Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Case 6 > CNS Cells and Synaptic Transmission > Flashcards

CNS Cells and Synaptic Transmission Flashcards

1
Q

What is the CNS organised into

A

Nuclei, tracts and layers (laminae

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

Describe white matter tracts

A

Corticospinal, fascicles (fasiculus= a bundle), cortical medulla, internal capsule and corpus callosum

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

What is the function of the corpus callosum

A

To connect the hemispheres

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

What is a nuclei

A

A cluster of cell bodies and their dendrites where synapses are made and information is processed

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

What do nuclei form

A

The grey matter areas of the brain and the spinal cord

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

What is white matter

A

Bundles of myelinated axons which form tracts connecting nuclei

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

What are supporting cells in the CNS called

A

Glia

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

What does white matter connect

A

Groups of cells

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

How many layers of the cortex are there in the human brain

A

6 therefore there is diversity

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

What are laminae connected by on the same side

A

Associated fibres

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

What are laminae connected by on opposite sides

A

Commissural fibres

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

What does the reticular arrangement of the CNS around the brainstem mean

A

There are diffuse connections between neurones

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

What is the main job of the neuroglia

A

Myelination

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

What is the function of oligdendrocytes

A

Myelination

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

What is the function of astrocytes

A

Blood-brain barrier, maintaining extracellular potassium, maintaining extracellular glutamate levels, regulating concentrations of Ca2+ Cl- and water, provide metabolic support for neurones, development of the CNS, neurogenesis, glial scars, astrocytomas

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

What is the function of microglia

A

Defense, “hoovers”

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

What is the function of ependyma

A

Lining ventricular system, very important for CSF

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

Describe oligodendrocytes

A

Small, round cell body with about 5 processes that branch and myelinate several axons (10-25)

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

What do oligodendrocytes determine

A

Sheath thickness and establishment of Nodes of Ranvier

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

Describe myelination by oligodendrocytes

A

Post-natally in humans takes several months and adds about 1 kilo to brain weight (myelination responsible for 40-50% of brain weight); myelin sheaths show no sign of deterioration as you get older

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

What does degeneration of myelin sheaths result in

A

Multiple sclerosis

22
Q

Describe oligodendrogliomas

A

Average age of onset 34 years, lead to seizures due to frontal lobe damage

23
Q

Describe astrocytes

A

Star-shaped interconnected neuroglial cells that can be visualised with antibodies to GFAP (glial fibrillary acidic protein).

24
Q

Describe intracellular calcium

A

Must be kept low

25
Q

Describe interconnections between glial cells

A

Glial syncitium- focus on astrocytes whose processes are coupled by gap junctions which have pores in them. A pair of astrocytes is coupled by about 200 gap junctions. The pores allow molecules of

26
Q

How can astrocytes communicate with eachother

A

Linked by gap junctions (glial syncitium)

27
Q

Describe the function of astrocytes in relation to he blood-brain barrier

A

Some mechanisms of transport are active, some passive. In the BB possible to use pulse ultrasound to target specific areas of the brain with drugs. Astroglial regulation of local blood flow link neural activity to the local circulation by releasing vasodilators and vasoconstrictors

28
Q

Describe the function of astrocytes in maintaining extracellula potassium ion levels

A

Extracellular potassium ion levels must be kept around 2.0-2.5 mM. Astrocytes directly from the extracellular space by K+ pumps, redistribute K+ within the glial syncitium for subsequent dischatge into the extracellular/ perivascular space

29
Q

What does elevated K+ lead to

A

Dyshomeostasis as seen in epilepsy

30
Q

Describe the function of astrocytes in maintaining extracellular glutamate levels

A

Extracellular gluatamate levels must be kept around 3mM as excess glutamare is highly toxic to neurones and results in cytotoxic cell death. Excess glutamate is absorbed by astrocytes, repackaged and sent back to the neurone

31
Q

Describe the function of astrocytes in maintaining ion elevels

A

Regulate concentrations of Ca2+, Cl- and water in the extracellular space

32
Q

Describe the function of astrocytes in metabolic support

A

Provide metabolic support for neurones

33
Q

Describe the function of astrocytes in disease/ pathology

A

Astrocytomas, astrogliosis (isolation of damaged area, rebuilding BBB, rebuilding new circuitry), epilepsy (rarely epileptic seizures when things go wrong)

34
Q

Describe the function of astrocytes in control of breathing

A

Astrocytes in the chemosensory areas of the brainstem are highly sensitive to pH, they release ATP to stimulate chemosensitive neurones that cause increases in breathing

35
Q

Why do CNS neurones require protection from pathogens

A

CNS neurones do not replicate

36
Q

Describe microglia

A

Immune system of the brain. Normally resting cells that become activated by brain injury (infection, inflammation, trauma, hypoxia etc.). When activated they clear up (phagocytose). They migrate to different sites of damage

37
Q

Describe ependymal cellsq

A

Ciliated, cuboidal epithelial cells that line the ventricular system of the CNS

38
Q

What do modified ependymal cells in the choroid plexus do

A

Produce cerebrospinal fluid

39
Q

What are ependymomas

A

Tend to be benign but are space-occupying

40
Q

What is the tripartite synapse composed of

A

One presynaptic nerve terminal, two astrocyte processes plus the postsynaptic membrane

41
Q

What is the major excitatory neurotransmitter in the CNS

A

Glutamate

42
Q

Describe glutamate

A

Found in 80% of cortical neurones, all neurones from one region of the brain to the other use glutamate whether they are carrying an excitatory or inhibitory action

43
Q

What is the major inhibitory neurotransmitter in the CNS

A

GABA

44
Q

Describe cholinergic neurones

A

Two main groups in the pons whose axons run postrally and terminate in the substantia nigra and subthalamic nucleus and are involved in stereotypes movements

45
Q

What are forebrain cholinergic nuclei involved in

A

Memory

46
Q

What is ACh metabolised by

A

Actylcholinesterase (AChE)

47
Q

What monaime neurotransmitetr originate in the brainstem

A

Noradrenaline and dopamine

48
Q

Describe noradrenaline

A

Locus coeruleus- pons projecting to entire cerebral and cerebellar cortex, thalamus and spinal cors. Lateral tegmental- spinal projection (urinary competence) hypothalamus to control releasing factors

49
Q

Describe dopamine

A

Substantia nigra- corpus striatum (Parkinson’s disease). Alterantions in dopamine levels may be involved in schizophrenia

50
Q

Describe the rahpre nuclei in the midline of the brainstem

A

Only neurones in the CNS that contain and use seretonin (5-HT) as their neural transmitter. Spinal projections- analgesia in dorsal horn, bladder control (promotes continence). Rostral projection- to hypothalamus and cerebral cortex, modulates sleep/wake states, possibly involved in schizophrenia and very recently cot death

Case 6 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions