basics mbbs

1. Prefrontal cortex

↓

2. Motor cortex

↓

3. Corticospinal tract

↓

4. Anterior horn cell (LMN)

↓

5. Peripheral nerve

↓

6. Neuromuscular junction

↓

7. Muscle

Ascending highway

Receptor

↓

Sensory nerve

↓

Spinal cord

↓

Brain

Decision

↓

Motor cortex

↓

Basal ganglia

↓

Cerebellum

↓

Corticospinal tract

↓

Anterior horn

↓

Peripheral nerve

↓

Acetylcholine

↓

Muscle contraction

↓

Muscle spindle

↓

Golgi tendon organ

↓

Brain

Anterior horn

↓

Peripheral nerve

↓

Neuromuscular junction

↓

Acetylcholine

↓

Muscle membrane

↓

Action Potential

↓

Sarcoplasmic Reticulum

↓

Calcium release

↓

Actin + Myosin

↓

Contraction

👉 Prefrontal Cortex

Ye CEO hai.

Iska kaam:

Decision.

Planning.

Thinking.

Step 2

CEO bolta hai

Haath uthao.

Lekin CEO ko pata hai kaunsa muscle?

❌ Nahi.

Toh signal gaya

↓

Motor Cortex.

Step 3

Motor Cortex

Imagine Google Maps.

Uske paas poori body ka map hai.

Step 4

Basal Ganglia

Basal ganglia body ka quality control manager hai.

Ye check karta hai

Extra movement to nahi?

Galat movement to nahi?

Isliye Parkinson me movement slow ho jata hai.Phir yea brain sei puchega movement kru ya nahi

Step 5

Cerebellum

Ye body ka

Auto Correct.

Ye continuously bolta hai

Balance maintain karo.

Target miss mat karo.

Isliye cerebellum disease me patient finger-nose test fail karta hai

Weakness

↓

1. Distribution?

↓

2. Tone?

↓

3. Reflex?

↓

4. Babinski?

↓

5. Wasting?

↓

6. Fasciculations?

↓

7. Sensation?

↓

8. Pain?

↓

9. Cranial nerves?

↓

10. Higher functions?

↓

LOCALIZE THE LESION

Brain?

↓

Motor cortex?

↓

Internal capsule?

↓

Brainstem?

↓

Spinal cord?

↓

Anterior horn cell?

↓

Root?

↓

Plexus?

↓

Peripheral nerve?

↓

Neuromuscular junction?

↓

Muscle?

Scenario	Answer
Adult bacterial meningitis	Streptococcus pneumoniae
Hostel + petechial rash	Neisseria meningitidis
Neonate	GBS + E. coli + Listeria
Elderly / Pregnancy	Add ampicillin for Listeria
HIV + meningitis	Cryptococcus neoformans
Viral CSF	Lymphocytes + normal glucose
Bacterial CSF	Neutrophils + ↓ glucose + ↑ protein
TB CSF	Lymphocytes + ↓ glucose + cobweb clot
Gold standard	CSF culture
Best test for viral meningitis	CSF PCR
Most common neurological sequel	Sensorineural hearing loss
Most dangerous error	Delaying empiric antibiotics

Situation	Think First
Neonate	GBS + E. coli + Listeria
Hostel + petechiae	Neisseria meningitidis
Adult	Streptococcus pneumoniae
Elderly	Add Listeria coverage (Ampicillin)
HIV	Cryptococcus neoformans
Viral meningitis	Enterovirus
CSF neutrophils + ↓ glucose	Bacterial
CSF lymphocytes + normal glucose	Viral
CSF lymphocytes + ↓ glucose + cobweb clot	TB
Gram-positive lancet diplococci	Streptococcus pneumoniae
Gram-negative kidney-shaped diplococci	Neisseria meningitidis
India ink positive	Cryptococcus
Hearing loss	Most common neurological sequela
Don’t delay antibiotics	Even if CT/LP is pending
Dexamethasone	Before or with first antibiotic dose

Most common adult bacterial meningitis	Streptococcus pneumoniae
Hostel + petechiae	Neisseria meningitidis
Neonate	GBS, E. coli, Listeria
Elderly	Add Listeria coverage (Ampicillin)
HIV	Cryptococcus neoformans
Viral meningitis	Enterovirus
Viral CSF	Lymphocytes + normal glucose
Bacterial CSF	Neutrophils + ↓ glucose + ↑ protein
TB CSF	Lymphocytes + ↓ glucose + cobweb clot
First investigation	Blood cultures (without delaying therapy)
Confirmatory test	CSF analysis
CT before LP	Papilledema, focal deficits, seizure, immunocompromised, markedly altered consciousness
Steroid timing	Before or with first antibiotic
Worst mistake	Delay antibiotics

Top 20 FMGE One-Liners

1. Most common adult bacterial meningitis → Streptococcus pneumoniae

2. Most common viral meningitis → Enteroviruses

3. Hostel + petechial rash → Neisseria meningitidis

4. Neonate → GBS, E. coli, Listeria

5. Elderly/pregnant/immunocompromised → Add ampicillin (Listeria coverage)

6. Most common fungal meningitis in HIV → Cryptococcus neoformans

7. First-line test (if safe) → Lumbar puncture with CSF analysis

8. Gold standard → CSF culture (for bacterial diagnosis)

9. Best test for viral meningitis → CSF PCR

10. CSF bacterial → Neutrophils, ↓ glucose, ↑ protein

11. CSF viral → Lymphocytes, normal glucose

12. CSF TB → Lymphocytes, ↓ glucose, ↑ protein, cobweb clot

13. CT before LP → Papilledema, focal deficits, recent seizure, immunocompromised, suspected mass lesion

14. Do not delay empiric antibiotics in suspected bacterial meningitis

15. Dexamethasone → Before or with first antibiotic dose

16. Most common neurological sequela → Sensorineural hearing loss

17. Waterhouse–Friderichsen syndrome → Meningococcemia

18. India ink positive → Cryptococcus

19. Gram-positive lancet diplococci → Streptococcus pneumoniae

20. Gram-negative kidney-shaped diplococci → Neisseria meningitidis

HEART ATTACK

Coronary artery occlusion

↓

O₂ ↓

↓

Oxidative phosphorylation ↓

↓

ATP ↓

↓

Na⁺/K⁺ ATPase failure

↓

Na⁺ ↑ inside

↓

Water ↑

↓

Hydropic swelling

↓

Reversible injury

↓

Persistent ischemia

↓

Necrosis

Parallel pathway

O₂ ↓

↓

Anaerobic glycolysis

↓

2 ATP + Lactic acid

↓

Adenosine + Bradykinin

↓

Pain nerve endings

↓

Chest pain

DEJERINE (MEDIAL MEDULLARY) SYNDROME

Artery:

• Anterior spinal artery

Structures:

• Pyramid

• Medial lemniscus

• Hypoglossal nerve

Clinical:

• Contralateral UMN weakness

• Contralateral vibration/proprioception loss

• Ipsilateral tongue paralysis

• Tongue deviates toward lesion

• Pain & temperature preserved

IOC:

MRI brain (DWI)

WALLENBERG

Artery:

PICA ⭐

Structures:

Nucleus ambiguus

Vestibular nuclei

Inferior cerebellar peduncle

Spinothalamic tract

Spinal trigeminal nucleus

Sympathetic fibers

Clinical:

Ipsilateral:

• Facial pain loss

• Horner syndrome

• Ataxia

• Dysphagia

• Hoarseness

• ↓ Gag reflex

Contralateral:

• Pain & temperature loss (body)

No UMN weakness

IOC:

MRI DWI