Human Physiology: Respiratory and Circulatory Systems

Study Notes

Breathing refers to the physical act of inhaling and exhaling air.
Internal respiration involves cellular processes of utilizing oxygen and producing carbon dioxide.
The lungs are essential for oxygen intake and carbon dioxide expulsion.
Gas exchange occurs primarily in the alveoli, where oxygen enters the blood, and carbon dioxide is released.
The pathway for air: Nasal/Oral Cavity → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli → Lungs.
The right lung consists of three lobes: superior, middle, and inferior, while the left lung has two lobes: superior and inferior.

Circulation is the process of pumping blood throughout the body.
Coronary circulation pertains to blood flow in the heart.
Pulmonary circulation refers to blood flow from the heart to the lungs for oxygenation.
Systemic circulation involves blood flow from the heart to the rest of the body.
The heart has four chambers: right atrium, left atrium, right ventricle, and left ventricle.
Deoxygenated blood returns to the right side of the heart, while oxygenated blood exits from the left side.
Blood flow sequence: Body → Right Atrium → Right Ventricle → Lungs (via Pulmonary Arteries) → Left Atrium → Left Ventricle → Body (via aorta).

Bicuspid (2 leaflets) is found on the left side of the heart.
Tricuspid (3 leaflets) is located on the right side.
Pulmonary valve controls blood flow from the right ventricle to the pulmonary arteries.
Aortic valve controls blood flow from the left ventricle into the aorta.
The aorta is the largest artery, distributing oxygen-rich blood to the body.

Blood consists of four main components:
- Red Blood Cells: Transport oxygen and carbon dioxide.
- White Blood Cells: Defend against infections and foreign substances.
- Platelets: Aid in blood clotting to prevent excessive bleeding.
- Plasma: The liquid component that carries nutrients, hormones, and waste.

Arteries: Carry blood away from the heart; have thick walls to withstand high pressure.
Veins: Return deoxygenated blood to the heart; possess valves to ensure one-way flow.
Capillaries: Tiny vessels facilitating the exchange of oxygen, nutrients, and waste; have the thinnest walls.

DNA stands for deoxyribonucleic acid, the hereditary material in all known living organisms.
Gregor Mendel is recognized as the father of genetics, known for his work with pea plants.
DNA has four nitrogenous bases: Cytosine (C) pairs with Guanine (G), while Adenine (A) pairs with Thymine (T).
DNA is wrapped around proteins called histones and organized into structures known as chromosomes.
Humans have a total of 46 chromosomes: 23 from the father and 23 from the mother. The 23rd pair determines biological sex.
Genes are DNA segments that code for specific traits, while phenotype refers to an organism's observable characteristics.

Dominant traits are expressed when at least one dominant allele is present.
Recessive traits are only expressed when two recessive alleles are present.
Homozygous individuals have identical alleles for a gene; heterozygous individuals have different alleles.
Punnett squares are tools used to predict offspring genotypes based on parental crosses.
Non-Mendelian inheritance refers to patterns that diverge from classical Mendelian genetics.
Incomplete dominance leads to hybrid traits seen in the phenotype, while codominance showcases both alleles' traits fully expressed in the offspring.