Cells and Tissues: Muscle and Nervous Tissue Flashcards

1
Q

Muscle tissue description

A

tissue that is made of contractile cells (muscle fibres) that contract to make body parts move and generates heat

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2
Q

What is muscle tissue comprised of?

A

It is made up of elongated cells (muscle cells or muscle fibres or myocytes)

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3
Q

What is the function of muscle tissue?

A

To use energy from the hydrolysis of ATP to generate contractile forces, producing body movements, maintains posture and generates heat

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4
Q

What are the three types of muscle tissue?

A

Skeletal, cardiac and smooth muscle (these comprise more than 50% of body tissue mass)

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5
Q

Where are skeletal muscle attached?

A

To bones via tendons

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6
Q

What is skeletal muscle comprised of?

A

Long, cylindrical fibres in the tissue that make it look striated. It is also multinucleated (many peripheral nuclei pushed to the side)

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7
Q

The function of skeletal muscle?

A

Motion, posture, heat production and protection

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8
Q

Is skeletal muscle voluntary?

A

It is considered voluntary because contraction and relaxation are under conscious control. However, some things like posture are not voluntary

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9
Q

What is the stapedius and where is it located?

A

The smallest skeletal muscle in the body (1.25mm) and is located in the ear

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10
Q

What is hyperacusis?

A

Excessively sensitive hearing -

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11
Q

What is Bell’s Palsey?

A

A condition where paralysis of the facial nerve causes muscular weakness in one side of the face and hyperacusis

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12
Q

What is the sartorius and where is it located?

A

The longest skeletal muscle (60cm) which is located in the anterior region of the thigh?

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13
Q

What is the function of the sartorius?

A

Flexes, abducts, and laterally rotates thigh/hip; flexes knee

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14
Q

What are myofibrils?

A

Protein structures (diameter is 2 micrometres) that run the entire length of the sarcoplasm (cytoplasm), made up of filaments

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15
Q

What is sarcoplasm?

A

The cytoplasm in skeletal muscle

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16
Q

What is sarcolemma?

A

is the plasma membrane of a striated muscle fibre cell

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17
Q

What are myofibrils made of?

A

Thin and thick filaments

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18
Q

What type of filament is Actin?

A

The thin filament in myofibrils (8 nm diam; 1-2 μm long)

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19
Q

What type of filament is myosin?

A

The thick filament in myofibrils (16 nm diam; 1-2 μm long)

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20
Q

What is a sarcomere?

A

A structural unit of a myofibril in striated muscle

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21
Q

What is epimysium?

A

dense irregular connective tissue surrounding a muscle

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22
Q

What is perimysium?

A

the sheath of connective tissue surrounding a bundle of muscle fibres

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23
Q

What is endomysium?

A

a layer of areolar connective tissue that ensheaths each individual muscle fibre/ muscle cell. Capillaries and nerves are on this layer

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24
Q

What is the A band?

A

The dark middle area of the sarcomere, containing all thick filaments

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25
Q

What is the I band?

A

Area of sarcomere containing thin filaments only

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26
Q

What is the H zone?

A

Area of sarcomere containing thick filaments only

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27
Q

What is the M line?

A

Middle of the sarcomere, holds thick filaments in place and binds to titin

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28
Q

What is the Z disc?

A

Provides anchorage for thin filaments (I band) and titin while also linking filaments of adjacent sarcomeres

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29
Q

What is titin?

A

The ‘molecular spring’ that links the M line to the Z disc

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30
Q

What does cardiac muscle consist of?

A

Fibres that join end-to-end through intercalated discs. It is striated and branched with a single central nucleus.

31
Q

What are intercalated discs and what do they contain?

A

Attachment sites between the transverse lines between cardiac muscle cells, containing desmosomes and gap junctions

32
Q

The function of desmosome in the intercalated disc

A

To bind intermediate filaments and provide adhesion in vigorous contractions

33
Q

The function of gap junctions in the intercalated disc

A

For communication, cell co-ordination and rapid conduction throughout the heart

34
Q

Where is cardiac muscle tissue found?

A

The heart wall

35
Q

What is the function of cardiac muscle tissue?

A

To pump blood to all parts of the body

36
Q

Where is smooth muscle tissue located?

A

Located in the walls of hollow internal structures

e.g. intestines (peristalsis); blood vessel walls (constriction); Iris of the eye, reproductive; digestive; respiratory; urinary; skin erector pili

37
Q

Is cardiac muscle tissue voluntary?

A

No, it is involuntary

38
Q

Is smooth muscle tissue voluntary?

A

No, it is involuntary

39
Q

What is smooth muscle comprised of?

A

It contains bundles of thin (actin) and thick (myosin) filaments
It is short, small, spindle-shaped, about 30-200 μm long; 3-8 μm thickest in the middle Non-striated (smooth) and has a single central nucleus

40
Q

What are dense bodies?

A

These are similar to Z discs which contain protein Actinin. Thin filaments (actin) and intermediate filaments attach themselves to dense bodies

41
Q

How do smooth muscle cells twist during contraction?

A

The intermediate filaments are non-contractile so when the cell contracts the filaments force the cell to contract around these “stable rods” causing it to twist

42
Q

What is the function of smooth muscle tissue?

A

Motion - the constriction of blood vessels and airways, propulsion of foods through the gastrointestinal tract, contraction of urinary bladder and gallbladder

43
Q

Nervous tissue description

A

tissue that contains conducting nerve cells and supportive neuroglia that carries information from one part of the body to another through nerve impulses

44
Q

The two components of the nervous system

A

The central nervous system (CNS) and the Peripheral nervous system (PNS)

45
Q

What is in the CNS?

A

Brain, spinal cord and optic nerve

46
Q

What is in the PNS?

A

All other nervous tissue outside of the CNS

47
Q

What is the role of the PNS?

A

Afferent division: to send information to the CNS

Efferent division: to send information from the CNS to the organs (muscles and glands)

48
Q

Nervous system function

A

Maintain homeostasis(along with the endocrine system)
Initiates voluntary movements
Responsible for perception, behaviour and memory

49
Q

What is the nervous tissue sensory function?

A

Detection of internal and external stimuli and transfer to CNS

50
Q

What is the nervous tissue integrative function?

A

analysis and storing of information

51
Q

What is the nervous tissue motor function?

A

stimulation of effectors (e.g. muscle and glands) through PNS

52
Q

What does nervous tissue consist of?

A

Neurons and neuroglia that have both conscious and unconscious control

53
Q

What are neurons comprised of?

A

a cell body into which short, branched dendrites convey nerve impulses (action potentials) and from which a longer, single axon conducts nerve impulses to another neuron or tissue.

NEURONS DO NOT DIVIDE and have a high metabolic rate

54
Q

What is a dendrite?

A

The receiving/input part of the neuron

55
Q

What is an axon?

A

carries the nerve impulse away from the neuron. It is the output portion of the neuron

56
Q

Features of multipolar neurons

A

Have 2 or more dendrites and a single axon.
Most common neurons in CNS
All motor neurons (control skeletal muscle) are in this class
Some of the longest (spinal cord to toe muscles)

57
Q

Features of bipolar neurons

A

Two distinct processes
–1 dendritic process (can branch at the tip but not at cell body)
–And 1 axon
Has the cell body between axon and dendrite
Rare and small (30μm)
Special sense organs (sight, smell, hearing) relay information from receptor to neurons

58
Q

Features of Unipolar neurons

A

The dendrites and axon are continuous
Cell body off to one side
Whole thing from where dendrites converge called an axon
Most sensory nerves are unipolar
Very long (1m) like motor nerves CNS-toe tip.

59
Q

Features of an anaxonic neuron

A

RARE
Anatomy cannot distinguish dendrites from axons
Found in the brain and special sense organs

60
Q

What are the functions of the neuroglia

A
The physical structure of nervous tissue
Repair framework of nervous tissue
Undertake phagocytosis
Nutrient supply to Neurons
Regulate interstitial fluid in neural tissue.
61
Q

Where are neuroglia found?

A

in both the CNS and PNS

62
Q

How big are neuroglia?

A

They are smaller than neurons but more numerous

63
Q

Features of neuroglia

A

They can communicate but do not propagate action potentials and can divide in the mature nervous system

64
Q

What is the Myelin sheath?

A

Covers the axon of some neurons and helps speed neural impulses

65
Q

What are Astrocytes?

A

CNS neuroglia that is responsible for the support and repair of neurons. They maintain the environment around neurons through maintaining the blood-brain barrier, regulate ions, influence the permeability of vessels

66
Q

What are Gliotransmitters?

A

Method of communication between astrocytes and neurons

67
Q

What are Ependymal cells?

A

CNS neuroglia that produces Cerebrospinal fluid, line ventricles in the brain, contain cilia for movement and microvilli for sampling and monitoring

68
Q

The function of Cerebrospinal fluid?

A

A mechanical buffer that moves nutrients and waste

69
Q

What are Oligodendrocytes?

A

Type of glial cell in the CNS that wrap axons in a myelin sheath. These can myelinate more than one neuron cell’s axon at a time.

70
Q

What are Microglia?

A

Phagocytic glia that provides protection

71
Q

What are the two cells in the PNS?

A

Schwann cells and Satellite cells

72
Q

What are Schwann cells?

A

PNS glia that can form the myelin sheath for one axon, or provide support for multiple non-myelinated axons

73
Q

What are satellite cells?

A

PNS cells that surround the neurons to provide support and help with fluid exchange