Rifampin (Rifadin®) is effective in treating active tuberculosis because it targets which of the following pathways?
- administered several months w/out a break w/ other drugs to prevent resistance
- used along w/ isoniazid, ethambutol, pyrazinamide, streptomycin
A patient bites down rapidly on an unexpected hard surface while chewing. Cessation of motor unit recruitment in jaw closing muscles is caused by stimulation of
C) periodontal mechanoreceptors
In hydrocephalus, excess cerebral spinal fluid is found within which of the following?
- aka "water on the brain"
- abnormal accumulation of CSF in ventricles of brain
- increases intracranial pressure in skull
- enlarged head
- mental disability
Which of the following primary grooves uniting in the distal pit on the occlusal surface of the mandibular second molar represents the one that normally has no counterpart in the distal pit of the first molar?
C) DF Triangular groove
bc of the presence of the small distal cusp on the mandibular 1st molar
Which of the following conditions represents an intoxication rather than an infection?
aka botulinis intoxication
- paralytic disease caused by botulinum toxin from C. botulinum (gram + anaerobic spore forming rod)
- bacteria colonizes the GI tract, enters from wounds, or from food (esp canned food)
- babies- "floppy baby syndrome"
- toxin is killed by heat
- paralysis usually starts at face and spread to limbs; can get respiratory failure
- toxin inhibits Ach release at NMJ
Which of the following best describes the cervical margin on the facial crown surface of the maxillary first molar?
C) Irregularly convex toward apex
Which of the following teeth represents the one most likely to present with three roots?
B) Maxillary 1st premolar
- this tooth normally has 2 roots (facial and lingual)
- kidney shaped bc of the interradicular groove
A patient has an extremely wide, notched tooth in the mandibular left central incisor position. Clinical and radiographic examinations reveal 28 teeth have erupted, but four third molars have not erupted. Which of the following conditions exists?
E) Gemination- 2 crowns dev from 1 tooth bud
- share a single root and root canal--> wide, notched tooth
c) fusion- 2 tooth buds fuse; dentin is connected
d) concrescence- 2 completely separate teeth fused at cementum
Steroid-induced osteoporosis mechanisms of action:
1. directly inhibit osteoblasts
2. directly enhance bone resorption
3. inhibit GI Ca2+ absorption
4. increase urine Ca2+ loss
5. inhibit sex steroids
Most common location for atherosclerotic aneurysm?
abdominal aorta> coronary artery
Initially, the developing heart is
Cells that will form the vertebrae have their origin in which of the following?
- present in developing embryo of vertebrates
- somite= masses of mesoderm along 2 sides of neural tube
- eventually becomes:
1. vertebrae (sclerotome) and rib cartilage
2. skeletal muscle (myotome)
3. dermis (dermotome)
- specify migration paths of neural crest cells and spinal nerve axons
A 5-year-old child with vesicular lesions limited to the palate and the posterior oropharyngeal mucosa has an oral temperature of 101°F (38°C). The most probable diagnosis is
.E) herpetic gingivostomatitis.
A) herpangina- mostly in children
- painful ulcers/vesicles in posterior oral cavity and pharynx- tonsillar pillars, soft palate
- self-limited <1 week
- Coxsackie A virus
- usually children; fecal-oral
- anywhere in oral cavity; esp palate, tongue, buccal mucosa
a) recurrent oral herpes- most occur at vermillion of lips "herpes labialis", HARD PALATE
-recurrent is usually UNILATERAL
- HSV1 stays latent in trigeminal ganglion
When the mandible performs a laterotrusive movement, the laterotrusive-side condyle moves primarily about which of the following axes?
- moves down and laterally
When viewed from the sagittal plane, the axial inclination of the anterior teeth
Each of the following is attributable to hepatic failure EXCEPT one. Which one is the EXCEPTION?
C) Mallory bodies
- aka alcoholic hyaline
- inclusion found in liver cells of people suffering from alcoholic liver disease
- pink, eosinophilic
- characteristic twisted rope appearance
- most common in ALCOHOLIC HEPATITIS and ALCOHOLIC CIRRHOSIS
Between which of the following permanent teeth is the lingual embrasure smaller than the facial embrasure?
Protein and RNA synthesis occur in each of the following phases of the cell cycle EXCEPT one. Which one is the EXCEPTION?
- mitosis involves division
A patient presents with symptoms of an acute abscess on the maxillary left lateral incisor. There are no clinical signs of decay or restoration. Radiographically, which of the following will most likely be shown as the cause of the abscess?
E) Dens in dente
- outer surface of tooth folds inward
- coronal and radicular forms
- from infolding of dental papilla during tooth dev
- most common in MAX LATERAL INCISORS
- the malformation frequently results in early pulp NECROSIS
In general, enzyme-deficiency diseases are inherited by which of the following modes?
1. Fabry's- lyososome storage disease
- lack alpha-galactosidase; build up ceramides
- failure of heart
- brain problems
- renal failure
2. Hunter's- gargoylism, mental retardation, no corneal clouding (unlike hurler's)
- x-linked recessive
- Mucopolysaccharide storage disease
- deficient in L-iduronate sulfatase
- accumulation of heparan sulfate, dermatan sulfate
The bulk of a tooth consists of
Nongonococcal urethritis is often caused by microorganisms of which of the following genera?
B) Chlamydia Trachomatis (Chalmys= cloak)
- obligate intracellular organisms that cause mucosal infections; can't make own ATP
2. nongonococcal urethritis
1. Types A,B,C- chronic infection; blindness in Africa
Multiple, lytic lesions of bone characterize each of the following conditions EXCEPT one. Which is the EXCEPTION?
The human immunodeficiency virus preferentially infects which of the following cells?
Each of the following fluids is considered one that can transmit HIV EXCEPT one. Which one is the EXCEPTION?
A) Breast milk
C) Amniotic fluid
D) Helper T
If the anticodon on transfer-RNA is 5'ACG3', then which of the following is its corresponding codon on messenger-RNA?
ALWAYS WRITE IN A 5'--> 3' direction!
Which main product of protein nitrogen metabolism is found in human urine?
UREA CYCLE in liver:
- amino groups from AMMONIA and L-ASPARTATE--> urea
- urea is found in blood; excreted as urine; a little as sweat
Which of the following represents the location of the lingual height of contour on the crown of the mandibular second premolar?
Which of the following cells are the most radiosensitive?
- the least differentiated the cell, the more susceptible it is to radiation
Each of the following statements about poliovirus infections is correct EXCEPT one. Which one is the EXCEPTION?
B) "polio= gray--> spinal cord" + "itis"= inflammation
Picornavirus + strand RNA
- 3 diff types w/ diff capsid protein
- human enterovirus--> GI tract
- spread via fecal-oral route; highly contagious human-to-human contact
- 90% are asymptomatic
- if enter bloodstream--> can enter CNS= muscle weakness and flaccid paralysis
- Poliomyelitis "polio" or "infantile paralysis"
In the temporomandibular joint, a very dense collection of organized elastic fibers is found in which of the following areas of the articular disc?
Which of the following represents the mechanism of action of diphtheria toxin?
- causes PHARYNGITIS and PSEUDOMEMBRANE in throat
MOA- inhibit elongation factor 2
A stab wound creating a pneumothorax on the left side will usually result in collapse of which of the following?
Tension pneumothorax- life threatening condition that results from progressing of a simple pneumothorax--> forms one-way valve at the point of rupture so air is trapped and P is put on the lung (can't inflate completely)
- trachea moves to the unaffected side
- similar to cardiac tamponade--> differentiate the 2 w/ x-ray
Most common causes of pneumothoroax:
1. spontaneously (males w/ marfan syndrome)
2. stab wound
Plasmid-mediated antibiotic resistance has been observed in diseases caused by each of the following EXCEPT one. Which one is the EXCEPTION?
Which of the following conditions is most commonly associated with acute pancreatitis?
- autodigestion of pancreas by pancreatic enzymes
-I GET SMASHeD (causes):
IN ORDER OF MOST FREQUENT CAUSES:
6. autoimmune disease
7. scorpion sting/snake bite
9. Drugs (e.g. sulfa)
- epigastric abdominal pain radiating to back
*** ELEVATED LIPASE
- can lead to DIC
- ARDS (pancreatic enzymes ac on lungs)
- diffuse fat necrosis (lipase)
- pseudocyst formation
- hypocalcemia (Ca2_ collects in panreatic soap deposits
Chronic Pancreatitis- associated w/ ALCOHOLISM
Acute- #1 cause= GALLSTONES
Ameloblasts will not differentiate from preameloblasts unless they