Brainscape's Knowledge GenomeTM

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


See full index

Histology > Nerves And Muscles > Flashcards

Nerves And Muscles Flashcards

1
Q

Why are nerve cells highly metabolically active

A

They maintain a large surface area of a cell membrane and constantly require energy to develop electrochemical gradients

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

How does the structure of a nervous out reflect its activity

A

Large nucleus with a large central nucleus: reflects a high degree of transcriptional activity

There is an abundant rough ER found in the cytoplasm: reflects the synthesis of proteins in the cytoplasm of the nerve cell body

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

What is Nissl substance

A

The abundant rER in nerve cell cytoplasm

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

Are peripheral motor ganglia synaptic stations?

A

Yes

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

Describe sensory ganglia

Eg

A

Contain cell bodies of sensory afferent pseudo unipolar neurons which transmit impulses from the peripheral receptors to the central nervous system

They are not synaptic stations

Eg dorsal root ganglia of spinal nerves and sensory ganglia of cranial nerves

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

What is the largest sympathetic ganglion

A

The stallate / cervicothoracic ganglion

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

What is the stellate ganglion formed from

A

The fusion of the inferior cervical ganglion and the first thoracic ganglion

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

The structure of sympathetic ganglia is similar to which other ganglion type

How are they different

A

Sensory ganglia

The sympathetic neuron cells are multipolar

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

What are the prevertebral ganglia

A

Ganglia in the sympathetic chain that lie below the end of the spinal cord which innervate the pelvic viscera

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

What is a nerve trunk

A

A nerve

Long collections of long cylindrical processes that contain nerve fibres

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

What is myelin

A

A leopard protein complex characterised by a large proportion of lipid ( 70–85%) relative to the proportion of protein (15 –30%)

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

How is the myelin sheath formed in the PNS

A

By Schwann cells, the PM of which wrap tightly around the axon in numerous concentric layers, preventing most leakage across the axon membrane

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

How much of the sheath does each Schwann cell form

How long are the nodes of Ranvier

A

1mm

0.5μm

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

Are Schwann cells associated with small diameter axons

A

Yes but these are simply enveloped by the cytoplasm of the Schwann cell and are non myelinated

These are not visible with LM unless silver or gold based techniques are used

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

How do oligodendrocytes form a myelin sheath

A

Individual oligodendrocyte from similar segment of myelin sheath around the axons like Schwann cells but for many separate axons simultaneously

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

Name a demyelinating disease of

a) PNS
b) CNS

What happens in each

A

a) Guillan-Barré syndrome - autoimmune attack on Schwann cells
b) MS - autoimmune attack against oligodendrocytes

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

Name a disease affecting the motor end plate

Describe it

A

Myasthenia gravis

The binding of ACh to this post signup take membrane is reduced due to decrease number of functional ACh receptors affecting the neuromuscular transmission

It is an autoimmune disease manifested by symptoms of fatigue and muscle weakness

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

Are all the cranial nerves mixed

A

No some are purely sensory or motor

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

Which is the most important cranial nerve of the parasympathetic outflow

A

10 (vagus)

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

How do the sympathetic preganglionic nerves leave the spinal cord

A

With the ventral roots of the T1 - L3/4 passing via the white rami communicantes to the paravertebral chain

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

How do parasympathetic ganglia appear

A

As slight swellings in nerve trunks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 3 cranial parasympathetic nerves

A

Oculomotor
Facial
Glossopharnygeal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How big are first order autonomic neurons

Are they myelinated

A

About 2-5μm in diameter

Yes
Second order axons are non myelinated however

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How fast do autonomic nerves conduct

A

Myelinated: 10m/s

Non myelinated: 1m/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How much of our body weight is skeletal muscle

A

40%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a muscle fibre

A

The highly specialised muscle cell

It is a big elongated structure formed by the fusion of many cells

It contains many peripheral nuclei and its surface is bound by A single cell membrane: the sarcolemma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is a myofibril

A

A closely packed, cylindrical array of filaments lying within the cytoplasm of the muscle cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is a myofilament

A

Are you strand of filamentous actin or myosin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where are myosin filaments linked

A

At the M line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the sarcomere

A

The unit of contraction and the part of the myofibril between the 2 Z line a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Light I bands contain what

A

Actin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the A bands

A

Dark bands of thick myosin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the H band

A

The myosin regions not overlapping with actin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Why are I bands called I bands

A

They are monofringent and this isotopic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What does monofringent mean

A

Does not alter the plane are polarised light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How does the A band affect polarised light

A

They are bifringent so alter the polarised light in 2 planes and are anisotropic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How is calcium re-accumulated after muscle contraction

A

By the fenestrated collar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What are red muscle fibres

A

What is rich in myoglobin giving it the red colour

These are type one fibres and contain the most myoglobin and the greatest number of mitochondria you had that metabolism it depends on oxidative phosphorylation primarily

Capable of sustaining contraction and generate a slow twitch response to stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are Type II muscle fibres

A

White fibres

Contain much less myoglobin and a few mitochondria

They respond quickly to stimulation but cannot sustain contraction for long periods of time

They are specialised for anaerobic metabolism

40
Q

Where are the following muscle fibres found:

a) type I
b) type II

A

a) in the postural muscles and limbs

b) in muscles responsible for intense but sporadic contraction eg biceps

41
Q

Is a muscle either red or white fibre?

A

No Most muscles contain a mixture of type one and two fibres as well as scattered intermediate fibres

42
Q

What are tendons made from

Why are they white

A

Connective tissue

They have a sparse blood supply

43
Q

How does the tendon’s college fibres merge with the muscle

A

Blends with the epimysium and penetrates the muscle along with the perimysium

44
Q

What is the epimysium and perimysium

A

Epimysium: A dense collagenous she is investing the muscle

Perimysium: A loose collagenous tissue surrounding each muscle bundle

45
Q

What is endomysium

A

Loose connective tissue up occupying the spaces between individual muscle fibres

46
Q

How does this size of cardiac muscle cells compare to skeletal muscle cells

A

Cardiac are much smaller

Cardiac=15μm in diameter and 100μm long
Skeletal= 100μm in diameter and several cm long

47
Q

Describe the position of nuclei in cardiac muscle cells

Skeletal?

A

Each cell has 1 nucleus which lies deep in the cells

Skeletal muscle cells are multinucleate (can contain 100s of nuclei) which are found just inside the surface membrane, at the periphery of the fibre

48
Q

How are cardiac muscle cells linked togther

A

By specialised intercellular junctional regions called intercalated discs

49
Q

What are intercalated discs

A

Complex interdigitating junctions present at the sidelines

The action filament of the terminal sarcomere of each cell insert into a meshwork of specific protein adhesion molecules, forming a mechanically strong attachment between the cells through intermediate like junctions, Such that the pull of one contractile unit can be transmitted across the access to the next

50
Q

How are cardiac muscle cells electrically linked

A

Along the side of the cells, next to the into collated discs, the cell membranes of adjacent cells come into close proximity to form gap junctions

51
Q

Describe T tubules

A

They run in at the Z lines in the cardiac muscle and enter at the Boundry between the A and I bands in skeletal muscle

They are closing associated with membranes of the SR in both

In cardiac muscle the T tubule from diads with a terminal cisterna of the SR rather than triads as occurs in skeletal

52
Q

True or false

The SR is less extensive in cardiac muscle

A

True

53
Q

True or false:

The innervation of cardiac muscle is different from skeletal muscle

A

True

End plates are not present in cardiac

54
Q

Where is the nucleus in smooth-muscle cells

A

In the centre

55
Q

What are the equivalent of Z lines in the smooth-muscle

A

Dense bodies

56
Q

What are dense bodies dense in

A

Electron dense

57
Q

How are dense bodies bound to actin

A

By α- actin

58
Q

How are the membranes of adjacent smooth-muscle cells separated

A

By a space containing into cellular matrix and collagen fibres

59
Q

How is force transmitted between smooth-muscle cells

A

By junctions similar to desmosomes and there are regions where the adjacent membranes are parallel and very close together forming gap junctions which ensure electrical continuity between the cells to synchronise contractions

60
Q

What is similar to the T tubular system in smooth-muscle

A

Caveolae

These are in pocketings of the plasma membrane

61
Q

What are the two types of smooth muscle

A

Unitary/ visceral

Multi unit

62
Q

Describe visceral smooth-muscle

A

Individual muscle fibres are linked by gap junctions and act as a unit

It is found predominantly in the wall of hollow viscera such as blood vessels and the gastrointestinal tract

63
Q

Describe multi unit smooth-muscle

A

Consists of individual units without gap junctions. Muscle fibres are not linked, each one contracts independently.

It is found in locations such as the iris of the eye in which fine graded contractions take place

64
Q

How big are smooth-muscle cells

A

Diameter: 2-10μm
Length: 50-400μm

65
Q

What are the three layers of arteries, arterioles and veins

A

Tunica intima
Tunica media
Tunica adventitia

66
Q

Describe tunica intima generally

What is it like in veins

A

The innermost coat of the walls of blood vessels

It is the endothelial am with adjacent basement membrane and some support in connective-tissue

in veins the internal elastic laminar is not that obvious

67
Q

Describe the tunica intima in arteries

A

In arteries extends to and includes the internal elastic lamina – a substantial fenestrated tube elastin which can be easily identified in muscular arteries and arterioles

Large elastic arteries such as the aorta contain so many layers of elastin that is difficult to decide which one is the most substantial inner layer

68
Q

Describe the tunica media

A

The middle layer

This is the part of the wall that contains smooth muscle
The outside is sometimes marked by the external elastic lamina

69
Q

Describe the tunica media in arteries

A

Arteries always contain a substantial tunica media

In elastic arteries there is more elastin than smooth-muscle or collagen

In muscular arteries smooth-muscle predominates. Large muscular arteries contain many layers of smooth-muscle separated by incomplete sheets of elastin and collagen

Arterioles also have predominant tunica media but that muscle is decrease as they become smaller. Small arterioles my only contain a single layer of smooth muscle

70
Q

Describe the tunica media of veins and venules

A

Veins have less smooth muscle than arteries
In areas where veins aren’t supported by surrounding tissue (eg in the legs) the amount of muscle is larger

Small venules lack muscle in their wall and may only consist of endothelium and a layer of connective tissue around it

71
Q

Describe tunica adventitia

A

The outercoat

It is the sheath of connective tissue surrounding the puzzle and ties it into a tissue to which it runs

Consist mainly of collagen and is usually the most prominently in the wall of a vein

this is where you find the innervation of the vessel

72
Q

What is the blood supply to blood vessels with thick walls

Which layer is it in

A

The vasa vasorum

Tunica adventitia

73
Q

What are ‘resistance vessels’

What makes them responsible for peripheral resistance

A

Arterioles

Their small diameter (20-130μm)

74
Q

How does the tunica media change as arterioles become smaller

A

The number of muscle layers decreases and the internal elastic lamina is lost

75
Q

True or false

The lumen of arteries is similar to the size of the wall

A

True

76
Q

Name a vein that has thicker muscular walls

Why is this

A

The saphenous vein

To withstand the hydrostatic pressure of a column of blood

77
Q

How big are capillaries

A

5-10μm

78
Q

What are capillaries lined by

A

Endothelium (simple squamous epithelium) on a basement membrane

79
Q

What are pericytes

A

Associated with capillaries

Cells with contractile properties that wrap around the endothelial cells

Pericytes are undifferentiated cells, capable of giving rise to fibroblasts, smooth muscle cells and endothelial cell precursors for growth, branching and repair

80
Q

What are the 3 types of capillaries

A

Continuous

Fenestrated

Sinusoidal/ discontinuous

81
Q

Describe continuous capillaries

Where are they found

A

The most common capillary

Have continuous endothelial wall and are less permeable

They are found in connective tissue, muscle, lungs, brain and skin

82
Q

Describe fenestrated capillaries

A

Have circular pores in the endothelium or very thin regions which is crossed only by a diaphragm that is thinner than a cell membrane

Their basement membrane is continuous

83
Q

Where are fenestrated capillaries found

A

Kidneys
Small intestine
Endocrine glands

84
Q

Describe sinusoidal capillaries

A

Fenestrated with the largest open pores without diaphragms in the endothelium

The basement membrane is discontinuous and highly permeable

85
Q

Where are sinusoidal capillaries found

A

Where a close relationship between the circulation and parenchymal cells is required

Eg liver, spleen, lymphatic tissue, bone marrow and some endocrine glands

86
Q

What are the 3 routes for exchange across the capillary wall

A

Diffusion across the endothelial wall

Diffusion between cells

Pinocytosis

87
Q

Which substances easily cross capillary walls with or without fenestrations

What substances require fenestrations

A

Lipid soluble substances eg CO2, O2, alcohol

Water and hydrophilic substances

88
Q

Where is the junctional seal in between capillary endothelial cells impermeable

A

In most of the CNS

89
Q

What is pinocytosis

A

Large molecules can cross the endothelium in vesicles that are formed at one surface and discharge at the other

This is a feature of all capillaries especially in continuous capillaries

It is possible that vesicles May join together under some conditions to form a transitory channel across the endothelial layer

90
Q

How can capillaries be made visible in LM

A

Injection of a special dye eg gelatin Carmine

Perfusion fixation which preserves then in their natural, open state

91
Q

Where are lymphatic capillaries not found

A 
CNS
bone
Cartilage 
Bone marrow 
Epithelia 
Placenta
92
Q

How do the walls of lymphatic vessels relate to those of blood vessels

A

Larger lymphatic vessels resemble veins (and venules) and veins and lymph vessels have valves

Lymphatic capillaries are like those of blood vessels

93
Q

How to tell the difference between lymphatics and blood vessels in LM

A

Presence of RBCs

If perfused, blood vessels are empty but the lymphatics contain a gel of plasma protein

94
Q

What is the tunica intima like in lymphatics

A

Consists of endothelium and a v thin sub-endothelial layer of supporting tissue

Projects into valves which are composers of little supporting tissue (reticulin fibres and minimal ground substance) lines in both sides by endothelium

95
Q

What is the tunica media like in lymphatics

A

Contains less smooth muscle, separated by collagen

96
Q

What is the tunica adventitia like in lymphatics

A

Consists of connective tissue with fibroelastic fibres

97
Q

Describe the wall of lymphatic capillaries

A

Consists of a single layer of thin endothelial cells, the basement membrane being rudimentary or absent

Histology (9 decks)

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