Levels of Organisation and Human Systems

Flashcards covering key concepts related to human organ systems, diseases, and physiological processes.

What are the main levels of organization in multicellular organisms?

Cells → tissues → organs → organ systems → organism

Name the main organ systems in the human body.

Circulatory, digestive, respiratory, excretory, nervous, endocrine, reproductive, muscular, skeletal, immune.

What is the function of the heart?

Pumps blood around the body, supplying oxygen and nutrients and removing carbon dioxide and waste.

Describe the structure of arteries, veins, and capillaries.

Arteries: thick, elastic walls for high pressure. Veins: thin walls, valves to prevent backflow. Capillaries: one cell thick for diffusion.

How is the structure of the heart related to its function?

Left ventricle has thick muscular wall for high-pressure systemic circulation; valves prevent backflow; chambers separate oxygenated and deoxygenated blood.

What is the function of red blood cells?

Transport oxygen using haemoglobin.

What is the function of white blood cells?

Fight infection (phagocytosis and antibody production).

What is the function of platelets?

Aid blood clotting to prevent blood loss.

What is the function of plasma?

Transports nutrients, hormones, carbon dioxide, and waste products.

Describe coronary heart disease and treatments.

Arteries become blocked by fatty deposits. Treatments include stents and statins.

What are the components of the human digestive system?

Mouth, oesophagus, stomach, small intestine, large intestine, pancreas, liver, gallbladder.

What is the function of enzymes in digestion?

Break down large molecules into smaller molecules: amylase (starch → maltose), protease (protein → amino acids), lipase (fats → glycerol + fatty acids).

How do pH and temperature affect enzyme activity?

Optimum pH and temperature produce maximum activity. Deviation can denature the enzyme, reducing activity.

What is the role of bile in digestion?

Produced by liver, stored in gallbladder; neutralises stomach acid and emulsifies fats for digestion.

What are the main types of disease?

Communicable (infectious) and non-communicable (chronic) diseases.

Give examples of communicable diseases and how they spread.

Measles (airborne), HIV (bodily fluids), Salmonella (contaminated food), Malaria (vector).

How can the spread of diseases be reduced?

Vaccination, hygiene, isolating infected individuals, controlling vectors, safe food preparation.

Explain how lifestyle factors affect disease risk.

Diet, exercise, smoking, alcohol, and obesity influence risk of cardiovascular disease, type 2 diabetes, and some cancers.

Describe the structure and function of plant tissues involved in transport.

Xylem: transports water, strengthened by lignin. Phloem: transports sugars, uses companion cells for active transport.

Explain how the structure of the lungs allows efficient gas exchange.

Alveoli have large surface area, thin walls, and good blood supply for diffusion of oxygen and carbon dioxide.

How do capillaries adapt for diffusion?

Thin walls (one cell thick), large network for high surface area, close to body cells.

What is the effect of exercise on the circulatory system?

Increases heart rate and stroke volume to deliver more oxygen to muscles.

How do the digestive, circulatory, and respiratory systems work together?

Digestive system provides nutrients, respiratory system provides oxygen, circulatory system transports both to cells for respiration.

What are the main risk factors for cardiovascular disease?

Smoking, high blood pressure, high cholesterol, obesity, lack of exercise.

How can non-communicable diseases be prevented?

Healthy diet, regular exercise, avoid smoking and excessive alcohol, maintain healthy weight.