Lecture 18 - Fetal and Neonatal Physiology

Question 1

Describe fetal circulation. .

L18 S4-7

Answer 1

Umbilical vein provides blood from placenta and umbilical arteries carried waste back to the placenta.

Left and right ventricles pump in parallel (right more than left)

Oxygenated blood is preferentially pumped to heart, upper torso, and brain.

Less oxygenated blood shunted to lower body.

Blood simply passes though the lungs as liver as they are not active.

Question 2

What is surfactant, what does it do and when is it produced?

L18 S10

Answer 2

Lipoprotein complex that lowers surface tension.

Allows for increased pulmonary compliance.

Produced around the last 3 months of gestation.

Question 3

Describe fetal nervous system development.

L18 S12-13

Answer 3

Present at 10 weeks

Motor:

• initial movement are jerky and not controlled
• *week 16-20 limbs are more powerful and can be felt moving
• movements are reflexive

Sensory:

• week 16 able to swallow
• week 18 nerves partially myelinated (wont be fully until 1 year)
• week 24 blinking
• *week 26 rapid development
• week 31 thalamic connections

Question 4

What milestones occur in weeks 9-12 of fetal development?

L18 S14

Answer 4

• ossification of bone
• fingers and toes develop
• amniotic fluid swallowed and urinated
• testicles descend
• intestines accumulate meconium

Question 5

What milestones occur in weeks 13-16 of fetal development?

L18 S15

Answer 5

• sensory organs develop
• eyes move closer together
• mouth makes sucking motions
• ears move upwards
• scalp grows hair
• kidneys are formed

Question 6

What milestones occur in weeks 16-20 of fetal development?

L18 S16

Answer 6

• skin coated with vernix caseosa, waxy protective substance

- silky hair on all skin

Question 7

What milestones occur in weeks 21-31 of fetal development?

L18 S17

Answer 7

• eye lids no longer fused
• bone marrow synthesizes erythrocytes
• eyelashes appear
• lungs produce surfactant
• finger and toe nails develop

Question 8

Define full gestation, premature, and neonate.

L18 S22

Answer 8

Full gestation:
-37-42 weeks

Premature:
-prior to 37 weeks

Neonate:
-first 28 days

Question 9

What is the most important event that occurs immediately after birth and why?

L18 S23-24

Answer 9

Strong first breath to open collapsed alveoli.

Stimuli for this are hypoxia and cold air

Question 10

What is an apgar score?

L18 S37

Answer 10

Appearance, pulse, grimace, activity, respiratory

0-2 for each category, max score of 0 which is rarely seen due to normal early cyanosis

Performed at 1 and 5 minutes after birth