Human Physiology Flashcards for NEET — 20 cards

First 8 of 20 Human Physiology flashcards

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1. Card 1 of 20

   Define Vital Capacity (VC) and write its formula using respiratory volumes.

   Hint: It includes Expiratory Reserve Volume, Tidal Volume, and Inspiratory Reserve Volume.

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   Answer

   Vital Capacity is the maximum volume of air a person can breathe in after a forced expiration (or breathe out after a forced inspiration). Formula: $VC = ERV + TV + IRV$.

2. Card 2 of 20

   What factors cause a 'right shift' in the Oxygen Dissociation Curve, promoting the release of oxygen?

   Hint: This phenomenon is known as the Bohr effect.

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   Answer

   High $pCO_2$, low pH (high $H^+$ concentration), and higher temperature. These conditions are typically found in the tissues, where oxygen is needed.

3. Card 3 of 20

   Which occupational respiratory disorder is caused by inhalation of fine dust from grinding or stone breaking, leading to lung fibrosis?

   Hint: Workers in such industries must wear protective masks.

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   Answer

   Silicosis (or Asbestosis). These disorders cause proliferation of fibrous tissues, resulting in severe lung damage.

4. Card 4 of 20

   What enzyme complex is required to convert inactive prothrombin into active thrombin during the blood coagulation cascade?

   Hint: Calcium ions ($Ca^{++}$) are absolutely essential for these reactions.

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   Answer

   Thrombokinase. Once formed, thrombin then converts soluble fibrinogen into the insoluble fibrin threads that form the clot.

5. Card 5 of 20

   Define Cardiac Output and state the formula used to calculate it.

   Hint: Stroke volume is normally ~70 mL and heart rate is ~72 beats/min.

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   Answer

   Cardiac Output is the volume of blood pumped out by each ventricle per minute. It averages about 5000 mL (5 litres) in a healthy individual. Formula: $\text{Cardiac Output} = \text{Stroke Volume} \times \text{Heart Rate}$.

6. Card 6 of 20

   Categorize humans, birds, and bony fishes based on their primary mode of nitrogenous waste excretion.

   Hint: Ammonia requires the most water to eliminate; Uric acid requires the least.

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   Answer

   Humans: Ureotelic (excrete Urea). Birds: Uricotelic (excrete Uric Acid as a paste/pellet to conserve water). Bony Fishes: Ammonotelic (excrete highly toxic Ammonia directly into water).

7. Card 7 of 20

   Which specific part of the nephron is lined by simple cuboidal brush border epithelium and reabsorbs 70-80% of electrolytes and water?

   Hint: The brush border microvilli massively increase the surface area for reabsorption.

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   Answer

   The Proximal Convoluted Tubule (PCT).

8. Card 8 of 20

   In the Renin-Angiotensin mechanism, what are the primary effects of Angiotensin II?

   Hint: Renin is released by the Juxtaglomerular (JG) cells when blood pressure drops.

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   Answer

   1. It is a powerful vasoconstrictor, which increases glomerular blood pressure and GFR. 2. It activates the adrenal cortex to release Aldosterone, causing reabsorption of $Na^+$ and water from the DCT.