Neonatal Physiology Flashcards

1
Q

Describe the ductus venous and what vasculature it drains into?

A

bypasses the liver and drains into the inferior vena cava

continuation of the umbilical vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Ductus arteriosus?

A

connects pulmonary artery with descending thoracic aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Relaxation of the smooth muscle layer of the ductus arteriosus is mediated by what?

A

PGE2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe where blood flow comes from to RA in neonatal system?

A

oxygenated (mixed) blood from IVC

deoxygenated blood from SVC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where does the RA of the neonatal heart pump blood to?

A

to the LA (through the foramen ovale) mainly blood from IVC

To the RV- mainly blood from SVC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where does the LA of neonatal heart receive blood from?

A

mixed blood (oxygenated and deoxygenated) from the RA (through the foramen ovale)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What chamber of the neonatal heart does the LA pump blood?

A

mixed blood into the LV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the factors/stimuli for initiation of respiration?

A

chemical (transitory hypoxia of fetus and neonates)

thermal

sensory and physical

mechanical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the factors considered chemical stimuli (transitory hypoxia of fetus and neonates), that aid in the initiation of respiration?

A

Fetal factors:
Compression of umbilical cord
Changes in Maternal posture
Fall in maternal oxygenation (bearing down )

Neonatal factors:
Cessation of placental gas exchange
Cessation of umbilical cord pulsation
Cutting of the cord
Temporary asphyxia * respiratory center stimulated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does thermal stimuli initiate respiration in the neonate?

A

Change in temp from intrauterine (98.6° F) to Extra uterine (70.75° F) , Excite nerve impulse in skin stimulate respiratory center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the sensory and physical stimuli that aid in causing the neonate to initiate respiration?

A

-Tactile stimuli—Touch
-Auditory –sounds- noise
-visual- Light
-respiratory center stimulated

Mechanical Stimuli
Compression of chest in birth canal
Sudden expansion (Recoil of chest wall) -ve pressure
Inspiration (mechanical suctioning)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the normal rate of respiration for the neonate?

A

30-50 breaths /min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the normal breathing of a neonate.

A

Nature: diaphragmatic with some synchronization with chest movement

initially shallow and irregular
later ,deep & regular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Be able to map out cues (flow diagram) showing establishment of respiration for the baby.

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do the umbilical arteries form postnatally?

A

medial umbilical ligament

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What does the umbilical vein form postnatally?

A

ligamentum teres (round ligament)

17
Q

What structure does the ductus venosus form?

A

fibrous cord - ligamentum venosum

18
Q

How does the ductus venosus form a fibrous cord?

A

Contraction of the muscle wall of the DV (within 1-3 hours after birth) and cessation of the blood flow

19
Q

How does closure of the foramen ovale happen?

A

Opening of pulmonary circulation and cessation of the umbilical flow→ ↓ pressure in the RA

↑ pressure in the LA

Reverse pressure gradient across the FO

Functional closure of the small valve over the FO
Structural closure requires 3-9 months

20
Q

Postnatally, is there a thinning of muscle layer of the pulmonary arteries?

A

yes there is

21
Q

What is the average hr of the infant post-nasally?

A

Heart rate —initially 175-180 beats /min——–gradually 120-150 beats /min

22
Q

Describe neonatal jaundice.

A

Bilirubin formed in the fetus can cross the placenta into the mother and be excreted through the liver of the mother, but immediately after birth, the only means for ridding the neonate of bilirubin is through the neonate’s own liver, which for the first week or so of life functions poorly and is incapable of conjugating significant quantities of bilirubin with glucuronic acid for excretion into the bile.

Consequently, the plasma bilirubin concentration rises from a normal value of less than 1 mg/dl to an average of 5 mg/dl during the first 3 days of life and then gradually falls back to normal as the liver becomes functional.

23
Q

When the baby’s initial plasma bibirubin concentration rises from a normal value to higher during the first 3 days of life and gradually falls back, what is this called?

A

physiologic hyper-bilirubinemia

24
Q

Know the difference in reactions of the neonate in response to hypothermia and hyperthermia.

A
25
Q

What is the immature liver of the neonate typically deficient in?

A

ü Glucoronyl enzyme - Physiological jaundice
ü Prothrombin and coagulation factors - bleeding tendency
ü Glycogen stores - hypoglycemia

26
Q

Why are neonates susceptible to dehydration, acidosis and electrolyte imbalance?

A

inability to concentrate urine

27
Q

When does the fetus synthesize immunoglobulins? Describe where the immunoglobulins are before then?

A

Fetus synthesize Immunoglobins—20th week of gestation (IgM, IgG, IgE)

IgG cross placenta
IgM does not cross placenta
IgA secrete in colostrums of mother

28
Q

Describe the sensory adaptations of the eyes for the infant.

A

structurally incomplete, ciliary muscles immature - Poor accommodation & fixation (Hypermetropia in first month)

29
Q

Describe the sensory adaptation of the tear glands for the newborn.

A

not active till 2-4 weeks of life

30
Q

Describe the sensory adaptations of hearing for the newborn.

A

startle reflex, crying
Low frequency voice, cry
can identify mother’s voice by 3rd day of life

31
Q

Describe the sensory adaptation of smell for the newborn.

A

reacts to strong smell

32
Q

Describe the sensory adaptation of taste for the newborn.

A

can distinguish taste

33
Q

Describe the sensory adaptation of touch for the newborn.

A

can perceive touch all over the body, responds to patting, rubbing