Brainscape's Knowledge GenomeTM

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


See full index

Tissues Of The Body > Nerves > Flashcards

Nerves Flashcards

0
Q

What are the different meninges? What are leptomeninges?

A 
CRANIUM
							  DURA MATER (thickest)
						    ARACHNOID MATER
									PIA MATER (thinnest - strongly adhered to brain)
									BRAIN

Leptomeninges = arachnoid mater + pia mater

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

What are meninges?

A

Membraneous covering of the brain and spinal cord

note: meniges of spinal cord more simple than the meninges of the brain

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

How does CSF flow through the meninges?

A

Separation of layers = subarachnoid space cisterns

Occur due to dilation

  • failure of arachnoid mater to adhere to pia mater
  • or: failure of arachnoid mater to follow the furrows in the brain

+ blood vessels

Bleeds = CSF carries blood away = attempts to prevent hydrostatic pressure from climbing too high

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

What is the function of the CSF? How is it formed?

A

Supplies the CNS with nutrients and fluid, and carries away metabolites.

Formed by choroid plexus

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

What are the consequences in changes in hydrostatic pressure in the CSF?

A

Increase in hydrostatic pressure = restricts blood flow to the brain

Decrease in hydrostatic pressure = collapse of veins = increased bleeding

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

What are the membranous envelopes of cranial and spinal nerves?

A

Stratified squamous epithelium

Epineurium = ensheaths entire nerve

(note: interfasciular bands attach adjacent nerve fascicles)

Perineurium = ensheaths a nerve fascicle (collection of axons)

Endoneurium = ensheaths a single axon

(Oligodendrocyte/Schwann cell envelops some axons)

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

What are the functional units of the nervous system?

A

Glia (90%) = maintain homeostasis, form myelin, support and protect neurones

Neurones (10%) = electrically excitable cells that process and transmit information through electrochemical signals

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

What is the distinction between “heavy” and “light” connections?

A

Heavy = 1 nerve cells 1000s of nerve cells

Light = 1 nerve cells 1 nerve cell

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

What is the difference between divergence and convergence?

A

Divergence = output from one neurone to many

Convergence = output from many neurones to one

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

What are dendrites? What is the dendritic tree?

A

Specialisations of cell bodies which increase the surface area for conduction of impulses in the cell body

Dendritic tree = proximal dendrites (thick diameter) —> lots of distal dendrites (thin diameter)

(so there is no difference in electrical resistance at either points at synapses)

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

What is a dendritic spine?

A

Appendage of a dendrite that help transmit electrical signals, and act as an anatomical substrate for memory storage (associated with learning)

Down’s syndrome = reduced capacity to express dendritic spines = reduced learning ability

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

What are bipolar neurones? Give an example of where they are located.

A

Interneuron

1 dendrite + 1 axon

e.g. retina

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

What are (pseudo)unipolar neurones? Give an example of where they are located.

A

No dendrites + 1 axon

e.g. primary sensory neurones

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

What are multipolar neurones? Give an example of where multipolar neurones are located.

A

Multiple dendrites + 1 axon

e.g. motor neurones

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

What are two examples of input summation?

A

TEMPORAL = excitatory & inhibitory inputs summated with respect to their time of arrival on the cell body/dendrites

SPATIAL = excitatory & inhibitory inputs summated with respect to their relative spatial location on the cell body or dendrites

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

Outline the different components of a neurone.

A

INITIAL SEGMENT:

  • Cell body (+ dendrites)
  • Axonal hillock = “zig-zag” in initial segment where action potentials can travel back up to the cell body as well as down the axon

Axonal membrane & Internodal membrane

Myelin sheath + Nodes of Ranvier

AXONAL TERMINAL

16
Q

What are the functions of axons? What are collections of axons called in the CNS and PNS, respectively?

A
  • summates all inputs to the neurone
  • initiates all-or-none action potentials
  • conducts action potentials away from cell body

Collection of axons (CNS) = fibre tracts (exception: optic nerve)
Collection of axons (PNS) = nerves

17
Q

What is the difference between excitatory and inhibitory neurones?

A

Excitatory = cause depolarisation
Neurotransmitters: glutamate, aspartate

Inhibitory = cause hyperpolarisation
Neurotransmitters: glycine, gamma-aminobutyric acid

18
Q

What is the structure and function of sensory neurones?

A

Pseudo-unipolar (fastest conducting)

Transduces electromagnetic/mechanical energy into electrical impulses via receptors

Sensory Receptor —> Cell body —> CNS

“Afferents”

19
Q

What is the structure and function of motor neurones?

A

Multipolar

Integrate a large array of inputs to synthesise a single output

CNS —> Cell Body —> Effector

“Efferents”

20
Q

What is the structure and function of interneurones?

A

Multipolar

Information relay (therefore majority of neurones)

Sensory neurones —> Cell Body (brain/spinal cord) —> Motor neurones

21
Q

What are the different neuroglial cells?

A

Ependyma = line ventricles and central canal of spinal cord for circulation of CSF

Astrocytes = transfer nutrients/waste between neurone and blood

  • blood brain barrier
  • phagocytic functions
  • physical support for neurones

Oligodendrocytes = myelination (CNS)
Schwann cells = myelination (PNS)
Myelination insulates neurones, allowing faster saltatory conduction

Microglia = immunity & inflammation

Satellite cells = physical support of neurones in PNS

22
Q

What are ganglia? What is the equivalent in the CNS?

A

Collections of neuronal cell bodies in the PNS (swellings)

CNS = collections of neuronal cell bodies = nuclei

23
Q

How many cranial & spinal nerves are there in the PNS?

A

Cranial nerve axons = 10

Spinal nerve axons = 31

24
Q

Outline the structure of grey and white matter in the nervous system.

A

Grey matter = butterfly/H-shape (post-ganglionic neurones; unmyelinated)
White matter = surrounds grey matter (pre-ganglionic neurones; myelinated)

Posterior grey matter = dorsal horn = receives sensory input

Anterior grey matter = ventral horn = stimulates motor neurones

Central canal (lined by ependyma)

Either side = lateral horn

25
Q

What is the structure of somatic efferents?

A

Active or inactive (inactive during REM sleep)

Voluntary control

Single neurone

Neurotransmitter = acetylcholine

Effector = skeletal muscle

26
Q

What is the structure of parasympathetic nerves?

A

Long pre-ganglionic neurone (myelinated), short post-ganglionic neurone

Synapse between neurones = Acetylcholine, nAChR

End plate synapse = Acetylcholine, mAChR

27
Q

What is the structure of sympathetic nerves?

A

Short pre-ganglionic neurone (myelinated), long post-ganglionic neurone

Synapse between neurones: ACh, nAChR

End plate:

1) Noradrenaline one alpha/beta receptor
2) Direct release of adrenaline/noradrenaline from pre-ganglionic neurone from adrenal medulla into bloodstream

28
Q

Give some examples of effector organs in the autonomic nervous system. Give some examples of organs not innervated by either the parasympathetic or sympathetic nervous system.

A

Visceral organs e.g. cardiac muscle
Smooth muscle e.g. airways, GI, blood vessels
Secretory glands e.g. serous/mucous secretions

Exceptions:

  • sweat glands
  • ejaculatory mechanisms
29
Q

What does an overactive parasympathetic nervous system cause? What does an overactive sympathetic nervous system cause?

A

Overactive parasympathetic = dilated blood vessels —> shortage of substrates to the brain —> faints

Overactive sympathetic = constricted blood vessels —> shortage of substrates to tissues —> tissue necrosis of peripheries

30
Q

Outline the functions and anatomy of sympathetic neurones.

A

Fight-or-flight response

  • Diversion of blood to muscles and heart
  • Increase in heart rate/force of contraction
  • Increase in blood pressure
  • Reduced blood flow to GI & skin
  • Hyperventilation

Thoracolumbar (all 12 thoracic & first 2 lumbar segments)

Pre-ganglionic = cholinergic
Post-ganglionic = nicotinic receptors, noradrenergic/adrenergic (adrenal medulla)
Effector organs = alpha and beta receptors

31
Q

Outline the functions and anatomy of parasympathetic neurones.

A

Rest-and-digest

  • Promotes digestion
  • Decrease in heart rate/force of contraction
  • Promote sleep and bladder emptying
  • Increased bloodflow to GI & skin

Craniosacral (cranial/cervical + 2-4 sacral segments)

Pre-ganglionic: ACh
Post-ganglionic: nAChR, cholinergic
Effector organs: muscarinic receptors

32
Q

What are some examples of cranial nerves?

A
  • occulomotor nerve = constricts pupil
  • facial nerve = serous secretions (nasal, lacrimal)
  • glossopharangeal = serous secretions (submandibular & sublingual)
  • vagal = slowing of activity e.g. heart rate
33
Q

What is the sympathetic chain?

A

Base of skull to sacrum

Bundles of ganglia

Retroparavertebral position

34
Q

What is Horner’s syndrome?

A

Lesion in sympathetic trunk of neck/cancer in apex of lung
—> compression of cervical nerves

  • pupil constriction (unilateral mitosis)
  • partial ptosis (drooping of upper eyelid)
  • anhydrosis of one side of the face
  • enophtalmos (eye looks sunken)
35
Q

What is the pathology of a demyelinating disease? Give an example of a demyelinating disease.

A

Damage to the myelin sheath, so conduction velocity is slower

S&S:

  • blurred vision
  • weakness/fatigue
  • lack of coordination
  • difficulty controlling bowel movements/urination

e.g. Multiple sclerosis (autoimmune destruction of myelin)

36
Q

What are the types of glial cells and their functions?

A

Astrocytes (CNS) = blood-brain barrier (transfer of nutrients and waste)

Oligodendrocytes (CNS) = myelination

Microglia (both) = immune & inflammatory functions

Schwann cell (PNS) = myelination

Satellite cells = physical support of peripheral neurones

Tissues Of The Body (15 decks)

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