histology Flashcards
(176 cards)
1
Q
what do cells consist of
A
cytoplasm enclosed within a lipid sheath
2
Q
what is cytosol
A
solution of salts and organic compounds
3
Q
where does cytoskeleton radiate
A
from the nucleus outwards to the cell surface
4
Q
what does lipid bilayer separate
A
the cell contents from the external environment
5
Q
what is phospholipid head
A
water loving = hydrophilic
6
Q
what is phospholipid tail
A
water hating = hydrophobic
7
Q
how are phospholipid arranged
A
in a bilayer
8
Q
what can cells absorb
A
gases or small hydrophobic compounds directly across the plasma membrane
9
Q
how are anchored proteins anchored to the membrane
A
by acyl chain
10
Q
how does solute move through membrane proteins
A
downhill its electrochemical gradient
11
Q
example of membrane protein
A
cystic fibrosis transmembrane regulator
12
Q
what is the CFTR
A
chloride channel found on the apical surface of epithelial cells
13
Q
what does CFTR regulate
A
the fluidity of the extra-epithelial mucous layer
14
Q
what does water follow
A
the efflux of sodium chloride by osmosis
15
Q
how do transporters work
A
by binding solute on one side of the membrane (conformational change) that exposes the solute biding site on the other side of the membrane for release
16
Q
how does passive transport work
A
without an energy source
17
Q
which way does passive transport move solute
A
downhill
18
Q
does active transport require energy
A
yes
19
Q
which way does active transport work
A
uphill
20
Q
what are the 2 types of active transport
A
- primary
- secondary
21
Q
what is primary active transport
A
use ATP
22
Q
how does secondary active pump work
A
driven by ion gradient
23
Q
what are the 3 types of receptors
A
- endocytosis
- anchorage
- signalling
24
Q
what are the 2 form of receptor mediated endocytosis
A
- phagocytosis
- pinocytosis
25
what are specialised phagocytic cells
- macrophages
| - neutrophils
26
what is pinocytosis
phagocytosis on a small scale and occurs continually
27
example of molecule that is pinocytosed
LDL
28
what is the endoplasmic reticulum
```
an array of interconnecting tubules
or
flattened sacs (cisternae)
```
29
what is endoplasmic reticulum contiguouos with
outer nuclear membrane
30
what are the 2 types of ER
- rough
| - smooth
31
what does RER carry
ribosomes on its cytosolic surface
32
what does SER do
lipids and sterols are synthesised
steroids and drugs are metabolised
33
what does SER store
calcium that can be released in to the cytosol
34
what is the Golgi apparatus
flattened cisternae arranged in a stack
35
what does the golgi apparatus do
proteins, lipids and sterol from the ER are exported to the Golgi apparatus to complete maturation
36
what do lysosome mature from
the vesicles that bud from the golgi
37
what do lysosomes contain
digestive enzymes such as lipase, proteases, nucleases and amylases that work in acidic environments
38
what does the membrane of a lysosome contain
proton ATPase pump to acidify the lumen of the organelle
39
what do lysosome fuse with
phagocytosis vesicles to digest their contents
40
what do peroxisomes contain
enzymes for the catabolism of long chain fatty acids
41
what is hydrogen peroxide
highly reactive oxidising agent
42
what can catalase reduce
H2O2 to water
43
what is mitochondria
engines of the cell
44
what does mitochondria produce
ATP
45
where are mitochondria abundant
in cells with high energy demand
| e.g. hepatocytes or muscle cells
46
what does the mitochondria have of its own
genome encoding 13 proteins
47
what is mitochondria's membrane like
double membrane
48
what does central matrix contain
enzymes for the Kreb cycle
49
what is mitochondria's inner membrane like
highly folded into cristae
50
what do Cristae do
increase the surface area
51
how is ATP moved
using the H+ electrochemical gradient
52
what are the other roles of mitochondria
- roles in apoptosis
- supply substrates for biosynthesis
- synthesis of porphyrin
53
what is the most prominent cellular organelle
nucleus
54
what is nucleus membrane like
double membrane
55
what does nucleus membrane contain
nuclear pores
56
are euchromatin active or not
active
57
where is rRNA transcribed
in the nucleolus
58
what does the nuclear compartment of the nucleus contain
nucleolus
59
what is the cytoskeleton
complex network of structural proteins that regulate the shape, strength and movement of the cell
60
what are the components of cytoskeleton
- microtubules
- intermediate filaments
- microfilament
61
what makes up microtubules
alpha and beta tubular
62
what is special about tubular structures
they resist bending and stretching
63
what are the 2 proteins in microtubule
- kinesin
| - dynein
64
what do intermediate filaments form
a network around the nucleus extending to the periphery of the cell
65
how do intermediate filaments contact with adjacent cells
via desmosomes
66
what is function of intermediate filaments
structural integrity
67
what are microfilaments
polymers of actin
68
what does the actin microfilaments control
- cell shape
- presents cellular deformation
- involved in cell-cell and cell-matrix adhesion
69
what does the cytoskeleton determine
cell shape and surface structures
70
what is the apical surface of some epithelium covered in
tiny microvilli
71
what does microvilli form
brush border
72
what do microvilli look like
finger-like projections
73
what do microvilli do
increase surface area for uptake
74
what is at the core of microvilli
20-30 cross linked actin microfilaments
75
what do cilia do in respiratory tract
moving and clearing the mucus that is used to trap dust
76
what happens to cilia in people that smoke
become paralysed
77
what is special about motile cilia
are longer
78
what is at the core of motile cilia
axoneme
79
what is flagella like
related to cilia but longer
80
when is cell motility essential
development
81
what is cell motility essential for in adults
- macrophages migrate to site of infection
- keratinocytes migrate to close wound
- osteoblast tunnel into a remodel bone
- fibroblast migrate to site of injury to repair extracellular matrix
82
what is filopodia
actin remodelling in one dimension
83
what is lamelliopodia
remodelling in 2 dimension
84
what is pseudopodia
3 dimensional projections
85
what is thrombocytopenia
platelet deficiency
86
what are the 4 major tissue types
- epithelium
- connective tissue
- muscle
- neural tissue
87
how are epithelium held tightly together
by intercellular junction
88
how is epithelium separated from extracellular matrix
basal lamina
89
what does epithelium cover
surfaces and line passageways
90
what does epithelium do
protection and regulate absorption and secretion
91
what does connective tissue do
support other tissues and give organs shape
92
example of connective tissue
collagen
93
example of bone cells
osteoblast
94
cartilage cells
chondrocytes
95
what is the extracellular matrix
gel matrix outside the cell
96
what does extracellular matrix determine
tissue properties
97
what is ECM in bone
calcified
98
what is ECM in tendons
tough and rope like
99
what is ECM in neural tissue
absent
100
what does ECM determine
- cell shape
- migration
- cell-cell communication
- signalling
- proliferation
- survival
101
what is the gel of ECM made from
polysaccharides
102
example of polysaccharide
- glycosaminoglycans
| - GAGs
103
what are hyaluronan
large hydrated GAG
104
where is hyaluronan secreted into
joint space in synovial joints
105
what does hyaluronan do
lubricate and help reduce compressive forces
106
what are aggrecan
large proteoglycan
107
what does aggrecan form
part of the articular cartilage of koitns
108
what is decorin
small proteoglycan
109
what does collagen produce
tensile strength
110
what does elastin do
elasticity
111
how can ECM be degraded and remodelled
by proteins of the matrix metalloproteins
112
what is basal lamina
basement membrane
113
another name for basement membrane
lamina propria
114
what des basement membrane do
separate cells from underlying tissue
115
what does breach of basal lamina mean
cancer cells
carcinoma-in-situ
116
examples of immunoglobulin-like cell adhesion
iCAM
| vCAM
117
what do selections interact with
carbohydrate ligand
118
what are integrins
membrane glycoproteins with alpha and beta subunits
119
another name for tight junction
zonula occludens
120
where do tight junction form
the top (apical) side of the epithelial cells in intestine, skin and kidney
121
what do gap junction allow
low-molecular- weight substances to pass directly between cells
122
what are the channel in gap junction regulated by
intracellular calcium, pH and voltage
123
what are adherent junction
multi protein intercellular adhesive structure prominent in epithelial tissues such as fascia adherens
124
what do adherent junction attach to
actin microfilaments inside the cell
125
what do desmosome provide
strong attachment between cells and are prominent in tissue
126
how to cells adhere to non basal lamina ECM
via secreted proteins such as fibronectin and collagen
127
what kind of signals can cell receive
- chemical
- mechanical
- electrical
128
what are examples of chemical signals
- hormones
| - neurotransmitters
129
what are examples of mechanical signals
biomechanical
130
what do kinases do
phosphorylate
131
what is signal transduction from the receptor to the site of action in a cell mediated by
small signalling molecules called second messengers
132
what are examples of second messengers
- cAMP
- IP3
- diacylglycerol
133
what does IP3 do
mobilise calcium from intracellular stores
134
when are G proteins active
when GTP bound
135
when are G protein inactive
when GDP bound
136
what does kinase do
phosphorylates
137
what does phosphatase do
de-phosphorylate
138
what does somatic mutation in BRAF cause
malignant melanoma
139
what is mutation in malignant melanoma
V600E
140
what is each strand of DNA made up of
- deoxyribose-phosphate backbone
- adenine
- thymine
- guanine
- cytosine
141
how are the 2 strands of DNA held together
hydrogen bonds between the bases
142
what is DNA wrapped around
histone proteins
143
what does DNA wrapped around histone form
nucloeosomes
144
how is RNA transcribed
from DNA
145
what does helicase do
unwind double helix
146
how is DNA synthesised
in 5' to 3' direction
147
are introns coding regions
no
148
what are the phases of cell cycle
G1
S
G2
M
149
how long does it take to complete a cycle
20-24 hours
150
what are the phases of mitosis
- prophase
- metaphase
- anaphase
- telophase
151
when is p53
between G1 and S
152
what are main components of DNA replication
- DNA helicase
- DNA primase
- DNA polymerase
- DNA binding proteins
153
how does DNA helicase work
hydrolyses ATP to unwind the double helix
154
how to DNA strands pair up
antiparallel fashion
155
what is the leading strand
3-->5
156
what does DNA primase do
synthesise a short RNA molecule which acts as a primer
157
what does DNA polymerase do
extends the primer by adding nucleotides to 3' end
158
what are the little bits of DNA on the lagging strand called
Okazaki fragments
159
what does DNA ligase do
join the two DNA fragments together
| Okazaki fragments
160
what is prophase
centrosome forms
| at the end the nuclear membrane breaks down and spindle attach
161
what is metaphase
chromosomes are aligned
162
what is anaphase
cohesin breaks down and sister chromatids are pulled in opposite directions
163
what is telophase
new membrane forms around the daughter cells
164
where are most of the cells during cell cycle
in G0
165
what does cyclin E activated
CDK 2
166
what does cyclin D activate
CDK4
167
what does CDK 4 activate
Rb
168
what does Rb release
transcription factor E2F
169
what does cyclin B activate
CDK 1
170
what is mature mRNA transported through
the nuclear pore into the cytoplasm
171
what is mRNA translated into
ribosomes
172
where are ribosomes formed
in nucleolus
173
what is primary protein structure
sequence of amino acids
174
examples of secondary protein structure
- alpha helice s
- beta strand
- triple helix
175
what is tertiary proteins structure
3D arrangement
176
what is folding of polypeptides facilitated by
molecular chaperones
| e.g. heat shock protein
