Usmle step 1 important points

U need to memorize some of the important values…like:
• Serum ca,k,cl,na,hco3,phosphorus,magnesium…anion gap,ph.
• ABGs(arterial blood gases):Po2,Pco2,O2 saturation.
• Gh,serum osmolarity,urine osmolarity.
• BUN,Uric acid,creatinine,albumin,bilirubin(direct,idirect).
• Protein in urine.
• Alt,Ast,amylase.cholestrol,glucose.
• Esr,pt,apt,fibrinogen,platelet count.
• Mch,mchc,mcv.
• Hb,retic count,hct and erythrocyte count.
Important topics:
-Opening in diaphragm.
-Respiratory capacities.
-celiac truk and branches
-type of hyaline cartilage
-cns recepters
-pharyngeal pouches,clefts
-epithelium derivatives
-skull foramina
-cytochrome inducers and inhibitors.
-heart blood supply
-page 600 azim shaikh
-dna and rna viruses
-bones of hand
-purines and pyrimidines
-ulcerative colitis and crohn’s
-tumor markers
-type of errors—biostat
-reflexes values
-age related type of meningitis
-cardiac enzymes
-carotid sheath content
-chemorecepter and baroreceptor
-hormones second messengers
-T and B cells’ CD numbers
-Amino acids derivatives
-Glycogen storage diseases
-joint classifications.
-cartilage types(hyaline,fibrocartilage,elastic
-bones classifications
-thirst is stimulated by:

  1. increased ECF osmolarity.
  2. decreaded volume of ECF.
  3. Angiotensin III

-Median nerve:
>Descends on Lateral side of axillary and brachial arteries.
>Enters palm Behind the flexor retinaculum.
>supplies most of the flexors of the forearm(arm flexors supplied by musculocutaneous nerve)
>supracondylar fracture cause median nerve injury---------apelike hand deformity

-Ulnar nerve:
>Descends on Medial side of axillary artery and brachial artery.
>passes behind Medial epicondyle of humerous.
> enters palm anterior to the flexor retinaculum.
>injury leads to claw deformity.

Radial nerve:
-Descends Infront of lateral epicondyle.
-supplies extensors of arm and forearm.
-lesion causes wrisr drop.

Axillary nerve:
-passes through Quadrangular space.
-lies against surgical neck of humerus.
-lesion wil cause paralyzed deltoid and loss of cutaneous sensation over lower 1/3 of deltoid region.

-chlorpromazine can cause parkinsonism
-parkinsonism is aggrevated by Haloperidol
-Digoxin toxicity can increase by chlorothiazide
-centraly acting antihypertensive is methyldopa
-Serotonin is secreted from carcinoid tumor which is responsible for sign and symptoms.

FOOT everters and inverters:
-tibialis anterior
-tibialis posterior

-peroneus longus,brevis and tertius

-Granulation tissue in MI appears within 9-10 days and becomes prominent within 2-3 weeks.
Conducting system blood supply:
-SA node__RCA(sometimes LCA,but mainly RCA)
-AV node__RCA
-AV bundle__RCA

ECG diagnosis of MI:
A.Anterior wall(LAD):v1-v4
1.anteroseptal__LAD (v1-v2)
2.anteriolateral__LAD or LCX(v4-v6)

B.Lateral wall(LCX)__I,aVL

C.Inferior wall(RCA)__II,III,aVF

-posterior interventricular artery accompanies middle cardiac vein
-Anterior interventricular artery is accompanied by great cardiac vein.

_heparin____monitor aptt
_warfarin___monitor pt

-on contraction of diaphragm the intrathoracic pressure decreases.

_Lateral horn is present in T1-L2
_Dorsal colums present only above T5
_Large ventral horn is present in

-Eosinophilia present in:
hodgkin lymphoma and polyarteritis nodosa.
-PGI2__by endothelial cells
-TXA2__by platelets

Blood transfusion induced electrolye embalance is as follows:
-metabolic acidosis
-left shift of oxy-hem curve

*common peroneal nerve injury__loss of everion and dorsiflexion
*Tibial nerve injury__loss of inversion and planteflexion.

-pelvic parietal peritoneum is supplied mainly by Obturater nerve.

Lymph drainage:
*labia majora and glans penis—superior inguinal L.N
*cervix—internal and external iliac L.N
*prostate__internal iliac L.N
*Urinary bladder__internal and external iliac L.N

-allantois__Urachus__median umblical ligament
-Somatotropic (acidophilic) adenoma__gigantisim
-corticotropic (basophilic) adenoma__cushing disease
-GH adenoma—acidophil
-ACTH adenoma—basophil
-TSH adenoma—basophil(chromophobe)

*in axila—cords of brachial plexus
*base of neck----roots
*posterior triangle of neck—trunk and division

*detoxification of drugs—ESR
-Boat shaped cyst—pneumocystis carnii

-Epidural __middle meningeal artery
-Subdural__superior cerebral vein

TYPHOID fever investigations:
-1st week____blood culture
-2nd week___antibody/widal
-3rd week___stool
-4th week___urine culture

-vit b12 absorbed from terminal ileum
-middle rectal artery remains in true pelvis

-renal medullary rays—collecting ducts
-Anxiolytic effect by GABA
-lipid which does not contain glycerol is sphingomyelin

-taste fibers from anterior 2/3 tongue passes thru internal capsule

-for controlling tachycardia;;
-glucose transported mainly by facilitated diffusion
-amino acids—Na cotransport

-carcinoma—thru lympatic

-night terrors happens in NON-REM
-nightmares happens in REM

-glutamate for fast pain fibers
-substance p for slow fibres

-glutamate released by rods and cons

-blood brain barriers made by astrocytes

-fungiform—salty and sweet
-foliate—sour taste
-circumvillate—bitter taste

Stretch reflex:
-Ia fibers affected

  • alpha motorneurons

Inverse muscle stretch reflex:
-Ib fibres
-gamma motorneurons
-Golgi tendon organs

-Horner’s syndrome happens if lesion above T1
-in the cerebellum…granule cells is the only excitatory neurons while all others are inhibitory

-trouble going downstairs==Trochlearnerve damage

-trigeminal neuralgia—v2+v3

-Glossopharyngeal nerve supplies carotid body and parotid gland

-loss of accommodation causd by damage to midbrain
-lesion to pretectum leads to loss of reaction to liht but intact accommodation

-liquid dysphagia is due to neuromuscular incordination
-study brain stem lesions very well…for example medial medullary syndrome…etc

-nuclei which lies beneath the fourth ventricular floor:

-spinal cord ends:
*in infants:L3
*in adults:lower border of L1

-Subarachinoid space ends at (S2-S3)
-internal capsule—projection fibres
-at the level of superior colliculus—occulomotor nerve nucleus-midbrain—red nucleus

-genu+anterior 2/3 of posterior limb-----------------àmotor
-increased plasma osmolarity stimulates osmorecepters in anterior hypothalamaus.

-intestinal cells of kajal are the pacemakers of GI smooth muscles.
-vommiting and swallowing centres is in the medulla

-most colonic water absorption occur in proximal colon
-in multiple myeloma,the alkaline phosphatase is not increases.
-tight junction in colon
-leaky junction in small intestine and gall bladder

-ABO incompatability in infants:
*O motheràA orB baby
*A motheràB or AB baby
*B motheràA or AB baby

-progesteron is reason behind increased temperature during ovulation

-Fibroadenomaànot precursor of CAàbelow 25 yr
-Fibrocystic changesàprecursor fro CAà20-50 yr

-Granulosa cell tumoràcall exner bodies
-Dysgerminomaàshriler duval bodies

–in renal failure:
*early stage—dilute urine
*late stage____concentrate urine

-fat absorption occur primarily in jejunum

-oblique fissure extends from T3—6th costal cartilage on both lungs
-groove for subclavian artery is at first rib.
-azygos vein enters thorax inlet
-right middle lobe has 2 bronchopulmonary segment
-diaghragm is not attached to T 10
-Tendon of popletial muscle is intracapsular
*flexing knee and thighàsartorius
*flexing knee and extending hipàsemitendinous
*flexing hip and extending kneeàrectus femoris

-Conus medullaris is pial extension to the coccyx
-revise muscles of laryns…narroeing,widening,tensing vocal cord…etc
-absorption of short chain FFA happens in colon
-osteosarcoma in metaphysis
-occulocardiac reflex mediated by trigeminal
-thyroid derived from endoderm
-albumin has low molecular weight and high concentration
-amoebic abcess occur in
Cecum>ascending colon>sigmoid >rectum

-somites are present in paraxial mesoderm
-strongest layer in small bowel in circular layer
-embryonic primary vesicle is mesencephalon
Lymph drainage of
-lateral handàinfraclavicular
-medial handàepitrochlear

-lateral ventricle roof formed by body of corpus callosum
-dermatome of perineal region is S3S4
-CVAàheart sounds in JVP
C wave first sound
V wave 2nd
A wave 4th

-in cell cycle:
Align 2 chromosomesàmetaphase

-noradrenaline and serotonin metabolized by MAO
-adrenaline by COMT
-liver makesàfactors 1,2,7,9,10 but not 4(calcium)
-connections of cerebulum
*cerebellum to midbrain through superior cerebellar peduncle<SCP>
*cerebellum to pons through MCP<middle>
*cerebellum to medulla through ICP<inferior>
-narcolepsyàdefect in hypothalamus
-U wave in papillary repplarization
Pt had ankle sprain:
-if pt can stand on toeàrupture of plantaris tendon
-if cannot stand on toeàrupture of achiles tendon


●Short pitch///frequency.
●Long duration ====0.14 seconds.
>>>Mitral valve=== Best heard at apex///5th
Left ics////9cm left Lateral to
>>>Tricuspid valve===== 4th left ICS near to
Sternum. (Some references say right
4th ics).
●Splitting ===mostly pathologic due to early MV valve closure due to inspiration which delays tricuspid valve closure.

● High frequency ////pitch
●Short duration (o.11–.14 second )
●Sharp sound
●Intensity///sharpness due to
Tautness of A & P valves
●Splitting===mostly physiological
Due to early Aortic valve closure.
●Aortic valve===Best heard at right 2nd ics.
●pulmonary valve===Best heard at left 2nd ics.

●Normal in children, Adolescent, pregnancy
●Abnormal in adults= IHD (MR,TR=== pansystolic murmur ))))

●By atrial contraction against hypertrophic left ventricle in HCM.
● Coincides with A wave of jvp///P wave of Ecg.
●Abnormal mostly
●can’t be heart in AF.
“Storage of different blood products”!
Whole blood is stored at 4° C for 3 weeks.
Packed cells (RBCs) are stored at 1-6° C for 35 days.
FFP (fresh frozen plasma) and cryoprecipitate can be stored at -40° C for 2 years.
Platelets are stored at 22° C for 5 days.