Schizoprehnia Flashcards

1
Q

What is schizophrenia?

A

A chronic or relapsing form of psychosis. Involves altered perceptions of reality, disordered thinking, and social dysfunction that can affect various aspects of the individual’s life.

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

What age is schizophrenia typically diagnosed?

A

15-35

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

What socioeconomic class is schizophrenia more common in?

A

Higher incidence in lower socioeconomic classes (but this may be a consequence, not cause)

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

Is there a genetic aspect to schizophrenia?

A

Yes - risk significantly increased in those with positive FH, with risk being proportional to degree of genetic relationship

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

What is the % of risk of schizophrenia if both parents affected or identical twin is affected?

A

50%

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

What is the % of risk of schizophrenia with one affected parent or sibling

A

10%

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

Give some environmental for schizophrenia

A

o Childhood trauma e.g. poverty, poor maternal boning, exposure to natural disasters
o Heavy cannabis use in childhood
o Maternal health issues e.g. malnutrition, infections such as rubella/CMV
o Birth trauma e.g. blood loss, hypoxia
o Urban living, immigration to more developed countries

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

What are the 6 subtypes of schizophrenia?

A
  1. Paranoid
  2. Hebephrenic
  3. Catatonic
  4. Undifferentiated
  5. Residual
  6. Simple
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the most common type of schizophrenia?

A

Paranoid

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

What 2 features characterise PARANOID schizophrenia?

A
  1. Paranoid delusions
  2. Auditory hallucinations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What type of schizophrenia is typically diagnosed in adolescents/younger adults?

A

Hebephrenic

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

What type of schizophrenia is characterised by auditory hallucinations and paranoid delusions?

A

Paranoid schizophrenia

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

Why is the outlook for hebephrenic schizophrenia poor?

A

as negative symptoms may develop rapidly

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

What 4 characteristics are seen in hebephrenic schizophrenia?

A
  1. Mood changes
  2. Shallow affect
  3. Unpredictable behaviour
  4. Fragmentary hallucinations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is shallow affect?

A

A similar meaning to blunted affect, but it is often used to describe the emotional experience of persons with psychopathy. A person with shallow affect will feel little emotion about situations that would expect to elicit specific feelings.

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

Which type of schizophrenia is characterised by psychomotor features?

A

Catatonic

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

What psychomotor features are seen in catatonic schizophrenia?

A

Posturing –> This is when a person holds a specific position, which would often be uncomfortable to people who aren’t experiencing catatonia

Rigidity

Stupor –> a state close to unconsciousness

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

What is undifferentiated schizophrenia?

A

When patients’ symptoms do not fit neatly into one of the other categories

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

What is residual schizophrenia?

A

The individual has suffered an episode of schizophrenia but there are no longer any delusions, hallucinations, disorganized speech or behavior
- Characterised by negative symptoms
- Positive symptoms have ‘burnt out’

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

What type of schizophrenia is characterised by negative symptoms and patients have never experienced positive symptoms?

A

Simple schizophrenia

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

What are positive symptoms in schizophrenia? Give some examples

A

Reflect an excess or distortion of normal function

  • Thought echo (hearing own thoughts out loud)
  • Thought insertion or withdrawal
  • Thought broadcasting
  • 3rd person auditory hallucinations
  • Delusional perception
  • Passivity and somatic passivity
  • Odd behaviour
  • Thought disorder
  • Lack of insight
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is thought echo?

A

The person hears his or her own thoughts as if they were being spoken aloud.

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

What is thought insertion?

A

Experiencing one’s own thoughts as someone else’s (one still experiences oneself as the owner of an inserted thought but attributes it to another agency)

Example:
Thoughts are put into my mind like “Kill God.” It is just like my mind working, but it isn’t. They come from this chap, Chris. They are his thoughts.

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

What is thought withdrawal?

A

The delusion that thoughts have been taken out of the patient’s mind.

The patient may experience a break in the flow of their thoughts believing that the missing thoughts have been withdrawn from their mind by some outside agency.

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

What is thought broadcasting?

A

Delusion that one’s thought is projected and perceived by others (i.e. belief that others can hear your thoughts)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is an auditory hallucination?

A

Auditory hallucinations happen when you hear voices or noises that don’t exist in reality.

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

What is delusional perception?

A

A true perception to which a patient attributes a false meaning.

For example, a perfectly normal event such as the traffic lights turning red may be interpreted by the patient as meaning that the martians are about to land.

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

What is passivity and somatic passivity?

A

Experience of bodily sensations (including actions, thoughts, or emotions) imposed by external agency.

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

What is thought disorder?

A

A thought disorder involves a disturbance in how thoughts are organized and expressed. It causes disorganized thinking and leads to people expressing themselves in unusual ways when speaking or writing.

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

What is lack of insight?

A

A symptom of severe mental illness experienced by some that impairs a person’s ability to understand
and perceive his or her illness (reason why they don’t seek treatment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What are Schneider’s first-rank symptoms?

A

Schneider’s first-rank symptoms of schizophrenia are symptoms which, if present, are strongly suggestive of schizophrenia.

  1. Thought echo
  2. Thought insertion or withdrawal
  3. Thought broadcasting
  4. Auditory hallucinations
  5. Delusional perception
  6. Passivity/somatic passivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are negative symptoms in schizophrenia? Give examples

A

Refer to a diminution or absence of normal behaviours related to motivation and interest (N.B. overlap with depressive disorders)

  • Blunted affect (affect is a person’s expression of their emotional state)
  • Apathy
  • Social isolation / anhedonia (lack of interest/enjoyment from life’s experiences)
  • Poverty of speech (alogia)
  • Poor self-care
  • Avolition (severe lack of motivation/inability to complete purposeful tasks)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What investigations can be done in schizophrenia?

A

Rule out any potential other causes of altered mental state

Labs:
o Baseline bloods e.g. FBC, FTFs, U&Es, LFTs, CRP, fasting glucose
o Urine culture (to rule out UTI causing delirium)
o Urine drug screen (to rule out intoxication)
o HIV if applicable
o Syphilis serology (if applicable)
o Serum lipids (before starting antipsychotics)

Imaging:
o CT head (if organic cause is suspected)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How long must symptoms be present for before diagnosis of schizophrenia?

A

Requires a first rank symptom or persistent delusion to be present for at least one month AND no other cause for psychosis (e.g. drug intoxication).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the care programme approach (CPA)?

A

The Care Programme Approach (CPA) is a package of care for people with mental health problems.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the 4 stages of the CPA?

A

1) Assessing health and social needs
2) Creating a care plan
3) Appointment a key worker to be the first point of contact
4) Reviewing treatment

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

What class of drug is used in schizophrenia?

A

D2 (dopamine) receptor antagonists

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

What are the 2 subtypes of D2 (dopamine) receptor antagonists used in schizophrenia?

A

Typical and atypical

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

Wht is the effect of ‘typical’ D2 receptor antagonists?

A

Older and cause generalised dopamine receptor blockade

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Give 3 examples of ‘typical’ D2 receptor antagonists

A
  • Haloperidol
  • Chlorpromazine
  • Flupentixol decanoate (depot injection)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Give 5 side effects of ‘typical’ D2 receptor antagonists

A
  1. Extrapyramidal side effects (EPSE’s)
  2. Hyperprolactinaemia
  3. Metabolic side effects
  4. Anticholinergic side effects
  5. Neurological side effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What extrapyramidal side effects are seen with ‘typical’ D2 receptor antagonist use?

A

Parkinsonism, akathisia, dystonia, dyskinesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What can hyperprolactinaemia due to ‘typical’ D2 receptor antagonist use cause?

A

Sexual dysfunction, risk of osteoporosis, amenorrhoea in women, galactorrhoea, gynaecomastia and hypogonadism in men

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are the metabolic side effects of ‘typical’ D2 receptor antagonist use?

A

Weight gain, increased risk of T2D, hyperlipidaemia, increased risk of developing metabolic syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the anticholinergic side effects of ‘typical’ D2 receptor antagonist use?

A

Tachycardia, blurred vision, dry mouth, constipation, urinary retention

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

What are the neurological side effects of ‘typical’ D2 receptor antagonist use?

A

Seizures, neuroleptic malignant syndrome (potentially life-threatening)

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

Wht is the effect of ‘atypical’ D2 receptor antagonists?

A

More selective in their dopamine blockade and also block serotonin 5-HT2 receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Give some examples of ‘atypical’ D2 receptor antagonists

A
  • Olanzapine
  • Risperidone (depot injection)
  • Clozapine
  • Amisulpride
  • Quetiapine
  • Aripiprazole
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Which antipsychotic is used when schizophrenia is resistant to other antipsychotics?

A

Clozapine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Which antipsychotic is less likely to cause EPSEs than others? Why?

A

Aripiprazole - a partial dopamine agonist and so is less likely to cause EPSEs than others

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What are the side effects of atypical D2 receptor antagonists?

A

Less likely to cause EPSEs and hyperprolactinaemia, but still cause the other debilitating side effects as typical ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What 2 side effects are less common with atypical antipsychotics compared to typical?

A
  1. EPSEs
  2. Hyperprolactinaemia
53
Q

What is the prognosis of schizophrenia?

A

Rule of quarters:

  • 25% never have another episode
  • 25% improve substantially with treatment
  • 25% show some improvement
  • 25% are resistant to treatment
54
Q

Is a predominance of positive or negative symptoms better for prognosis in schizophrenia?

A

Prognosis improves with a predominance of positive symptoms.

55
Q

Give some other factors for a better prognosis in schizophrenia

A

Prognosis improves with; higher IQ/education, sudden onset, precipitating factor, strong support network

56
Q

Difference between an illusion and a hallucination?

A

An illusion is based on a real sensory stimulus that is interpreted incorrectly whereas a hallucination is created by the mind without any stimulus

57
Q

What are the 3 types of illusions?

A
  1. Affect
  2. Completion
  3. Pareidolia
58
Q

What is a ‘pareidolia’ illusion?

A

Seeing shapes in inanimate objects (e.g. faces in clouds)

59
Q

What is a ‘completion’ illusion?

A

The mind completes partial images (e.g. triangles optical illusion)

60
Q

what is an ‘affect’ illusion?

A

Based on current affect (e.g. see a monster in the cupboard when scared)

61
Q

What is the difference between negative and positive symptoms?

A

A positive symptom is something added on to what most people experience (i.e. a hallucination)

Negative symptoms are the lack of a normal experience (i.e. lacking concentration)

62
Q

What are positive symptoms?

A

A cluster of psychotic symptoms including hallucinations and delusions.

63
Q

What are negative symptoms?

A

A cluster of symptoms that often occur in chronic schizophrenia including poverty of speech, flat affect, poor motivation, poor attention and neglect.

64
Q

What is delusion of control/passivity?

A

The subject believes their thoughts, feelings and/or actions are not their own but are being imposed/controlled by an outside force

65
Q

What are ideas of reference?

A

The belief that innocuous events have direct personal significance to the subject (e.g. believing something on the TV is a direct message to them).

66
Q

What is thought broadcast?

A

The subject believes their thoughts are being shared with others (e.g. being broadcast on the radio)

67
Q

What is psychosis?

A

Psychosis is an umbrella term for a group of symptoms. It is not a diagnosis in itself but a feature of many other diagnoses.

Often described as the experience of being out of touch with reality, struggling to distinguish what is real from what is not.

Not confined to mental disorder

Describes the experience of hallucinations, delusions and/or thought disorder.

68
Q

Give some examples of conditions that can lead to psychosis

A

Schizophrenia
* Schizoaffective
* Mood disorders –> Depression, bipolar
* Organic disorders –> Dementia, delirium, encephalitis, metabolic disorders
* Illicit substances –> intoxication, withdrawal
* Alcohol –> Intoxication, delirium tremens, withdrawal
* Sleep deprivation
* Bereavement

69
Q

What are the 3 clusters of psychotic symptoms?

A
  1. Hallucination
  2. Delusion
  3. Thought disorder
70
Q

What is a delusion?

A

A false, unshakable belief held with intense conviction
* Held despite evidence to the contrary
* Not a belief held by others in the same culture

71
Q

What is thought disorder?

A
  • An abnormality in the mechanism of thinking
  • To the observer their speech doesn’t make sense
72
Q

What is the most implicated neurotransmitter in schizophrenia?

A

Dopamine (DA)

73
Q

What is the dopamine hypothesis of schizophrenia?

A

The dopamine hypothesis of schizophrenia postulates that HYPERACTIVITY of dopamine D2 receptor neurotransmission contributes to positive symptoms of schizophrenia, whereas negative and cognitive symptoms of the disorder can be attributed to HYPOFUNCTIONALITY of dopamine D1 receptor

74
Q

What 4 neural pathways can dopamine be implicated in in schizophrenia?

A
  1. Mesocortical
  2. Mesolimbic
  3. Nigrostriatal
  4. Tuberoinfundibular
75
Q

What does increased mesolimbic dopamine activity lead to?

A

Positive symptoms

76
Q

What does decreased mesolimbic dopamine activity lead to?

A

Negative symptoms

77
Q

How do antipsychotics work at dopamine post-synaptic receptors?

A

Antipsychotics are all antagonists at dopamine post-synaptic receptors (there are 5 types, mainly D2)

78
Q

Are negative or positive symptoms often the focus of medical treatment?

A

Positive

79
Q

Taking an antipsychotic reduces the risk of relapse by how much in schizophrenia?

A

1/3

80
Q

Stopping an antipsychotic within 6 months increases risk of relapse by how much in schizophrenia?

A

4x

81
Q

What are some risk factors for relapse in schizophrenia?

A
  • Poor compliance
  • On-going symptoms
  • Substance use
  • Lack of insight
  • Stopping medication suddenly
82
Q

Do males or females generally have a BETTER prognosis in schizophrenia?

A

Females

83
Q

What is acute psychotic disorder?

A

Patient has psychotic symptoms which last LESS THAN 28 days

84
Q

If psychotic symptoms last MORE THAN 28 days, what is the diagnosis?

A

Schizophrenia

85
Q

What is schizoaffective disorder?

A

Schizoaffective disorder is a mental health problem where you experience psychosis as well as mood symptoms.

Psychotic and affective symptoms are simultaneously present and equally prominent

86
Q

What is delusional disorder?

A

Delusional disorder is a type of psychotic disorder. Its main symptom is the presence of one or more delusions.

87
Q

Are hallucinations present in delusional disorder?

A

Hallucinations aren’t present or are only fleeting

88
Q

Examples of delusional disorders:

A
  1. Othello syndrome
  2. De Clerambault’s syndrome
  3. Folie a deux
  4. Cotard’s syndrome
  5. Ekbom’s syndrome
  6. Fregoli’s syndrome
  7. Capgras syndrome
89
Q

What is othello syndrome?

A

They believe their partner is cheating on them. Risk to the partner and the other individual of violence and stalking.

90
Q

What is cotard’s syndrome?

A

A nihilistic delusion without other psychotic symptoms. They believe they are dead, rotting or have lost body parts.

91
Q

What delusional disorder involves the belief that they are infested with parasites despite no evidence of this?

A

Ekbom’s syndrome

92
Q

What is the risk to patient in Ekbom’s syndrome?

A

Risk of self-harm through excoriation or trying to get the parasites out

93
Q

What delusional disorder involves the belief that someone from a higher social standing is in love with them and sends them secret messages to convey their love?

A

De Clerambault’s syndrome AKA erotomania

94
Q

What is folie a deux?

A

AKA induced delusional disorder.

The dominant partner has a delusional belief and then the dependent partner develops the same belief.

The dominant partner requires treatment but the dependent partner recovers upon separation.

95
Q

What is Fregoli’s syndrome?

A

They believe multiple people are actually one individual in disguise who is persecuting them

96
Q

What delusional disorder involves the belief that a relative has been replaced by an imposter?

A

Capgras syndrome

97
Q

What is the management of people with suspected psychosis?

A

People with suspected psychosis should be referred urgently to secondary care mental health services for assessment and management

N.B. The specific service depends on the urgency and level of risk but could include Crisis, Home Based Treatment, CMHT or hospital admission.

98
Q

For first presentations of people presenting with psychosis, what care will they be under?

For how long?

A

If this is their first presentation then they will be under the care of the Early Intervention in Psychosis Services for the first 3 years

99
Q

What is involved in choosing an antipsychotic medication?

A

Large studies have found the efficacy of all antipsychotics to be equal (except Clozapine)

We therefore choose medication based on their side-effect profiles and patient choice

100
Q

When would intramuscular (IM) preparation of an antipsychotic be chosen over oral?

A

IM used in acute agitation when we are unable to give oral medication or need a more rapid onset of action.

101
Q

What is a depot injection?

A

A depot injection is a slow-release form of medication.

102
Q

When would a depot injection be chosen to deliver antipsychotics over oral?

A

Good if poor medication compliance as can last from 1 week to 3 months

Many patients prefer them as they’re able to get on with their lives

103
Q

What are the disadvantages of depot injections of antipsychotics?

A
  • Oral medication is also required until plasma levels are stable (usually 3 to 4 depots)
  • It can take months to establish whether it’s working
104
Q

Prior to commencing antipsychotics, investigations need to be completed.

What observations need to be completed? Why?

A

BP and BMI –> 2nd generation can cause metabolic side effects

Heart rate –> some increase QTc

105
Q

What bloods need to be completed prior to commencing antipsychotics? Why?

A

FBC, U&E, LFT, TFTs

Prolactin –> can be raised due to DA inhibition

HbA1c and lipids –> 2nd generation can cause metabolic side effects

106
Q

Impact of dopamine on prolactin?

A

Dopamine restrains prolactin production, so the more dopamine there is, the less prolactin is released.

If dopamine is increased or if dopamine receptors hyperfunction, PRL may be reduced.

107
Q

Why would you need an ECG before commencing antipsychotics?

A

Many antipsychotics can increase QTc

108
Q

What is the main action of antipsychotics?

A

The main action of antipsychotics are post-synaptic dopamine antagonists

109
Q

What neural pathway is the intended site of action of antipsychotics?

A

Mesolimbic pathway

(High levels of schizophrenia in this pathway cause positive symptoms)

110
Q

What is the function of the mesolimbic pathway?

A

Motivation, emotion, reward

111
Q

In which neural pathway does dopamine antagonism cause elevanted prolactin?

A

Tuberoinfundibular Pathway

112
Q

In which neural pathway does dopamine antagonism cause extra-pyramidal side effects?

A

Nigrostriatal pathway

113
Q

What is the effect of dopamine antagonism on prolactin levels?

A

Dopamine antagonism causes increased prolactin levels (as dopamine normally reduces prolactin levels)

114
Q

Give 3 examples of ACUTE extra-pyramidal side effects (EPSEs) from antipsychotics

A
  1. Acute dystonia
  2. Parkinsonism
  3. Akathisia
115
Q

Give an example of a CHRONIC EPSE from antipsychotics

A

Tardive dyskinesia

116
Q

What class of drug is acute dystonia as a result of antipsychotics managed with?

A

Anticholinergics

117
Q

What is acute dystonia?

A

An acute dystonic reaction is characterized by involuntary contractions of muscles of the extremities, face, neck, abdomen, pelvis, or larynx in either sustained or intermittent patterns that lead to abnormal movements or postures.

I.e. spasms (e.g. torticollis)

118
Q

What is torticollis?

A

Torticollis is a common phenomenon when your neck muscles spasm and your neck twists to the side.

119
Q

What are the 4 cardinal motor symptoms of parkinsonism?

A
  1. Tremor
  2. Rigidity
  3. Bradykinesia
  4. Postural instability
120
Q

What class of drug is parkinsonism as a result of antipsychotics managed with?

A

Anticolinergics

121
Q

What is akathisia?

A

Restlessness i.e. inability to keep still

122
Q

What is akathisia as a result of antipsychotics managed with?

A

Sedatives or medication change

123
Q

What is tardive dyskinesia?

A

Tardive dyskinesia (TD) is a condition where your face, body or both make sudden, irregular movements which you cannot control.

I.e. choreoathetoid movements

124
Q

What tardive dyskinesia as a result of antipsychotics managed with?

A

reduce dose or change drug

125
Q

How do anticholinergics affect tardive dyskinesia as a result of antipsychotics?

A

Make it WORSE

126
Q

Presentation of schizoaffective disorder?

A

Schizophrenia and mood disorder in the same episode with at least several of the positive symptoms in schizophrenia

  • Schizomanic –> manic symptoms
  • Schizodepressive –> depressed symptoms
127
Q

How do typical antipsychotics cause hyperprolactinaemia?

A

Typical antipsychotics block dopamine inhibition of the pituitary and cause prolactin rise.

Secretion of prolactin by the pituitary is under inhibitory control via dopamine from the hypothalamus. Interference with dopamine secretion or action leads to an increase in serum prolactin.

128
Q

What is the effect of ACh on the heart rate?

A

Slows heart

(by activating the M2 muscarinic receptor (M2R) that, in turn, opens the acetylcholine-activated potassium channel (IK,ACh) to slow the firing of the sinus node)

129
Q
A