Human physiology is a critical component of the International Baccalaureate (IB) Biology syllabus. This study note document will cover Option D - Human Physiology, breaking down complex concepts into manageable sections. The primary areas of focus include digestion and absorption, the blood system, defense against infectious disease, gas exchange, neurons and synapses, and hormones, homeostasis, and reproduction.
Digestion is the process by which large, insoluble food molecules are broken down into small, soluble molecules that can be absorbed into the bloodstream. Absorption is the uptake of these molecules into the body's cells.
Example:
Example: Glucose absorption involves active transport using sodium-glucose transport proteins (SGLT) in the intestinal lining.
The blood system is responsible for the circulation of blood, which transports nutrients, gases, hormones, and waste products.
The cardiac cycle includes the systole (contraction) and diastole (relaxation) phases of the heart.
$$ \text{Cardiac Output} = \text{Heart Rate} \times \text{Stroke Volume} $$
Note:
Note: The left side of the heart deals with oxygenated blood, while the right side deals with deoxygenated blood.
The skin acts as a physical barrier to pathogens.
A cascade of reactions involving clotting factors leads to the formation of a blood clot.
Antibiotics inhibit the growth of or kill bacteria.
Occurs when bacteria mutate and develop resistance to antibiotics.
Common Mistake:
Common Mistake: Assuming antibiotics are effective against viral infections. They are only effective against bacterial infections.
Gas exchange involves the transfer of oxygen and carbon dioxide between the lungs and blood.
Small air sacs in the lungs where gas exchange occurs.
Tip:
Tip: Remember the high surface area and thin walls of alveoli facilitate efficient gas exchange.
Neurons are specialized cells that transmit nerve impulses.
Synapses are junctions between neurons where neurotransmitters are released to propagate the signal.
A rapid change in membrane potential that travels along the neuron.
$$ \text{Resting Potential} \approx -70 , \text{mV} $$
Chemical messengers that regulate physiological processes.
The maintenance of a stable internal environment.
Involves the production of gametes and the process of fertilization.
Determined by the presence of the Y chromosome.
Determined by the absence of the Y chromosome.
Understanding diagrams of reproductive systems and processes.
This study note document has provided an overview of key topics within human physiology as outlined in the IB Biology syllabus. By breaking down complex concepts and using examples, notes, and tips, we have aimed to make this information more digestible and easier to understand.