Brainscape's Knowledge GenomeTM

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


See full index

Histology > Contractile cells > Flashcards

Contractile cells Flashcards

1
Q

4 groups of contractile cells

A

muscle cells
myoepithelial cells
myofibroblasts
pericytes

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

muscle cells

A

striated (voluntary)

cardiac and smooth (involuntary)

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

myofibroblasts

A

contractile role and collagen secretion

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

pericytes

A

smooth, muscle-like cells surrounding blood vessels

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

myoepithelial cells

A

component of certain secretory glands

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

skeletal muscle

A

voluntary movement
influenced by nervous system
maintenance of posture

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

development of skeletal muscle

A

embryogenesis
fusion of precursor cells (myoblasts)
syncytium with hundreds of nuclei beneath cell membrane

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

structure of skeletal muscle

A 
long thin cylindrical structure
50-60 um diameter
up to 10cm long
hexagonal profile (cross section)
fibrocollagenous septa
numerous nuclei at side
mitochondria and glycogen
external lamina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

satellite cells

A

adult muscle

muscle precursor cells dividing to form new muscle cells

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

sarcolemma

A

cell membrane

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

sarcoplasm

A

cell cytoplasm

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

sarcoplasmic reticulum

A

ER

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

contractile elements of skeletal muscle cells

A

myofibrils
thin cylindrical structures 1-2 um in diameter
overlapping, repeating assemblies of thick (myosin) and thin (actin) filaments

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

sarcomere

A

functional unit of myofibrils

plates of accessory proteins hold filaments in place and divide myofibrils

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

arrangement of contractile proteins in sarcomeres

A

thick filament surrounded by 6 thin filaments

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

bands in contraction

A

thick and thin filaments slide past eachother
decrease in width of light bands
width of dark bands is unchanged

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

A band

A

dark band
thick filament band
includes zone where thin filaments overlap with thick filaments

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

H zone

A

pale staining area in centre of A band

no thin filaments overlap with thick filaments

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

I band

A

zone of thin filaments not overlapping with thick filaments

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

Z line

A

dark band in centre of I band

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

M line

A

runs down centre of H band

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

myosin molecules

A

2 tadpole shaped heavy chains
tails coil around eachother
4 small light chains attached to head portions
tail portions aggregate to form filament
head portions project out in regular helical pattern

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

thin filaments

A

8nm diameter
thin filament (F actin) formed by polymerisation of single molecules of globular actin (G actin)
polar
G-actin molecules point in same direction

2 actin filaments attach by tail ends to alpha actinin in Z line, opposite direction

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

thick filaments

A 
myosin
polar
2 myosin filaments attach by tail ends
face opposite direction, away from M line
isoforms present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

accessory proteins of molecules

A 
actinin
nebulin
myomesin
titin
desmin
C protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

actinin

A

holds actinin filaments in lattice arrangement in Z disk

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

Z disk proteins

A

actinin
filamin
amorphin
Z protein

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

nebulin

A

associated with actin containing thin filaents

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

myomesin

A

holds myosin filaments in lattice arrangement
region of M line
associated with creatine kinase and M protein

30
Q

titin

A

long elastic protein
runs parallel to filament array
links ends of thick filaments to Z disk

31
Q

desmin

A

link adjacent myofibrils to eachother

link myofibrils to membrane

32
Q

C protein

A

myosin binding protein

localised in 7 stripes running parallel to M band in first half of A band

33
Q

use of ATP by myosin binding to actin

A

ATP bound to myosin head hydrolysed to ADP and phosphate
myosin binds loosely to actin
phosphate released and myosin binds tightly to actin

34
Q

binding of myosin to actin

A

folding of myosin to cause movement of it relative to actin filament
ADP released, fresh ATP binds and myosin returns to non attached state

35
Q

tropomyosin

A

long rod like protein winding around actin to stabilise and stiffen it

36
Q

troponin complex

A

regulates actin and myosin binding

attached to tropomyosin and contains 3 polypeptides: troponins T, I and C

37
Q

troponin T

A

binds complex to tropomyosin

positions complex at site where actin binds to myosin

38
Q

troponin I

A

physically prevents myosin binding to actin

39
Q

troponin C

A

binds Ca2+ ions, causing a conformational change in troponin complex allowing myosin access to actin

40
Q

how are nerve signals conveyed?

A

excitation of muscle cell membrane conveyed to interior of cell via membranous channels (transverse tubular system of T tubules) extending from muscle surface to surround each myofibril

41
Q

terminal cisternae

A

2 portions of sarcoplasmic reticulum running alongside T tubule
high conc of Ca2+ ion channels in wall
membrane excitation of tubule system causes channels to open

42
Q

membrane triad

A

association of T tubules and sarcoplasmic reticulum forms 3 tubules in cross section
surrounds every myofibril in AI junction - 2 triads to each sarcomere

43
Q

T tubular system

A

internal membrane system
extends from the surface membrane as thin tubules
deep through muscle fibre along region of AI junction
2 extensions of sarcoplasmic reticulum with high Ca2+ conc

44
Q

differences between cardiac and skeletal muscle

A

cardiac muscle cells mononuclear and shorter (nuclei)

long cardiac muscle fibres produced by lining cells via anchoring cell type junctions

population of stem cells, analogous to satellite cells of skeletal muscle, not present in cardiac cells - no regeneration

45
Q

structure of cardiac muscle cells

A

15 um diameter
100 um long
central nucleus
intercalated disks

46
Q

3 types of cell junction in intercalated disks

A

desmosomal junctions - intermediate filaments

adherent-type junctions anchor actin fibres of sarcomeres to end of cell

communicating gap junctions facilitate passage of membrane excitation and synchronisation of contraction

47
Q

molecular basis of contraction of cardiac muscle

A

transverse T tubule have wider invaginations of cell surface

sarcoplasmic reticulum not as regular or as organised as in skeletal muscle

association of cardiac sarcoplasmic reticulum is form of dyads, not triads, and is in region of Z lines rather than AI junction

48
Q

smooth muscle cells structure

A

less organised system of contractile proteins than skeletal and cardiac muscle cells
anchored together into functional units by BM material
spindle shaped
20um - 500 um
single, centrally located nucleus elongated in shape
external lamina
bundles by fine collagenous tissue containing blood vessels and nerves

49
Q

where are smooth muscle cells located?

A

gut, urinary bladder and uterus
blood vessel walls and secretory gland ducts
sustained slow or rhythmic contractions not under voluntary control

50
Q

cross sectional/longitudinal smooth muscle cells

A

polygonal profiles

linear bundles

51
Q

contractile proteins in smooth muscle cells

A

bundles of contractile proteins crisscrossing the cell inserted into anchoring points (focal densities)

52
Q

how does a mass of smooth muscle cells function as one unit?

A

tension generated by contraction transmitted through focal densities surrounding network of external lamina

53
Q

how is energy supplied in smooth muscle cells?

A

numerous mitochondria

located with ER around nucleus, in area devoid of contractile filaments

54
Q

nexus junctions

A

gap junctions in smooth muscle

55
Q

invaginations in smooth muscle cells

A

similar to T tubules

56
Q

contraction of smooth muscle cells

A

contraction of cell membrane results in shortening of the cell, which assumes a globular shape
elongated shape in relaxed state

57
Q

filaments in smooth muscle

A

thin filaments of actin (isoform specific to smooth muscle) associated with tropomyosin - no troponin

thick filaments composed of myosin (different type than skeletal muscle) - only binds to actin if its light chain is phosphorylated

58
Q

control of Ca2+ ion movements

A

relaxed - Ca2+ ions sequestered in sarcoplasmic reticulum
excitation - released into cytoplasm and bind to calmodulin (calcium binding protein)

calcium-calmodulin complex activates enzyme myosin light-chain kinase - phosphorylates myosin light chain and allows it to bind to actin

59
Q

functional types of smooth muscle

A

unitary and multiunit

sheets with cells arranged circumfrentially or longitudinally

60
Q

unitary smooth muscle

A

generate own low level of rhythmic contraction, stimulated by stretch, transmitted cell to cell via gap junctions
innervated by ANS
increases or decreases levels of spontaneous contraction, not initiate it
slow contraction, no action potentials, low fast myosin

61
Q

phasic smooth muscle

A

iris of eye
ANS controls contraction
vas deferens and large arteries
rapid contractions, distinct action potentials, high fast myosin

62
Q

myofibroblasts

A

spindle shaped cells
secrete collagen
well defined contractile properties

63
Q

myofibroblasts structure

A

actin and desmin
lack external lamina
spindle shaped cells

64
Q

myofibroblasts after damage

A

become active and proliferate
repair defects from tissue death
secrete collagen for firm scaffold to consolidate a damaged area
myofibrils contract and pulls extracellular matrix together to reduce physical size of damaged area

65
Q

pericytes

A 
spindle-shaped cells
circumfrentially arranged around capillaries and venules
external lamina
little cytoplasmic differentiation
actin and myosin
66
Q

pericytes after tissue damage

A

proliferate
assume role of primitive mesenchymal cells
differentiate into myofibroblasts and mesenchymal tissue

67
Q

myoepithelial cells structure

A 
layer of flat cells
around acini and ducts
dark staining rounded nuclei
clear cytoplasm
contractile proteins
desmosomes
desmin
68
Q

myoepithelial cells around acini

A

stellate, multi processes morphology in 3D

contractile meshwork enclosing secretory units of glands

69
Q

myoepithelial cells around ducts

A

fusiform

surround periphery of ducts

70
Q

myoepithelial cells function

A

controlled by ANS and contract and expel glandular secretions

Histology (10 decks)

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