Respiration and Circulation — Class 12 Maharashtra HSC Biology revision notes
A 6-page visual revision sheet for Respiration and Circulation, written for Class 12 Maharashtra HSC Biology. Formulas, diagrams and the traps that cost marks, laid out to be read the night before rather than the term before. Free, and it opens inside CapCompass.
Page 1 as PDF
Respiration and Circulation in one look
700 million alveoli doing the exchange, a double pump doing the delivery
Respiration, the energy conversion
- respiration: biochemical, orderly oxidation of organic compounds to liberate chemical energy as ATP
- C6H12O6 + 6O2 → 6CO2 + 6H2O + 38 ATP
- respiratory surface: where gases exchange with the environment
- an efficient one is large in area, thin, highly vascular and permeable, and moist
Gaseous exchange in plants
- land plants: continuous air spaces through stem, leaf, root
- O2 diffuses in via stomata, CO2/water vapour diffuse out
- aerated soil: O2 dissolves in the moisture film around root tissue, then diffuses in
- woody plants exchange gases through lenticels, pores in the otherwise impervious bark
Respiratory surfaces across animals
- protists, sponges, coelenterates (aquatic): plasma membrane
- flatworms, annelids, frog (aquatic/semiaquatic): moist body surface
- insects (terrestrial): tracheal tubes + spiracles
- spiders, scorpions (terrestrial): book lungs
- Limulus (aquatic): book gills; fish (aquatic): internal gills
- reptiles, birds, mammals (terrestrial): lungs
- one process, diffusion, across all of them: the same three rules of area, thinness, moisture
Human respiratory tract: upper
- nasal chamber, 3 regions: vestibule (hair-filtered), respiratory (warms/moistens air), olfactory (smell)
- pharynx: nasopharynx → oropharynx (shared with food) → laryngopharynx; carries the tonsils
- larynx (voice box): true vocal cords produce sound; opens via the glottis
- leaf-shaped epiglottis guards it, blocking food from entering the trachea
Trachea and bronchi
- trachea: 10-12 cm, held open by 16-20 C-shaped cartilage rings
- lining: ciliated pseudostratified, with mucous glands
- right/left primary bronchi → secondary, tertiary bronchi → terminal bronchioles → alveoli
Page 1 of 6. The full sheet, all 6 pages, opens free in the app.
What this Respiration and Circulation sheet covers
- Respiration, the energy conversion
- Gaseous exchange in plants
- Respiratory surfaces across animals
- Human respiratory tract: upper
- Trachea and bronchi
- Lungs and alveoli
- Breathing: an active pressure pump
- Lung volumes and capacities
- External respiration: gas exchange at alveoli
- Oxygen transport and CO poisoning
- Bohr effect vs Haldane effect
- Carbon dioxide transport, three routes
- Chloride shift (Hamburger's phenomenon)
- How O2 and CO2 ride in blood
- Cellular respiration and its ATP
- Regulation of breathing
- Respiratory disorders
- Transportation in organisms
- Open vs Closed, Single vs Double circulation
- Blood, composition
- Erythrocytes (RBCs)
- The five leucocytes, by proportion
- Platelets and clotting
- Heart, external anatomy
- Heart, internal: chambers
- Heart valves
- The heart in section
- Conducting system of the heart
- ECG, the three waves
- The cardiac cycle, 0.8 sec
- Cardiac output and rate control
- Artery, Vein, Capillary
- Blood pressure
- Vessel disorders
- Lymphatic system
- Traps that cost marks
- Tricks that save time
How CapCompass uses this sheet
These notes are not a standalone PDF. CapCompass plans Biology chapter by chapter against your real exam dates and free hours, and when the plan reaches Respiration and Circulation the sheet opens inside the study block itself — at the page covering the sub-topic that block is on, with the timer still running. Revision arrives at the moment the plan says revise, instead of having to be gone looking for.
More Biology Class 12 revision notes
- Biodiversity, Conservation and Environmental Issues
- Biotechnology
- Control and Co-ordination
- Ecosystems and Energy Flow
- Enhancement of Food Production
- Human Health and Diseases
- Inheritance and Variation
- Molecular Basis of Inheritance
- Organisms and Populations
- Origin and Evolution of Life
- Plant Growth and Mineral Nutrition
- Plant Water Relation
- Reproduction in Lower and Higher Animals
- Reproduction in Lower and Higher Plants