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Understanding the Lymphatic System: Functions, Lymphocytes, and Composition

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1. Know the functions of the lymphatic system

· Produce, maintain, and distribute lymphocytes and other lymphoid cells that provide defense against infections and foreign substances PRIMARY FUNCTION. Return of excess fluid to bloodstream. Transport of lipids absorbed in digestive tract

2. Know the three subtypes of lymphocytes and what type of immunity each is responsible for

· T cells à Cell-mediated immunity (4+ subtypes)

  • Cytotoxic T Cells (Tc) - direct cellular attack
  • Helper T Cells (TH) and Suppressor T Cells (TS) - regulatory roles
  • Memory T Cells.

B Cells à Antibody-mediated immunity

  • Antibodies (immunoglobulins)
  • Antigen - usually proteins (specific chemical targets)

· NK Cells à Immunological surveillance

3. Know where the three types of lymphocytes

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Cell Biology: Structure, Function, and Division

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Cell Structure and Function

A cell is the smallest structural and functional unit of life that can carry out the three vital functions: nutrition, reproduction, and interaction.

  • Nutrition: obtaining energy, renewing the cellular structure, and obtaining biomolecules.
  • Interaction: cells can adapt to changes in their environment and continue performing the activities they need to live.
  • Reproduction: formation of new cells.

Types of Cells

Prokaryotic Cells

Prokaryotic cells do not have membrane-bound structures, are relatively small, have a single circular chromosome, have isolated ribosomes in their cytoplasm, and have cavities in their cytoplasm that function as mitochondria. Organisms belonging to the Monera kingdom have prokaryotic cells.

Eukaryotic

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English Phonetics: Consonants and Articulation

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Vowels and Consonants

A vowel is a sound produced without any closure in the mouth or throat. There's no obstruction in the buccal cavity. A consonant, conversely, involves at least one stoppage of airflow during vocalization.

Places of Articulation

The place of articulation describes where the obstruction occurs in the vocal tract. It's the point of contact between an active articulator (usually part of the tongue) and a passive articulator (typically part of the roof of the mouth).

  • Bilabial: Both lips.
  • Labio-dental: Upper lip and upper front teeth.
  • Dental: Tongue tip/blade and upper front teeth.
  • Alveolar: Tongue tip/blade and alveolar ridge.
  • Post-alveolar: Tongue blade and back of the alveolar ridge.
  • Palatal: Tongue front and hard palate.
  • Velar: Tongue
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Understanding the Circulatory and Respiratory Systems

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Blood Flow and the Circulatory System

Blood flow refers to the circulation of blood pumped by the heart through the circulatory system. In humans, blood circulation is:

  • Double: Blood passes through the heart twice in every complete cycle.
  • Complete: Oxygen-rich blood and carbon dioxide-rich blood do not mix because the two sides of the heart are separated by the septum.

Pulmonary Circuit

The pulmonary circuit, or shorter circuit, is the path blood takes between the heart and the lungs. The right side of the heart pumps blood through this circuit.

  1. Blood carrying carbon dioxide, waste, and nutrients picked up throughout the body enters the right atrium through the inferior vena cava and then passes into the right ventricle.
  2. The blood leaves the right
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Understanding the Human Senses and Their Disorders

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Sense of Smell: Enables the body to detect chemical molecules in the air. Molecules are detected by chemoreceptors in the nasal cavities. Sensations they receive are called smells.

Types of Nasal Mucous Membranes:

  • Respiratory Mucous Membrane: Has blood vessels that warm inhaled air and hairs that trap dust particles.
  • Olfactory Mucous Membrane: Contains the olfactory receptors. Chemoreceptors converge in the olfactory bulb. Receptors transmit impulses along the olfactory nerve to the brain when stimulated by chemicals.

Sense of Taste: Enables the body to detect flavors. Four basic tastes: sweet, salty, sour, and bitter. Chemoreceptors respond to chemicals dissolved in saliva, located mainly on the tongue, but also on the palate, pharynx, and larynx.... Continue reading "Understanding the Human Senses and Their Disorders" »

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Understanding DNA and RNA: From Structure to Gene Expression

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DNA: Structure and Essential Functions

Deoxyribonucleic Acid (DNA) is the genetic material, composed of chains of deoxyribonucleotides (Adenine, Guanine, Cytosine, Thymine – A, G, C, T). Except in some viruses, DNA typically comprises two nucleotide chains.

It is found in the nucleus of eukaryotic cells (as linear molecules) and in the cytoplasm of prokaryotic cells, some viruses, and certain organelles like mitochondria and chloroplasts (where it is circular in shape).

DNA Structure

The structure of DNA can be described at different levels:

  • Primary Structure: Consists of a linear sequence of nucleotides.
  • Secondary Structure: The renowned Double Helix Model, proposed by Watson & Crick in 1953. Key features include:
    • Double chains of deoxyribonucleotides.
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Population Genetics: An Evolutionary Overview

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Population Genetics

Microevolution

Change in the collective genetic material of a population.

Bell Curve

Shows the frequency of a trait in a population.

Gene Pool

Describes the total genetic information available in a population.

Hardy-Weinberg Genetic Equilibrium

Principle based on a set of assumptions about an ideal hypothetical population that is not evolving.

Immigration

Movement of individuals into a population.

Emigration

Movement of individuals out of a population.

Gene Flow

Process of genes moving from one population to another.

Sexual Selection

Tendency of females to choose the males they mate with based on certain traits.

Stabilizing Selection

Individuals with the average form of a trait have the highest fitness.

Disruptive Selection

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Stages of Cell Division and Meiosis

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Name the stage of cell division in which paired homologous chromosomes get shortened and thickened?

Ans: Pachytene is the stage of cell division in which paired homologous chromosomes get shortened and thickened.

Which structure of animal cell forms the asters of spindle?

Ans: Centrosome is that structure of animal cell which forms the asters of spindle.

Name the cells in which meiosis occurs?

Ans: Meiosis occurs in the reproductive cells or germ cells.

At which stage of meiosis crossing over of genetic material takes place?

Ans: Pachytene is the stage of meiosis in which crossing over of genetic material takes place.

What is Go phase?

Ans: A stage when cell cycle is arrested during interphase is called Go phase.

Name the cell division concerned with

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How Your Body Fights Germs and Illnesses

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Understanding Microorganisms and Disease

Viruses (e.g., flu, polio, common cold, AIDS, Ebola, chickenpox, measles, rubella, smallpox, mumps) are microscopic, measured in nanometers. Bacteria (e.g., tuberculosis, botulism, meningitis, tonsillitis, bronchitis, cystitis) are visible with an optical microscope, typically 1-5 micrometers. Fungi (e.g., athlete's foot, thrush, ringworm, candidiasis) are visible with an optical microscope, around 50 micrometers. Protozoa (e.g., malaria, dysentery) are also visible with an optical microscope, around 50 micrometers.

These microorganisms cause infectious diseases, which are illnesses that can spread to other people. Diseases not caused by pathogens are known as non-infectious diseases.

Vectors and Lifestyle

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Human Body Systems: Digestive and Respiratory Organs Explained

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Digestive System Organs

Esophagus

  • Tube approximately 25 cm long.
  • Located behind the trachea and in front of the spinal cord.
  • Drives the food bolus from the pharynx to the stomach.
  • Its muscles produce peristaltic movements to ensure food reaches the stomach.
  • Produces mucus, which favors food transit.

Pylorus

  • A sphincter that communicates with the small intestine (duodenum).

Shared & Digestive System Components

Pharynx

  • A duct located behind the mouth.
  • Contains lumps called tonsils.
  • Communicates the mouth with:
    • Esophagus
    • Back of the nostrils
    • Larynx
    • Middle ear

Epiglottis

  • A flap located in the lower part of the pharynx.
  • Closes the entrance to the larynx during swallowing.
  • Prevents food from entering the respiratory tract.

Cardia (Cardiac Sphincter)

  • A sphincter that
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