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Brain and Cognition > Chapter 2 Brain anatomy > Flashcards

Chapter 2 Brain anatomy Flashcards

1
Q

What are the three types of glial cells?

A

Astrocytes (Blood brain barrier), Microglial cells (phagocytes), Oligodendrocytes (myelin production CNS, Schwann cells myeling production PNS)

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2
Q

What does a neuron look like?

A

Dendrites receive input
Soma is cell body
AP originates in axon hillock
AP travels down axon to axon terminal
Synapse is the end where the next neuron meets

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3
Q

What is the difference between presynaptic and postsynaptic?

A

presynaptic: axon output makes connection to new neuron
postsynaptic: dendrite makes connection to previous neuron

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4
Q

What is the resting potential and why is it negative?

A

-70 mV
It’s negative, so it stores energy, because of deviation from electrochemical equilibrium

Lipid membrane has more K+ channels (more permeable for K+) and therefore more K+ travels out than Na+ can enter

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5
Q

How do ions travel in a neuron?

A

Via channels (passive) or pumps (active)

Channels can be normal or voltage-gated (open with change in voltage)
Pumps: Na+/K+ pump: pumps in K+, pumps out Na+ ; against concentration gradient

The channels and pumps are located in nodes of ranvier

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6
Q

What are the 7 phases of generating an action potential and what happens in each phase?

A

1) Resting phase: K+ channels always open
2) Depolarization: Na+ gated channels open –> more + in
3) Overshoot: most positive point, Na+ g.c. begin to close. K+ g.c. begin to open –> more + out
4) Repolarization: Na+ g.c. closed, K+ open –> more + out
5) Hyperpolarization: K+ still open –> too much + out of cell
6) Recovery phase: K+ close
7) Resting phase

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7
Q

What is the absolute and relative refractory period and what are the consequences?

A

Absolute = v.g. Na+ channels can’t open (from overshoot until hyperpolarization)
Relative = neuron can only generate AP with larger than normal depolarization (from hyperpolarization until new resting phase)

Consequences:
- Limits amount of AP’s
- Makes sure AP moves in one direction toward axon terminal

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8
Q

What is decremental conduction?

A

Passive conduction of EPSP and IPSP through the cytoplasm of the soma.
If EPSP is large enough, AP will be triggered in axon hillock

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9
Q

What are the two types of synaptic transmission?

A

1) Electrical
2) Chemical (dominant)

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10
Q

How does chemical synaptic transmission work? Describe in 5 steps.

A

1) Electrical current arrives in presynaptic terminal
2) Voltage-gated Ca2+ channels open
3) Fusion vesicles with presynaptic membrane
4) Release neurotransmitters in synaptic cleft
5) Neurotransmitters bind to post-synaptic receptors, that can create IPSP or EPSP

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11
Q

Name two types of postsynaptic receptors

A

1) ligand-gated ion channels : fast communication
2) GPCRs: G protein coupled receptors : slow communication via second messenger

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12
Q

Name the 6 most abundant neurotransmitters and their functions

A

1) Glutamate: excitatory, most prevalent
2) GABA: inhibitory, most prevalent
3) ACh: Acetylcholine: neuromuscular junctions
4) Dopamine: motor control/cognition/arousal
5) Norepinephrine/noradrenaline (NE): arousal, fight-flight
6) Serotonin: mood/cognition

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13
Q

Where is dopamine produced and what can a lack of it cause?

A

Substantia Nigra + ventral tegmental area (VTA) in midbrain
Lack of it can result in Parkinson, schizophrenia and susceptibility to addiction

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14
Q

Where is noradrenaline/norepinephrine produced?

A

Locus Coeruleus (LC)

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15
Q

Where is serotonin produced and what can a lack of it cause?

A

Produced in Raphe nucleus (part of reticular formation in brainstem)
Lack of it can result in depression

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16
Q

What are conditional neurotransmitters?

A

Neurotransmitters that only acts when other factors are present (e.g. another neurotransmitter)

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17
Q

How are neurotransmitters deactivated after release? Name three ways

A
  • Active reuptake by presynaptic terminal
  • Enzymatic breakdown
  • Diffusion of transmitter to another region
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18
Q

How does electrical synaptic transmission work, what are the necessary anatomical features and what are the limits of it?

A

Anatomical structures = gap junctions
Two neurons share the same cytoplasm (isopotential) via these gaps

It is useful for quick communication

Limits:
- Can’t amplify a signal
- Passive conduction

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19
Q

What is the difference between a microcircuit and a macrocircuit?

A

Micro = connected neurons that process specific kinds of information, such as generating movement

Macro = multiple microcircuits with often long-distance connections between various brain regions

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20
Q

What does corticofugal connections mean?

A

These are projections extending from central structures (e.g. cortex) to the PNS

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21
Q

What are the two divisions of the PNS?

A

1) Somatic system (voluntary)
2) Autonomic system (sympathetic (fff) - parasympathetic (rest))

22
Q

What do these terms mean: dorsal - ventral - caudal - rostral

A

Dorsal = back
Ventral = belly
Caudal = tail
Rostral = beak

in terms of the brain:
Dorsal = superior = top
Ventral = inferior = bottom
Caudal = posterior = back
Rostral = anterior = front

23
Q

What do these terms mean: lateral - medial - distal - proximal - ipsilateral - contralateral?

A

Lateral = toward the side
Medial = toward the middle
Proximal = closeby
Distal = far away
Ipsilateral = on the same side of the body (LL or RR)
Contralateral = on the opposite side of the body (LR or RL)

24
Q

What are the three different cross-sections of the brain and what do they look like?

A

1) Sagittal: vertically from nose to back
2) Coronal: vertically from ear to ear
3) Axial: horizontally

25
Q

What is the difference between nucleus and ganglion? What is the dorsal root ganglion?

A

Nucleus is bundle of neurons in CNS, ganglion is bundle of neurons in PNS.

The dorsal root ganglion is a combination of sensory neurons near the spine

26
Q

What is the difference between afferent and efferent communication?

A

Afferent = toward CNS (sensory)
Efferent = away from CNS (motor)

27
Q

What is the difference between grey and white matter?

A

Grey = neurons + cell bodies (outer layer brain, inner part spinal cord)

White = axons, glial cells
- In brain grouped in association tracts and projection tracts
- In spinal cord the outer part
- Commissures = bundles of axons (e.g. corpus callosum)

28
Q

How is the brain protected? Name at least the three meninges

A

From outside to inside:
1) Skull
2) Meninges:
- Dura mater = thick
- Arachnoid mater
- (subarachnoid space with CSF = reduces shock, cleans brain)
- Pia mater (infection = meningitis)
3) Brain

29
Q

What are ventricles and how are the connections between them called

A

Ventricles contain CSF
- First/second Lateral ventrical (right and left)
- Caudal third ventricle
- Fourth ventricle near brainstem

Lateral - caudal connection = interventricular foramen
Caudal - fourth connection = cerebral aqueduct
Eventually all moving down spinal cord

30
Q

What are the two sources of blood in the brain?

A

1) Internal carotid arteries
2) Vertebral arteries (in spine and becomes basilar artery in caudal portion of brain)

31
Q

What is the circle of Willis?

A

A circular structure of arteries that combines the internal carotid arteries and the basilar artery (from vertebral arteries)

32
Q

What are the 4 main parts of the CNS?

A

1) Spinal cord
2) Brainstem + cerebellum
3) Diencephalon (thalamus, hypothalamus)
4) Telencephalon/cerebrum (limbic system, basal ganglia, cortex)

33
Q

What are the dorsal and ventral horn?

A

Located in spinal cord
- Dorsal = sensory input enters (afferent)
- Ventral = motor output leaves (efferent)

34
Q

What are the 4 parts of the brainstem?

A

1) Medulla
2) Pons + cerebellum
3) Midbrain
4) Reticular formation

35
Q

What is the function of the Medulla?

A

Pyramidal decussation = crossing of motor axons (left brain to right body)

Autonomic functions –> heart rate, sneezing, blood pressure

36
Q

What is the function of the Pons?

A

Bridge from forebrain to cerebellum
Contains nuclei for sleep, swallowing, facial expressions

37
Q

What is the function of the cerebellum?

A

Motor control, balance, cognitive processing

70 billion neurons, but not enough studied

38
Q

What is the function of the midbrain?

A

Dorsal part = tectum
- Superior and inferior colliculi combine visual, auditive and tactile information

Ventral part = tegmentum
- Contains substantia nigra + VTA –> Dopamine
- Periaqueductal grey = pain signal modulation

39
Q

What is the function of the reticular formation?

A
  • Arousal and attention
  • Raphe nuclei –> Serotonin
40
Q

What is the function of the Thalamus and what are the functions of the 4 main nuclei?

A

Switch board of the brain and receives input from all sensory areas except olfaction

Main nuclei:
1) LGN: vision
2) MGN: audition
3) VPN: somatosensation
4) Pulvinar: attention

41
Q

What is the massa intermedia?

A

This connects both sides of the thalamus and is a bridge of grey matter

42
Q

What is the function of the hypothalamus?

A

Homeostasis (temperature, metabolism rate, day/night cycle (circadian rhythm)

Production hormones or control of production in for example pituitary gland

43
Q

What are the three main parts of the limbic system?

A
  • Hippocampus: spatial processing, memory
  • Amygdala: emotions, fear
  • Cingulate cortex (CC)
44
Q

What is the function of the basal ganglia? (Neostriatum, Globus pallidus, Nucleus accumbens)

A
  • Movement memory
  • Neostriatum: putamen + caudate nucleus (learning, memory, rewards)
  • Globus pallidus (position body)
  • Nucleus accumbens (dopamine, motivatie)
45
Q

What are the four different lobes of the brain? What are some of their functions?

A

Frontal: executive functions + motor control
Parietal: somatosensation + unimodal association area (S2)
Temporal: audition
Occipital: vision

46
Q

Where are the following structures:
- Lateral silvian fissure
- central sulcus
- Preoccipital notch
- Longitudinal fissure

A
  • Lateral sylvian: between frontal and temporal
  • Central sulcus: between frontal and parietal
  • Preoccipital notch: between occipital and temporal
  • Longitudinal fissure: between both hemispheres
47
Q

What is the function of the precentral and postcentral gyrus?

A

Precentral = primary motor cortex
Postcentral = primary somatosensory cortex

48
Q

What is the structure of neocortex? How does that compare to older evolutionary parts?

A

Neocortex has 6 layers of grey matter, organized in microcolumns

Evolutionary older parts have less layers and are called paleocortex

49
Q

What are the 5 main divisions of the cerebral cortex concerning function?

A

1) Primary sensory
2) Primary motor
3) Unimodal association
4) Multimodal association
5) Paralimbic/limbic areas (between limbic area and cortex)

50
Q

What can be found in the paralimbic areas?

A

Olfactorcentric formation, hippocampocentric formation

51
Q

How does the brain develop?

A
  • Synaptogenesis –> formation of synapses
  • Synaptic pruning –> use it or lose it!
  • Growth dendritic trees
  • Extension of axons
  • Myelination of glial cells
  • Gray matter loss when maturing

IMPORTANT: neuron amount doesn’t increase

52
Q

Where is neurogenesis possible?

A

In hippocampus and olfactory bulb –> Memory!

Brain and Cognition (11 decks)

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