Midterm 1 (without 0.4 + 0.5 readings) Flashcards
1
Q
Bupivacaine is markedly toxic if inadvertently given intravenously, causing what possible effects in the body?
A
- excitation,
- nervousness
- tingling around the mouth
- tinnitus
- tremor
- dizziness
- blurred vision
- seizures
^^ these are followed by a depression:
- drowsiness
- loss of consciousness
- respiratory depression
- apnea
2
Q
When has bupivacaine caused death?
A
Bupivacaine has caused several deaths by cardiac arrest when epidural anesthetic has been accidentally inserted into a vein instead of the epidural space.
3
Q
What are the known risks about acute exposure to fentanyl through epidurals with the fetus?
A
- Prolonged labor (opioid and local anesthetic epidural may reduce uterine activity)
- Increased need for forceps and C-section
- Fetal and maternal respiratory depression
(*most serious risk) - Problems with breast feeding (may be due to disrupted oxytocin release in labor)
- Maternal hypotension (low blood pressure)
4
Q
If administered improperly, the epidural may puncture
the dura and cause _____________?
A
a prolonged headache
5
Q
When was morphine first introduced into the epidural space? What year was it first officially used in child birth?
A
It was first introduced in 1979, and was used for the first time in an epidural infusion for pain relief during labour in 1980
6
Q
What is an opiod?
A
any substance that acts on the opioid pain receptors in the body, that bind to 1 or more of the different types of opioid receptors in the body
**can be naturally occurring or synthetic
7
Q
When was cocaine clinically used for the first time? For what purpose?
A
In 1884 by Sigmund Freud, who used it on a patient with a morphine addiction
8
Q
What was the first synthetic version of cocaine?
A
PROCAINE, developed in 1904
LINDOCANE was influenced by this as another synthetic version of cocaine in 1943 that was heavily used in WW2
9
Q
What do raw coca leaves cause when injested?
A
a mild stimulant that suppresses hunger, thirst, pain and fatigue
10
Q
When was cocaine first used in an epidural?
A
In 1885 in New York
11
Q
What is the most common local anesthetics found in epidurals?
A
BUPIVACAINE
12
Q
What is the most common opiod found in epidurals?
A
FENTANYL
13
Q
What are the 2 common ways of local anesthetic administration?
A
- topical anesthesia (applied externally and has a rapid onset with high concentration) –> ex. over the counter tooth gel
- Infiltration anesthesia (applied through injection) –> used for minor surgical procedures
14
Q
What are the 5 ways opiods can be delivered?
A
- orally
- trandfermally (through skin, ex. patch)
- Intravenously (into blood)
- subcutaneously (into lower layer of skin)
- injected into the epidural or subarachnoid space
15
Q
Where is epidural anesthesia injected?
A
in the space immediately outside the DURA MATTER (why it’s called an epiDURAl)
**most widely used in childbirth
16
Q
What is spinal anesthesia?
A
involves injecting medication into the subarchnoid space (CSF)
*Synonyms: a spinal block, subarachnoid anesthesia, intrathecal anesthesia
17
Q
What does Neuraxial blockade mean?
A
it refers to local anesthetics being delivered around the nerves of the CNS (includes both spinal and epidural anesthesia)
**does not having both forms of epidurals at the same time, just Neuraxial blockade is an umbrella term that includes both
18
Q
When drugs are in the epidural space, what can they do?
A
- diffuse across spinal cord meninges
- exit invertible foramina to reach muscle space
- diffuse into epidural fat
- diffuse into ligaments
19
Q
What determines how drugs diffuse in the body?
A
Fat solubility –> whether the substances mixes better with fat or water
20
Q
Is epidural morphine better or worse than systemically (ex. IV) administered morphine?
A
Epidural morphine > systemical morphine
21
Q
What is a more effective epidural than just morphine alone?
A
An epidural with morphine and bupivacaine is more effective than morphine alone
22
Q
What are local anesthetics? How do they work?
A
medication that causes absence of pain sensation
**must cross the spinal cord in order to work
They work by reversibly BINDING TO THE SODIUM CHANNELS ON MEMBRANES OF THE NEARBY NEURONS
(this prevents the sodium ions from entering inside the neuron, resulting in the action potentials of those neurons to be inhibited, aka no longer able to send pain signals)
23
Q
What type of neural fibers do local anesthetics have a better effect on?
A
On neural fibers that are ACTIVELY TRANSMITTING than those not. Meaning…
**neural fibers with faster firing rates are more susceptible to local anesthetics
24
Q
What is the order of how nuerons are effected by local anesthetics?
A
- autonomic
- temperature
- pain
- touch
- pressure
- vibration
- proriveption
- motor
**local anesthetics reduce sensory functions more than motor functions, but all of them are effected
25
How do opiods work?
by binding to different types of opiod receptors (e.g. mu, kappa, delta opiod receptors) found in the brain, spinal cord, and nervous tissue
26
What are the main potential risks of epidurals?
1. respiratory depression
2. low blood pressure
27
Describe the characteristics of fentanyl
- highly FAT-soluble
- acts primarly through supraspinal/systemic effects (aka. quick effects on brain way faster than effects on spinal cord)
- quickly absorbed by blood
*blood levels of fentanyl after epidural can reach the SAME levels of IV administered fentanyl
28
Describe the characteristics of morphine
- highly WATER-soluble
- acts primarily through direct spinal effects
*more likely than fentynal to be absorbed into the epidural space
29
What does bupivacaine have a higher potential of compared to other agents?
higher risk for DIRECT CARDIAC TOXICITY than other agents
30
When local anesthetics are absorbed in injection, the PNS and CNS are depressed in a _______________ manner
DOSE DEPENDENT MANNER
(can lead to CNS respiratory depression or cardiac arrest)
31
What type of blood is fentanyl diffused into when delivered epidurally?
MATERNAL BLOOD
*repeated administration of fentanyl runs an increased risk of the drug being taken up by fetal tissues
32
What is the concentration of fentanyl in the blood during respiratory depression?
greater than 2ng/mL concentration in the blood
*the concentration it takes for respiratory depression is assumed to be lower for babies, but no direct evidence
33
What is fentanyl likely to cause based on it's solubility? What about for morphine?
As fentanyl is fat-soluble, it is more likely to cause early-onset respiratory depression
As morphine is water-soluble, it is more likely to cause BOTH early + late onset respiratory distress
34
What are some of the different factors that are a possible reason for congenital insensitivity/congenital analgesia?
- excessively high levels of endorphins
- problems with their nociceptive sensory fibers and the corresponding peripheral nociceptors.
35
In what ways is pain influenced by cultural factors?
People who are raised in cultures where they are taught to show pain stoically (without showing one's feelings or complaining about pain) will show LESS discomfort than those who are taught to focus directly on the pain
36
In what ways is pain influenced by cognitive or psychological factors?
Stress and depression can increase feelings of pain while while other factors such as a calm attitude can reduce the negative experience of pain.
**Distress and anxiety are two of the cognitive factors
that most often amplify pain.
How much attention is being focused on the pain by the individual or those close to them can effect pain levels also: (ex. in experiments where men were interviewed about their sensations of pain, those men who knew
that their sympathetic wives were listening behind a two-way mirror evaluated their pain as more intense than those men who did not have this sympathetic ear.)
37
Pain becomes less active when _________ are played?
SOUNDS
studies have shown that simply listening to sounds when receiving a painful stimulus reduces the perception of pain.
38
There are various types of _______ whose free endings form _________.
nerve fibers (axons)
nociceptors
39
What does the thickness of the myelin sheath and the diameter of the fiber on the axon effect?
They both affect the speed at which these axons conduct nerve impulses.
*the greater the diameter of the fiber and the thicker its myelin sheath, the FASTER A FIBER WILL CONDUCT NERVE IMPULSES
40
What pain occurs from A delta fibers?
FAST PAIN (goes away pretty quick, comes from the stimulation and transmission of nerve impulses of these A delta fibers)
**A fibers are mylienatied --> why the pain is fast, because of faster nerve impulses
(A delta fibers carry messages at the speed of a messenger on a bicycle)
41
What pain occurs from C fibers?
SLOW PAIN (persists longer, comes from stimulation and transmission over non-myelinated C-fibers)
(C fibers carry messages at the speed of a messenger on foot)
42
C fibers are estimated to account for about _____% of all nociceptive fibers.
70%
43
Which fibers carry the signals that trigger your withdrawal reflex?
A DELTA FIBERS (The fast-pain pathways)
can happen in milliseconds, like when you step on a nail.
44
What are the types of neural pathways that DECEND from the CNS?
they DIMINISH THE PAIN signals travelling up the ascending pathways from the body to the brain.
*can sometimes even completely eliminate certain forms of pain
45
What theory is now recognized as best describing the mechanisms involved in the descending control of pain?
GATE-CONTROL THEORY OF PAIN:
theory where at each of the main points along the ascending pain pathways, there are "gates" that can be closed to make it harder for nociceptive impulses to get through (depending on how open the gates are at each of these relay points, a nociceptor will not always create the same level of pain intensity even with the same stimulus)
46
What are the 3 different levels of the CNS where
neural mechanisms can act as a gate/filter to reduce the transmission of pain impulses?
1. SPINAL CORD
2. BRAIN STEM **including the midbrain and medulla oblongata
3. THE BRAIN (including the prefrontal cortex)
47
What is visceral pain caused by?
caused by activation of nociceptors of the internal organs (internal organs are largely innervated by C fibers)
48
What are some characteristics/way to describe visceral pain?
- highly sensitive to distension, ischemia and inflammation (yet visceral organs are LESS sensitive to other stimuli that would normally evoke pain in other organs such as burning or cutting)
- the pain tends to be vague and is usually described as deep or dragging.
- can be associated with nausea and changes in heart rate and can evoke emotional responses.
**These qualities of visceral pain are due to the low
density of sensory innervation of viscera & the extensive divergence of visceral input onto the central nervous system (CNS).
49
What do all cognitive, emotional and sensory processes that affect pain perception arise from?
they arise from THE CONTEXT SURROUNDING THE PAINFUL EXPERIENCE (different contextual factors play an important role in the perception of pain)
EXAMPLES:
- physical properties of the medication (colour, shape, taste and smell)
- characteristics of the hospital room
- the sight of health professionals and medical instruments
- the interaction between patient and doctor.
50
What do both contextinduced positive expectation and
contextinduced conditioning produce?
BRAIN CHANGES that are associated with the activation of at least two neurochemical systems:
1. endogenous opioid system
2. endocannabinoid systems.
51
What has Cholecystokinin (CCK) been found to reduce?
been found to reduce PLACEBO ANALGESIA (perceived reduction of pain from placebo) with its anti-opioid action
52
There is agreement that administration of ___________ along with _________ activates a descending pain modulating network
A placebo
Positive verbal suggestions
53
Which main 3 brain regions are activated with a positive therapeutic context?
1. DLPFC (dorsolateral prefrontal cortex)
2. PAG (periaqueductal grey)
3. rACC (rostral anterior cingulate cortex)
These functions are activated and deactivated by the placebo response
54
What is the nocebo response phenomenon?
Opposite to the placebo response, the nocebo response is induced by negative expectations.
Ex. if a placebo is given within a negative context along with a negative verbal suggestion of pain, a nocebo response can occur.
55
What are some real examples of how someone might experience a nocebo response?
- can also occur when patients distrust medical personnel or the prescribed therapy
- negative diagnoses and prognoses can lead to
an amplification of pain intensity, and can have effects on the emotional state of patients
56
What can the nocebo hyperalgesic effect be mediated by?
CCK!
this suggests that anticipatory anxiety has an important role in nocebo hyperalgesia as CCK is linked with anxiety/panic attacks.
57
What are nocebo effects associated with?
its associated with decrease in dopamine and opioid activity in the nucleus accumbens.
58
What is the nocebo hyperalgesic effect?
an increase in pain after implementation of a non-hyperalgesic procedure or substance, i.e. placebo. or WHEN NEGATIVE EXPECTATIONS INCREASE PAIN
59
What's the difference between analgesia vs. hyperanalgesia vs algesia
Analgesia = the inability to feel pain (in practice, often partial)
Hyperanalgesia = An increased sensitivity to feeling pain and an EXTREME RESPONSE to pain
Algesia = sensitivity to pain
60
What is anxiety-induced hyperalgesia?
attention is focused on the IMPENDING PAIN, and the biochemical link between this anticipatory anxiety and the pain increase involves CCK.
61
What is stress-induced analgesia?
a general state of arousal that stems from the focus of attention on an environmental stressor.
**some evidence shows that stress-induced analgesia results from activation of endogenous opioid systems.
62
How do CCK, HPA and NAcc respond to a negative context/negative expectations?
CCK: ACTIVATES to have facilitating effect on pain transmission
HPA: ACTIVATES (related to anticipatory anxiety)
NAcc: DEACTIVATION, reduce μ‑opioid receptor and dopamine receptor signalling in the NAcc.
63
An individual’s interpretation of the meaning of pain is not always associated with __________.
Prognosis --> the likely course of a disease or ailment.
Different religions and cultures attribute different meanings to pain and suffering, and this can lead to different experiences of pain
64
Does anaalgesia has the possibility to activate the same mesolimbic reward network other feel good stimuli?
YES for sure.
Food, money and drugs of abuse
65
For the Greeks, there was nothing more dangerous for woman than ____________?
than her uterus spontaneously moving around her abdominal cavity ---> they believed that as it moves it put pressure on other organs, or illness/death
**thought that the uterus wondered around in response to SMELLS that caused distress and sometimes hysteria (emotional/out of control)
66
How did the conceptions of hysteria shift?
Jean-Martin and his 2 students Pierre Janet and Sigmund Freud, developed a new method for treating hysteria with psychoanalysis
- said that men could also have "hysteria"
- they believed that early childhood experiences (sexual abuse) is what created one to be "hysteric" later in life
67
Describe the uterus in it's pregnant and non-pregnant state
Not pregnant state: a pear shaped pelvic organ that sits between the baldder and the rectum
Pregnant state: the uterus grows and expands upwards into the abdominal cavity, above the bladder and rectum
68
Describe the 4 subdivisions of the uterus:
- the FUNDUS: part of the uterus that contracts the strongest during labour and is where labour contractions start
- the UTERINE BODY/CORPUS: the largest subdivision of uterus, situated right below the fundus.
- the CERVIX: the neck of the uterus, the lowermost, cylindrical portion.
- the ISTHMUS: the transition zone between the uterine body and the cervix (*the area of lower, "bikini-line" caesarean incisions)
69
What is the cervix composed of?
composed of fibrous connective tissue and is about 2.5cm long (projects slightly into the vagina)
70
What are the 3 layers of the uterine wall?
1. the ENDOMEDRIUM: the inner-most layer, closest to the baby during pregnancy
2. the MYOMETRIUM: the middle and most prominent layer (**most important layer of uterus - thick in upper part of uterus and thinniner in cervix and isthmus)
3. the PERIMETRIUM: outer connective tissue composed of the serous membrane
71
What is MYOMETRIUM mainly consisted of?
consists mainly of smooth muscle fibers united by connective tissue that contains lots of elastic fibers
72
How do smooth muscle fibers interact with other vessels and cells?
they take MULTIPLE DIRECTIONS and INTERTWINE to surround the blood vessels, lymphatic vessels and nerve cells
73
In the fundus and uterine body, muscle makes up _______ of the tissue mass, whereas in the cervix, muscle makes up ________% of the tissue mass
MOST
ONLY 10%
74
What is controversial about the human myometrium?
There is not a clear answer as to whether or not strict layering exists in the human myometrium
75
Describe the 3 main parts the nervous system is divided into?
1. Central Nervous System:
- "backbone"
- brain and spinal cord
2. Peripheral Nervous System:
- consists of the nerves going to and from the spinal cord and brain (CNS)
- cranial and spinal nerves
**connects the CNS to the muscles and glands and sensory organs of the body
3. Enteric Nervous System:
- regulates mobility of the esophogas, stomach, and intestines
- regulates the secretion of digestive enzymes and acids
76
What are the 2 subdivisions of the PNS?
1. Somatic Nervous System
- touch, hearing, etc.
- muscles that move the body
2. Visceral Nervous System
- visceral sensations and control of visceral muscles
*visceral = internal organs
77
What are the 2 subdivisions of the Somatic Nervous system?
1. Moter (Efferent)
- motor movement of all skeletal muscles
2. Sensory (Afferent)
- General: touch, pain, pressure, vibration, temps (sensing movement in skin body wall & limbs)
- Specialized: vision, hearing, smell, equilibrium
78
What are the 2 subdivisions of the Visceral Nervous System?
1. Motor (Efferent) --> Autonomic NS
- movement sensed of smooth muscle, cardiac muscle and glands
*Splits into the Sympathetic (flight or fight) and Parasympathetic (rest and digest/calm and connection)
2. Sensory (Afferent)
- pain, temp, chemical changes, irritation in viscera, nausea and hunger.
79
What is vassopressin?
an important element of the fight or flight mechanism along with keeping the body's fluid volume balanced and helps to raise blood pressure.
one ingredient in the internal "power drink" that stimulates defensive actions and behaviours that are typically associated with males.
80
Does the oxytoxin system effect both male and females?
yes - has crucial significance for humans and other mammals
*a connection does exist though between oxytocin and the female sex hormone (estrogen) and between vassoppression and the male sex hormone (testoserone)
81
What is the level of oxytocin in the blood during nursing associated with?
a high level of oxytocin in the blood was correlated with the mother's sensations of calm, lack of stress, and ability to interact with their babies.
82
What is meant by the calm and connected system?
the oxytocin system!
83
What are some main ways your body changes during the fight or flight reponse?
- digestion stops to focus on using the blood supply for other more important functions
- increased heart activity and elevated blood flow in all muscles
- liver releases stored energy of glucose (bring extra energy for muscles)
- pupils will widen to see better
- might appear pale or flushed due to a decrease of blood circulation
- higher levels of stress hormones (cortisol)
*the substance noradrenaline plays an important role in making this happen
84
Opposite to the fight or flight reaction, the calm and connection reaction is marked by lower ______________ and lower levels of the ___________________________.
blood pressure
stress hormone cortisol
85
What is the role of the cerebral cortex?
it serves as our MEMORY CENTRE and manages our conscious thought processes, such as the ability to plan or make associations
also important for registering our awareness of touch and activating certain emotions
86
What is the role of the lower brain (limbic system & brain stem)
it operates subconsciously, what keeps us alive.
manages heartbeat, breathing and blood pressure (especially from brain stem)
emotional impulses, feelings, memorization (limbic system)
87
Define Innervation
The supply of nerve fibres functionally connected with a part of the body
Innervation can be MOTOR: nerve fibres that carry signals towards certain part of the body to stimulate actions in this part of the body.
Innervation can also be SENSORY: nerve fibres that carry information about sensations away from a particular part of the body, towards the spinal cord.
88
Define Denervation
The partial or complete DISCONNECTION of nerve fibres that were previously connected with a part of the body.
Denervation leads to partial or complete
cessation of motor and/or sensory innervation of that part of the body.
89
Define Interoception
The sense of the internal state of the body
It includes visceroception and proprioception
90
Define Visceropception
The perception of bodily signals arising specifically from the viscera (i.e., the internal organs): the heart, lungs, stomach, and bladder, uterus, gut, and other internal organs in the trunk of the body.
91
Define Proprioception
The sense of the relative position of one's own parts of the body and strength of effort being employed in movement
92
How do the perceptions of pain differ between the alternative media and the mass media?
Mass media:
- pain is a self-evident, indisputable fact
- Unavoidable except through pain medication
- It’s so bad, it makes you want to die
- Makes women go mad (an turn violent on
men)
Alternative media:
- pain is not the only sensation during labour
- also shows other sensations (bliss, joy, satisfaction,
ecstasy, excitement) can be much more
powerful than the pain
93
What are some differences that change how people perceive birth?
- if you identify as female/have female anatomy
- changes between those who have experienced and/or been present during a natural & intervention-free childbirth vs. those who have not
94
What are the 2 ways that new information can FAIL to change our knowledge?
1. Its credibility is assessed as low (information discarded)
2. Its credibility is assessed as acceptable, but it clashes with our pre-existing knowledge
(information retained but not integrated into knowledge ---> filed as ‘exception’)
95
Why is the alternative media unlikely to be a source of new knowledge?
- The new information often clashes with our pre-existing knowledge
- Even when we find it credible, it’s hard to know what to do with this new information
96
What are the different types of muscle fibres?
- smooth ( found in most of the internal organs,
including the digestive system, bladder, and blood vessels)
- cardiac
- skeletal (attached to the bones and help us move
around)
*The myometrium of the uterus contains
only smooth muscle fibres
97
Can women control their uterine muscles
intentionally?
AKA: can women make themselves go into labour intentionally? -------> NO
98
Can skeletal muscles fibres be willingly controlled? What about smooth muscles fibres?
Skeletal muscle fibres can be volitionally controlled (consciously moved)
^^ this direct control over muscles happens through the peripheral nervous system (PNS)
Smooth muscle fibres cannot be volitionally controlled (consciously moved)
99
How many times the weight of a non pregnant uterus the weight of a pregnant uterus? What about volume?
Weight: 10-20x more heavy than non pregnant
Volume: 5000x more volume than non pregnant
(10ml ---> 5 liters)
100
How do smooth muscle fibers differ in the pregnant vs non pregnant uterus?
- the length of fibres is 10x longer in the pregnant uterus
- the width of fibres is 3x longer in the pregnant uterus
101
When does the non-pregnant uterus contract?
- all the time, spontaneously
- during menstration
- during orgasm
102
Uterine innervation vs denervation of uterus
Uterine innervation = nerves being supplied to the uterus
(good and healthy supply of nerves)
Denervation of uterus = Loss of nerve supply in uterus
(their muscular functionality is lost)
103
For a pregnant person, when does the uterus contract?
*orgasms in pregnancy
*labour and birth
*the post-partum period
104
The pregnant uterus enters a state of __________ before becoming active again in late pregnancy
uterine quiescence
(a state of inactivity to prevent preterm labor)
*exits this state when in late pregnancy to have baby at a healthy time
105
Explain motor innervation in the non-pregnant uterus
Motor innervation = autonomic control over contractility
- Neural fibres exit the spinal cord, innervating all pelvic
cavity organs, including the uterus, bladder, and rectum
- Sympathetic fibres exit at higher levels along the spinal cord compared to parasympathetic fibres
106
How does autonomic control occur over smooth muscles?
Nerve fibres release neurotransmitters onto muscle cells through autonomic varicosities
varicosities = little circles that carry little dots (neurotransmitters) within the autonomic muscle fibres.
107
Explain sensory innervation in the non-pregnant uterus
Sensory innervation = carrying visceral sensations
- Sensory nerves from the uterus enter the spinal cord at higher levels than those from the cervix and upper part of the vagina
108
What are some types of visceral sensations?
*distension/stretch
*inflammation
*ischemia
109
What are some types of visceral sensations?
*distension/stretch
*inflammation
*ischemia (condition in which blood flow (and thus oxygen) is restricted or reduced in a part of the body)
110
In comparison to other smooth muscles of the body the uterus has a relatively _________ density of
nerves to smooth muscles cells
LOW --> the uterus has a low density of nerves to smooth muscle cells
111
During pregnancy (with high levels of ovarian hormones), what does the density in the uterus (more smooth muscles cells than nerves) decrease even further?
- hypertrophy (increase/growth of muscle cells) of uterine myocytes (muscle cells)
- decrease in number of nerve fibres
112
How does the # of uterine nerve fibres change when non-pregnant, pregnant, and in labour?
Very high when not pregnant (about 900 frofiles), drops a LOT during pregnancy (to less than 50 frofiles) and then up a bit to 100 frofiles during labour.
113
Explain what motor denervation does for the pregnant uterus
(orchestrated by ovarian hormones)
- helps in maintaining uterine quiescence
- inhibition is relative rather than absolute (e.g., abortion can be induced by strong pharmacological stimulation at any point in gestation)
- uterine tone maintenance remains, but there is resistance to propagated (coordinated) contractions
- control of contractility becomes predominantly hormonal
114
why are smooth muscles always contracting?
to maintain the fitness of the muscle!
115
what effects the contractility?
even though the contractility are controlled by nerves, they are also influenced by peripheral nervous system processes but also hormones (like oxytocin)
116
Why is the myometrium denervated during pregnancy?
to prevent preterm labour and allows for normal progression and successful healthy delivery
**the myometrium can do this by temporarily depriving its nerve supply during pregnancy
117
What layer of the uterus releases the hormones?
Endometrium (uterine lining)
consists of glands and tiny blood vessels
118
What could be some reasons for sensory denervation in the pregnant uterus?
*not very well understood (or appreciated; few studies)
- could serve to reduce contractility (stretch sensations can induce contraction of the myometrium and other muscles)
- may be selective to the uterine muscle
- stretch sensations from the myometrium would be
essentially undetectable
119
What are the common explanations of pain associated with normal labour contractions? What is the problem with these common explinations?
- Stretching of the cervix
- Contraction of uterine muscle
However, we know with scientific knowledge that:
- Stretch receptors in the uterus disappear during
pregnancy
- Stretch receptors in the cervix disappear at the onset of labour
- Muscle fibres in the cervix are almost completely
replaced by connective tissue
120
What are the stages of labour?
“Stage 1”: The uterus contracts and stretches the cervix to open to approximately 10 cm diameter (MOST PAINFUL STAGE)
*“Stage 2”: The baby passes through the ‘birth canal’ and is born
*“Stage 3”: The placenta is born (‘expelled’)
*Post-partum: Uterus contracts in order to return to its original shape
121
What is the most painful stage of labour?
STAGE 1: Getting to “full dilation’ (10 cm diameter) is usually the longest, hardest, and potentially most painful part of giving birth
122
When there is no contractions, where is the person giving birth most likely to still feel pain?
The strongest sensations are felt at the lower back when in between contractions
123
Is there still pain in between contractions when in labour?
Generally no - pain during labour is felt only during contractions, in between contractions there is no pain
124
Posterior vs Anterior position?
anterior = babies head is in the position of coming out first
posterior = babies head is in the position of coming out last (feet first - breech birth)
125
What are some possible reasons for why labour hurts (that do not contradict scientific knowledge)?
**Vasoconstriction of uterine blood vessels
**Release of chemicals from muscle exertion
Also:
*Inflammation
*Reduced oxygen delivery to tissues (ischemia)
126
What does injecting muscle metabolites result in?
Injecting muscle metabolites evokes sensations of muscle fatigue and pain
*some physiological concentrations of metabolite combinations:
- protons, lactate, Adenosine triphosphate (ATP)
127
Explain the vasoconstriction of uterine blood vessels during childbirth, what do they do?
They occur at the peak of contractions, when the myometrium is contracting
- Contractions reduce blood flow to the uterus (and the baby)
- the contracting myometrium compresses the blood vessels that course through it
- the stronger (and longer) the contraction, the more blood flow is reduced
- some hypoxia (low levels of oxygen in body tissues) happens during every contraction
128
What are some benefits to labour pain?
- Guides the birthing woman through the birth process
(How to move, how to stand, what to do)
- Focuses the woman’s mental and physical resources on the birth process
*** Can regulate the strength of contractions (this greatly benefits the baby - and the mother)
Pain during labour as the body’s way of PREVENTiNG INJURY to mom and baby
129
Where are some of the fetus’s blood vessels contained?
in a tiny hairlike projections (villi) of the placenta
The mother’s blood passes through the space surrounding the villi (intervillous space)
Only a thin membrane (placental membrane) separates the mothers blood and the villi
130
What are the basic functions of the placenta?
Transport of oxygen, nutrients, waste products
131
Pain leads to the release of ....
* stress-related hormones and neurotransmitters
* endogenous opioids
132
What hormone does pain surpress?
OXYTOCIN
Meaning, pain can serve to reduce the strength and duration of contractions, especially during stage 1 of
labour.
133
What is nociception?
The encoding and processing of harmful stimuli in the nervous system, leading to A BODY'S ABILITY TO SENSE POSSIBLE HARM
NOCICEPTION DOES NOT MEAN PAIN.
It's the sensory process that produces the nerve signals that trigger pain, and does not create a painful sensation
134
In the study from Denmark, what did they notice about epidurals in hospital vs at home
Epidurals are rarely used in Denmark, so when they're used they are needed.
They noticed that women who gave birth at the hospital were 4 times more likely to receive an epidural
135
What are some things to change during birth to make it more comfortable and easy?
NOT LYING DOWN - standing up is typically better
In warm water - shown to reduce pain significantly
136
What are the 2 sections nociceptive input can be subdivided into?
Visceral and Non-Visceral
Visceral = interal organs (ex. liver, gut, stomach)
**carried largely by C fibers
Non-Visceral = any parts of the body that are not internal organs (bones, ligaments, skin, etc.)
**Carried largely by A-delta fibres
137
What fibres carry visceral organs?
mostly C FIBERS (slow pain)
138
What fibres carry non-viseral parts of body?
mostly A-DELTA (fast pain)
139
What is exteroception?
Think of our 5 senses
140
What is proprioception?
The sense of where one’s own body is in space
(Signals from joints, tendons, muscles)
141
What is visceroception?
The sense of the physiological condition of the body
(Signals from inner organs)
142
What is placebo analgesia?
When positive expectations reduce pain
143
What part of the brain is linked to having expectations
The dorsolateral prefrontal cortex
144
Which parts of the brain are linked with increase in endogenous opioids?
more endogenous opiods = mimic stress response
rostal Anterior Cingulate Cortex (ACC)
Periaqueductal Gray (PAG)
^^controls the release of endogenous opioids
145
When expecting pain, it creates a state of anticipatory anxiety, which has what effects on the body?
- increases muscle tension and any related pain
- increases stress and weakens the body’s own ability to cope with pain
- suppresses endogenous opioids
146
What is the anxiety-promoting hormone?
Cholecystokinin (CKK)
also has a facilitating effect on pain transmission
147
What does the hypothalamic-pituitary-adrenal axis do?
release cortisol, suppress immune system
STRESS
148
What suppress endogenous opioids?
Nucleus Accumbens (NAcc)
149
Where does the thalamus send projections to?
– Posterior Insula
– Anterior Cingulate Cortex (ACC)
– Somatosensory Cortex
150
What is the brain activity that occurs only during
first-person experience of pain?
Primary somatosensory cortex and secondary somatosensory cortex (located in the posterior insula)
151
Which areas of someone's brain who are feeling empathy for someone else's pain would activate?
Both the Anterior Cingulate Cortex (ACC) and the bilateral anterior insula
152
When feeling pain, we will expirience all regions of pain ________ & __________, but when observing pain, only the _________ areas are activated
Sensory and affective
Affective
153
At what level do the most prominent individual differences in pain experience occur?
At cortical regions of the brain
(think about the experiment with the hot pad and the high vs low sensitivity groups)
154
How do we know whether a baby is in pain?
- crying
* facial expressions
* body movement
* physiological stress response
155
Describe newborns heads
Soft, still developing and not yet connected skull bones
an opening in their skull
