2 - Hana Postpartum Hemorrhage

Q1. Explain the mechanism of oxygen transport via blood in a healthy person.

A: Oxygen (O₂) binds to haemoglobin (Hb) in red blood cells, forming oxyhaemoglobin. It is transported in the blood and released to the tissues for cellular respiration.

Q2. What does a pulse oximeter measure?

A: A pulse oximeter measures the percentage of haemoglobin saturated with oxygen (SpO₂)

Normal = 95–100%.

Q3. How does postpartum haemorrhage affect oxygenation/perfusion of tissues?

A: Blood loss reduces blood volume and the number of haemoglobin, so less oxygen is delivered, leading to reduced tissue perfusion.

Q4. Describe the short-term sympathetic nervous system response to raise blood pressure.

A: A drop in blood pressure is detected by baroreceptors in the aortic arch and carotid sinus. The medulla oblongata activates the sympathetic nervous system, causing the heart to increase rate and contractility, and the arterioles to vasoconstrict. This raises blood pressure back towards normal.

Q5. Describe the long-term renin–angiotensin–aldosterone system (RAAS) response to raise blood pressure.

A: A drop in blood pressure reduces renal perfusion. The kidneys release renin, which converts angiotensinogen (from the liver) into angiotensin I. ACE enzyme (in the lungs) converts this to angiotensin II. Angiotensin II causes vasoconstriction and stimulates aldosterone release from the adrenal cortex. Aldosterone increases sodium and water reabsorption in the kidneys, raising blood volume and blood pressure back to normal.

Q6. Explain how Hana maintains ATP production with low oxygen delivery.

A: Normally cells use aerobic respiration with oxygen to make lots of ATP. With low oxygen, cells switch to anaerobic glycolysis, making only a small amount of ATP and producing lactic acid.

Q7. How is water balance and blood volume maintained during dehydration?

A: Osmoreceptors in the hypothalamus detect increased osmolality. The pituitary gland releases antidiuretic hormone (ADH), at the same time the adrenal cortex releases Aldosterone to the kidneys bothe ADH & Aldosterone reabsorb water. This reduces urine output, conserving water and maintaining blood volume.