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Biology: Human Physiology, Health, and Response - Lifestyle, Mental Health, and Access to Healthcare

Grade 8IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Human Physiology and Homeostasis: The body maintains a stable internal environment through feedback loops. For example, blood glucose levels are regulated by insulin and glucagon to stay around 90 mg/dL90\text{ mg/dL}.

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Lifestyle and Non-Communicable Diseases (NCDs): Poor diet, lack of exercise, and substance abuse (tobacco/alcohol) increase the risk of diseases such as Type 2 Diabetes and Cardiovascular disease. Obesity is often categorized using the Body Mass Index (BMIBMI).

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Mental Health and Neurobiology: Stress triggers the release of hormones like cortisol (C21H30O5C_{21}H_{30}O_{5}) and adrenaline. Chronic stress can lead to an imbalance in neurotransmitters like Serotonin and Dopamine, affecting mood and cognitive function.

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Access to Healthcare: Health outcomes are influenced by socio-economic factors. Universal Health Coverage (UHC) aims to provide quality services without financial hardship. Access is measured by the availability, affordability, and acceptability of medical services.

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The Role of Exercise: Physical activity improves cardiovascular health by increasing the stroke volume of the heart and reducing the Resting Heart Rate (RHRRHR).

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Nutritional Requirements: A balanced diet must provide sufficient kilojoules (kJkJ) to match the Total Daily Energy Expenditure (TDEETDEE).

📐Formulae

BMI=mass (kg)height (m)2BMI = \frac{\text{mass (kg)}}{\text{height (m)}^2}

Maximum Heart Rate (MHR)=220−age\text{Maximum Heart Rate (MHR)} = 220 - \text{age}

Energy Balance=Energy Intake−Energy Expenditure\text{Energy Balance} = \text{Energy Intake} - \text{Energy Expenditure}

Heart Rate (bpm)=Number of beats countedTime in seconds×60\text{Heart Rate (bpm)} = \frac{\text{Number of beats counted}}{\text{Time in seconds}} \times 60

💡Examples

Problem 1:

An individual has a mass of 75 kg75\text{ kg} and a height of 1.8 m1.8\text{ m}. Calculate their Body Mass Index (BMIBMI) and determine their weight category.

Solution:

BMI=751.82=753.24≈23.15BMI = \frac{75}{1.8^2} = \frac{75}{3.24} \approx 23.15

Explanation:

Using the formula BMI=massheight2BMI = \frac{\text{mass}}{\text{height}^2}, we find the value is approximately 23.1523.15. Since this value falls between 18.518.5 and 24.924.9, the individual is in the 'Healthy Weight' category.

Problem 2:

During a 15-second interval after exercise, a student counts 32 heartbeats. Calculate the heart rate in beats per minute (bpm).

Solution:

Heart Rate=3215×60=32×4=128 bpm\text{Heart Rate} = \frac{32}{15} \times 60 = 32 \times 4 = 128\text{ bpm}

Explanation:

To find the beats per minute, we multiply the number of beats found in a fraction of a minute by the factor required to reach 60 seconds (in this case, 60/15=460 / 15 = 4).

Problem 3:

A patient's medical bill is Rs 5000. If their insurance covers 80%80\%, calculate the out-of-pocket expense.

Solution:

5000×0.201000\begin{array}{r} 5000 \\ \times 0.20 \\ \hline 1000 \end{array}

Explanation:

If the insurance covers 80%80\%, the patient pays 20%20\%. 20%20\% of Rs 5000 is Rs 1000. This reflects the 'affordability' aspect of healthcare access.