Quiz 1 Material Flashcards
Which classes of CFTR mutations involve CFTR present in the membrane, with loss of control over ion pumps?
Classes IV, VI
Which classes of CFTR proteins involve an underproduction or lack of production of CFTR?
Classes I, V
What classes of CFTR mutations involve incorrect folding or sorting of CFTR proteins?
Classes II, V
Which classes of CFTR mutations involve an inability to hydrolyze ATP?
Class III
Where are acetylcholine receptors found?
The postsynaptic membranes of neurons and muscles
Postganglionic sympathetic neurons innervating abdominopelvic organs arise where?
The preaortic ganglia
Preganglionic sympathetic neurons arise from what part of the spinal cord?
T1-L2 lateral horn gray matter
Preganglionic parasympathetic neurons in the vagus nerve arise where?
The medulla
Postganglionic parasympathetic neurons destined for abdominopelvic organs arise where?
Intramural ganglia
What are primordial germ cells (PGCs)?
cells that arise from the yolk sac which migrate into the embryo to become gametes
A teratoma is derived from what type of cell? Which germ layers can be found there?
PGCs; cells from all 3 germ layers
Where are PGCs found in a male fetus?
the seminiferous tubules
When does the first meiotic division complete in oogenesis?
puberty
What is the first step of fertilization?
capacitation of sperm
What is the second step in fertilization?
penetration of the corona radiata
What is the third step in fertilization?
penetration of the zona pellucida
What is the fourth step in fertilization?
contact of the sperm and oocyte; triggering the zona reaction
What is the fifth step in fertilization?
fusion of the sperm and oocyte
What is another name for the outer cell mass formed during morulation/gastrulation?
the trophoblast
What is another name for the inner cell mass formed during morulation/gastrulation?
the embryoblast
Is the embryoblast or the trophoblast responsible for the development of all structures seen in an adult?
the embryoblast
True/False: The embryoblast is pluripotent during the morula stage
False; it is totipotent (able to becoem embryonic, placental, or amnionic tissue)
About what day after fertliization does implantation occur?
Day 7
About what time does the amnionic cavity and bilaminar disk form?
week 2
When does gastrulation and neurulation occur?
Week 3
What is a hydatidiform mole?
A pregnancy without an embryo
What is the ploidy of a complete hydatidiform mole?
diploid (XX, XY)
How can a complete hydatidiform mole form?
dispermic fertilization OR normal fertilization followed by loss of female pronucelus and mitosis of male pronucleus
What is the ploidy of a partial hydatidiform mole?
triploid (XXX, XXY, XYY)
How does a partial hydatidiform mole form?
dispermic fertilization
What is the last structure during morulation containing totipotent cells?
the morula
About what time is a blastocyst formed during gastrulation?
about day 5
Trisomy of sex chromosomes often results in what condition?
Klinefelter’s syndrome
Monosomy (XO) manifests as what clinical condition?
Turner’s syndrome
Monosomy is often caused by what chromosomal defect?
nondisjunction in meiosis I or II
What does primary active transport require to move a particle against its concentration gradiant?
ATP
What are the two types of secondary active transport?
Transport by symporter or by antiporter
What type of junction primarily promotes cell-cell adhesion?
an adherens junction
Adherens junctions are characterized chiefly by what type of protein?
cadherin
What is the primary purpose of desmosomes?
To anchor cells to neighbors via intermediate filament cytoskeleton
What two major types of proteins compose desmosomes?
Desmoplakins (type of cadherin) and keratin
What is the function of a hemidesmosome?
To anchor the cytoskeleton of a cell to the basal lamina
What two types of protein primarily compose hemidesmosomes?
integrins and keratin
What type of protein primarily makes up gap junctions?
connexin proteins
What types of protein primarily makes up tight junctions?
claudins and occludins
What is the major difference between healing a wound by first intention and by second intention?
First intention involves healing where the edges of the wound are closely reapproximated; second intention involves tissue deposition from the bottom of the wound toward the top
What is the major difference between dense regular and irregular CT?
dense regular CT will fibers arranged in parallel, while irregular will be randomly arrayed
What four cell types are resident in CT?
macrophages, fibroblasts, mast cells, and adipocytes
What are the three most important transient cells in CT?
plasma cells, neutrophils, and lymphocytes
What are the two main places where dense regular CT is found?
tendons and ligaments
What is the main function of ground substance in CT?
Helping CT to form a viscous barrier and provide shock absorption
What are the three main cell types found in ground substance?
GAGs, Proteoglycans, and structural glycoproteins (such as fibronectin and laminin)
What type of collagen fibers form reticular fibers? Where are they found?
Type III collagen; found in extensible organs, blood vessels, and smooth muscle
What is the main function of matrix metalloproteases?
To degrade the ECM
What is the most important cytokine in the synthesis/deposition of connective tissue during remodeling?
TGF-beta
What characterizes Ehler-Danlos syndrome?
Defective collagen synthesis and processing
What are possible clinical presentations of Ehler-Danlos syndrome?
hyperextensive skin, joint hypermobility, tissue fragility, and possibly a Gorlin sign (ability to touch nose with tongue)
What is the characterization of Marfan syndrome?
An autosomal dominant disorder affecting elastin protein
What are potential CV disorders resulting from Marfan syndrome?
mitral valve prolapse, aortic aneurysm, and dissection
What are potential ocular disorders resulting from Marfan syndrome?
dislocated lenses, retinal detachments
What are common clinical signs of Marfan syndrome?
tall stature, with disproportionately long extremities, joint hypermobility, and scoliosis
What characterizes a hypertrophic scar?
collagen fibers are parallel to skin layer, and stay within wound area
What characterizes a keloid scar?
collagen fibers are random and disorganized, possibly more blood vessels, and the scar extends beyond the wound area
What is the main function of laminin in the body?
It acts a major protein constitutent of hemidesmosomes, and helps to anchor cells to the basement membrane
What neuronal cell bodies are housed in ventral horn gray matter of the spinal cord?
somatic motor neutron cell bodies
What neuronal cell bodies are housed in dorsal horn gray matter of the spinal cord?
somatic and visceral sensory neuron cell bodies
What neuronal cell bodies are housed in the lateral horn gray matter of the spinal cord?
preganglionic visceral motor neuron cell bodies
In what section of the spinal cord are lateral horns found?
the thoracic (T1-T12)
Regarding the spinal cord; what is meant by the acronym DAVE?
Dorsal Afferent; Ventral Efferent
A motor neuron destined for the body wall or limbs would exit the spinal cord through which root and ramus?
Through the ventral root and then the ventral ramus
What step of collagen synthesis is dependent on vitamin C?
the use of prolyl and lysyl hydroxylases to stabilize collagen and strengthen cross-linking
Define gastrulation
The process by which the bilaminar disc becomes trilaminar, as well as beginning of morphogenesis
The epiblast and hypoblast are derived from what structure?
the inner cell mass
The hypoblast eventually develops into what structure?
the yolk sac endoderm
the epiblast eventually develops into what structures?
the ectoderm, endoderm, and mesoderm
The primitive streak forms on what axis of the embryo?
cranial-caudal axis
the primitive pit (inside the primitive node) forms at what end of the primitive streak?
the cranial end
What is secreted by the primitive node to initiate/maintain the primitive streak?
nodal
Nodal has what role in establishing left-right asymmetry?
Nodal activates a pathway upregulating pitx2, and a master gene involved in laterality and lateral plate mesoderm
A mutation in what three primary areas will cause a laterality defect in the developing fetus?
Mutations in cilia, nodal, or pitx2
What is the pathology of primary ciliary dyskinesia?
A mutation in dynein causes defective nodal cilia rotation, causing a failure of left-right asymmetry to establish
What is the pre-chordal plate?
an area formed cranial to the notochord that is important to head organization; it is the source of important molecules like Sonic hedgehog
What is formed from paraxial head mesoderm?
head muscle and some bone
Where does cardiogenic mesoderm orginate?
the head; it proceeds cranially rostral to the neural plate
What does the paraxial mesoderm give rise to?
somites, through which sclerotomes and dermamyotomes are developed
What is formed from the intermediate mesoderm?
the urinary system and part of the genital system
What two divisions develop in the lateral plate mesoderm?
somatic and splanchnic mesoderm
What develops from somatic lateral plate mesoderm?
the inner lining of the body wall, dermis, and part of the limbs
What develops from the splanchnic lateral plate mesoderm?
coverings for visceral organs and part of wall of viscera
What occurs during neurulation?
The formation of the neural plate, followed by the neural groove, and closure of the groove to form the neural tube
What substance is secreted by ectoderm to block neural plate formation?
BMP4
How does the notochord initiate formation of the neural plate?
at gastrulation, the notochord secretes BMP4 binding molecules around the area of the neural plate
Where do neural crest cells come from?
between the roof plate of neural tube and overlying surface of ectoderm
From the 4th somite, which direction does the closure of the neural tube proceed in?
cranially and caudally
When does fusion of the neural tube begin?
About day 22
What is the primary cause of anencephaly?
failure of the cranial portion of the neural tube to close
Why is myeloschisis so severe?
It is characterized by neural tissue exposed to the outside environment
What is spina bifida with meningocele?
A neural arch defect with a cyst-like sac filled with CSF protruding through the vertebral column
What is spina bifida with myelomeningocele?
A neural arch defect with part of the spinal cord or nerve roots contained within the meningeal cyst
Most neural tube defects can be prevented with maternal intake of what substance?
folic acid (vitamin B9)
What molecules are important for positional information along the cranial-caudal axis?
Hox genes
What is contained within the ependymal layer of the neural tube?
ependymal cells, which line the brain ventricles and produce CSF
What is contained within the ventricular layer of the neural tube?
proliferating cells
What is contained within the mantle layer of the neural tube?
cells that will migrate to form GRAY matter of CNS
What is contained within the marginal layer of the neural tube?
axons of cells from the mantle layer, that will form WHITE matter of CNS
The alar and basal plates are formed from which layer of the neural tube?
the mantle layer (now called mantle zones)
The alar (roof) plate is responsible for secreting what molecules? What does it eventually develop into?
BMPs and Wnt; the dorsal horn
The basal (floor) plate is responsible for secreting what molecules? What does it eventually develop into?
Sonic hedgehog; the ventral horn
What is the effect of normal CFTR in the lumen of the sweat duct?
Cl- intake through CFTR activates ENaC to increase Na+ movement into the cells
What is the effect of normal CFTR in the airway or gut?
Cl- efflux through CFTR inhibits ENaC and limits both Na+ and H2O movement into the cells
How are dichorionic diamniotic conditions achieved for twins?
division of the morula at 3-4 days
How are monochorionic diamniotic conditions achieved for twins?
division of the zygote at the early blastocyst state (division of developing ICM only)
How are monochorionic monoamniotic conditions achieved for twins?
division of the zygote at bilaminar embryo even up to right before gastrulation
What are the functions of oligodendrocytes? Where are they found?
the maintain neurons and myelinate axons (multiple); they reside in the CNS
What are the functions of astrocytes? Where are they found?
They contain GFaP, they ensheath synapses, produce growth factors and help capillaries; they reside in the CNS
What are microglia? Where are they found?
Microglia are CNS macrophages; they can release cytokines and are used for neuronal pruning
What are Schwann (satellite) cells? Where are they found?
They myelinate neurons (just one section) and share many functions with oligodendrocytes; they are found in the PNS
What are radial glia?
cells with long radial processes that help guide developing neural cells from the ventricular zones to the mantle zones.
What composes a motor unit?
a motor neuron and all the muscle cells it stimulates
What role does a ryanidine receptor (RyR) have in skeletal muscle contraction?
Cell depolarization causes RyR to unplug causing Ca2+ efflux
What role does SERCA play in all muscles types?
SERCA is response for pumping Ca2+ back into the sarcoplasmic reticulum
What is the most common cause of Duchenne muscular dystrophy?
Mutations in dystrophin
What is the function of the dystrophin protein?
to connect skeletal muscle to to the outer membrane and displace force of contraction
What is the pathology of Lambert Eaton Syndrome?
autoantibody blockage of VGCC decreasing/blocking Ca2+ entry at presynaptic terminal, leading to little/no Ach release into cleft
What is the pathology of myasthenia gravis?
autoantibodies block/destroy Nm receptors on postsynaptic membrane
What follows troponin C binding Ca2+?
tropinin moves tropomyosin out of the way so that the myosin head can bind actin
What protein primarily makes up thick filaments in skeletal muscle?
myosin
What protein primarily makes up thin filaments in skeletal muscle?
actin
What zone/band shortens during the myosin power stroke?
the H zone
Once ATP binds the myosin head what is released?
actin
What occurs in order for the myosin head to reach the relaxed position?
hydrolysis of ATP
What is released from the myosin head in order to trigger the next power stroke?
Pi (inorganic phosphate)
What are common signs of Grave’s disease?
ptosis, heat intolerance, unintentional weight loss, tremors, enlarged thyroid
What is a common sign of iodine deficiency?
a goiter
Define pleiotropy
The ability of a single mutation to present with variable phenotypes
What is the most common genetic mutation causing sickle cell disease?
A missense mutation in beta-globin gene
What are the most common genetic causes of beta-thalassemia?
Nonsense, frameshift, or splice site mutations in beta-globin gene
What is the most common cause of caudal regression syndrome/caudal dysgenesis?
defective formation of caudal mesoderm
What are 4 common symptoms of caudal regression syndrome?
inversion and rotation of lower extremities, anomalies of lumbar/sacral vertebrae, imperforate anus, and agenesis of kidneys and UT
What is the most common cause of gastroschisis?
failure of lateral folds to migrate and fuse
What is the cause of omphalocele?
Failure of midgut viscera to return to the abdominal cavity
What is embryologic origin of a sacrococcygeal teratoma?
the primitive streak
How is Hirschprung’s disease characterized?
Failure of neuroblasts from neural crest cells to migrate to intestines to form the enteric nervous system
What protein needs to be downregulated in order to facilitate an epithelial to mesenchymal transition?
E-cadherin
What are the two steps of deposition of CT in wound healing?
1) Migration
2) Deposition
In wound healing, what cell type is seen migrating towards the clot within 24 hours?
Neutrophils
In wound healing, by day 3 most neutrophils have been replaced by what cell type?
Macrophages
In wound healing, collagen fibers are first seen in the wound as early as what day?
About day 3; collagen deposition can continue for weeks
Wound contraction, a feature of healing by second intention, is initiated by formation of a network of what cell type?
Myofibroblasts
What is the approximate wound strength of a wound healing by first intention after 1 week?
10%
What is the amount of time that it generally takes for a wound healing by first intention to reach its maximum of 70-80% wound strength?
About 3 months
Does a complete or partial hydatidiform mole present with some evidence of embryonic development, possibly including fetal blood vessels?
Does a complete or partial hydatidiform mole present with some evidence of embryonic development, possibly including fetal blood vessels?
What is the cause of caudal regression syndrome or caudal dysplasia?
Defective formation of caudal mesoderm
What is the most likely embryonic origin of a sacrococcygeal teratoma?
Primitive streak
Does skeletal or smooth muscle require phosphorylation to activate ATPase activity?
Smooth muscle
What happens in smooth muscle once calcium is released from the sarcoplasmic reticulum?
Ca2+ binds CaM -> CaM-Ca2+ activates MLCK -> MLCK phosphorylates myosin heads -> Increased myosin ATPase activity
What triggers Ca2+ storage release in smooth muscle?
Extracellular Ca2+
What is the difference in site of antibody activity in myasthenia gravis and lambert-eaton myasthenic syndrome?
