PBL 2 Flashcards

1
Q

where is the midbrain?

A

between the cerebrum and the pons

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

what is the tectum?

A

where the 4 colliculi are found

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

what are the 3 regions of the midbrain?

A

tectum (behind cerebral aqueduct), tegmentum (in front of cerebral aqueduct) and basis pedunculi (2 anterolateral portions)

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

what is the structure called that surrounds the cerebral aqueduct?

A

the periaqueductal grey
a nucleus that plays a critical role in autonomic function, motivated behavior and behavioural responses to threatening stimuli. and is the primary control centre for pain.

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

where is the tectum?

A

directly inferior to pineal gland

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

how are the colliculi separated?

A

by the cruciform sulcus

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

what are the functions of superior colliculi?

A

for reflexes that govern movements of the head, eyes, and trunk in response to visual stimuli.

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

what are the functions of inferior colliculi?

A

relaying impulses from the receptors for hearing in the inner ear to the brain and reflex centres for the startle reflex (sudden movements of the head, eyes, and trunk that occur when you are surprised by a loud noise).

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

describe the general structure of the cerebral peduncles?

A

they extend from the cerebral hemispheres to converge as they meet the pons

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

how are cerebral peduncles separated?

A

by the interpeduncle fossa

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

what are the functions of the cerebral peduncles?

A

consist of axons of the corticospinal, corticobulbar, and corticopontine tracts, which conduct nerve impulses from motor areas in the cerebral cortex to the spinal cord, medulla, and pons, respectively

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

what does the tegmentum consist of?

A
medial lemniscus
anterolateral tracts
fibres from superior cerebellar peduncles
red nucleus
raphe nuclei neurones
ventral tegmental area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the basis pedunculi consist of?

A

cura cerebri

substantia nigra

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

where is the pons found?

A

above the medulla but below the midbrain

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

what does the pons consist of?

A

mainly nerve fibres that connect the 2 hemispheres of the cerebellum

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

what is behind the basal pons?

A

the pontine tegmentum

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

what is the ventral region of the pons?

A

The ventral pons contains the pontine nuclei, which are responsible for coordinating movement. Fibres from the pontine nuclei cross the midline and form the middle cerebellar peduncles on their way to the cerebellum

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

what is the dorsal region of the pons?

A

The tegmentum forms part of the reticular formation – a set of nuclei found throughout the brainstem that are responsible for arousal and attentiveness.

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

what do the middle cerebellar peduncles do?

A

connects the transverse fibers of the pons with the cerebellum,

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

where do we find the fourth ventricle?

A

in the pons

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

describe the anterior surface of the medulla oblongata?

A

anterior median fissure, which is continuous along the length of the spinal cord.
pyramids are paired swellings found between the anterior median fissure and the ventrolateral sulcus.
olives are another pair of swellings located laterally to the pyramids

22
Q

describe the posterior surface of the medulla oblongata?

A

the fasciculus gracilis and fasciculus cuneatus are seen, separated by the posterior intermediate sulcus.

23
Q

where is the medulla?

A

it extends from the foramen magnum to the inferior border of the pons

24
Q

what is the function of the midbrain?

A

It is associated with vision, hearing, motor control, sleep and wakefulness, arousal (alertness), and temperature regulation.

25
Q

what is the function of the pons?

A

It is a group of nerves that function as a connection between the cerebrum and cerebellum

26
Q

what is the function of the medulla oblongata?

A

passes messages between your spinal cord and brain. It’s also essential for regulating your cardiovascular and respiratory systems.

27
Q

what is brain death?

A

where a person no longer has any activity in their brain stem and has permanently lost the potential for consciousness and the capacity to breathe

28
Q

what are the criteria for determination of brain death?

A
  • A person must be unconscious and fail to respond to outside stimulation.
  • A person’s heartbeat and breathing can only be maintained using a ventilator.
  • There must be clear evidence that serious brain damage has occurred, and it can’t be cured.
  • The doctors will run a series of tests. Two doctors have to agree on the results for a diagnosis of brain death to be confirmed. The tests are carried out twice to minimise and chance of error.
29
Q

what are some of the tests to determine if a patient is brain dead?

A
  • A torch is shone into both eyes to see if they react to light (Testing CN II and III)
  • The cornea is stroked with a tissue or piece of cotton wool to see if the eye reacts (Testing CN V and VI)
  • Pressure is applied to the forehead and the nose is pinched to see if there is any movement in response (Testing CN V and VII)
  • Ice-cold water is inserted into each ear, which would usually causes the eyes to move (Testing CN VIII, IV, VI, and III)
  • A thin, plastic tube is placed down the trachea to see if it provokes gagging or coughing (Testing CN IX and X)
  • The person is disconnected from the ventilator for a short period of time to see if they make any attempt to breathe on their own
30
Q

how do ultrasounds work?

A

Ultrasound waves are produced by a transducer, which emits ultrasound waves, and detects the ultrasound echoes reflected back. The ultrasound transducers are made of special ceramic crystal materials called piezoelectric which are able to produce sound waves when an electric field is applied to them, but can also work in reverse, producing an electric field when a sound wave hits them. When used in an ultrasound scanner, the transducer sends out a beam of sound waves into the body. The sound waves are reflected back to the transducer by boundaries between tissues in the path of the beam. When these echoes hit the transducer, they generate electrical signals that are sent to the ultrasound scanner. Using the speed of sound and the time of each echo’s return, the scanner calculates the distance from the transducer to the tissue boundary. These distances are then used to generate two-dimensional images of tissues and organs.

31
Q

what are the 3 types of ultrasound scans?

A
  • external ultrasound scan – the probe is moved over the skin
  • internal ultrasound scan – the probe is inserted into the body
  • endoscopic ultrasound scan – the probe is attached to a long, thin, flexible tube (an endoscope) and passed further into the body
32
Q

during an ultrasound scan, why does the technician apply gel?

A

This keeps air pockets from forming between the transducer and the skin, which reduces acoustic impedance and reflection to allow for a clear image to be produced.

33
Q

why can cranial ultrasound only be used on babies?

A

because it can’t penetrate through bone but baby skulls are not fully formed so it can be used to see the brain

34
Q

how do MRIs work?

A

employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field. When the radiofrequency field is turned off, the MRI sensors are able to detect the energy released as the protons realign with the magnetic field. The faster the protons realign, the brighter the image

35
Q

why would we give contrast agents in MRI scans?

A

they may be given to a patient intravenously before or during the MRI to increase the speed at which protons realign with the magnetic field.

36
Q

what can MRIs be used for?

A

non-bony areas/soft tissues/ brain

37
Q

why is MRI good for brain imaging?

A

it doesn’t use X-rays

38
Q

how does a computed tomography work?

A

the patient lies on a bed that slowly moves through the gantry while the x-ray tube rotates around the patient, shooting narrow beams of x-rays through the body. Instead of film, CT scanners use special digital x-ray detectors, which are located directly opposite the x-ray source.

39
Q

what are CT scans good for?

A
  • soft tissues
  • the pelvis
  • blood vessels
  • lungs
  • brain
  • abdomen
  • bones
40
Q

how are CT and MRI scans different?

A

• A CT scan uses X-rays, but an MRI uses magnets and radio waves.
• Unlike an MRI, a CT scan does not show tendons and ligaments.
• MRI is better for examining the spinal cord.
• A CT scan is better suited to cancer, pneumonia, abnormal chest x-rays, bleeding in the brain, especially after an injury.
• A brain tumour is more clearly visible on MRI.
• A CT scan shows organ tear and organ injury more quickly, so it may be more suitable for trauma cases.
• Broken bones and vertebrae are more clearly visible on a CT scan.
• CT scans provide a better image of the lungs and organs in the chest cavity between the lungs
. MRI is More expensive

41
Q

how does a PET scan work?

A

A radioactive tracer may be injected, swallowed or inhaled, depending on which organ or tissue is being studied. The tracer collects in areas of your body that have higher levels of chemical

42
Q

what are PET scans good for?

A

in revealing or evaluating several conditions, including many cancers, heart disease and brain disorders

43
Q

what are the risks of PET scans?

A
  • Cause a major allergic reaction, in rare instances
  • Expose your unborn baby to radiation if you are pregnant
  • Expose your child to radiation if you are breast-feeding
44
Q

outline the design of randomised controlled trials?

A

we have a control group and an intervention group. the intervention group receives treatment under investigation and the control group receives a placebo/old drug. we randomly assign people to groups to create 2 groups which are as similar as possible (age range, general health, similar treatments)

45
Q

what is blinding?

A

when patient don’t know what group they are in which increases the internal validity

46
Q

what is double blinding?

A

when the researchers and patients don’t know which groups the patient are in

47
Q

why is a control group important?

A

as it allows for comparison of treatment

48
Q

when would randomised controlled trials be unethical?

A

when patient would have to go under harm or were denied treatment

49
Q

what is statistical power?

A

the probability that the test correctly rejects the null hypothesis. That is, the probability of a true positive result.

50
Q

what does a high statistical power mean?

A

the chances of a false negative or false positive decreases

51
Q

what does statistical power depend on?

A

the statistical significance used
the magnitude of the effect f interest in the population
the sample size used

52
Q

how can we increase the statistical power?

A

Use a larger sample.
Improve your process to decrease standard deviation
Use a higher significance level to increase the probability that you reject the null hypothesis.
Choose a larger value for Differences.
Use a directional hypothesis (whether the effect with increase/decrease)