Tag: PGI Exam

Cervical incompetence

Cervical incompetence

→ M/C cause of 2nd trimester loss

→ Painless, sudden dilatation of internal OS

→ Sudden rupture of membrane & expulsion of fetus.




→ Forcible Dilatation of cervix

→ Cervix Surgery

Cerebral blood supply

Cerebral blood supply

Normal Cerebral Blood Flow = 750 mL/min (Or) 55 mL/100g/min

Note: Flow is ½ of liver blood flow

Brain O2 consumption = 46 mL/min (20% total body O2 consumption)

→ Blood supply in Grey matter > White matter.

→ Brain HIGHLY SENSITIVE to HYPOXIA, Hippocampus is the most sensitive.

Munro Kellie Doctrine:

At any point of time, “Volume of CSF, Blood, Brain Tissue” SHOULD BE CONSTANT.

Significance: On alterations of any one value  Compresses the other two values.

Ex. ↑ CSF pressure  Compress Brain tissue & Blood flow.

Regulation of cerebral blood flow

Regulation of cerebral blood flow

Major Regulating factors – Blood pressure, PCO2 & Temperature.

The mechanism involved in each one of the factors are:

1.Blood pressure Fluctuation Bt. 65 – 140 mm Hg NO CHANGE in blood flow


2. PCO2

↑ PCO2 -↑ Blood Flow

3. Temperature

On ↓ Body Temp. by 1° C -↓ cerebral flow by 7% – INDUCED HYPOTHERMIA in

neurosurgical procedures – Minimizes blood loss

Indications for cerclage

Indications for cerclage

1. History based indication-

→ RPL of 2nd trimester (≥2)

→ H/O PTL (Preterm Labor)

2. USG based indication

→ Length of cervix < 2.5cm + pt. giving H/O ≥ 1 second trimester abortion

3. Emergency Cerclage/ Rescue Cerclage

→ Cervix has begun dilating then do cervical cerclage. In this remember: –

  1. Dilation of cervix <4cm

Contraindications for cerclage

Contraindications for cerclage

→ Cervical dilatation ≥ 4 cm

→ Ruptured membranes

→ Presence of gross anomaly of fetus

→ Vaginal bleeding Present

→ Pelvic infection +nt.

→ Placenta Previa- relative contraindication


Cells of CNS

The cells present in CNS are:

  • Neurons
  • Glial cells
  • 1.Neurons:
  • Neurons are-
  • Unipolar-Seen in invertebrates
  • Pseudo unipolar-Seen in dorsal root ganglion
  • Bipolar-Seen in Retina & nose
  • Multipolar-Seen in Spinal motor neurons
  • 2.Glial cells:
  • They are-
  • Macroglial cells-Astrocyte, Oligodendrocyte, Schwann cell
  • Microglial cells-Phagocytic cells

Causes of Intrauterine growth restriction

Causes of Intrauterine growth restriction

Maternal Causes:


• Placental insufficiency

• Chronic renal disease

• Heart disease (NYHA 3 & 4)

• Connective tissue disorders

• Infections

• Diabetes with vasculopathy

• Diabetes with PIH

Placental Causes:

• Placental insufficiency

• Abnormal placentation

• Calcification in placenta

Fetal Causes:

• Chromosomal abnormality

• Genetic disease

• Infections

Causes of isolated spontaneous abortion

Causes of isolated spontaneous abortion

The causes for isolated spontaneous abortion in 1st & 2nd trimester include:

Chromosomal abnormalities:

1.Aneuploidy M/C

2.Trisomy – 2nd best answer

3.Monosomy X (20%)- 3rd

4.Trisomy 16 (16%)

Germ plasm defects

Fetal causes

• Weather it is first or second trimester the m/c cause is chromosomal abnormality.

The frequency of abortion during 1st trimester is 50% and during 2nd is 35%

Cardiac Muscle-Unique features

Cardiac Muscle-Unique features

1. Gap junctions

SINGLE NUCLEUS CENTRALLY placed – Seen in Intercalated disc region.

→ Protein subunit – CONNEXONS – 6 subunits of “Connexin”



→ Entire cardiac muscle unit contracts as single unit – FUCNTIONAL SYNCYTIUM.

2. Elasticity

→ Cardiac muscle ELASTICITY – Due to TITIN (Spring type protein)  “Stretch  Recoil”.

→ Titin mutation – Non-elastic cardiac muscle.

→ On stretching  ↑ Stretch (Non-elastic nature)  Dilated Cardiomyopathy (DCM).


Calcium Induced Calcium Release

EXTRACELLULAR calcium induces  INTRACELLULAR calcium release (Stored in sarcoplasmic reticulum).

4.Sarcoplasmic reticulum

Presence of WELL-DEVELOPED sarcoplasmic reticulum (SR) & SERCA pump.

SERCA pump & SR – Aids calcium storage.


INHIBITS SERCA pump & interferes with calcium storage.

Cardiac muscle v/s Skeletal muscle

Cardiac muscle v/s Skeletal muscle

Properties Cardiac muscle Skeletal muscle
Muscle action INVOLUNTARY

Regulated by pacemaker

(SA node)



Tetany CAN’T BE tetanized CAN BE tetanized
Functional unit Sarcomere (Actin, Myosin, Tropomyosin, Troponin C etc.,) Sarcomere (Actin, Myosin, Tropomyosin, Troponin C etc.,)
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