precomp 2a for comp 2: Weeks 7 and 8

What abnormalities can G-banded karyotyping detect?

Aneuploidies (trisomies, Turner), large structural changes, deletions, and anomalies such as the Philadelphia chromosome in CML

The ovarian ligament doesn’t have

Any major blood vessels

Anterograde means

Away from the nucleus

Retrograde means

Towards the nucleus

What is the gold standard for identifying both known and unknown mutations?

Sanger sequencing

What is a key difference between RT-PCR and qPCR?

RT-PCR = reverse transcription of mRNA to cDNA

qPCR = quantifies amplified DNA in real time via fluorescence

What does flow cytometry measure?

• Cell size, granularity

• Protein expression (surface or intracellular) via fluorescence-labeled antibodies

What is ELISA used for?

• Hormones (e.g., HCG, TSH)

• Viral/bacterial antigens

• Antibodies post-vaccination or infection

Southern blot: When is it used?

• Large deletions/duplications

• Triplet repeat expansions (Fragile X, myotonic dystrophy)

• Methylation (Prader-Willi/Angelman)

Which blot detects DNA-binding proteins?

Southwestern blot

What’s the difference between gene knockout and knockin?

• Knockout: Delete a gene

• Knockin: Insert a gene or variant at a specific location

What does real-time quantitative PCR (qPCR) measure during each cycle of DNA amplification?

Fluorescence emitted by probes or dyes to quantify DNA amplification in real time.

Uses: Residual disease (leukemia), viral loads (HIV, EBV, H1N1), antibiotic resistance (MRSA), COVID-19 detection.

What is digital PCR (dPCR) best used for in clinical applications?

Detection of rare alleles and low-level variants (e.g., in hematologic malignancies or transplant monitoring). It partitions DNA into many reactions for precise quantification.

How does flow cytometry work and what does it detect?

Measures cell size, granularity, and surface/intracellular protein expression using fluorescent-tagged antibodies.

Uses:

– CD4+ T-cell counts in HIV

– Leukemia phenotyping

– HSC validation pre-transplant

– Transplant rejection vs infection

– Contamination in transfusions

What distinguishes ELISA from flow cytometry in diagnostic use?

ELISA detects soluble antigens or antibodies in fluids (e.g., serum, plasma).

Uses:

– Hormones (HCG, TSH)

– Viral/bacterial antigens

– Antibodies from infection or vaccination (COVID-19, Hep B, HIV)

Which test uses fluorescent dyes hybridized to exon arrays to analyze mRNA expression levels?

DNA Microarray – detects mRNA expression by converting mRNA to cDNA, labeling it, and hybridizing to gene-specific chips.

Use: Gene expression profiling, SNP detection, genotyping.

Which method separates DNA by size and detects large deletions or triplet expansions?

Southern blotting

Applications: Fragile X, Friedreich ataxia, Prader-Willi/Angelman, HER2+ breast cancer, malaria detection.

Limitation: Time-intensive and requires large DNA quantities.

Where do pelvic splanchnic nerves synapse?

In the organ wall or in minute pelvic ganglia near the organ

Where do sympathetic fibers to the ovaries or testes synapse?

Ganglia near the ovarian or testicular artery

Do pelvic splanchnic nerves synapse in the sympathetic chain?

No — they are parasympathetic and bypass the chain

Array CGH only works on

Non-dividing cells

aCGH can detect

Microdeletions and duplications, but not balanced translations

Where do sympathetic preganglionic neurons to the midgut synapse?

In the superior mesenteric ganglia (prevertebral ganglia)

Where do sympathetic preganglionic neurons to the hindgut synapse?

In the inferior mesenteric ganglia (prevertebral ganglia)

Where do sympathetic preganglionic neurons to the ovaries or testes synapse?

In ganglia near the ovarian or testicular arteries (preaortic ganglia)

Where do vagus nerve (CN X) parasympathetic preganglionic fibers synapse?

In the walls of foregut and midgut organs

Sympathetic innervation of the midgut: spinal level, ganglia, and artery?

• T9–T12

• Superior mesenteric ganglion

• Superior mesenteric artery

Sympathetic innervation of the hindgut: spinal level, ganglia, and artery?

• T12–L2

• Inferior mesenteric ganglion

• Inferior mesenteric artery

Troponin C is found in

Skeletal and cardiac contraction

Smooth muscle calcium receptor and activates MLCK

Calmodulin

“Anchoring tropomyosin”

Troponin T

“Inhibits contraction”

Troponin I

A histology slide of articular cartilage shows large proteoglycan aggregates that provide compressive strength by trapping water molecules.

Which molecule is primarily responsible for this function?

Aggrecan

_____ forms reticular fibers that normally support soft tissues such as the liver, spleen, bone marrow, and lymph nodes.

Type 3

“contains common bile duct and duodenum”

Hepatoduodenal ligament

What are the contents of the hepatoduodenal ligament?

• Common bile duct

• Proper hepatic artery

• Portal vein

What are the foregut derivatives?

Esophagus, stomach, proximal duodenum, liver, gallbladder, pancreas, spleen (embryologically mesodermal but shares blood supply)

What is the gastroesophageal junction?

The anatomical transition from the esophagus to the stomach’s cardia

What structures are derived from the midgut?

• Distal duodenum

• Jejunum

• Ileum

• Cecum

• Appendix

• Ascending colon

• Proximal 2/3 of transverse colon

Decorin

A small proteoglycan that binds to collagen fibrils and regulates fibrillogenesis.

“Helps maintain glomerular charge selectivity” “in basement membrane”

Decorin

“Regulates the breakdown of MMPs”

Tissue inhibitors of metalloproteinases

“ Sparse fibers, abundant ground substance” and “diffusion of nutrients” is a tip-off for

Loose (areolar) connective tissue

“Stains silver” is a tip-off for

Reticular fibers found in type 3 collagen

Type V collagen

fibrillar collagen + integrin-binding globular domain → vascular smooth-muscle regulation.

Fibronectin

glycoprotein bridging cells and ECM in wound healing.

Decorin ➡

Diameter

Perlecan ➡

Permeability

“Looks like IV, but is fibrillar + binds integrins“

Type 5 collagen

B cells produce

Antibodies

Antigen presentation is gone by

Dendritic cell/macrophages/ B cells

To prevent uncontrolled tearing, the physician performs a mediolateral episiotomy. Compared to a midline incision, what is the main advantage of the mediolateral approach?

It avoids injury to the external anal sphincter

The _______ forms the roof of the perineum and the floor of the pelvic cavity.

pelvic diaphragm

______ link keratin IFs between cells

Desmosomes

“Mesh-like network” is a tip-off off for

Reticular fibers in type 3 collagen

which type of myosin is responsible for contraction

Myosin 2

Myosin 1 and 5 are responsible for

vesicle/organelle transport along actin

“550-850” and “subtle rearrangement” are terms associated with

High-resolution banding

If you want to look for a known abnormal sequence or microdeletion in dividing cells, use

FISH (Metaphase)

If you are looking for weird and complex chromosomal rearrangements where you don’t know the origin, use

Spectral karyotyping

EDS affects which type of collagen

3 and 5

Procollagen N-proteinase is affected in

EDS

“Neonatal blistering” is a tip off for

Junctional epidermolysis bullosa

Function of Hyaluronic Acid

Lubrication and shock absorption

Does Alpert Syndrome affect the eyes?

Yes— “ocular abnormalities with the lens/iris”

“Duodenum trapped behind the SMA” is a tip off term for

SMA syndrome

“Short vasa recta and many arcades” is a tip-off term for

Ileum

The appendix is supplied by the

Ileocolic artery

The cecum is supplied by the

Ileocolic artery

The proximal 2/3 of the transverse colon is supplied by the

Middle colic artery

The descending colon is supplied by

The left colic artery

A hydrocele is caused by

The tunica vaginalis not being closed

The Vasectomy is cut in a

Ductus deferens

“Broad ligament, around the uterine tube” is a tip-off term for

Mesosalpinx

Why are women more predisposed to UTIs

Shorter urethras

In micturition, ____ is the parasympathetic step

Detrusor contraction

The internal sphincter is ______ in micturition

Sympathetically controlled

“Connected by canaliculi” is a tip-off for

An osteocyte

“Ruffled border”

Osteoclast

What is responsible for sarcolemma stability?

Dystrophin

What cross-links actin

Filamen

“Uncaps barbed ends” and “platelet activation”

Gelsolin

Vimentin is found in

Mesenchyme intermediate filaments

Direct branches from the inferior mesenteric artery

Left colic

Sigmoid arteries

Superior rectal artery

Intercalated discs are in

Cardiac muscle

MG affects the ____ receptors

Post synaptic

The superior gluteal artery passes between the lumbosacral trunk and ______

S1 nerve root

Colchicine and vincristine disrupt _____, not actin

microtubules

Kinesin →

Anterograde

Dynein →

Retrograde

Paclitaxel (Taxol) MOA

stabilizes microtubules, preventing breakdown

Vincristine / vinblastine MOA

bind β-tubulin → prevent polymerization → mitotic arrest in metaphase.

A defect in Hydroxylation of proline residues by prolyl hydroxylase leads to

Osteogenesis imperfecta

The male equivalent of the uterine artery

Inferior vesicle artery

ECM → receptor “middleman” for growth factors.

Syndecan

“Fast oxidative, red, intermediate, fatigue resistant “

Type IIa

“Fast glycolytic, white, few mitochondria and fatigue quickly”

Type IIb