Hair Structure, Bonds, and Circulatory System Functions
Hair Structure and Chemical Bonds
Differences and Hair: Hair, including the hair on the scalp, serves a profound aesthetic function. It differs from hair found elsewhere on the body.
Peptide Bond: A peptide bond is the union of two amino acids in a chain. These bonds can only be broken with very strong acids.
Hydrogen Bond: A hydrogen bond is an attraction between hydrogen (H) and oxygen (O) atoms within the same chain. These bonds can be broken with water or heat.
Ionic Bonds: These bonds involve the attraction between hydrogen and oxygen atoms, as well as sulfur atoms. They are electric attractions (+ and -) and cation-anion attractions between two chains. These bonds can be altered by changes in pH.
Disulfide Bond: A disulfide bond involves two sulfur atoms (in two chains) and can be altered by oxidizers and reducers.
Hair Structure Components
The structure of hair includes the medulla of the cortex, melanin glands, the cortex, and cuticles.
Nail Structure and Function
Nail Plate: The nail plate is a convex, hard, translucent, and flexible structure covering the dorsal part of the distal phalanges of the fingers and toes. It originates from epidermal cells and undergoes a keratinization process.
Function: Nails protect and facilitate activities involving finger pressure.
Parts: The nail consists of the cuticle, lunula, nail plate, free nail margin, distal phalanx, and bone matrix (the set of cells that produce the nail).
Circulatory and Lymphatic Systems
The circulatory system is composed of blood circulation and lymphatic circulation.
Blood Circulatory System
The blood circulatory system consists of:
- Heart: (2 atria, 2 ventricles, and 2 tubes)
- Blood Vessels:
- Arteries: Carry blood from the heart to various organs and tissues.
- Veins: Carry blood to the heart from organs and tissues.
- Capillaries: Facilitate the exchange of gases and substances between the blood and tissues.
Blood Composition and Functions
Blood: A red liquid tissue that flows through the blood vessels, driven by the heart. It is formed by plasma and cellular components, including:
- Red blood cells (function: carry oxygen and carbon dioxide)
- White blood cells (function: involved in the body’s defense mechanisms)
- Platelets (function: involved in the blood clotting process)
Functions: Blood transports nutrients and oxygen to the organs, collects waste products for removal, regulates temperature, transports hormones, and defends the body.
Heart Function
The heart has the ability to contract automatically. These contractions function as a pump that drives blood throughout the body. The heart includes the right and left atria and ventricles. They communicate through the mitral valve (left atrium and ventricle) and tricuspid valve (right atrium and ventricle).
- Systole: Contraction movement (atrial systole, ventricular systole)
- Diastole: Relaxation movement (atrial diastole and ventricular diastole)
Veins: Possess valves that prevent blood without oxygen from flowing backward.
Arteries: Carry oxygenated blood.
Why does warmth produce vasodilation? Because more blood circulates from the body’s interior, increasing temperature.
Where does the red color of blood come from? From the hemoglobin inside red blood cells.
The Journey of a Molecular Oxygen from the Lungs to the Heart: It is direct, through the pulmonary veins to the left atrium and then to the right ventricle and out to the body.
Why do people who stand for a long time have swollen legs? Because blood does not circulate normally; it costs more for the blood to circulate.
Blood Vessels Connected to the Atria: Right atrium -> vena cava, and left atrium -> pulmonary veins.
Blood Vessels Connected to the Ventricles: Right ventricle -> pulmonary artery, and left ventricle -> aortic artery.
Pulmonary Circuit
The pulmonary circuit is a closed circuit where blood moves, allowing the lungs to collect blood loaded with carbon dioxide (CO2) and remove it, while loading oxygen (O2). It takes the dirty blood, cleans it, and sends it out clean.
General Circuit
The general circuit is the circuit between the heart and blood throughout the body and back to the heart.
Cardiac Rhythm: The brain controls the movement of muscles and heart rate, making it faster or slower based on demand.