The Human Brain Flashcards

1
Q

What does failure of the spinal cord closing cause?

A

Spina bifida or anencephaly

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2
Q

What prevents most neural tube defects?

A

Folic acid

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3
Q

What are the primary brain vesicles?

A

Prosencephalon
Mesencephalon
Rhombencephalon
Spinal cord

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4
Q

What are the secondary brain vesicles?

A
Telencephalon
Diencephalon 
Mesencephalon 
Metencephalon 
Myelencephalon 
Spinal cord
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5
Q

What does a dorsal fold in the rhombencephalon make?

A

Metencephalon

Myelencephalon

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6
Q

What does the prosencephalon become?

A

Telencephalon

Diencephalon

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7
Q

What are the adult derivatives of the telencephalon?

A

Olfactory lobes
Hippocampus
Cerebrum

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8
Q

What are the adult derivatives of the diencephalon?

A

Retina (optic vesicle)
Epithalamus
Thalamus

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9
Q

What are the adult derivatives of the mesencephalon?

A

Midbrain

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10
Q

What are the adult derivatives of the metencephalon?

A

Cerebellum

Pons

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11
Q

What are the adult derivatives of the myelencephalon?

A

Medulla

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12
Q

Meninges of the spinal cord

A
Dura mater (outermost)
Arachnoid 
Pia mater (innermost)
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13
Q

Where is most of the cerebrospinal fluid formed?

A

Cerebral ventricles

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14
Q

Sites of origin of CSF?

A

Choroid plexus
Ependyma
Parenchyma

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15
Q

What is the function of CSF?

A

To act as a buffer/cushion for the brain’s cortex providing basic mechanical and immunological protection to the brain

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16
Q

Where does CSF occupy?

A

Subarachnoid space

Ventricular system around the inside of the brain and spinal cord

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17
Q

What does it mean if CSF pressure is elevated?

A

Cerebral blood flow may be constricted

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18
Q

What is hydrocephalus?

A

Abnormal accumulation of CSF in the brain ventricles

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19
Q

What causes hydrocephalus?

A

Impaired flow of CSF

Impaired reabsorption or excessive production of CSF

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20
Q

What is a lumbar puncture?

A

CSF is extracted through a needle between the 3rd and 4th lumbar vertebrae

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21
Q

What is aqueductal stenosis?

A

Narrowing of the aqueduct of Sylvius which blocks the flow of CSF in the ventricular system
Life threatening in a short period of time
Restricts blood flow to the brain

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22
Q

What is an ependymal cell?

A

A type of neuronal support cell that forms the epithelial lining of the ventricles of the brain and central canal of the spinal cord

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23
Q

Structure of a ependymal cell

A

Have cilia on their surface

Influence the flow of CSF, bringing nutrients to neurons and filtering harmful molecules

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24
Q

What is the function of the layer of ependymal-derived cells surrounding the blood vessels of the choroid plexus?

A

To produce CSF through selective uptake of water and other molecules from blood into cells
Then transported across cells
Secreted into lateral ventricles as CSF

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25
Q

Where are tanycytes found?

A

The lining of the floor of the third ventricle of the brain

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26
Q

Structure of tanycytes?

A

No cilia
Long processes and large end feet that connect to brain capillaries and neurons distant from ventricle
Connected to one another by tight junctions

27
Q

What do tanycytes do?

A

Facilitate transport of hormones and other substances in the brain

28
Q

What is the blood-brain barrier?

A

A highly selective, semi-permeable membrane barrier which separates circulating blood from the brain extracellular fluid in the CNS

29
Q

What forms the BBB?

A

Endothelial cells connected by tight junctions

30
Q

What does the BBB allow to pass through passive diffusion?

A

Water
Some gases
Lipid-soluble molecules

31
Q

What does the BBB allow selective transport of?

A

Glucose

Amino acids crucial to neural function

32
Q

What cells are necessary to create the BBB?

A

Astrocytes

33
Q

Where does the BBB occur?

A

Across all capillaries

34
Q

What is the average rate of cerebral blood flow in adults?

A

750ml per minute

About 15% cardiac output

35
Q

How is cerebral blood flow safeguarded?

A

Autoregulation

Small arteries - arterioles - constrict and dilate under complex physiological control systems

36
Q

What is metabolic regulation?

A

Negative feedback system which balances cerebral blood flow to demand

37
Q

What is myogenic regulation?

A

Transmural blood pressure changes are detected by vascular smooth muscles in arterioles
Calibres are then adjusted to maintain blood flow

38
Q

What is neurogenic regulation?

A

Vascular smooth muscle in the resistance arterioles are controlled via sympathetic innervation, input from the appropriate brainstem autonomous control centre
Nitric oxide released by parasympathetic fibres may also play a part

39
Q

What is the brainstem composed of?

A

Medulla oblongata
Pons
Mesencephalon

40
Q

What does the brainstem do?

A

Regulates vital cardiac and respiratory functions

Ascending and descending tracts travel through the brainstem

41
Q

What does the cerebellum do?

A

Muscle tone
Co-ordination
Motor error
Learning

42
Q

What is cerebellar ataxia?

A

Loss of cerebellar neurons

Jerky imprecise movements

43
Q

What does the diencephalon do?

A

Links midbrain to cerebrum

Contains the thalamus, hypothalamus and pineal

44
Q

What is the cerebrum?

A

2 cerebral hemispheres

6 lobes

45
Q

What are the lobes of the cerebrum?

A
Frontal
Parietal 
Occipital 
Temporal 
Central 
Limbic
46
Q

Function of the medulla oblongata?

A
Regulates breathing
Heart and blood vessel functions
Digestion 
Sneezing and swallowing 
Large lesions = death
47
Q

Functions of the pons?

A

Bridges the sides of the cerebellum

Connects to cerebellum via peduncles

48
Q

Functions of the thalamus?

A

Processing and relay centre
All special sense except smell
Arousal/emotion
Higher functions

49
Q

Functions of the pineal?

A

Endocrine organ

Produces melatonin and serotonin

50
Q

Functions of the hypothalamus?

A

Eating
Drinking
Sexual behaviour
Stress

51
Q

What is Broca’s Aphasia?

A
Damage to the left frontal lobe 
Impaired speech (grammar, syntax and word structure)
52
Q

What is Wernicke’s Aphasia?

A

Posterior temporal lobe damage

Superficially fluent speech but the inability to understand more than the most basic words

53
Q

Types of modern brain mapping

A

PET scans
fMRI
Regional blood flow

54
Q

What is lateralisation?

A

Right hand controlled by the left side of the brain and vice versa

55
Q

What makes up the limbic system?

A
Limbic lobe 
Hippocampus 
Amygdala 
Thalamus 
Hypothalamus
56
Q

What is the limbic system involved in?

A

Memory
Emotions
Motivation

57
Q

Where is the basal ganglia located?

A

Deep within the hemispheres

58
Q

What diseases is the basal ganglia implicated in?

A

Parkinson’s

Huntington’s

59
Q

What do association fibres do?

A

Link areas within a hemisphere

60
Q

What do commissural fibres do?

A

Connect between hemispheres

61
Q

What do projection fibres do?

A

Link to non-cortical areas

62
Q

What is the role of the upper motor neurons?

A

Taking impulses from the relevant part of the brain down to the synapses with the lower motor neurones.

63
Q

What is the role of the lower motor neurons?

A

Connect with the target muscle

They run between the UMN synapse and the final action point

64
Q

What is the role of the lower motor neurons?

A

Connect with the target muscle

They run between the UMN synapse and the final action point