cilia B Flashcards
two classes of cilia
- motile
2. sensory
most motile cilia also possess ___
sensory function
Motile cilia are required for the _____.
movement of fluid
in the respiratory, neural, and reproductive tracts
Motility is produced by _____
axonemal dynein dependent sliding motion between the doublet microtubules of the ciliary
axoneme
Motile cilia typically have a _____ arrangement
9+2 microtubule
with 9 doublet microtubules organized around a central pair of singlet microtubules.
Not all motile cilia
have the _____
central pair microtubules (e.g. Nodal Cilia possess a 9+0 arrangement but still beat).
The distinguishing factor between motile and immotile cilia is the presence of
_____
axonemal dynein arms between the doublet microtubules.
Non-motile, sensory or
primary cilia possess a _____ arrangement and lack _____
9+0 microtubule
axonemal dynein arms
why are cilia used for cell signaling?
- cilum concnetrates the signal with a high receptor surface to volume ratio
- signal is localized
- signal is polarized
- receptors are positioned away from the interfering cellular domains
- cilium can function as a mechanical detector of flow
Cilia can sense:
- physical stimuli
- light
- chemical stimuli
physical stimuli includes:
1. mechanical strainchemical stimuli (hormones, chemokines, growth factors, and morphogens) 2. temperature 3. osmolality 4. gravity
chemical stimuli includes:
- hormones
- chemokines
- growth factors
- morphogens
chemical or physical stimuli and light can produces an ____
array of downstream events including:
- cellular proliferation
- cellular motility
- polarity
- growth
- differentiation
- tissue maintenance
The ______ signaling pathway is well established to signal through cilia.
hedgehog (Hh)
Activation and repression of the target of the _____ requires cilia.
Hh paracrine signaling pathway (Gli(glioma tumor) transcriptional activator)
Additional signaling pathways, like _____ function through cilia
Wnt, PDGF, FGF
Both motile and immotile cilia are important for _____
development and tissue homeostasis.
In the case of Hh signaling, downstream targets facilitate:
- Limb formation
- Bone formation and homeostasis
- Neurogenesis
Both ciliary-based motility and signaling are required for the vast list of developmental
and tissue homeostasis functions that include:
- Tissue and cellular polarity
- Organogenesis
- Tissue patterning (neural and limb pattern)
- Bone formation
- Cell fate specification
- Eye development
- Left-right axis determination (laterality)
- Craniofacial development
- Neural tube formation
- Retinal degeneration (Degenerative)
- Tubule formation (kidneys, liver, pancreas)
- Renal cystic disease (Degenerative)
An example of the coordinated efforts of both motile and sensory cilia function during
development is the _____
ciliary node that establishes the left-right asymmetry of the body
plan (laterality)
The ciliary node is an ____
invagination of ciliated cells that forms during gastrulation on the midplate after anterior-posterior positioning is already established
Nodal cilia possess a ____ The signals are then detected by _______.
9+0 organization yet they beat in a rotary fashion (at 600 rpm!) to produce a net leftward flow of signaling molecules / morphogens.
non-motile sensory cilia that reside near the periphery of the ciliary node to
signal organogenesis
Clinical abnormalities associated with ciliopathies:
- Cystic kidneys
- Nephronophthisis
- Obesity
- Polydactyly
- Retinal degeneration
- Amnosia
- cancer/tumorogenesis
- urinary tract malformation
- cognitive impairment
- diabetes mellitus
- infertility
- occiptial meningoencephalocoel
- microphthalmia
- lung hypoplasia
- renal hypodysplasia or dysplasia
- bile duct dilation
- situs inversus
Cystic kidneys
– Multilumen formation and growth of fluid filled cysts.
Nephronophthisis
– Progressive renal damage
Polydactyly
– Postaxial polydactyly with an extra digit on the ulnar side of hand or foot.
Retinal degeneration
– Deterioration of retina
amnosia
loss of olfaction
Diabetes mellitus
– Type 2 diabetes develops from obesity
Occipital meningoencephalocele
– Neural tube defects with hernial protrusion of the brain material
Microphthalmia
– Small eye developmental disorder
lung hypoplasia
incomplete lung development
renal hypodysplasia or dyplasia
abnormal or missing kidney fornmation
bile duct dilation
progressive dilaiton of the bile duct
situs inversus
left-right laterally defects to random organ position
