Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Repro > Fetal And Neonatal Phys > Flashcards

Fetal And Neonatal Phys Flashcards

1
Q

Describe glucocorticoids in fetal growth

A

Promote storage of glucose as glycogen in fetal liver
Increases greatly during final month of gestation in prepartaion for increased glycolytic activity required during and immediately after delivery

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

Describe insulin near term of fetal growth

A

Contributes to storage of glucose as glycogen as well as to uptake and utilization of amino acids and lipogenesis
Near term, fetal glucose metabolism becomes sensitive to insulin
Maternal insulin cannot cross placenta

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

Describe GH postnatally

A

May have only minimal effect of fetal growth because fetal liver has relatively few GH receptors
GH acts on liver to trigger production of somatomedin or IGF-1

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

Describe IGF-1 and IGF-2 on fetal growth

A

Mitogenic peptide
Extremely important for fetal growth
IGF-1 and 2 are present in fetal circulation from end of 1st trimester
Levels increase in both mother and fetus
Brith weight correlates positively with IGF levels

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

Describe thyroid hormones on fetal growth

A

Obligatory for normal growth and development
Before 2nd trimester, most of T4 in fetus is maternal
Fetal production of TSH and T4 begin to increase in 2nd trimester, concurrent with development of hypothalamic-pituitary portal system

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

What does hypothyroidism do to fetal growth?

A

Adverse effects on fetal growth

Reduction in size of organs like heart, kidney, liver, muscle, and spleen

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

Describe development of the heart

A

Heart begins beating during 4th week after fertilization
Initially contracting at 65 beats per min
Rate increases steadily to 140 bpm immediately before birth

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

Describe blood cells during 3rd week

A

Nucleated red blood cells formed in yolk sac and mesothelium of placenta

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

Describe blood cells during 4-5th weeks

A

Non-nucleated RBCs form by fetal mesenchymal and endothelial cells of fetal blood vessels

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

Describe blood cells during 6th week

A

Liver forms blood cells

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

Describe 12 weeks (3rd month) of blood cells

A

Spleen and lymphoid tissue begin forming RBCs

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

Describe blood cells after 3rd month

A

Bone marrow becomes principal source of RBCs (and most white blood cells)
Other structures lose ability to form blood cells, except for continued lymphocyte and plasma cell production in lymphoid tissue

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

Describe erythrocytes in fetus

A

Fraction of total erythrocytes that are reticulocytes (immature, non-nucleated erythrocytes with residual polyribosomes) is high in young fetus but decreases to 5% at term (compared to less than 1% in adult)
Life span of fetal erythrocytes depends on age of fetus
In term fetus, 80 days (2/3 that in adult)
Life span of less mature fetus is shorter

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

Describe hemoglobin (Hb) in fetus

A

Hb begins to be formed in 3rd week
Content in fetus blood rises by midgestation (=level in normal adult)
Concentration at term is higher than Hb concentration in maternal bood
Fetal Hb has higher affinity for O2 (can carry 20-30% more O2 than maternal Hb)

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

Describe development of nervous system

A

Most of reflexes of fetus involving spinal cord and brain stem are present by 3rd-4th months after pregnancy
Cerebral cortex development continues after birth
Myelinization of some major tracts of brain becomes complete only after 1 year of postnatal life

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

Describe development of GI tract

A

Ingestion of amniotic fluid begins in 2nd trimester
During last 2-3 months, GI function approaches that of normal neonate
Small quantitates of meconium (amniotic fluid, mucus, epithelial cells, residues) are continually formed in GI tract and excreted from anus into amniotic fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe fetal metabolism

A

Accumulation of significant amounts of calcium and phosphate during period of ossification
Iron accumulates rapidly starting at 12 weeks of gestation
About one third of iron in fully developed fetus is stored in liver
Enough iron is stored and can b used for several months after birth (used for formation of additional Hb)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe development of kidneys

A

Urine excretion begins in 2nd trimester
Fetal urine accounts for 70-80% of amniotic fluid
Renal control systems for regulation of extracellular volume, electrolyte balance, and acid-base balance are almost non-existent until late fetal life
Functional development is not complete until end of 1st month of life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe development of respiratory system

A

Respiration cannot occurs during fetal life because there is no air to breath in amniotic cavity
During last 3 or 4 months of pregnancy, respiratory movements are inhibited, and lungs remain almost completely deflated
Inhibition of respiration prevents filling of lungs with fluid and debris from meconium
Small amounts of fluid are secreted into lungs by alveolar epithelium up until birth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What stimulates breathing at birth?

A

Asphyxiation during birth

Sudden drop in ambient temperature and cooling of skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What causes delayed breathing at birth?

A

Use of general anesthesia during delivery
Prolonged labor
Head trauma of infant during birth (depressed respiratory center)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are causes of hypoxia during delivery? Tolerance?

A 
Causes: 
Compression of umbilical cord
Premature separation of placenta
Excessive uterine contractions
Excessive anesthesia of mother (depressed maternal breathing)

Neonates have higher tolerance for hypoxia
Durations between cessation of breathing and death: 8-10 min (adults 4 min)

23
Q

Describe alveoli inflation and deflation

A

At birth, alveoli are collapsed due to surface tension of amniotic fluid filling them
More than 25 mm Hg negative inspiratory pressure is needed to overcome surface tension and open alveoli for 1st time
1st inspirations of normal neonate are capable of creating 60 mm Hg negative pressure in intrapleural space
1st inspiration brings in 40 ml of air
Deflation also requires strong positive pressure to overcome viscous resistance of fluid in bronchioles
Less effort needed after 1st breath
Breathing does not become completely normal until 40 min after birth

24
Q

Describe surfactant

A

Decreases surface tension in alveoli
Secreted by type II alveolar epithelial cells
Main constituent is phospholipid (phosphtidylcholine)
Synthesis begins in last trimester
Once alveoli are open, difficult to close while exhaling
Pressure needed to collapse alveoli with surfactant is nearly 4-5 times greater than without

25
Q

Describe respiratory distress syndrome (RDS)

A

Common in premature infants and infants born to diabetic mothers
Failure to secrete adequate amounts of surfactant resulting in collapsed alveoli and development of pulmonary edema

26
Q

What are the shunts in fetal circulation?

A

Placenta
Ductus venosus
Foramen ovale
Ductus arteriosus

27
Q

Describe placenta as a shunt

A

Massive blood flow to placenta shunts blood away form lower trunk and lowers effective blood flow to all abdominal viscera (including kidneys)

28
Q

Describe umbilical arteries

A

Branch repeatedly under amnion and form dense capillary networks within terminal villi

29
Q

Describe umbilical vein

A

Returns oxygenated blood (which has PO2 30-35 mm Hg) back to fetus from placenta
This blood enters ductus venosus

30
Q

Describe ductus venosus

A

Second shunt
Bypasses liver, which is largely nonfunctional
Allows blood from umbilical vein to enter inferior vena cava directly

31
Q

What shunt bypasses liver to allow blood from umbilical vein to enter inferior vena cava directly?

A

Ductus venosus

32
Q

What branch repeatedly under amnion and form dense capillary networks within terminal villi?

A

Umbilical arteries

33
Q

What returns oxygenated blood (which has a PO2 of 30-35 mmHg) back to fetus from placenta?

A

Umbilical vein

34
Q

Describe foramen ovale

A

Third major shunt through which blood enters right atrium and then crosses foramen ovale to enter left atrium
Oval hole in septum dividing atria, located on posterior aspect of right atrium

35
Q

What is the oval hole in the septum dividing the atria that allows blood to shunt from the right atria to the left atria?

A

Foramen ovale

36
Q

How much of the combined cardiac output (CCO) gets shunted through the foramen ovale?

A

Of the 69%, 27% goes through

37
Q

Describe the blood incoming from the superior vena cava

A

Does not shunt through foramen ovale

Goes through tricuspid valve to right ventricle

38
Q

Describe ductus arteriosus

A

Fourth major shunt
Right to left shunt
Directs blood from pulmonary artery to aorta
Contains substantial smooth muscle in its vessel wall

39
Q

What shunts blood from pulmonary artery to aorta?

A

Ductus arteriosus

40
Q

What maintains patency of ductus arteriosus?

A

Active relaxation of smooth muscle, medaited by prostaglandins (PGE2)

41
Q

What causes systemic vascular resistance at birth, and what does that do?

A

Loss of blood flow from placenta causes 2x increase in resistance
Increases aortic pressure
Increases pressures in left ventricle and left atrium

42
Q

What causes pulmonary vascular resistance to decrease?

A

Lung expansion
Vasodilation (from local prostaglandins) takes place when aeration of lungs eliminates hypoxia of lungs from fetal life
Resistance is reduced, which reduces pulmonary arterial pressure, right ventricular pressure, and right atrial pressure

43
Q

What causes the foramen ovale to close?

A

Reversal of pressure gradient across atrial septum pushes foramen ovale’s valve on left side of septum against the opening
Due to increased venous return to left atrium and left atrial pressure and decreased in right atrial pressure
As the flap of foramen ovale pushes against septum, blood flow from left to right is prevented
Flap is eventually sealed shut

44
Q

Describe closure of ductus arteriosus

A

As aortic pressure exceeds the pressure of pulmonary artery, blood flow through ductus arteriosus reverses (now from aorta into pulmonary artery)
Well-oxygenated aortic blood now flows through ductus arteriosus
High PO2 causes vasoconstriction, which functionally closes ductus arteriosus
Falling prostaglandin levels also contribute to rapid closure
Within 1-8 days, constriction is usually sufficient to stop all blood flow through ducts
During 1-4 months, it becomes anatomically occluded

45
Q

Describ patent ductus arteriosus (PDA)

A

Ductus arteriosus remains open
Babies often have heart murmur
Opening allows oxygen-rich blood from aorta to mix with oxygen-poor blood from pulmonary artery
Can put strain on heart and increase blood pressure in lung arteries

46
Q

Describe closure of ductus venosus

A

Immediately after birth, blood flow through umbilical vein ceases, but most of portal blood still flows through ductus venosus
Within 1-3 hours, muscle wall of ductus venosus contracts strongly and closes
Portal venous pressure rises, forcing venous blood flow through liver sinuses
Rarely fails to close

47
Q

Describe immature kidneys in neonate

A

Functional development is not complete till the end of first month of life
High fluid turnover (rate of fluid intake/excretion relative to weight 7x greater than in adult)
Rapid acid formation
Can only concentrate urine to 1.5x plasma osmolality (3-4x in adult)
Problems with acidosis and dehydration

48
Q

Describe liver in neonate

A

Poor conjugation of bilirubin
Deficiency in forming plasma proteins and coagulation factors
Deficient gluconeogenesis
Infant uses its stored fats and proteins for metabolism until mother’s milk can be provided

49
Q

Describe need for calcium and vitamin D in neonate

A

Because neonate is in a stage of rapid ossification of its bones at birth, a ready supply of calcium throughout infancy is necessary
Adequate amount can be supplied in milk
Absorption of calcium by GI tract is poor in absence of vitamin D
Rickets can develop with deficiency

50
Q

Describe necessity for iron in diet of neonate

A

Infant’s liver has stored enough iron to keep forming blood for 4-6 months after birth (as long as mother has adequate amounts of iron during pregnancy)
Severe anemia can occur in 3rd month if mother’s diet was insufficient

51
Q

Describe need for vitamin C in diet for neonate

A

Vitamin C not stored in fetal tissues

Adequate amounts can be provided in breast milk

52
Q

Describe immunity of neonate

A

Neonate inherits a great degree of immunity from mother
Neonate does not form antibodies of its own
By end of 1st month, there is decrease in baby’s gamma globulins
Antibodies inherited from mother protect infant for about 6 months against major diseases (except whooping cough)

53
Q

Describe intrauterine growth restriction (IUGR)

A

Abnormality of fetal growth and development
Growth-restricted fetus at substantial risk for morbidity and mortality
Brith asphyxia, neonatal hypoglycemia, hypocalcemia, meconium aspiration, persistent pulmonary hypertension, pulmonary hemorrhage, delayed neurologic development, hypothermia
May occur as a result of decreased placental reserve caused by any insult
Mothers who smoke during pregnancy tend to have small placentas and are at risk

Repro (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions