Block 4 Review Flashcards
(97 cards)
1
Q
The ectoderm is the precursor for what structures?
A
nervous system and epidermis
2
Q
The precursor of gut, lung, and liver is the what?
A
endoderm
3
Q
The precursor of muscles and connective tissue is the what?
A
mesoderm
4
Q
What part of the DNA provides instructions for producing a multicellular animal?
A
non-coding regulatory DNA
5
Q
DNA contains regulatory elements that serve as binding sites for what?
A
gene regulatory proteins
6
Q
In most organisms, coding sequences in DNA are ___
A
similar
7
Q
What type of DNA sequences provide uniqueness to organism?
A
non-coding sequences
8
Q
Cells make developmental decisions long before they show any outward signs of ____
A
differentiation
9
Q
cells that are fated to develop into a specialized cell type despite changes in environment are called ____
A
determined
10
Q
cells that can change rapidly due to alterations in environment are called ____ _____
A
completely undetermined
11
Q
cells that have some attributes of a particular cell type but can change with environment are called ____
A
committed
12
Q
Most important environmental cues are signals from where?
A
neighboring cells
13
Q
Define inductive signaling
A
induction of a different developmental program in select cells in a homogeneous group leading to altered character
14
Q
Few cells closest to the source take on induced character. Why?
A
signal is limited in time and space
15
Q
What are the two types of signals in inductive signaling?
A
short range: cell-cell contacts
long range: substances that can diffuse through the extracellular medium
16
Q
A long range inductive signal that imposes a pattern on a field of cells is called what?
A
a morphogen
17
Q
morphogens exert graded effects by forming ___ of different concentrations
A
gradients
18
Q
Each concentration of morphogen can direct the target cells into a different ____ pathway
A
developmental
19
Q
What are morphogen gradients formed by? (2 things)
A
localized production of an inducer; localized production of an inhibitor
20
Q
A positive feedback system stars off ___ and ___
A
homogenous and symmetrical
21
Q
true or false?
The environment of a positive feedback system imposes weak asymmetry
A
true
22
Q
Positive feedback involving intracellular signals also make cells ___
A
polarized
23
Q
Broken asymmetry is “___ or ___” phenomenon
A
all or nothing
24
Q
true or false?
postive feedback is irreversible
A
true
25
Asymmetry is generated by ___ feedback
postive
26
What is phase 1 of neural development?
different cell types develop independently at different locations in embryo according to local program and are unconnected (genesis of neurons)
27
What is phase 2 of neural development?
axons and dendrites grow out along specific routes setting up a provisional but orderly network of connections between various parts of the system (outgrowth of axons and dendrites)
28
What is phase 3 of neural development?
continues into adult life, connections are adjusted and refined through interactions with distant regions via electric signals (refinement of synaptic connections)
29
Tip of axon/dendrite has an irregular, spiky enlargement called what?
growth cone
30
Growth cone crawls through surrounding tissue, trailing the axon or dendrite behind. One of the growth cones starts migrating fast and develops __-____ proteins which form an ___
axon-specific; axon
31
growth cone behavior is dictated by its ___ machinery?
cytoskeletal
32
growth cones throw out ___ and ___
filopodia and lamelopodia
33
Monomeric GTPases __ and ___ control the assembly/disassembly of actin filaments, which control movement of growth cone
Rho and Rac
34
growth coins exploit two major cues to find their way. What are they?
extracellular matrix environment; chemotactic factors
35
Netrin, Slit, and Semaphorin are examples of what?
chemotactic factors
| netrin is attractant; slit and semaphorin are repellents
36
axonal growth cone reach target cells, halt, communicate and make ___ with target cells
synapses
37
What regulates which growth cones synapse and where?
signals from target tissue
38
Target cell produces limited amount of ____ factors needed for survival
neurotrophic
39
Activity dependent synaptic remodeling depends on what?
electrical activity and synaptic signaling
40
"Neurons that ___ together, ___ together"
fire; wire
41
Name layer of skin:
| made of epithelial cells; forms the outer covering of skin; creates water barrier; continuously repaired and renewed
epidermis
42
name layer of skin:
| second layer; rich in collagen; provides toughness
dermis
43
name layer of skin:
| fatty subcutaneous layer
hypodermis
44
Starting from the outermost cell layer, name all of the cell layers/types
squame flaking off; keratinized squames; granular cell layer; prickle cell layers; basal cell layer; basal lamina; connective tissue of dermis
45
epidermis is a stratified layer made of ___
keratinocytes
46
the basal cell layer is attached to what?
basal lamina
47
Prickle cells have numerous desmosomes that attach tufts of ___ filaments
keratin
48
granular cells are sealed together to form what?
waterproof barrier
49
granule cell layer forms a boundary between inner metabolically active strata and outer dead epidermis. true or false?
true
50
true or false?
| outermost layer is called squame, flattened dead cells densely packed with keratin but with no organelles
true
51
are basal cells dividing cells?
yes
52
time for birth of cell in basal layer to shedding from surface is how long?
1 month
53
Stem cells provide an indefinite supply of fresh ___ cells to epidermis
differentiated
54
The following are characteristics of what:
not terminally differentiated; can divide without limit; undergo slow division; when divide, give rise to 1 cell with stem cell characteristics and the other with the ability to be differentiated
stem cells
55
True or false?
| stem cells are not tissue specific
false, they are
56
to maintain a steady pool of stem cell production, precisely ___% of daughter cells must remain as stem cells
50
57
Explain divisional asymmetry
asymmetric division may create 2 cells, one with stem cell characteristics and another with factors that give it the ability to differentiate
58
Explain environmental asymmetry
division makes 2 identical cells but environmental may influence/alter 1 cell
59
true or false?
| in regards to regulation of epidermal stem cells, contact with basal lamina controls numbers of stem cells
true
60
loss of contact with basal lamina triggers what?
terminal differentiation
61
proliferative potential directly correlates with expression of what? (helps mediate adhesion to basal lamina)
B1 subunit of integrin
62
Mixed with stem cells are other cells that divide frequently. what are these cells called?
transit amplifying cells
63
True or false?
| transit amplifying cells can divide an unlimited amount of times
false; duh. that would be cancer. divide for a limited number of times
64
The free surfaces of cilia on olfactory receptors have ___ receptor proteins
odorant
65
what type of receptors are olfactory receptors?
G protein coupled
66
Odorant receptor genes:
___ in a dog
___ in humans
1000; 350
67
Each neuron expresses only one gene, enabling the cell to respond to only one what?
class of odorant
68
____ features of the odorant recognized by the receptor
structural
69
The activation of the G protein that is coupled with the olfactory receptor leads to an influx of sodium and calcium into the the cell which generates what?
action potential that is sent to brain
70
what are the relay stations in the brain called?
glomeruli
71
where are glomeruli located?
olfactory bulbs - one on each side of the brain
72
how many glomeruli are in one bulb in a mouse brain
1800
73
individual olfactory neurons survive for how long?
only a month
74
Regeneration of olfactory receptor cells is one of the only few instances of adult ____
neurogenesis
75
Epidermal cells: A matrix of ___ and ___ made into a sheet lined with a thin membrane of silicone on the outside can form an artificial matrix
collagen and glycosaminoglycan
76
___ and ____ ___ from patient's tissue migrate towards artificial skin and reform the connective tissue underneath
fibroblasts; blood capillaries
77
What are the two places in the brain where stem cells are prevalent?
ventricles: migrate to olfactory bulb
hippocampus: involved in learning and memory
78
cultures established from dissociated brain tissue show ____ which are clusters of neural stem cells
neruorspheres
79
neurospheres produce both ___ and ___ cells
neurons and glial cells
80
neural stem cells grafted into adult brain have remarkable ability to adjust their ___ and ___ to match their location
behavior and function
81
grafted cells produce neurons that connect with host neurons and give rise to ____ that secrete ___ ____
glial cells; myelin sheath
82
Retinoid acid causes stem cells to develop into what?
adipocyte, neuron, or smooth muscle cell
83
IL-3 and IL-1 cause stem cell to develop into what?
macrophage
84
fibroblast growth factor causes stem cell to develop into what?
astrocytes and oligodendrocytes
85
The ability of a cell to give rise to all cells of an organism, including embryonic and extra embryonic tissues is called what?
totipotency
86
The ability of a cell to give rise to all cells of the embryo and subsequently adult tissues is called what?
pluripotency
87
The ability of a cell to give rise to different types of a given lineage is called what?
multipotency example: blood stem cells can become red or white
88
Founder stem cells define the size of large final structures. If the adult organ needs to be renewed, founder stem cells can divide as stem cells giving rise to one daughter stem cell and a set of cells that have a set number of what?
transit amplifying divisions
89
The immortal stand hypothesis ensures integrity of the genome because the template is never lost. true or false?
true
90
Embryonic stem cells are derived from the ___ stage of embryo
blastocyst
91
embryonic stem cells give rise to disorganized growths called ____
teratomas
92
what are some limitations of embryonic stem cell usage?
tissue rejection; genetic instability
93
IPS : inducing pluripotent stem cells involves what?
supplying transcription factors to a somatic cell to trick it into thinking its a stem cell
94
Describe somatic cell nuclear transfer
Take an egg cell and remove nucleus. Fuse it with a somatic cell. Stimulate cell division - blastocyst forms with DNA from somatic cell. Extract inner cell mass and now you have cultured pluripotent embryonic stem cells
95
a pro erythroblast contains a large ___ but loses it completely when it differentiates into a mature RBC
nucleus
96
bone marrow has capacity to become multiple tissues. true or false
true
97
Mesenchymal stem cells and adipose tissue are in bone marrow. What do they differentiate into?
not blood like hematopoietic stem cells.
MSC can become other types of tissue
