Chromosome Stuff
What is the ploidy & DNA content in metaphase of mitosis?
Diploid (2n), 4C.
Name three types of cell-to-cell signaling
Endocrine, Paracrine, Autocrine
What is rigor mortis, and what causes it?
Ca²⁺ influx → crossbridges form, lack of ATP prevents detachment.
Name the 5 radiographic densities on X-ray, black → white.
Air, fat, water/soft tissue, bone, metal.
Where are preganglionic sympathetic neuron cell bodies located?
Intermediolateral cell column, T1–L2.
In oogenesis, primary oocytes remain arrested in which stage until puberty?
Dictyotene of prophase I.
What causes B thalassemia?
Splicing errors that alter the B subunit of hemoglobin distrupting the quaternary structure
Where does the brachial plexus and subclavian artery and vein exit the neck?
Define orthostatic hypotension.
Drop in systolic ≥20 mmHg on standing.
What are 4 classic signs of Horner’s syndrome?
Ptosis, miosis, anhidrosis, vasodilation.
Which three mechanisms introduce genetic variability in gametogenesis?
Crossing over, random segregation, gamete selection.
Distinguish between the 3 methods of exocrine glandular secretion. Provide examples of each
merocrine: secretion is exocytosed (protein component of breast glands)
Apocrine: the top part of the cell is lost with the secretion (lipid component of breast gland)
Holocrine: whole cell is sacrificed with the secretion produced (ex. Sebaceous glands)
Compare skeletal muscle, cardiac muscle, and smooth muscle t Tubules.
Skeletal -triad
cardiac - diad
smooth - none
Which imaging modalities use no ionizing radiation, and one limitation?
Ultrasound; poor penetration through bone/gas.
MRI; loud and long and have to stay still
Describe the structure of the enteric nervous system, including its major plexi and the effect of the parasympathetic and sympathetic innervation on it?
Layers:
Myenteric plexus (Auerbach’s): Between longitudinal & circular muscle layers; controls motility (peristalsis, muscle tone).
Submucosal plexus (Meissner’s): In submucosa; regulates secretion, absorption, and blood flow.
Innervation:
Parasympathetic (vagus & pelvic splanchnic nerves): ↑ motility & secretion.
Sympathetic (thoracolumbar): ↓ motility & secretion, contracts sphincters.
Balanced pericentric inversion carriers are phenotypically normal. What is a pericentric inversion and why are miscarriages common?
A pericentric inversion is a chromosomal rearrangement in which a segment that includes the centromere is reversed 180° after two breaks, involving both arms of the chromosome.
Crossover → gametes with duplications/deletions.
Which DNA repair pathway fixes DNA damage from sunlight, and what syndrome results if defective? (and what is the damage)
Nucleotide excision repair of thymidine dimers; Xeroderma pigmentosum.
Name the branches of the external carotid artery (6)
superior thyroid, lingual, facial, ascending pharyngeal, occipital, posterior auricular
Korotkoff sounds disappear, reappear, then vanish again. Name this phenomenon.
Auscultatory gap.
Which motor, sensory, and Rami are segmentally distributed?
Sensory: The afferent (sensory) fibers are distributed segmentally. The dermatome map represents this sensory distribution.
Motor: Segmental organization is found in motor fibers running with the intercostal nerves (T1–T11).
Dorsal Rami: All dorsal rami (which are mixed nerves) are distributed segmentally.
A Down syndrome patient has a Robertsonian translocation. Provide his cytogenetic notation.
46,XX,rob(14;21)(q10;q10),+21.
(14 could be any of the Afrocentric chromosomes 13, 14, 15, 22)
What are two kinds of activated macrophages, two pathways of activation, and the ideal function of the cells coming from each activation pathway?
Activated Macrophages: present in inflammation, causing morphological variants of activated macrophages:
Histiocytic giant cells: fusion of activated macrophages
Epithelioid cells: a lot of cytoplasm, looks like epithelium
Two pathways of activation:
Classical activation (m1): activated by interferon-y - Good pathogen killers
Alternative activation (m2): activated by interleukins (IL-4/IL-13) - Secrete growth factors, help with tissue repair
What are the contents of carotid triangle? Namely the arteries and
Nerves
- vagus, hypoglossal, ansa cervicales, accessory
Define pulse pressure. Describe an underlying mechanism leading to a wide pulse pressure, and a mechanism leading to a narrow pulse pressure.
Pulse pressure is the difference between the systolic and diastolic blood pressure (BPsys-BPdias).
Wide pulse pressure: >60mmgHg → caused by HTN, High cardiac output states (anemic, high thyroid), chronic aortic valve regurgitation (causes high stroke volume because blood filling the LV from the aorta → increase in amount sitting in the LV. meanwhile diastolic is dropping). Wide pulse pressure is a predictor of cardiovascular events.
Narrow pulse pressure: <30mmHg. Usually due to low systolic BP. (Examples include, valvular aortic stenosis and left ventricular contractile dysfunction). In response, sympathetic hormones and angiotensin II are released causing arteriole vasoconstriction and increased systemic vascular resistance, increasing the diastolic BP narrowing the difference between systolic and diastolic.
What are the subdivisions of the nervous system based on development, and what adult structures do they develop into?
Forebrain (prosencephalon)
Telencephalon - cerebral hemispheres and L&R lateral ventricles
Diencephalon - 3rd ventricle
Midbrain (Mesencephalon)
Mesencephalon - midbrain containing the cerebral aqueduct
Hindbrain (Rhombocephalon)
Metencephalon - pons & cerebellum - contains 4th ventricle
Myelencephalon - medulla oblongata - contains 4th ventricle