uWorld 10 Flashcards
what cells can act as the regenerative source of ciliated cells in the bronchioles
club (clara) cells- conciliated, secretory cells found predominantly in the terminal portions of the bronchioles
what dermatome innervates the anus, which one does the perianal region
pudendal nerve (S2-S4)
anus- S5
perianal region- S4
(anus looks like target of dermatomes with S5 as bullseye going out to L5 at the lateral thigh)
where does the spinal cord end in an adult and what happens if image occurs here
conus medullaris at approx L2 level
conus medullar is syndrome referes to legions at L2-
flaccid paralysis of the bladder and rectum, impotence and saddle (S3-S5 roots) anesthesia
mild weakness of the leg muscle if the lesion spares both the lumbar cord and adjacent spinal and lumbar nerve roots
common causes: disk herniation, tumors, spinal fractures
what is cauda equina syndrome
typically results from massive eruption of an intervertebral disk that is capable of causing compression of two or more of the 18 spinal nerve roots of the cauda equina
can also occur due to train or space-occupyin lesion of the lower vertebral column
symptoms:
low back pain radiating to one or both legs
saddle anesthesia (S3-S5 roots)
LOSS of ANOCUTANEOUS REFLEX (S3-S4)
bowel and bladder dysfunction (S3-S5 roots)
loss of ankle-jerk reflex with plantar flexion weakness of the feet
what is observer bias
investigators decision is affected by prior knowledge of the exposure status
fibroblasts begin synthesizing polypeptide chains that assemble into TRIPLE HELICAL STRUCTURES, followed by fibrils
fibrillar proteins hydrolyzed and separated into constituent amino acids, what amino acid is found in highest quantities in these proteins
GLYCINE
collagen is the most abundant protein in the human body and is synthesized by fibroblasts, osteoblasts, and chondroblasts
collagen is made up of 3 polypeptide ALPHA CHAINS held together by hydrogen bonds, forming a role-like TRIPLE HELIX (collagen molecule)
collagen molecules self-assemble into fibrils, which subsequently crosslink to form collagen fibers
GLY-X-Y IS THE STRUCTURE OF COLLAGEN thus GLYCINE is 33% of the amino acids not matter what
(proline residues are essential for alpha helix formation because there ring configuration
hydroxylysine is necessary for cross linking- which greatly increases tensile strength of assembled collagen fivers)
what causes photoaging of the skin
UVA which can penetrate deeper into the skin producing reactive oxygen species- activating multiple inflammatory cell-surface receptors and nuclear transcription factors
leads to DECREASED COLLAGEN FIBRIL PRODUCTION, and upregulatin of matrix metalloproteinases (collagenases) that degrade type I and III collagen and elastin
what is seen histologically in photoaging
THINNING OF EPIDERMIS
reduction in subcutaneous fat, blood vessels, hair follicles, sweat ducts, sebaceous glands
rete ridges at dermoepidermal junctions become flattened
loss of subcutaneous tissue causes the skin to become atrophic and more vulnerable to damage
what causes wrinkling of photo aged skin
INCREASED CROSSLINKING of collagen, along with desiccation of the stratum corneum,produces the charactpericic drinking of photo ages skin
what is adjustment disorder
increased anxiety, depression, or disturbed behavior that develops WITHIN 3 MONTHS of an IDENTIFIABLE STRESSOR and lasts NO MORE than 6 MONTHS after the STRESSOR ENDS
what is myoglobin and what does its oxygen dissociation curve look like
MONOMERIC protein and the primary oxygen storing protein in the skeletal and cardiac muscle tissue
only found in bloodstream after muscle injury
myoglobin curve is shifted ALL THE WAY TO THE LEFT and is HYPERBOLIC
where in the cell is Vitamin C active during collagen synthesis
ROUGH ENDOPLASMIC RETICULUM
collagen alpha-chains are synthesized by the RER ribosomes and directed to the cisternal of the RER where PROLINE and LYSINE resides are prosy-translationally HYDROXYLATED to hydroxyproline and hydroxylysine by lysyl hydrolyze- VITAMIN C is REQUIRED for this
pt with progressive lethargy w/ loss of appetite, constipation, muscle weakness, and increased thirst and urination for 3 wks
takes lots of vitamins and minerals for health
stuporous and has dry mucous membranes on exam
whats going on, what other condition do you see this metabolic abnormality
HYPERCALEMIA from taking VITAMIN D supplements
impaired depolarization of neuromuscular membranes (muscle weakness, constipation, mental status changes)
impaired concentration of urine (polyuria/dipsia)
bone pain from bone demineralization
hyervitaminosis D is also seen in GRANULOMATOUS disease (sarcoidosis, TB) b/c activated macrophages express 1-alpha hydroxylase)
glucagon works by stimulating what in what organ
Gs in HEPATOCYTES increasing GLYCOGENOLYSIS (breakdown of glycogen) and GLUCONEOGENESIS (production of glucose from noncarb sources glucagon-induced glycogenolyiss is the predominant initial means of rapidly increasing blood glucose levels during hypoglycemia
what enzymes does glucagon stimulate
activation of key glycogenolytic enzyme- GLYCOGEN PHOSPHORYLASE
stimulates gluconeogeneiss by activating- pyruvate carboxylase, phosphoenolpyruvate carboxykinase
decreased intracellular fructose-2,6-bisphosphate levels (inhibiting glycolysis)
