Introduction to the Human Body & Cell Metabolism
Introduction to the Human Body
The human body is a complex creation
Made up of millions of microscopic parts
Functions effectively for approximately 75 years.
Key Questions: How does it work? Why does it sometimes fail? What makes us thrive or fall ill?
Anatomy and Physiology: What They Are
Anatomy (ah-NAT-o-mee)
Definition: Study of the body's structure.
Focuses on the description of body parts (e.g., heart)
Looks at appearance, size, composition, organization, and location.
Origin: Greek word meaning "to dissect."
Historical context: Anatomical knowledge arose from dissection, often of bodies exhumed from graves.
Physiology (fiz-ee-OL-o-jee)
Definition: Study of how the body functions.
Explains physiological processes such as blood circulation, respiration, and digestion.
Pathophysiology (path-o-fiz-ee-OL-o-jee)
Definition: Study of the effects of diseases on body function.
Describes changes in normal physiological processes due to disease (e.g., heart attack effects).
Objectives
Define anatomy and physiology.
List the levels of organization of the human body.
Describe the 12 major organ systems.
Define homeostasis.
Describe the anatomical position.
List common terms used for relative positions of the body.
Describe the three major planes of the body.
List anatomical terms for quadrants and regions of the body.
Describe the major cavities of the body.
Key Terms
Anatomy, Physiology, Homeostasis, Anatomical Position, Organ Systems, Cavities, Quadrants, Regions, Planes of the Body.
The Body's Levels of Organization
The body is organized hierarchically from simple to complex, consisting of:
Atoms → 2. Molecules → 3. Cells → 4. Tissues → 5. Organs → 6. Organ Systems → 7. Human Organism.
Cells are the basic units of life and are organized into tissues which form organs, and then organ systems, ultimately creating a complete organism.
Major Organ Systems
Integumentary System
Components: Skin, hair, nails.
Functions: Protective covering, regulates body temperature, sensory functions.
Skeletal System
Components: Bones, cartilage, joints.
Functions: Support, protection of internal organs, movement assistance, blood cell production.
Muscular System
Types: Skeletal (movement), Cardiac (heartbeats), and Smooth (various organs).
Functions: Movement and posture maintenance.
Nervous System
Components: Brain, spinal cord, nerves, sensory organs.
Functions: Receives and interprets sensory information, initiates responses, responsible for higher functions (thinking, memory).
Endocrine System
Components: Glands that secrete hormones.
Functions: Regulates various body functions including metabolism, growth, and reproduction through hormone release.
Circulatory System
Components: Heart, blood vessels, blood.
Functions: Transports nutrients, oxygen, waste products, and hormones throughout the body.
Lymphatic System
Components: Lymph nodes, lymphatic vessels, lymph.
Functions: Fluid balance, defense against pathogens.
Immune System
Components: Various cells and tissues that defend against pathogens.
Functions: Immune response and pathogen elimination.
Respiratory System
Components: Lungs and airways.
Functions: Gas exchange; oxygen intake and carbon dioxide release.
Digestive System
Components: Stomach, intestines, liver, pancreas.
Functions: Nutrient intake, breakdown of food, and waste elimination.
Urinary System
Components: Kidneys, ureters, bladder.
Functions: Eliminates waste, regulates water and electrolyte balance.
Reproductive System
Components: Ovaries, testes, associated organs.
Functions: Produces gametes (sperm, eggs), facilitates reproduction.
Homeostasis
Homeostasis (ho-me-o-STAY-sis)
Definition: The body’s ability to maintain a stable internal environment despite changes in external conditions.
Examples: Maintaining a body temperature of approximately 98.6 °F (37 °C) and regulating blood sugar levels.
Failure to maintain homeostasis leads to disease.
Anatomical Terms and Planes
Anatomical Position: Standing erect, face forward, arms at the sides, palms and toes facing forward.
Relative Position Terms
Superior/Inferior: Above/below relative to another body part.
Anterior/Posterior: Front/back relative terms.
Medial/Lateral: Toward/away from the midline of the body.
Proximal/Distal: Closer to/further from the trunk of the body.
Superficial/Deep: Closer to/further from the body surface.
Central/Peripheral: Central means towards the center; peripheral means away from the center.
Body Planes
Sagittal Plane: Divides body into right and left halves.
Frontal Plane (Coronal): Divides the body into anterior and posterior sections.
Transverse Plane: Divides the body into superior and inferior sections.
Anatomical Regions and Cavities
Quadrants and Regions of the Abdominopelvic Cavity: Four quadrants (RUQ, LUQ, RLQ, LLQ) and nine regions (e.g., epigastric, umbilical).
Body Cavities:
Dorsal Cavity: Cranial and spinal.
Ventral Cavity: Thoracic (pleural and pericardial) and abdominopelvic (abdominal and pelvic).
Cell Metabolism
Overview of Metabolism
Metabolism: All chemical reactions involved in maintaining the living state of the cells.
Divided into two categories:
Anabolism: Building larger molecules from smaller ones; requires energy (ATP).
Catabolism: Breaking down larger molecules into smaller ones; releases energy.
Carbohydrates
Carbohydrates: Organic compounds composed of carbon, hydrogen, and oxygen.
Classified by size:
Monosaccharides: Simple sugars (e.g., glucose)
Disaccharides: Formed from two monosaccharides (e.g., sucrose).
Polysaccharides: Long chains of monosaccharides (e.g., glycogen, starch).
Breakdown of Glucose
Anaerobic Catabolism: Breakdown of glucose without oxygen, resulting in lactic acid and limited ATP (glycolysis).
Aerobic Catabolism: Breakdown of glucose with oxygen producing carbon dioxide, water, and more ATP (occurs in mitochondria).
Fats and Lipids
Lipids: include triglycerides, phospholipids, and steroids. Triglycerides are stored as fats; phospholipids form cell membranes.
Cholesterol: Important steroid for cell membrane structure and hormone synthesis.
Proteins
Proteins: Composed of amino acids, perform numerous essential functions in the body.
Protein Synthesis: Dependent on DNA coding for specific sequences of amino acids.
Breakdown of Proteins
Amino acids are examined for nitrogen to create urea, which is essential for excretion.
Protein Synthesis
DNA: Acts as the blueprint for protein synthesis, coded by sequences of nucleotides.
RNA: Transfers mRNA from the nucleus to the cytoplasm, where tRNA assembles amino acids to form proteins.
Microbiology Basics
Understanding Disease and Infection
Disease: A failure of the body to function normally.
Infection: Caused by pathogens invading the body.
Types of Pathogens
Bacteria: Single-celled organisms.
Classified by shape: cocci, bacilli, curved rods.
Viruses: Require host cells to replicate.
Fungi: Includes yeasts and molds, can cause infections.
Protozoa: Single-celled organisms, some are pathogenic.
Worms: Larger multicellular organisms, include helminths.
Arthropods: Can act as vectors for diseases.
Laboratory Identification
Techniques like Gram staining classify bacteria based on cell wall characteristics.
Cultures are used to identify pathogens present in infected tissues.
Spread of Infection
Pathogens spread through direct contact, airborne droplets, contaminated surfaces, etc.
Key to prevention includes understanding portals of entry and exit, as well as transmission methods.
Five Germ-Laden Stories Detailing Infection Spread
Dr. Semmelweis: Advocated handwashing; significant in reducing nosocomial infections.
Flora and Her Vaginal Itch: Illustrates the risk of antibiotics disrupting normal flora.
Rick, Nick, and the Sick Tick: Disease transmission via vectors; highlights the role of ticks in RMSF.
Typhoid Mary: Explains carrier state and fecal-oral transmission.
A Pox News Alert: Covers pox-related diseases and the origin myths linked to them.