
  • Regurgitation of food, particularly at night, aspiration pneumonia is a complication
  • Spontaneous chest pain due to oesophageal spasm
  • Ulceration resulting in substernal pain
147
Q

What does a CXR show in achalasia?

A
  • Dilated oesophagus
  • Fluid level seen behind heart
  • Fundal gas shadow is absent
148
Q

What does a barium swallow show in achalasia?

A
  • Lack of peristalsis
  • Synchronous contractions, sometimes with dilation
  • Birds beak due to failure of sphincter to relax
149
Q

When is oesophagoscopy used in achalasia?

A
  • To exclude a carcinoma at lower end of oesophagus

- Patients must have a 24-hour liquid only diet to remove food and debris

150
Q

Identify the treatments used for achalasia

A
  • Heller’s operation: surgical division of LOS
  • Nifedipine and sildenafil
  • Endoscopic dilatation using a hydrostatic balloon
  • Botulinum toxin A
151
Q

What is the success rate of endoscopic dilatation of the LOS in achalasia

A
  • 80%

- 50% require a second dilatation within 5 years

152
Q

Outline the MoA of botulinum toxin A

A
  • Inhibition of calcium dependent release of ACh from presynaptic terminal
  • Countering effect of selective loss of inhibitory neurotransmitters
  • Resulting in relaxing of LOS
153
Q

Identify one complication of achalaisa

A
  • Squamous carcinoma of oesophagus
154
Q

What is an oesophageal web? Where do they most occur and which type of imaging is most appropriate for viewing them?

A
  • Thin membranous flap covered with squamous epithelium
  • Anteriorly in the postcricoid region of the cervical oesophagus
  • Barium Swallow
155
Q

Identify a cause of an oesophageal web

A
  • Plummer-Vinson Syndrome (Paterson-Brown-Kelly Syndrome) associated with glossitis and angular stomatitis
  • Chronic iron deficiency anaemia
  • Treated with iron
156
Q

Identify two types of oesophageal rings

A
  • Mucosal / Schatzki / B ring located at the squamocolumnar mucosal junction
  • Muscular / A ring located proximal to the mucosal
157
Q

Identify the treatments for oesophageal rings

A
  • Reassurance
  • Dietary advice
  • Dilatation may be necessary
158
Q

What is an oesophageal diverticulum?

A
  • Abnormal pouch at a weak point in the wall of the GI tract
159
Q

Where does a Zenker’s diverticulum / pharyngeal pouch occur?

A
  • Upper oesophageal sphincter through the fibres of cricopharyngeus
160
Q

What is Killian’s dehiscence and what is its clinical significance?

A
  • A weakness in Zenker’s diverticulum
  • That allows a pulsion diverticulum
  • Which will collect food which may regurgitate into the mouth or lungs
161
Q

Where does a traction diverticulum occur? Identify the cause

A
  • Middle of the oesophagus

- Inflammation associated with diffuse oesophageal spasms or mediastinal fibrosis

162
Q

Where does an epiphrenic diverticulum occur, what condition is it associated with?

A
  • Just above the LOS

- Achalasia

163
Q

Outline the investigation and treatments of choice in oesophageal diverticulum

A
  • Barium swallow (since endoscopy may enter or perforate the pouch)
  • Myotomy and resection of the pouch
164
Q

Identify two causes of oesophageal infections and their presentation

A
  • Candida (white plaques)

- TB (ulceration and mediastinal lymphadenopathy)

165
Q

Identify two treatments of oesophageal infections given to patients on large doses of immunosuppressive agents

A
  • Nystatin
  • Amphotericin
  • Both of which are macrolide antifungal antibiotics
166
Q

Identify the epidemiology, clinical features and treatment of eosoinophilic oesophagitis

A
  • Common in children (atopic)
  • Dysphagia and chest pain
  • Fluticasone, budesonide syrup (glucocorticoids)
  • Elimination diets (more beneficial in children)
167
Q

Outline the pathology of aspiration pneumonia

A
  • Aspiration of gastric content into lungs

- Intense destruction due to gastric acid

168
Q

Which lobe is most likely to be affected by aspiration pneumonia

A
  • Right middle lobe
169
Q

Which type of bacteria is most responsible for aspiration pneumonia

A
  • Anaerobes
170
Q

Outline the treatment of aspiration pneumonia

A
  • Co-amoxiclav
  • Which covers gram-negative and anaerobes
  • Until specific cultures are obtained
171
Q

Oesophageal cancer is [A]th most common cancer worldwide

A
  • [A] = Sixth
172
Q

Identify the two types of oesophageal cancer

A
  • Squamous cell carcinoma

- Adenocarcinoma

173
Q

Where is squamous cell carcinoma of the oesophagus most common? Identify five risk factors

A
  • Africa, China, Iran
  • Alchohol
  • Tobacco
  • Red and processed meat
  • Low fruit and vegetable
  • Obesity
174
Q

Where is adenocarcinoma of the oesophagus most common? Identify two risk factors

A
  • Western countries
  • Barret’s oesophagus
  • Gastroesophageal reflux disease
175
Q

How does the location of an oesophageal squamous cell carcinoma and an adenocarcinoma differ?

A
  • SCC: Upper oesophagus

- AC: Lower oesophagus in columnar epithelium

176
Q

Outline 4 clinical features of oesophageal cancer

A
  • Progressive painless dysphagia or solids which progresses to fluids
  • Weight loss
  • Anorexia
  • Lymphadenopathy
177
Q

Outline the investigations used in oesophageal cancer

A
  • Endoscopy provides histological and cytological proof of adenocarcinoma
  • Barium swallow for differential diagnosis (motility disorder)
  • CT for metastasis
  • Endoscopic ultrasound for determining depth of penetration of tumour
178
Q

What are the criteria for endoscopy for oesophageal cancer?

A
  • Performed within 2 weeks
  • It patient is suffering from dysphagia
  • Or is over 55 and suffering from weight loss/ upper abdominal pain/reflux/dyspepsia
179
Q

Outline the main treatments of cancer of the oesophagus

A
  • Surgery if tumour has not infiltrated outside oesophageal wall
  • Chemotherapy (cisplatin, 5-fluorouracil) if stage 2b/3
  • Palliative: endoscopic laser therapy / expanding metal stents to improve QoL
180
Q

What fraction of patients are affected by undernutrition in hospital? Who is most likely at risk?

A
  • 1/3

- Elderly

181
Q

Identify 4 physical effects of undernutrition

A
  • Impaired immunity
  • Muscle weakness
  • Delayed wound healing
  • Increased risk of post-operative infection
182
Q

Identify the four steps of managing undernutrition in hospital

A
  • Normal diet (with food chart)
  • Supplements (high energy and protein drinks)
  • Enteral tube feeding (nasogastric tube)
  • Parenteral nutrition (PIC, central line)
183
Q

Why is the enteral route preferred?

A
  • Preserves integrity of mucosal barrier
  • Reducing risk of bacteraemia
  • Reduces risk of multi-organ failure
184
Q

What type of tube is used for short-term enteral feeding?

A
  • Nasogastric tube
185
Q

What type of tube is used for enteral feeding where there is gastric outlet obstruction or gastric stasis?

A
  • Nasojujunal tube
186
Q

What type of tube is used for long-term enteral feeding, why?

A
  • Percutaneous endoscopic gastrostomy

- More comfortable due to less irritation to nasal mucosa and tube is less likely to be pulled out

187
Q

Identify the main danger of gastrostomy

A
  • Inadvertent puncture of intra-abdominal organs

- Causing peritonitis and bleeding

188
Q

When is parenteral nutrition used? Why is it typically a last resort?

A
  • When enteral feeding is impossible
  • Expensive
  • Higher risk of complications
189
Q

Identify four routes for parenteral tube feeding

A
  • Peripheral venous cannula
  • Peripheral inserted canula (20cm)
  • Peripherally inserted central catheter (60cm)
  • Central line, via subclavian route due to lower infection rates
190
Q

Which routes of parenteral tube feeding allow for hyperosmolar solutions to be used?

A
  • Peripherally inserted central catheter

- Central line

191
Q

Outline 4 complications of parenteral tube feeding

A
  • Septicaemia due to line infection (importance of aseptic technique)
  • Hyperglycaemia (main component is glucose)
  • Fluid and electrolyte disturbances (re-feeding syndrome)
  • Hypercalcaemia
  • Rare allergic reactions to lipid
192
Q

What percentage of stroke victims require home enteral tube feeding?

A
  • 2%
193
Q

Outline the pathology of refeeding syndrome,

A
  • Nutrition is given to undernourished patient
  • Rapid conversion from a catabolic state to an anabolic state
  • Release of insulin, leading to cellular uptake of phosphate, potassium and magnesium ions
  • Which provoke falls in serum levels
194
Q

Identify one serious consequence of refeeding syndrome

How is Refeeding syndrome treated?

A
  • Cardiac arrhythmia

- I.V Pabrinex (containing high strength Vitamin B and C)

195
Q

When should artificial nutrition be given?

A
  • When it would be of overall benefit to the patient
  • Including patients who lack capacity (to whom nutirtion would be of overall benefit)
  • And incapacitated patients who are not expected to die within hours or days
  • Or incapacitated patients who are expected to die within hours or days and have specifically requested it be provided
196
Q

What should doctors do before withdrawing nutrition or hydration from a patient in a PVS?

A
  • Consult courts
197
Q

What is the importance of DNACPR

A
  • Aims to ensure patient dies a dignified death in a peaceful manner
198
Q

When is DNACPR generally appropriate

A
  • When it is clinically inappropriate
  • CPR will be unsuccessful or there are potential burdens and risks
  • Or cardiac or respiratory arrest is part of dying process
199
Q

How should doctors handle DNACPR when the patient lacks capacity?

A
  • Consult views of healthcare team

- Consult legal proxy

200
Q

When should CPR be performed?

A
  • If the cause reversible e.g. induction of anaesthesia

- In clinical emergencies where there is no DNACPR in place

201
Q

How should doctors respond to patients who ask for information that might encourage or assist them in ending their lives

A
  • Explain that it is a criminal offence to encourage or assist suicide
202
Q

What is meant by passive euthanaisia

A
  • Withholding or withdrawing life-extending treatment e.g. antibiotics, nutrition, hydration
203
Q

What is meant by active euthanasia?

A
  • Direct inducement of death e.g. administering overdose of painkillers
204
Q

What is voluntary euthanasia?

A
  • Patient expresses informed consent and wishes for someone to assist them in the dying process
205
Q

What is speculative euthanasia?

A
  • Individual assumes consent when consent cannot be given (comatose, infant, or dementia)
206
Q

What is involuntary euthanasia?

A
  • Patient refuses consent and does not wish to die
207
Q

What is indirect euthanasia?

A
  • Providing treatment to reduce pain
  • Whose side effects speed patients death
  • Doctrine of double effect
208
Q

What is assisted suicide?

A
  • Providing someone the means of killing themselves e.g. putting painkillers within reach
209
Q

What is the role of the coroner?

A
  • Investigate all deaths where the cause is unknown or may not be due to natural causes
210
Q

Identify four roles of death certification

A
  • Provide explanation to families about how they died (implication for future generations)
  • Enable family to register death to allow disposal of body and settlement of estate
  • Public health interventions
  • Measure exposure of risk factors
211
Q

Who is responsible for issuing the death certificate?

A
  • Doctor who cared for patient within last 14 days
212
Q

What categories of death must be reported to a coroner before the death is registered?

A
  • Accident
  • Suicide
  • Violence
  • Neglect
  • During or shortly after operation/anaesthesia
  • During or shortly after police or prison custody
213
Q

How is a death certificate written?

A
  • 1a: Immediate cause of death

- 1b / c: Sequence of events that led to death on subsequent lines

214
Q

What should be avoided on a death certificate?

A
  • Old age
  • Natural causes
  • Organ failure
215
Q

Outline Leventhal’s self regulatory model

A
  • Illness is dealt with in the same way as other problems
  • Problem or change in status quo motivates one to solve the problem and re-estalbish normality
  • Interpretation: Confronted with problem which will lead to a desire to return to normality
  • Coping: Coping strategies that should lead to normality
  • Appraisal: Have strategies been effective and has normality been achieved?
216
Q

Identify 5 factors that affect QoL

A
  • Physical health
  • Psychological state
  • Level of independence
  • Social relationships
  • Relationship to the salient environmental features
217
Q

What is a standards needs approach to QoL measures?

A
  • Assumes that needs rather than wants are central to quality of life
218
Q

What is a psychological-process approach to QoL measures?

A
  • Considers QoL to be constructed from individual evaluations of personally salient aspects of life
219
Q

Give an example of a unidimensional measure on a health questionnaire

A
  • Focuses on one aspect of health

- E.g. ‘how is your mood?’

220
Q

Give an example of a multidimensional measure on a health questionnaire

A
  • Focuses on health in broadest sense

- E.g. ‘how is good your health?’

221
Q

Define absolute poverty

A
  • Denotes a poverty level relative to a fixed standard of living, rather than the resign of the population.
222
Q

Define relative poverty and what classifies as poor and severe poverty

A
  • Compares each household income to the median income of their country
  • Where those with less than 60% of the median income classified as poor
  • Where those with less than 40% classed as severe poverty.
223
Q

Define material deprivation

A
  • When an individual is not able to afford certain possessions that most people take for granted.
224
Q

Define worklessness and how does it related to the concept of ‘life chances’?

A
  • When no one in a household is in work.

- Predictor of ‘life chances’ along with income, material deprivation and educational attainment at 16

225
Q

Identify four causes of poverty

A
  • Unemployment / low paid work
  • Inadequate benefits
  • Lack of affordable housing
  • Demographic factors e.g. disability, family size, BAME group
226
Q

Identify effects of poverty at each stage of life

A
  • Children: More likely to suffer chronic disease such as asthma
  • Adult life: More likely to suffer from long term conditions e.g. COPD, diabetes, hypertension
  • Later life: Poorer emotional wellbeing, mental and physical health
227
Q

Why is the relationship between poverty and health described as bidirectional?

A
  • Unemployment and poverty can contribute to poor health (social causation)
  • Poor physical and mental health also increases the likelihood of unemployment (social drift)
  • And the two can become mutually reinforcing
228
Q

Outline inverse care law

A
  • Availability of good medical or socialcaretends to vary inversely with the need of the population served
229
Q

Identify 5 actions to prevent poverty

A
  • School funding: early interventions, whole child approach
  • Jobs: More jobs, greater flexibility, minimum income for health living
  • Reduce fuel poverty and education people on improving their energy efficiency
  • Doctors: Advocate for health needs of their patients (commissioning responsibilities)
  • Sufficient supply of affordable housing
230
Q

What is persistent poverty?

A

Persistent poverty is defined as when an individual experiences relative low income in the current year, as well as at least two out of three preceding years.

Semester 4: Nutrition and Metabolism (17 decks)

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