Brainscape's Knowledge GenomeTM

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


See full index

Organisation of the Body: Tissues > Peripheral Nervous System Tissue > Flashcards

Peripheral Nervous System Tissue Flashcards

1
Q

Neuron definition

A

Cells that respond to stimuli by altering the ionic gradient across their plasma membranes. Functional units of both the CNS and PNS.

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

Three main parts of neurons

A

Cell body (soma), dendrites and axon

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

Cell body function

A

contains nucleus and most of the cell’s organelles and serves as as the synthetic or trophic centre for the entire neuron

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

Cell body components

A

Numerous free polyribosomes and highly developed RER, indicating active production of cytoskeletal proteins for transport and secretion. Basophilic Nissl polysomes appear under a light microscope. Golgi apparatus, located in cell body, mitochondria found throughout the cell.

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

Dendrite function

A

principle signal reception and processing sites on the neurons. conduct electrical impulses to cell body.

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

Dendrite structure

A

Short branched projections leading to the cell body. Thinner dendritic processes as they bench, with cytoskeletal elements predominating in the distal regions.

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

Dendritic spine function

A

Most synapses on dendrites in the CNS occur at the dendritic spines, which are dynamic membrane protrusions on the dendritic branches.

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

What sort of structures are dendritic spines?

A

Plastic, as they change morphology depending on actin filaments (neural plasticity)

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

What is neural plasticity involved in?

A

Underlies adaptation, learning and memory development

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

What are axons?

A

Long slender projections that arise from the cell body and conduct electrical impulses away from the soma to other cells

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

Axon structure

A

Very long process, that can be up to a metre in length. Plasma membrane of the axon is called the axolemma and its contents are the axoplasm.

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

Where does the axon originate from?

A

The Axon hillock on the soma

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

What is terminal aborisation?

A

Axons have small branches called collaterals, which each end with an axon terminal (terminal bouton). This contacts another neutron at a synapse to initiate an impulse in that cell.

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

What do axons lack and how is this overcome?

A

Axons lack a protein synthesis machinery, so all the organelles and proteins required by the axon (neurotransmitters) must be transported from the cell body after synthesis.

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

Anterograde transport and the microtubule involved

A

Movement away from the cell body, kinesin

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

Retrograde transport and the microtubule involved

A

Movement along dynein towards the soma.

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

What is transported via anterograde transport?

A

organelles and macromolecules synthesised by the cell body

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

What is transported via retrograde transport?

A

Materials taken up by endocytosis, including viruses and toxins

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

Two types of polarity exhibited by neurons

A

Structural and functional

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

Explain structural polarity

A

One end of the neurone specialised to receive impulses (dendrites contain neurotransmitter receptors at synapses) the other end is specialised to send signals (axon terminals contain vesicles with acetylcholine)

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

Explain functional polarity

A

Unidirectional impulse propagation

22
Q

How is neuronal form maintained?

A

By the cytoskeleton

23
Q

Cytoskeletal components

A

microtubules, neurofilaments and microfilaments

24
Q

Microfilaments function

A

Actin molecules allow changes in shape at dendritic spines, neural plasticity. Act as a scaffold for signal transduction systems

25
Q

Neurofilament functions

A

Maintain axonal structure

26
Q

What are Schwann cells + function?

A

A special form of glial supporting cell, provide axon insulation and maintain a constant ionic microenvironment.

27
Q

Structure of myelin sheath

A

In myelinated neurones in the PNS, Schwann Cells wrap around the axon to form multiple layers of Schwann cell membrane called the myelin sheath, which is mainly lipid. The Schwann cell membranes fuse together to form the mesaxon.

28
Q

What are the spaces between myelin sheath called?

A

Nodes of Ranvier

29
Q

Function of nodes of Ranvier

A

Increase the speed of transmittance, as saltatory conduction can take place

30
Q

Satellite cells structure

A

Form a thin glial layer around each large neuronal cell body in the ganglia of the PNS

31
Q

Satellite cell functions

A

Trophic or supportive effect on the neurones, insulating, nourishing and regulating their micro environments

32
Q

Difference in structure in unmyelinated axons

A

Still enveloped in Schwann cells, however they do not wrap many times to form a myelin sheath. Have a uniform distribution of voltage gated ion channels and no nodes of Ranvier so conduction is much slower

33
Q

How are nerve fibres organised in nerve?

A
  • individual cell wrapped in endoneurium
  • group of cells with endoneurium wrapped in perineurium to form fasicles
  • fascicles are grouped together and covered by one final epineurium
34
Q

What are the coatings all examples of?

A

Connective tissue

35
Q

Structure of each connective tissue

A

endoneurium- reticular fibres, scattered fibroblasts and capillaries

perineurium- flat fibrocytes, edges sealed together by tight junctions, form 2-6 layers

epineurium- dense irregular fibrous coat

36
Q

Function of perineurium

A

Regulates diffusion, thus acts as the blood b nerve barrier

37
Q

Structure of dorsal root

A
  • white matter surrounding brown matter
  • afferent root is the dorsal root, containing a dorsal root ganglia just before hand
  • sympathetic soma present in ganglia
38
Q

Sensory ganglia structure

A

contains large neuronal soma

associated with sheetlike extensions of small glial satellite cells.

cells supported by a distinct connective tissue capsule.

39
Q

Autonomic ganglia structure

A

intramural ganglia- found present in certain organs, associated with parasympathetic neurones

paravertebral- found adjacent to vertebral column

40
Q

Enteric ganglia

A

2 types -myenteric and submucosal plexuses

41
Q

Sensory neurone terminal structure

A

axon terminals called terminal boutons are distal terminations of the telondendria of an axon

42
Q

somatic motor neurone terminal structure

A

Neuromuscular junction that releases ACh onto a motor end plate. End plate is studded with nAChRs

43
Q

sympathetic autonomic motor neurone terminal structure

A

axon contains many varicosities that release neurotransmitter

44
Q

6 different types of sensory nerve endings

A

Hairs, Meissner corpuscle, Ruffini endings, Merkel discs, Pacinian Corpuscle and free nerve endings

45
Q

Explain root hair plexus

A

A web of sensory fibres surrounding the base of hair follicles in the reticular dermis that detects the movement of hairs

46
Q

Merkel cell structure and function

A

Each associated with expanded nerve endings which function as tonic receptors for light touch and sensing an object’s texture

47
Q

Meissner’s corpuscle structure and function

A

elliptical structure consisting of a sensory axon among flattened Schwann cells arranged perpendicular to the epidermis in the dermal papillae.

Initiate impulses when light touch disturb the shape, enabling the mechoreceptor to transduce an impulse

48
Q

Ruffini cell structure and function

A

collagenous fusiform capsules, anchored firmly to the surrounding connective tissue with sensory axons stimulated by stretch and torque

49
Q

Pacinian Corpuscle structure and function

A

large, oval shaped structures found deep in the reticular dermis and hypodermic with an outer capsule formed of thin concentric lamellae of flattened Schwann cells and collagen. Surround a highly branched, unmyelinated axon. Stretch mediated sodium channels

sense coarse touch, rough textures, pressure and vibrations.

Also located in walls of bladder, where detects if bladder is full

50
Q

Free nerving ending structures and functions

A

Found in the papillary dermis and extend into the lower epidermal layers which respond primarily to high and low temperatures, pain and itching

Organisation of the Body: Tissues (10 decks)

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