phpy 302 final material

forces affecting ultrafiltration: what two forces filter fluid out? what two forces oppose ultrafiltration?

PGC nBS Pbs nGC

What is the foreman ovale?

a shunt that connects the right atrium to the left atrium so blood can bypass the pulmonary vasculature (27%) - left ventricle will pump out about 34% CCO to aorta, which perfuses the upper body and brain

kidneys are covered by fibrous, non-distensible capsule. what is the hilus?

a slit in the capsule

when does fetal lung compliance reach adult level of lung compliance?

about 1 hour after birth

closure of the ductus venosus: when does it close? and how?

about 3 hours after birth vascular smooth muscle will cause functional closure of this pathway. as a result, pressure in the portal vein will increase, resulting in a diversion of the flow into the liver

umbilical vein partial pressure of O2?

about 30 mmHG (lower than maternal and intervillous space in order for O2 to diffuse into the umbilical vein)

fetal hemoglobin has a high affinity for O2. what is fetal Hb saturation? how much higher is the Hb concentration compared to adults? why?

about 85% 50% - many fetal tissues that are not normally erythropoietic in adults produce RBCs in fetus' -such as endothelium of blood vessels and liver

renal vasculature: arteries form a portal system where the blood flows from ________ arterioles (_____ resistance), to the ______________ (____ pressure), to the __________ arterioles (______ resistance)

afferent high glomerulus efferent high

a large fraction of fetal blood flow is from what artery via ____ umbilical arteries to the fetoplacental circulation within what?

aorta two umbelical arteries chorionic villi

what structures have the highest CCO% in the fetal circulation?

aorta - 69% placenta - 50% (umbilical vein and arteries) inferior vena cava - 69% ductus arteriosus - 59%

what does antenatal steroid therapy do? when is it given?

at risk for preterm delivery within 7 days - accelerates lung maturation and surfactant production

Functions of the kidney: humoral regulation of ________ and flow

blood pressure

by what fold does pulmonary vasculature flow increase?

by 4 fold

fetal blood flow: capillary network is where?

chorionic villi

Hb (O2) saturation in the fetal circulation. highest where? at aorta?

coming from placenta (85%), slowly decreases as it travels through ductus venosus and heart - at the aorta it is about 60% - comes back to the placenta at around 60% or back into circulation - through portal vein to ductus venosus at about 30%

what happens to pulmonary pressure over the next few months after birth? why? (3)

continues to drop. 1. regression of pulmonary arterial musculature 2. growth of new pulmonary vessels 3. decline in blood viscosity as hematocrit falls

two basic layers of the kidney?

cortex (outer) and medulla (inner)

inflation and function of the lungs at birth: what stimulates the production of surfactant? what fraction is from the mother and what fraction is from the fetus?

cortisol (and other hormones) 2/3 fetal 1/2 mother

closure of the foramen ovale: why is there a decrease in RAP?

decrease in blood flow down the descending aorta and hence a decrease in venous return to the RA

birth will do what to the pulmonary vascular resistance? what causes the change in resistance? (3)

decrease the resistance 1. change in resistance caused by the inflation of the lungs 2. increase in alveolar pO2/ decrease in alveolar PCO2 (causes pulmonary dilation) 3. increase in alveolar pH (causes pulmonary dilation)

what is infant respiratory distress syndrome usually caused by?

deficiency of pulmonary surfactant owing to prematurity

fetal blood flow: umbilical arteries have ____________ blood

deoxygenated

closure of the ductus arteriosus: what will eliminate or reduce this backwards blood flow? when will this normally happen?

ductus arteriosus muscular wall will contract b/c increased PO2 - about a week after birth

blood in the intervillous space: why is there an O2 saturation of 65%?

due to dissociation curve

when does adult Hb gradually replace HbF?

during the first 12 months of life

inflation and function of the lungs at birth: when does surfactant synthesis start?

during the saccular period

peritubular capillaries: from what kind of arterioles? what is the hydrostatic pressure? what is the colloid osmotic pressure?why?

efferent low high - due to ultrafiltration

Functions of the kidney: regulates the bodies fluid status, _____________ and __________ balance

electrolytes acid-base (Na+, K+, Ca2+, H+, Cl-)

nephron: most of the fluid and solutes are reabsorbed in the tubules. if not, what would happen?

entire volume of blood plasma would be excreted in about 30 min

where is the waste removed from the placenta?

excreted in the amniotic fluid

cardiopulmonary adjustments at birth: as the newborn exits the birth canal, it will take its first breath. what will this do to the lungs? blood flow? what will this vasoconstrict?

expansion of the lungs - circulatory changes that convert fetal pattern of blood flow to adult pattern umbilical arteries - and O2 delivery

what happens to pulmonary arterial and right ventricular pressure after birth? why?

fall abruptly - because an increased blood flow through pulmonary vasculature (vasodilation) and reduced pulmonary resistance

two distinct circulations of the placenta?

fetoplacental and uteroplacental

who has a higher cardiac output per unit body weight, fetus or adult?

fetus

kidney cortex: contain what two things?

glomeruli (capillaries) and highly convoluted epithelial structures in the form of tubules

forces affecting ultrafiltration: hydrostatic pressure in the glomerular capillaries (Pgc)? hydrostatic pressure in bowmans space (Pbs)? oncotic pressure of the filtrate in bowmans space (nBS)? oncotic pressure of the filtrate in glomeruli capillaries (nGC)?

high low low high

three major changes in metabolism accompanying birth are

hypoxia, hypothermia, hypoglycemia

decrease in blood flow down descending aorta is due to what three things?

increase in pulmonary blood flow - closing of the ductus arteriosus - increase in systemic resistance (due to the removal of the placenta)

closure of the foramen ovale: at birth, the decrease in pulmonary vascular resistance increases blood flow through the lungs, resulting in _______________ in the left atrium

increased venous return to the left atrium and increased pressure

closure of the ductus arteriosus: what happens to the blood flow here right after birth? why?

it will reverse directions - pulmonary resistance decreases (expansion of lungs) while systemic resistance increases, aorta (placenta being removed) - blood will flow from the aorta to the pulmonary artery through this duct

why is the first breath the most difficult of your life?

large negative pressure in the intrapleural space is necessary to overcome surface tension

the sum of the ventricular outputs of the two ventricles is ______________ than the CCO in the fetus. rise in the output of the left ventricle will __________ the stroke volume

larger double

what is the BP in the intervillous space?

maternal arterial BP

what is the flow in the intervillous space affected by? (3)

maternal arterial BP intrauterine pressure uterine contraction

what is the first breath triggered by? (4)

mild hypoxia, hypercapnia (above average CO2), tactile stimuli, cold skin

forces affecting ultrafiltration: what is GFR proportional to in terms of hydrostatic/oncotic pressure?

net hydrostatic (Pgc-Pbs) minus net oncotic pressure (nGC-nBS)

RBCs formed early in gestation are nucleated or not nucleated?

nucleated

do the left and right sides of the heart largely pump in parallel or series?

parallel - the inputs and outputs of these two sides mix

what does the massive blood flow to the placenta prevent the perfusion of?

perfusion of lower limbs and abdominal viscera (including kidney)

vasa recta?

peritubular capillaries that dip into the medulla

what provides the fetus with oxygen and nutrients?

placenta

four unique pathways of the fetal circulation:

placenta ductus venosus foramen ovale ductus arteriosus

autotransfusion at birth. what is it? what are the things that must happen in order for autotransfusion to occur? how much blood could this autotransfusion account for?

placental blood flows into the newborn since the umbilical vein does not constrict. infant held below the level of the placenta and umbilical cord not clamped about 100 mL (1/3 of total newborns blood volume)

blood in the inferior vena cava + blood from the _________ also enters the ductus venosus + CCO from the placenta... resulting in a total of ____% CCO entering the right atrium

portal vein - 69%

placenta: produces essential hormones such as (3)? performs what vital functions? (4)

progestins, estrogens, and chorionic gonadtropins gas exchange, nutrient transport, fluid balance, waste removal

why is the pulmonary resistance so high in the fetus?

pulmonary blood flow is reduced by hypoxic vasoconstriction - causes diversion of right ventricular flow through the ductus arteriosus (only 7% CCO enters the lung)

maternal blood flow: spiral arteries have ____________ spurts

pulsatile

maternal blood flow: intervillous space, what is the blood flow like here? whos blood is in this space, mother or fetus?

reduced force and velocity mothers

what enters the kidney? what exits the kidney?

renal artery and nerves renal vein, lymphatics and ureter

renal sinus: surrounded by what? (except where)

renal parenchyma, except at connection with upper end of ureter

kidney: urine filled spaces? (2)

renal pelvis renal calyces (major and minor)

closure of the foramen ovale: when there is an increase in LAP and a decrease in RAP, what happens to the foramen ovale? - how long does it take to seal?

reversal of the pressure gradient pushes a flap of tissue against the septum, closing the foramen ovale, tissue grows over the foramen ovale in a few months*

at birth, the pulmonary and systemic circulations shift from interconnected and parallel to

separate entities in series

kidney: renal capsule reflects into the sinus at hilus so that the inner layer lines the _________ and the outer layers anchor to ________________

sinus blood vessels and renal pelvis

maternal blood flow path?

spiral arteries to intervillous space to venous orifices to placental vein to uterine vein

closure of the ductus venosus: at birth, what does blood flow look like in this region?

still has majority of portal blood flow through the ductus venosus (blood flow through liver is still low)

closure of the ductus arteriosus: immediately after birth the ductus arteriosus is in what state?

still open

inflation and function of the lungs at birth: what increases lung compliance, thereby reducing the effort of inspiration?

surfactant

removal of the placenta increases what in the fetus? by how much? why?

systemic vascular resistance (doubles the resistance) - bc placental circulation is about 50% of the CCO and acts as a parallel path in systemic circulation. when this is abolished, systemic resistance will increase - since blood flow in aorta remains unchanged, pressure must be increase in both the aorta and left ventricle

closure of the ductus arteriosus: what happens after a month ? (3 reasons why this happens)

the lumen will become obliterated anatomically because of thrombosis, intimal thickening, and loss of smooth muscle cells

chorionic villi is fetal tissue protruding into where?

the maternal blood

what accounts for the low vascular resistance in fetus'?

the parallel path in systemic circulation, the placenta (50% CCO)

what is transpulmonary pressure (Ptp)?

the pressure difference between the intrapleural space and alveolar air space

deoxygenated blood in the placenta is oxygenated and goes where?

through the umbilical vein into the ductus venosus, which merges with the inferior vena cava

Functions of the kidney: filters _______ and _________ from blood, excreting them as what?

toxins and metobolic products urine

kidney medulla: parallel arranged __________ and small blood vessels

tubules

nephron: basic structural and functional unit of the kidney. urine formation by what two things?

ultrafiltration (primarily fluid) reabsorbing and secretion by the tubules

fetal blood flow path?

umbilical arteries from the fetus (two that extend to the chorionic villi) to capillary network in the chorionic villi (where there is diffusion of O2 and nutrients) to umbilical vein (which extends to the fetus)

What is the ductus arteriosus?

vessel a growing fetus has that connects the pulmonary artery with the aorta, instead of going to the lungs the blood goes to the aorta (69%) and then back to placenta (50%) - out of the 66% CCO to pulmonary vasculature, only 7% perfuses the nonfunctioning lungs. this is because it bypasses directly to the aorta through the ductus arteriosus (59%)

what does retractions look like in infant respiratory distress syndrome? alveoli? lung compliancy? intrapleural pressure? chest wall?

- alveoli are collapsed, fluid-filled and poorly expanded - lungs are less compliant than chest wall - negative intrapleural pressure - chest wall becomes distorted, caving in the ribs (beneath or above rib cage)

inflation and function of the lungs at birth: what is lacking in infants lungs who are born prematurely? what does this result in?

- insufficient surfactant - not structurally mature - excessive work to create adequate tidal volume - respiratory distress

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infant respiratory distress syndrome: characterized by what symptoms? (3)

1. increased work of breathing 2. impaired gas exchange 3. retractions

what does increased work of breathing look like? (5)

1. nasal flaring 2. use of accessory musculature 3. intercostal and subcostal retractions 4. tachypnea 5. grunting

infant respiratory distress syndrome: what two treatments are used to dramatically reduced mortality and improved clinical course of IRDS?

1. postnatal administrations of surfactant 2. antenatal steroid therapy for pregnant women

what causes the vasoconstriction of the umbilical arteries immediately upon birth? (2)

1. stretching of the umbilical arteries during delivery 2. sudden rise in systemic arterial PO2 in the newborn

maternal blood coming in the intervillous space: partial pressure of O2? partial pressure of CO2? pH?

100 mmHg 40 mmHg 7.40

what is the CCO to the lungs after birth?

100%

glomerular filration rate/min?

115 ml/min

what is a normal adult PTP in tidal breathing?

2.5 cm H2O

how much CO do the kidneys receive?

20%

what gestational age should the fetus be for a pregnant women to use antenatal steroids?

24 to 34 weeks gestational age

blood in the intervillous space: partial pressure of oxygen? hemoglobin oxygen saturation of what percent?

30 to 35 mmHg 65%

by what fold does pulmonary vascular resistance decrease?

5-fold

what percent of CCO enters the ductus venosus? what does the ductus venosus allow the CCO to bypass?

50% the liver

what percent of CCO enters the placenta? is it deoxygenated or oxygenated?

50% reaches placenta - deoxygenated blood and through two umbilical arteries

infants first inspiratory effort requires a transpulmonary pressure (Ptp) of ______ cm H20

60

what percent of CCO reaches the aorta?

69%

kidney medulla: how many renal pyramids per medulla? base facing where? tip facing where?

8 to 18 cortical-medullary border renal pelvis - tip is perforated to let urine flow into minor calyces

what is the ductus venosus?

A shunt at the end of the umbilical cord which allows blood coming from the placenta to bypass the liver and empty directly into the IVC