Science Notes 24

What does it mean to be undernourished?

What does it mean to be undernourished?

Insufficient calorie intake and lack of essential nutrients leading to adverse health effects.

Which countries are most in need of food?

South Sudan, Yemen, Ethiopia, Madagascar, and Afghanistan.

What are the main causes of hunger?

Conflict and instability, climate change and natural disasters, economic factors and poverty, and poor infrastructure and food distribution.

How can food waste be minimized?

Educate consumers on portion sizes, implement better supply chain practices, utilize food recovery networks, and encourage composting and recycling of food scraps.

What does a balanced diet consist of?

Carbohydrates, proteins, lipids, vitamins, minerals, dietary fiber, and water.

What are the four main nutrients and their roles?

Carbohydrates provide energy, proteins are for growth and repair, fats/oils provide insulation & energy, and vitamins support healthy gums.

What are the impacts of excessive sugar consumption?

Increased risk of cardiovascular disease, obesity, and diabetes.

What is photosynthesis?

A process that converts light energy into chemical energy (glucose).

What is the equation for photosynthesis?

6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂. carbon dioxide + water + sunlight -> oxygen and glucose

What is the purpose of cellular respiration?

To release energy by breaking down glucose.

What is the equation for cellular respiration?

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP). carbohydrate plus oxygen forms carbon dioxide plus water.

What are the three common types of forces?

Contact forces, non-contact forces, and friction.

What is a contact forces? Give an example

Forces that require one object to touch another (e.g., cricket ball and bat).

What are electrostatic forces?

Forces applied between electrically charged objects.

How is friction defined?

A force that resists or prevents the motion of two surfaces in contact.

What is the gravitational force?

The force that keeps you bound to the Earth.

What happens when an object experiences an unbalanced force?

The object will move in the direction of the greater force.

How does air resistance affect moving objects?

Air resistance increases with an object's speed and contact with more air particles.

What is terminal velocity?

The constant speed reached when the weight force and air resistance are balanced.

What is meant by mass versus weight?

Mass is the total amount of matter in an object, while weight is the force of gravity on that object.

What is the formula for calculating weight?

Weight = mass (m) × gravity (g).

What are the basic needs of cells?

Matter, energy sources, water, waste removal, and ions.

What is the primary function of the circulatory system?

To transport nutrients to organs and collect waste products.

What process occurs in the mitochondria for energy production?

Cellular respiration.

how is oxygenated blood transported to the heart

Oxygenated blood is transported from the lungs to the heart through the pulmonary veins.

What is the function of the heart?

To pump blood throughout the body continuously.

What are the roles of arteries and veins?

Arteries carry oxygenated blood away from the heart, and veins carry deoxygenated blood back to the heart.

What is the significance of valves in the heart?

Valves prevent the backward flow of blood within the heart.

How is blood oxygenated in the body?

Blood is oxygenated in the lungs before returning to the heart.

What are capillaries responsible for?

Exchange of oxygen, nutrients, and waste products between blood and tissues.

What happens during fainting?

A decreased blood flow to the brain leads to loss of consciousness.

What is the system of organs working together called?

Organ system.

What do epithelial tissues do?

Cover and protect surfaces, both inside and outside the body.

What nutrients are vital for cellular needs?

Oxygen, glucose, ions, and water.

What is the function of the sinoatrial node?

It acts as the natural pacemaker of the heart, controlling the heartbeat.

What is meant by homeostasis?

The maintenance of stable internal conditions in the body.

What occurs if the aorta is obstructed?

Oxygenated blood cannot be supplied to the body, leading to rapid organ failure.

What role does the pulmonary artery serve?

It carries deoxygenated blood from the heart to the lungs.

What happens if waste products are not removed from cells?

Cellular function deteriorates, potentially leading to organ failure.

What are the components of blood?

Plasma and blood cells.

Why is it important to maintain fluid balance in the body?

To ensure proper function of cells and organs.

How do oxygen and carbon dioxide exchange in capillaries?

Oxygen moves into tissues, and carbon dioxide moves into blood.

What happens to nutrients delivered by the circulatory system?

They provide energy and support growth and repair of tissues.

What is the role of red blood cells?

To carry oxygen throughout the body.

How does the heart keep blood moving?

By rhythmically contracting and relaxing.

What do the atria do?

They receive blood from the veins and send it to the ventricles.

What is the main energy source for living organisms?

Glucose.

What could happen if the heart were to stop beating?

Blood circulation would cease, leading to loss of consciousness and death.

What process is vital for sustaining life by converting food into energy?

Cellular respiration.

What happens if the pulmonary veins are blocked?

Oxygenated blood cannot return to the heart, causing oxygen deprivation.

What would occur without the presence of capillaries?

Exchange of oxygen and nutrients with tissues would be impossible.

What is the relationship between mass and weight?

Weight is dependent on mass and gravitational pull.

What causes the heart to contract?

Electrical signals from the sinoatrial node.

How does gravity affect circulation in the body?

It can influence blood flow; standing can impede blood return from the legs.

What is the function of the left ventricle?

To pump oxygenated blood to the body.

Why are the walls of ventricles thicker than those of atria?

To create sufficient pressure to pump blood out of the heart.

What role do hormones play in the circulatory system?

Hormones travel through blood to regulate activities in different organs.

How does the body respond to an increased need for oxygen during exercise?

Heart rate and breathing rate increase to supply more oxygen.

What happens to muscle tissues during rigorous activity?

They may produce lactic acid due to anaerobic respiration.

What could result from a malfunctioning sinoatrial node?

Irregular heartbeats leading to possible cardiac issues.

What is the significance of smooth muscle in blood vessels?

It regulates blood flow and pressure.

What might happen if valves in the heart fail?

Blood may leak backward, leading to reduced efficiency and fatigue.

What engages during increased physical activity?

The heart and respiratory system work together to supply oxygen and nutrients.

How does the heart ensure unidirectional blood flow?

Through the use of valves that only allow blood to flow in one direction.

What could occur if the circulatory system fails?

Cells and organs may become deprived of oxygen and nutrients, leading to death.

How does blood pressure aid circulation?

It pushes blood through the circulatory system to supply organs.

What is arterial blood?

Blood that is rich in oxygen, supplied from the lungs to the body.

How do valves function in the return of blood to the heart?

Valves prevent backflow, ensuring blood returns to the heart efficiently.

What symmetry is observed in the position of the heart?

It is slightly tilted left, with identical sides for atria and ventricles.

How does the body respond to low blood oxygen levels?

Breathing rate increases to take in more oxygen.

What can result from blocked arteries?

Reduced blood flow, potential organ damage, and heart attacks.

How does temperature affect blood flow?

Increased heat can dilate blood vessels, enhancing blood flow.

What is the effect of dehydration on the circulatory system?

It can reduce blood volume, affecting circulation and oxygen delivery.

What is the role of the lymphatic system in relation to blood?

It helps return leaked fluids back to the circulatory system.

What factors influence heart contraction strength?

Fitness level, hydration, and autonomic nervous system activity.

How does adrenaline affect heart function?

It increases heart rate and contractility, preparing the body for action.

Why is respiratory health crucial for the circulatory system?

To ensure adequate oxygen exchange for effective blood oxygenation.

What happens to blood flow during rest and activity?

It increases during activity and reduces during rest to conserve energy.

How is heart health measured?

Through blood pressure readings and heart rate assessments.

What impact does smoking have on the circulatory system?

It can lead to stiff arteries and reduced oxygen availability.

How do stress levels influence heart rate?

Increased stress can raise heart rate and blood pressure.

What dietary factors support circulatory health?

Balanced intake of nutrients, hydration, and low salt.

What is the relationship between exercise and cardiovascular health?

Regular exercise strengthens the heart and improves circulation.

What can result from irregular heart rhythms?

Compromised blood flow and increased risk of stroke.

How does blood distribution change during exercise?

More blood is directed to muscles and skin to support activity.

What factors can cause vascular injuries?

High blood pressure, cholesterol, and tobacco use.

How does eating a balanced diet influence the circulatory system?

It provides essential nutrients for heart function and vascular health.

What role does vitamin K play in the circulatory system?

It helps with blood clotting processes.

What symptoms might indicate circulatory issues?

Fatigue, shortness of breath, and swelling.