Fisiologia da Gravidez: Sistema Cardiovascular e Respiratório | Anatomia etc

Summary

In this video, the host discusses significant physiological changes during pregnancy, focusing on the cardiovascular and respiratory systems. The blood volume increases by 35-50% to supply more oxygen and nutrients to the fetus, with the heart rate and cardiac output also rising. Despite this, blood pressure may remain stable or decrease due to lowered vascular resistance. The respiratory system adapts with increased breathing depth and volume to meet the oxygen needs. Progesterone influences these changes and can cause nasal congestion. The video is educational and engaging for those interested in human anatomy and physiology.

Takeaways

• 🤰 Pregnancy brings significant changes to a woman's body to support the growing fetus.
• 🩸 Blood volume increases by 35-50% during pregnancy, starting from the 6th week and peaking at the 32nd week.
• 🚶‍♀️ Blood plasma volume increases more than the number of red blood cells, leading to relative physiologic anemia.
• 💓 Heart rate increases by 10-15 beats per minute, and cardiac output rises by 30-50% compared to pre-pregnancy levels.
• 🫀 The heart dilates to accommodate more blood and contracts more forcefully.
• 🌡 Despite the increase in blood volume, blood pressure may remain unchanged or decrease, especially in the first and second trimesters.
• 🔍 The decrease in blood pressure is due to reduced vascular resistance, influenced by the uterine placental bed and high levels of progesterone.
• 🤽‍♀️ Supine position can compress the inferior vena cava, reducing venous return and potentially causing hypotension, known as supine hypotension syndrome.
• 👃 Progesterone affects respiratory centers, increasing respiratory depth, tidal volume, and minute volume, leading to decreased arterial CO2 pressure.
• 🌬️ Progesterone can cause nasal congestion due to edema and increased secretion in the upper airways.

Q & A

What is the main focus of the video script?

The main focus of the video script is to discuss the physiology of pregnancy, with an emphasis on the cardiovascular and respiratory systems.

Why does the blood volume increase during pregnancy?

The blood volume increases during pregnancy by 35 to 50 percent to transport more oxygen and nutrients to the developing fetus.

When does the increase in blood volume begin and when does it peak?

The increase in blood volume begins around the 6th week and peaks at the 32nd week of pregnancy.

What is the consequence of the disproportionate increase in plasma volume compared to red blood cells during pregnancy?

The disproportionate increase in plasma volume compared to red blood cells can result in a condition known as relative or physiological anemia.

How does the heart rate change during pregnancy?

The heart rate increases by about 10 to 15 beats per minute during pregnancy.

What is the impact of the increased heart rate and stroke volume on cardiac output?

The cardiac output increases by 30 to 50 percent due to the increased heart rate and stroke volume.

Why does blood pressure not increase despite the increase in blood volume?

Blood pressure may remain unchanged or even decrease during pregnancy due to a decrease in vascular resistance.

What factors contribute to the decrease in vascular resistance during pregnancy?

The decrease in vascular resistance is due to the placental bed's low-resistance system and the relaxing effects of progesterone on the smooth muscle of blood vessels.

What is supine hypotension syndrome and how can it be prevented?

Supine hypotension syndrome occurs when the uterus compresses the inferior vena cava, leading to decreased venous return and cardiac output. It can be prevented by lying on the left side to relieve pressure on the vena cava.

How does the respiratory system change during pregnancy?

The respiratory system changes by increasing the depth of breathing, tidal volume, and minute volume to capture more oxygen.

What is the effect of progesterone on the respiratory system during pregnancy?

Progesterone acts on the central respiratory centers to increase the minute volume, leading to more CO2 being expelled and a decrease in arterial CO2 partial pressure.

What are the common respiratory symptoms experienced by pregnant women?

Pregnant women commonly experience nasal congestion or a stuffy nose due to progesterone's effect on the mucous membranes of the upper airways.

How does the mechanical aspect of respiration change as the uterus grows?

The diaphragm is compressed and elevated by up to four centimeters, and the thoracic diameter may increase slightly to compensate for the reduced diaphragmatic movement.