1. Human Anatomy & Physiology
Definition:
- Human Anatomy is the study of the structure of the human body and its parts. It is concerned with the physical organization of the body and the relationships between its various components.
- Human Physiology is the study of how the human body functions, including the mechanisms and processes by which body systems work together to maintain homeostasis and overall health.
Detailed Explanation:
A. Human Anatomy
- Skeletal System:
- Definition: The skeleton consists of bones and cartilage and provides structure, protection, and facilitates movement.
- Examples:
- Long bones: Femur, Humerus.
- Short bones: Carpals (wrist bones).
- Flat bones: Sternum, skull bones.
- Location: Throughout the body (e.g., bones of the arms, legs, spine, ribs).
- Muscular System:
- Definition: Muscles are responsible for movement and maintaining posture. There are three types of muscles: skeletal, cardiac, and smooth.
- Examples:
- Skeletal muscle: Biceps, quadriceps.
- Cardiac muscle: Found only in the heart.
- Smooth muscle: Walls of blood vessels, intestines.
- Location: Muscles are found in the limbs, torso, heart, and internal organs.
- Nervous System:
- Definition: The nervous system controls and coordinates body activities. It includes the brain, spinal cord, and nerves.
- Examples:
- CNS (Central Nervous System): Brain and spinal cord.
- PNS (Peripheral Nervous System): Nerves that extend from the spinal cord.
- Location: Brain is housed in the skull, spinal cord runs along the vertebral column.
- Circulatory System:
- Definition: The circulatory system is responsible for transporting blood, oxygen, nutrients, and waste products throughout the body.
- Examples:
- Heart: Pumps blood.
- Blood vessels: Arteries, veins, capillaries.
- Location: Heart is in the thoracic cavity, blood vessels are throughout the body.
- Digestive System:
- Definition: The digestive system breaks down food into smaller molecules for absorption into the bloodstream.
- Examples:
- Mouth: Digestion of carbohydrates begins with salivary amylase.
- Stomach: Pepsin digests proteins.
- Small intestine: Most nutrient absorption occurs here.
- Location: Mouth, stomach, small intestine, large intestine.
B. Human Physiology
- Cardiovascular System:
- Definition: The heart pumps blood through blood vessels, ensuring the delivery of oxygen and nutrients to tissues.
- Examples:
- Heart: Pumps oxygenated blood to the body.
- Arteries: Carry oxygenated blood from the heart to the body.
- Veins: Carry deoxygenated blood back to the heart.
- Location: Heart is located in the thoracic cavity, vessels are spread throughout the body.
- Respiratory System:
- Definition: The respiratory system ensures the exchange of gases (oxygen and carbon dioxide) between the blood and air.
- Examples:
- Lungs: Site of gas exchange.
- Trachea: Air passageway to the lungs.
- Alveoli: Tiny air sacs in the lungs where gas exchange occurs.
- Location: Lungs are in the thoracic cavity.
- Excretory System:
- Definition: The excretory system removes waste products from the body and maintains water and electrolyte balance.
- Examples:
- Kidneys: Filter blood to form urine.
- Bladder: Stores urine.
- Urethra: Excretes urine from the body.
- Location: Kidneys are in the abdominal cavity, bladder in the pelvic cavity.
- Endocrine System:
- Definition: The endocrine system regulates bodily functions using hormones produced by glands.
- Examples:
- Thyroid gland: Produces thyroxine, which regulates metabolism.
- Adrenal glands: Produce adrenaline for the fight or flight response.
- Location: Endocrine glands are located throughout the body (e.g., thyroid in the neck, adrenal glands on top of kidneys).
2. Microbiology
Definition:
Microbiology is the branch of science that deals with microorganisms, including bacteria, viruses, fungi, and protozoa. These microorganisms play crucial roles in health, disease, and the environment.
Detailed Explanation:
- Bacteria:
- Definition: Single-celled organisms that can be beneficial (e.g., gut flora) or harmful (e.g., Escherichia coli).
- Example: Staphylococcus aureus, Streptococcus pyogenes.
- Location: Found in various environments such as soil, water, and the human body.
- Viruses:
- Definition: Infectious agents that require a host cell to replicate. They consist of genetic material (DNA or RNA) encased in a protein coat.
- Example: HIV, Influenza, Hepatitis B.
- Location: Viruses are typically found in infected hosts (animals, plants, or humans).
- Fungi:
- Definition: Organisms that can be unicellular (yeasts) or multicellular (molds). Fungi can be pathogenic or beneficial (e.g., in food production).
- Example: Candida (yeast infection), Aspergillus (fungal lung infections).
- Location: Found in the environment, on the skin, and in body cavities.
- Protozoa:
- Definition: Single-celled organisms that can cause diseases in humans and animals.
- Example: Plasmodium (Malaria), Entamoeba histolytica (Amoebiasis).
- Location: Often found in contaminated water sources.
3. Biochemistry
Definition:
Biochemistry is the branch of science that deals with the chemical processes and substances that occur within living organisms. It studies biomolecules and their interactions.
Detailed Explanation:
- Proteins:
- Definition: Proteins are large molecules made up of amino acids. They play vital roles in structure, enzymes, transport, and immunity.
- Examples:
- Hemoglobin (transports oxygen in blood).
- Enzymes (e.g., amylase, pepsin).
- Location: Found throughout the body, including blood and cells.
- Carbohydrates:
- Definition: Carbohydrates are sugars and starches used as the primary source of energy.
- Examples:
- Glucose (simple sugar).
- Glycogen (stored form of glucose).
- Location: Found in blood (glucose) and liver (glycogen).
- Lipids:
- Definition: Lipids are fats and oils that store energy and are key components of cell membranes.
- Examples:
- Triglycerides (store energy).
- Phospholipids (cell membrane structure).
- Location: Stored in adipose tissue and cell membranes.
- Nucleic Acids:
- Definition: Nucleic acids store and transmit genetic information.
- Examples:
- DNA (deoxyribonucleic acid).
- RNA (ribonucleic acid).
- Location: Found in the nucleus of cells (DNA) and in the cytoplasm (RNA).
4. Pathology:
Pathology is the branch of medical science that deals with the study of diseases, including their causes, development, and effects on the body. Pathologists analyze changes in tissues, cells, and body fluids to diagnose diseases.
Branches of Pathology:
- Anatomical Pathology:
- Focuses on the structural changes in tissues and organs.
- Includes Histopathology (study of tissue samples), Cytopathology (study of individual cells), and Autopsy (post-mortem examination).
- Clinical Pathology:
- Deals with laboratory analysis of body fluids like blood, urine, and other fluids for diagnostic purposes.
- Includes Hematology, Clinical Chemistry, Microbiology, and Immunology.
Types of Pathological Conditions:
- Infectious diseases: Caused by bacteria, viruses, fungi, or parasites.
- Neoplastic diseases: Includes benign and malignant tumors (e.g., cancer).
- Inflammatory diseases: Body’s response to injury, infection, or other stimuli (e.g., arthritis).
- Degenerative diseases: Conditions where tissues or organs deteriorate (e.g., Alzheimer’s).
- Genetic diseases: Inherited abnormalities or mutations in genes.
Diagnosis in Pathology:
- Histopathological examination: Involves microscopic examination of tissue biopsies.
- Cytological examination: Involves the study of cells (e.g., Pap smear).
- Molecular pathology: Detection of genetic abnormalities using techniques like PCR.
Important Laboratory Techniques in Pathology:
- Biopsy: Removal of tissue for examination.
- Autopsy: Post-mortem examination to determine cause of death.
- Blood tests: Used to detect various diseases, including infections, anemia, and cancer.
- Urinalysis: Used for diagnosing kidney, urinary tract, and metabolic disorders.
5. Laboratory Techniques:
Common Laboratory Techniques in Pathology:
- Microscopy:
- Light Microscopy: The most commonly used microscope for observing stained tissue samples. It magnifies the sample by passing light through it.
- Electron Microscopy: Used to view cellular structures at a higher resolution, particularly for viruses and sub-cellular organelles.
- Fluorescence Microscopy: Uses fluorescent dyes to label specific cellular components for detailed study.
- Staining Techniques:
- Hematoxylin and Eosin (H&E): The most common stain used in histopathology. Hematoxylin stains the nuclei blue, while eosin stains the cytoplasm pink.
- Gram Staining: Differentiates bacteria into Gram-positive (purple) and Gram-negative (pink) based on their cell wall structure.
- Ziehl-Neelsen Staining: Used to identify acid-fast bacilli like Mycobacterium tuberculosis.
- Giemsa Staining: Used for blood smear examination, particularly to identify parasites like malaria.
- Blood Smear Examination:
- Blood smears are used to assess blood cell morphology, and help in diagnosing conditions like anemia, malaria, and leukemia.
- Procedure: A drop of blood is spread on a glass slide, air-dried, and then stained for microscopic examination.
- Clinical Biochemistry:
- Involves the analysis of blood, urine, and other bodily fluids to measure components like glucose, cholesterol, electrolytes, and enzymes.
- Common tests include Liver Function Tests (LFT), Renal Function Tests (RFT), and Blood Glucose.
- Microbiological Techniques:
- Culture: Growing microorganisms from a sample to identify infectious agents (bacteria, fungi, viruses).
- Antibiotic Sensitivity Testing: Identifying which antibiotics are effective against specific bacterial infections.
- Polymerase Chain Reaction (PCR): Amplifies specific DNA/RNA sequences to detect microorganisms or genetic mutations.
- Serological Tests: Used to detect antibodies or antigens related to infections, such as HIV, Hepatitis, or COVID-19.
- Cytology:
- Pap Smear: A screening test used to detect cervical cancer and pre-cancerous changes in the cervix.
- Fine Needle Aspiration (FNA): A procedure to extract cells from lumps or masses for cytological examination.
- Histopathology:
- Tissue Fixation: Preserving tissue samples in formalin to prevent decomposition.
- Embedding: After fixation, tissue is embedded in paraffin wax to make thin slices for examination.
- Sectioning: Thin tissue sections (4-5 microns) are cut and stained for microscopic examination.
- Flow Cytometry:
- A technique used to analyze the physical and chemical properties of cells. It’s widely used in the diagnosis of hematological diseases like leukemia.