2. Case Study Two Quiz: Postpartum Hemorrhage, Blood Loss, Perfusion, and Homeostasis Mechanisms in Human Tissues

What is considered a postpartum hemorrhage (PPH) in terms of blood loss?

Anything over 500 mL

What immediate effect does postpartum hemorrhage have on blood pressure?

It causes hypotension (a drop in blood pressure).

How is oxygen primarily transported in the blood?

It's mainly transported by binding to haemoglobin in red blood cells, with a small amount dissolving in plasma.

What does a pulse oximeter measure?

It measures the oxygen saturation (SpO₂) of haemoglobin in arterial blood.

How does reduced blood volume after PPH affect tissue oxygenation?

It leads to reduced oxygen and nutrient delivery to tissues and cells, resulting in impaired perfusion.

What is the stimulus in the sympathetic nervous system response to hypotension?

It is blood loss that lowers blood pressure.

What role do baroreceptors play in the sympathetic nervous system response to hypotension?

They detect the drop in blood pressure and send signals to the medulla oblongata in the brain.

What are the effectors in the sympathetic nervous system response to hypotension?

It activates, causing the heart to beat faster and harder, and blood vessels to constrict, raising blood pressure short-term.

What initiates the long-term renin-angiotensin-aldosterone-system (RAAS) response?

Low blood pressure and reduced kidney perfusion after blood loss.

What is the role of renin in the RAAS response?

It activates angiotensin II, which signals the adrenal glands.

What are the effects of angiotensin II in the RAAS response?

It causes vasoconstriction, raising blood pressure.

How does aldosterone affect blood volume?

It causes the kidneys to retain sodium and water, increasing blood volume and blood pressure.

How do cells maintain ATP production during hypoperfusion?

They use anaerobic respiration to create ATP, which does not require oxygen but produces lactic acid.

What triggers the release of antidiuretic hormone (ADH) in Hana's body?

Osmoreceptors in the hypothalamus detect increased blood concentration due to dehydration.

What effect does antidiuretic hormone (ADH) have on the kidneys?

It makes the kidneys reabsorb more water, reducing urine output.

What is the overall purpose of the body's response to dehydration?

To maintain blood volume and water balance despite not urinating.