General prac study

Question 1

Which ventricles produce the CSF?

Answer 1

The lateral and 4th ventricles

Question 2

Describe the journey of CSF from it’s production to re-circulation in 3 stages

Answer 2

It circulates from the ventricles and central canal through the median and lateral apertures to the subarachnoid spaces and into the dural sinuses for return to the venous system

Question 3

Which 2 liquids are mixed in the dural sinuses?

Answer 3

CSF and venous blood

Question 4

Name the major input of the basal ganglia (where it projects to), it’s location and describe it’s function

Answer 4

The major input of the basal ganglia (where the BG projects to) is the SMA (supplementary motor area)
The SMA is the ‘set’ in ‘ready, set, go’. It’s located anterior to MI and superior to the premotor areas which surround it bilaterally.

Question 5

What is the striatum comprised of?

Describe the views of these components whilst travelling through coronal brain slices from posterior to anterior.

How does this differ from the thalamus?

Answer 5

The caudate nucleus and putamen. They’re both smaller in the posterior slices and become larger more anterior, finally merging to form the striatum.

The thalamus has the opposite relationship- it increases in size as you travel from anterior to posterior slices

Question 6

The basal ganglia has 2 pathways, the direct and indirect. What is the main function of each pathway, and which pathway is active by default?

Answer 6

The main function of the direct pathway is to select and initiate willed movements, whereas the function of the indirect pathway is to suppress movements. The indirect pathway is active by default. To allow movement to occur, the direct pathway inhibits the indirect pathway, a process called disinhibition.

Question 7

Which areas are involved with the indirect basal ganglion pathway which are not involved with the direct basal ganglion pathway?

Answer 7

The direct basal ganglion pathway projects directly from the caudate/ putamen to the globus pallidus internus which inhibits the ventral lateral nucleus of the thalamus, whereas the indirect basal ganglionic pathway projects to both the globus pallidus internus and externus. In turn, the globus pallidus externus also projects to the subthalamic nucleus, which projects back to the globus pallidus internus, which then inhibits the ventral lateral nucleus of the thalamus.

The substantia nigra pars compacta projects to the caudate putamen in both pathways.

Question 8

What is the major difference between the direct and indirect basal ganglion pathways, and how does this effect the ventral lateral nucleus of the thalamus (thalamic relay nucleus)?

Describe how this effect takes place.

Answer 8

The major difference between the direct and indirect basal ganglionic pathways is that the indirect pathway involves the subthalamic nucleus & the globus pallidus externus.

The subthalamic nucleus is the only excitatory nucleus in the basal ganglia system. It projects glutamate to the globus pallidus internus and the substantia nigra pars reticulata, causing them to increase their inhibition of the VLo (thalamic relay nucleus). When the VLo is inhibited it sends less glutamate to M1.

Question 9

What are the excitatory and inhibitory neurotransmitters used in the basal ganglion pathways?

What is the substantia nigra pars compacta responsible for?

Explain how the SNpc sets off a relay of events causing inhibition in the indirect pathway.

Answer 9

The excitatroy neurotransmitter is glutamate, inhibitory is GABA and the substantia nigra switches from the indirect to the direct pathway using D1 and D2.

D1 is excitatory and D2 is inhibitory. D2 is used for the indirect pathway, causing the putamen to release GABA to the GPe, which then reduces it’s inhibition to the STN.

STN sends glutamate to the GPi and SNpr, which increases the GABA they send to the VLo.

Question 10

Which 2 main spaces/ compartments contain CSF?

Answer 10

The subarachnoid (outside brain and spinal cord) space and the INTRAventricular (inside brain and spinal cord) space.

Question 11

Where is CSF produced, and how does it get back to the venous system?

Answer 11

CSF is produced in the lateral and 4th ventricles. After circulating through the ventricles, it exits the ventricular space into the subarachnoid space, then returns to the venous system via the dural sinuses.

Question 12

How does CSF pass through the ventricular compartment to the subarachnoid compartment?

Answer 12

Through the median and lateral apertures (under the 4th ventricle)

Question 13

How does CSF pass through the subarachnoid space to the venous system?

Answer 13

The CSF passes through the subarachnoid compartment to the venous system through the arachnoid villi (arachnoid granulations macroscopically).

Question 14

What do the choroid plexus do? Where are they found?

Answer 14

The choroid plexus are found in the lateral and 4th ventricles. They produce CSF.

Question 15

Mechanical protection and buoyancy and neurochemical buffering are 2 jobs of the _ _ _

Answer 15

Mechanical protection and buoyancy and neurochemical buffering are 2 jobs of the CSF.

Question 16

How does CSF get from the lateral ventricles to the 3rd ventricle?

Answer 16

CSF gets from the lateral ventricles to the 3rd ventricle through the intERventricular foramen

Question 17

How does CSF move from the 3rd ventricle (hypothalamic recess) to the 4th ventricle?

Answer 17

CSF moves from the 3rd to the 4th ventricle through the cerebral aqueduct/ mesencephalic aqueduct

Question 18

How does most CSF move from the 4th ventricle to the cerebellomedullary cistern? Which space is the cerebellomedullary cistern part of? What happens to the remaining CSF?

Answer 18

Most of the CSF moves from the 4th ventricle to the cerebellomeduallary cistern (part of the subarachnoid space), through the lateral and median apertures. The remaining CSF drains down into the spinal cord through the central canal.

Question 19

What do the arachnoid villi (arachnoid granulations macroscopically) do?

Answer 19

The arachnoid villi pierce the dura and drip CSF into the dural sinuses.

Question 20

What are the 3 meninges?

Answer 20

Pia mater, arachnoid mater and dura mater

Question 21

Which 2 meninges does the subarachnoid space separate?

Answer 21

The subarachnoid space is between the arachnoid and pia mater

Question 22

Name the 5 cell types found in the CNS

Answer 22

Neurons, endothelial cells (line blood vessels), microglia and macroglia (oligodendrocytes and astrocytes)

Question 23

What comprises the internal capsule?

Answer 23

The internal capsule is comprised of axons travelling to and from the cortex and subcortex

Question 24

Which deep grey nuclei comprise the striatum?

Answer 24

The striatum is comprised of the head of caudate and the putamen

Question 25

Name the 5 subcortical nuclei of the basal ganglia

Answer 25

The subthalamic nucleus, the globus pallidus (internus, medial and externus), the striatum (the head of caudate {caudate nucleus} and putamen) and substantia nigra.

Question 26

This nucleus, part of the basal ganglia, has a role in motor processes (affected in Parkinson’s disease), learning, inhibitory action control and is part of the reward system. It is also shaped like a tadpole. Which nucleus am I referring to?

Answer 26

The caudate nucleus

Question 27

The lentiform nucleus (L shaped, but more of a right angle triangle ) is comprised of:

Answer 27

The lentiform nucleus is comprised of the putamen and globus pallidus

Question 28

The nucleus accumbens, at the inferior merger of the head of caudate and putamen, is associated with which neural process?

Answer 28

The nucleus accumbens is heavily implicated in reward and reinforcement

Question 29

Lesions to this deep grey nuclei produce a collection of movement disorders called parkinsonism, such as tremor, stooped posture inability to initiate movement and rigidity. What is the structure? Name the 2 parts and state their differences.

Answer 29

The substantia nigra, pars compacta and pars reticulata. The SNc is visible as dark grey in gross sections. The cells are rich w dopamine and melanin (black pigment accumulates with age).

The substantia nigra pars reticulata surrounds the SNc rim adjacent to the cerebral peduncle. The cells are rich in iron but contain no dopamine, and lack pigmentation.

Question 30

Name 5 functions of the thalamus

Answer 30

1. Sensory relay
2. Motor relay
3. Limbic functions
4. Eye movement/ tracking
5. Visual reflexes

Question 31

What is the function of the most inferior portion of the primary motor cortex? (Hint: It’s next to Broca’s area)

Answer 31

The function of the most inferior portion of M1 is motor output for the face, including lips, tongue, pharynx and larynx

Question 32

What is a major difference between the neural pathways for the somatic motor and visceral (autonomic) motor systems?

How do the speeds of transmission differ?

Answer 32

The somatic motor system contains one axon between skeletal muscle at the peripheral and the cell body in the cns (monosynaptic). Fast.

Visceral motor systems are disynaptic. They contain preganglionic and postgangionic fibres either side of the autonomic ganglion. Slow.

Question 33

What are the visceral effectors that the visceral motor systems innervate? How does this compare to the somatic motor systems?

Answer 33

The visceral motor systems innervate smooth and cardiac muscle as well as gland cells. The somatic motor system only innervates skeletal muscle.

Question 34

The visceral motor system (of the autonomic nervous system) is divided into 2 functions: Sympathetic and parasympathetic.

How do they compare in regards to heart rate, digestive response and access to glucose/ sweating?

Answer 34

The sympathetic response = ‘fight or flight’.

• Elevated heart rate
• Depressed digestive function
• Mobilized glucose reserve

The parasympathetic response= ‘rest and digest’

• Slower heart rate
• Increased digestive functions
• Stop sweating

Question 35

The sympathetic and parasympathetic systems vary in regards to the length of their pre and post-ganglionic fibres.

Which has short preganglionic and long postganglionic fibres?

What does that mean in regards to the locations of the gangions?

Answer 35

The sympathetic system has short preganglionic fibres and long postganglionic fibres (think quick to get to the ganglion for quick fight/flight response)!

Sympathetic ganglions will be located close to the spinal cord, whereas parasympathetic ganglions will be located much closer to the viscera.

Question 36

How is the autonomic NS involved with the process of arousal, orgasm and mictruition?

Answer 36

The parasympathetic system effects the gonads (lubrication and erection) during arousal, whereas the sympathetic system effects orgasm.

Mictruition is controlled by the parasympathetic system, meaning that you can wee during parasympathetic activation (think relaxation- wee). This is suppressed during sympathetic activation, meaning that you can’t wee. Think orgasm: Can’t wee

Question 37

What is special about T1-L1/2?

Answer 37

This is where the lateral horn is present, giving rise to preganglionic sympathetic neurons, which exit the spinal cord in the ventral root joining the spinal nerve, then they join a sympathetic ganglion (close to the spinal cord). These ganglions are part of the sympathetic chain/ trunk.

Question 38

What do the sympathetic ganglia do in the cervical region (neck region)?

Answer 38

In the cervical region the preganglionic fibres form 3 ganglia: Superio, middle and inferior cervical ganglion (the stellate ganglion- it’s big)!

Question 39

The paravertibral ganglia run the whole length of the vertebra. Each vertebral level has a ganglia alongside it, except for the cervical region. What happens at the bottom of the chain at the level of the sacrum?

Answer 39

At the level of the sacrum the 2 sides of chain (either side of the spinal cord) join up to form the terminal ganglion impar, below the coccygeal bone.

Question 40

In which spinal segments is the lateral horn of the spinal cord present? Where is it not present?

Answer 40

In the thoracic, lumbar and sacral segments. The lateral horn is not present in the cervical region.

Question 41

All viscera receive dual innervation. This statement refers to …

Answer 41

The presence of both sympathetic and parasympathetic innervation of viscera.

Question 42

Theories of emotion. What is the difference between the James-Lange and Cannon-Bard theories?

Answer 42

The James-Lange theory states that a stimulus causes a physiological response, which then registers cognitively as emotion.

The Cannon-Bard theory states that the experience of emotion in the thalamus causes a physiological response- this happens simultaneously eg we feel sad at the same time as we cry.

Question 43

How did Schachter-Singer evaluate theory of emotion in their 2 factor theory (contrary to the James-Lange and Cannon-Bard theories)?

Answer 43

Schachter-Singer state that the physiological arousal following a stimulus is cognitively appraised using higher cortical processes, and then the emotion is perceived.

Question 44

State the simplified summary of the James-Lang, Cannon-Bard and Schachter-Singer theories of emotion.

State the unique difference of the more contemporary Schachter-Singer 2 factor theory.

Answer 44

James-Lang: Stimulus–> physiological response –> emotion

Cannon-Bard: Stimulus–> emotional response (thalamus)–> physiological response (simultaneously)

Schachter-Singer: Stimulus–> physiological response–>cognitive appraisal of physiological response–> emotion

The unique difference of the Schachter-Singer theory is the involvement of higher-order cortical processes in cognitive appraisal.

Question 45

State the location and functions of the insular cortex

Answer 45

The insular cortex is buried deep in the lateral sulcus (which separates the frontal and parietal lobes from the temporal lobe).

It’s involved in processing pain and visceral sensation as well as emotional processing such as disgust. It’s also involved in taste.

Question 46

State the location and functions of the cingulate cortex, as well as it’s inputs and outputs.

Answer 46

The cingulate cortex is an important part of the limbic system. It’s directly above the corpus callosum. It’s involved in emotion formation, processing and learning.

It receives information from the thalamus and the neocortex, and projects to the entorhinal cortex (via the cingulum).

Question 47

The hippocampus and entorhinal cortex play an important role in _____ memories. Explain what they are, and how they differ from procedural memories.

What is a further speciality of the EC-hippocampal system? Think London cab drivers.

Answer 47

The hippocampus and entorhinal cortex play an important role in declarative memories, which are memories that you can declare, as opposed to procedural memories eg memories involved in learning a skill such as driving.

A further speciality of the EC-hippocampus system is spacial memory formation.

Question 48

Where is the entorhinal cortex found and what is it’s main function (as a hub for …)?

Answer 48

The entorhinal cortex is found in the medial temporal lobe and functions as a hub for memory, navigation and perception of time.

Question 49

The Papez circuit begins with the neo-cortex (emotional ‘colouring’) projecting to the cingulate cortex (which sits above the corpus calosum), which is responsible for emotional experience. Describe the rest of the journey around the circuit.

Hint: Emotion, memory, emotion, memory…

Answer 49

The cingulate cortex then projects to the hippocampus (learning and memory), which projects to the hypothalamus (emotional expression) via the fornix (C-shaped nerve bundle).

The hypothalamus then projects to the anterior nuclei of the thalamus (also involved in memory), which projects back to the cingulate cortex.

Question 50

Which nucleus does the rubrospinal pathway project from in the brainstem, and which part of the body does it signal movement for? How does this relate to what animal-types have prevalence of this pathway?

Answer 50

The rubrospinal pathway projects from the red nucleus, and signals for movement of the upper limbs (arms and hands).

Mammals such as humans and primates have prevalence of this pathway because we use our upper limbs a lot.

Question 51

The lateral subsystem of the voluntary motor system controls movement of limbs and axial skeleton, allowing us to move around the environment.

What are the 3 pathways of the medial subsystem, which originates in the brainstem and medulla?

Answer 51

The 3 pathways are:

• Tectospinal: Orienting in space (eyes, neck, torso)
• Vestibulospinal: Balance (act on axial skeleton to keep us upright)
• Reticulospinal: In the pons and medulla- regulate tone of reflexes +special portion of reticulospinal medullary pathway –>see visceral motor system lecture

Question 52

State the main functions of the lateral and medial motor subsystems

Answer 52

The lateral subsystems are about moving limbs and getting around, whereas the medial subsystem is about orienting our sensory apparatus to stimulus.

Question 53

Where does the tectospinal medial pathway (orienting eyes, neck and torso to stimulus) project from? Explain why this makes sense.

Answer 53

The tectospinal medial pathway projects from the superior and inferior colliculus. This makes sense because the superior colliculus orients the eyes reflexively to stimuli, whereas the inferior colliculus orients the head reflexively to audio stimuli.

Question 54

If I follow a command to ‘look over there’ and touch my nose respectively, which voluntary motor pathways am I using respectively?

Answer 54

I’m using my medial motor pathway to orient my head to the stimulus, and my lateral motor pathway to touch my nose.

Question 55

Why did Broca formulate the concept of the limbic system (now named the emotional motor system)?

Answer 55

Broca observed that people with damage to areas he named the limbic system had altered emotional regulation (processing/ expression).

Question 56

Which 2 areas did Broca identify as part of the limbic system, before Papez came along and added the hypothalamus and the anterior nucleus of the thalamus?

Answer 56

Broca originally identified the cingulate cortex and the hippocampus as controlling emotional expression.

Question 57

Mesencephalon is another word for…

Answer 57

midbrain

Question 58

Ventral rootlets of the spinal cord carry 2 types of efferent information. What are they, and what types of muscle do they innervate?

Answer 58

1. Somatic motor information to innervate skeletal muscle

2. Autonomic, sympathetic information to innervate visceral muscle

Question 59

What kind of neurons are first order somatosensory neurons?

Answer 59

Pseudo unipolar

Question 60

Dorsal root ganglia for somatosensory dorsal rootlets are outside of the CNS, true of false?

Answer 60

True

Question 61

Dorsal root ganglia for somatosensory dorsal rootlets are outside of the CNS, true of false?

Answer 61

True

Question 62

Where are the cell bodies of LMNs for the somatic motor system, and the autonomic motor system found?

Answer 62

Neuronal cell bodies for the somatic motor system are found in the vental horn of the spinal cord, and cell bodies for the autonomic motor system are found in the lateral horn (T1-L2) .

Question 63

A skeletal muscle cell is otherwise known as a…

Answer 63

neuromuscular junction

Question 64

A sympathetic motor axon originating the spinal cord section T1-L2 will innervate a _____ _____ or a _____

Answer 64

A sympathetic motor axon originating the spinal cord section T1-L2 will innervate a visceral muscle or a gland

Question 65

The intermediolateral cell column, or IML, is another name for the ____ ____

Answer 65

The intermediolateral cell column, or IML, is another name for the lateral horn

Question 66

Preganglionic sympathetic LMNs are found in the ___ ___ (T1-L2), whereas preganglionic parasympathetic neurons are found either in the _____ ____ ____ (S3-4) or the _____.

Answer 66

Preganglionic sympathetic LMNs are found in the lateral horn (T1-L2), whereas preganglionic parasympathetic neurons are found either in the sacral spinal cord (S3-4) or the brainstem.

Question 67

In regards to the basal ganglia, what kind of activity in the direct and indirect pathways will cause movement to occur?

Answer 67

Movement will occur with increased activity in the direct pathway and decreased activity in the indirect pathway

Question 68

The parasympathetic response is innervated by which nerves?

State the function of each.

Answer 68

CNIII Oculomotor: Pupillary dilation and cilliary contraction

CNVII Facial: Lachrymal and parotid glands
CNIX Glossopharyngel: Parotid glands

CNX Vagus: Heart, lungs, esophagus and viscera (rest and digest)

Sacral nerves 2, 3 and 4 innervate the gonads, bladder and large intestine

Question 69

State the processes dealt with by the cingulate cortex and the insular cortex respectively

Answer 69

The insular cortex is associated with emotional processing such as empathy and recognising emotions in others such as disgust. Also a role in pain processing.

The cingulate cortex is implicated in emotion, memory and learning as part of the ‘limbic system’.

Question 70

What would be the result of overstimulation of the subthalamic nucleus in the basal ganglia?

Answer 70

When it is overstiumlated, the subthalamic nucleus sends too much glutamate to the globus pallidus internus and substantia nigra pars reticulata, which then send too much GABA to the VLo (ventrolateral nucleus of the thalamus). This results in over-suppressed messaging to the cortex (M1), resulting in suppressed movement (eg Parkinson’s).