krit.club logo

Interaction and interdependence - Integration of body systems

Grade 11IBBiology

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

🔑Concepts

•

Integration of body systems is primarily achieved through the coordination of the nervous and endocrine systems, often linked by the hypothalamus.

•

Homeostasis is the maintenance of a constant internal environment, such as blood pHpH, body temperature, and blood glucose levels, despite changes in the external environment.

•

Negative feedback loops are the primary mechanism for homeostasis. A change in a variable (e.g., rise in glucose) triggers a response that counteracts the initial change.

•

The hypothalamus acts as a control center that receives sensory input and coordinates responses via the pituitary gland, releasing hormones like ADHADH (Antidiuretic Hormone) for osmoregulation.

•

Thermoregulation involves the integration of the integumentary, circulatory, and nervous systems to maintain body temperature at approximately 37∘C37^{\circ}C.

•

Respiratory and circulatory systems are integrated to maintain optimal gas exchange. For example, during exercise, the partial pressure of CO2CO_{2} (PCO2P_{CO_{2}}) increases, leading to a decrease in pHpH, which triggers an increase in heart and ventilation rates.

📐Formulae

RQ=Volume of CO2 producedVolume of O2 consumedRQ = \frac{\text{Volume of } CO_{2} \text{ produced}}{\text{Volume of } O_{2} \text{ consumed}}

CO=HR×SVCO = HR \times SV

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

ΔT=Tfinal−Tinitial\Delta T = T_{final} - T_{initial}

💡Examples

Problem 1:

During an exercise session, a student's heart rate (HRHR) increases to 120120 beats per minute (bpm). If their stroke volume (SVSV) is measured at 7575 ml per beat, calculate the total Cardiac Output (COCO) in liters per minute (L⋅min−1L \cdot min^{-1}).

Solution:

CO=120 bpm×75 ml/beatCO = 120 \text{ bpm} \times 75 \text{ ml/beat} CO=9000 ml/minCO = 9000 \text{ ml/min} CO=90001000=9.0 L/minCO = \frac{9000}{1000} = 9.0 \text{ L/min}

Explanation:

Cardiac Output is the volume of blood pumped by the heart per minute. It is calculated by multiplying the heart rate (frequency) by the stroke volume (volume per contraction). To convert ml to liters, we divide by 10001000.

Problem 2:

A cell is respiring a specific substrate. It consumes 66 moles of O2O_{2} and produces 66 moles of CO2CO_{2}. Calculate the Respiratory Quotient (RQRQ) and identify the likely substrate.

Solution:

RQ=6 moles CO26 moles O2=1.0RQ = \frac{6 \text{ moles } CO_{2}}{6 \text{ moles } O_{2}} = 1.0

Explanation:

An RQRQ value of 1.01.0 indicates that the substrate being oxidized is a carbohydrate (like glucose). The integrated response of the respiratory system ensures that O2O_{2} uptake matches the metabolic demand of the tissues.

Problem 3:

A patient has a mass of 8080 kg and a height of 1.81.8 m. Calculate their Body Mass Index (BMIBMI) and determine if it falls within the healthy range (18.518.5 to 24.924.9).

Solution:

BMI=801.82BMI = \frac{80}{1.8^{2}} BMI=803.24BMI = \frac{80}{3.24} BMI≈24.69BMI \approx 24.69

Explanation:

The calculated BMIBMI is approximately 24.6924.69. Since 24.6924.69 is between 18.518.5 and 24.924.9, the patient is within the healthy weight range. BMIBMI is used as an integrated indicator of body composition and potential health risks related to system stressors.