Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Histology > Nerves And Muscles > Flashcards

Nerves And Muscles Flashcards

(97 cards)

Start Studying
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
How much of our body weight is skeletal muscle
40%
26
What is a muscle fibre
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
27
What is a myofibril
A closely packed, cylindrical array of filaments lying within the cytoplasm of the muscle cell
28
What is a myofilament
Are you strand of filamentous actin or myosin
29
Where are myosin filaments linked
At the M line
30
What is the sarcomere
The unit of contraction and the part of the myofibril between the 2 Z line a
31
Light I bands contain what
Actin filaments
32
What are the A bands
Dark bands of thick myosin filaments
33
What is the H band
The myosin regions not overlapping with actin
34
Why are I bands called I bands
They are monofringent and this isotopic
35
What does monofringent mean
Does not alter the plane are polarised light
36
How does the A band affect polarised light
They are bifringent so alter the polarised light in 2 planes and are anisotropic
37
How is calcium re-accumulated after muscle contraction
By the fenestrated collar
38
What are red muscle fibres
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
39
What are Type II muscle fibres
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
Where are the following muscle fibres found: a) type I b) type II
a) in the postural muscles and limbs | b) in muscles responsible for intense but sporadic contraction eg biceps
41
Is a muscle either red or white fibre?
No Most muscles contain a mixture of type one and two fibres as well as scattered intermediate fibres
42
What are tendons made from Why are they white
Connective tissue They have a sparse blood supply
43
How does the tendon’s college fibres merge with the muscle
Blends with the epimysium and penetrates the muscle along with the perimysium
44
What is the epimysium and perimysium
Epimysium: A dense collagenous she is investing the muscle Perimysium: A loose collagenous tissue surrounding each muscle bundle
45
What is endomysium
Loose connective tissue up occupying the spaces between individual muscle fibres
46
How does this size of cardiac muscle cells compare to skeletal muscle cells
Cardiac are much smaller Cardiac=15μm in diameter and 100μm long Skeletal= 100μm in diameter and several cm long
47
Describe the position of nuclei in cardiac muscle cells Skeletal?
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
How are cardiac muscle cells linked togther
By specialised intercellular junctional regions called intercalated discs
49
What are intercalated discs
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
How are cardiac muscle cells electrically linked
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
Describe T tubules
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
True or false | The SR is less extensive in cardiac muscle
True
53
True or false: The innervation of cardiac muscle is different from skeletal muscle
True | End plates are not present in cardiac
54
Where is the nucleus in smooth-muscle cells
In the centre
55
What are the equivalent of Z lines in the smooth-muscle
Dense bodies
56
What are dense bodies dense in
Electron dense
57
How are dense bodies bound to actin
By α- actin
58
How are the membranes of adjacent smooth-muscle cells separated
By a space containing into cellular matrix and collagen fibres
59
How is force transmitted between smooth-muscle cells
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
What is similar to the T tubular system in smooth-muscle
Caveolae These are in pocketings of the plasma membrane
61
What are the two types of smooth muscle
Unitary/ visceral Multi unit
62
Describe visceral smooth-muscle
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
Describe multi unit smooth-muscle
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
How big are smooth-muscle cells
Diameter: 2-10μm Length: 50-400μm
65
What are the three layers of arteries, arterioles and veins
Tunica intima Tunica media Tunica adventitia
66
Describe tunica intima generally What is it like in veins
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
Describe the tunica intima in arteries
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
Describe the tunica media
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
Describe the tunica media in arteries
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
Describe the tunica media of veins and venules
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
Describe tunica adventitia
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
What is the blood supply to blood vessels with thick walls Which layer is it in
The vasa vasorum Tunica adventitia
73
What are ‘resistance vessels’ What makes them responsible for peripheral resistance
Arterioles Their small diameter (20-130μm)
74
How does the tunica media change as arterioles become smaller
The number of muscle layers decreases and the internal elastic lamina is lost
75
True or false | The lumen of arteries is similar to the size of the wall
True
76
Name a vein that has thicker muscular walls Why is this
The saphenous vein To withstand the hydrostatic pressure of a column of blood
77
How big are capillaries
5-10μm
78
What are capillaries lined by
Endothelium (simple squamous epithelium) on a basement membrane
79
What are pericytes
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
What are the 3 types of capillaries
Continuous Fenestrated Sinusoidal/ discontinuous
81
Describe continuous capillaries Where are they found
The most common capillary Have continuous endothelial wall and are less permeable They are found in connective tissue, muscle, lungs, brain and skin
82
Describe fenestrated capillaries
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
Where are fenestrated capillaries found
Kidneys Small intestine Endocrine glands
84
Describe sinusoidal capillaries
Fenestrated with the largest open pores without diaphragms in the endothelium The basement membrane is discontinuous and highly permeable
85
Where are sinusoidal capillaries found
Where a close relationship between the circulation and parenchymal cells is required Eg liver, spleen, lymphatic tissue, bone marrow and some endocrine glands
86
What are the 3 routes for exchange across the capillary wall
Diffusion across the endothelial wall Diffusion between cells Pinocytosis
87
Which substances easily cross capillary walls with or without fenestrations What substances require fenestrations
Lipid soluble substances eg CO2, O2, alcohol Water and hydrophilic substances
88
Where is the junctional seal in between capillary endothelial cells impermeable
In most of the CNS
89
What is pinocytosis
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
How can capillaries be made visible in LM
Injection of a special dye eg gelatin Carmine Perfusion fixation which preserves then in their natural, open state
91
Where are lymphatic capillaries not found
``` CNS bone Cartilage Bone marrow Epithelia Placenta ```
92
How do the walls of lymphatic vessels relate to those of blood vessels
Larger lymphatic vessels resemble veins (and venules) and veins and lymph vessels have valves Lymphatic capillaries are like those of blood vessels
93
How to tell the difference between lymphatics and blood vessels in LM
Presence of RBCs If perfused, blood vessels are empty but the lymphatics contain a gel of plasma protein
94
What is the tunica intima like in lymphatics
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
What is the tunica media like in lymphatics
Contains less smooth muscle, separated by collagen
96
What is the tunica adventitia like in lymphatics
Consists of connective tissue with fibroelastic fibres
97
Describe the wall of lymphatic capillaries
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.
© 2025 Bold Learning Solutions. Terms and Conditions