Biology Chapter on Cellular Level

Cellular Level

• Basic Unit of Life: Cells are the fundamental building blocks of all living organisms, specialized for specific functions such as movement, secretion, and respiration.
• Cell Membrane: Functions as a selective barrier controlling what enters and exits the cell, crucial for maintaining fluid balance and interacting with medications.
• Organelles:
  • Mitochondria: Powerhouses of the cell, responsible for producing energy (ATP) and utilizing oxygen.
  • Ribosomes: Sites of protein synthesis, essential for tissue repair.
• Cellular Respiration:
  • Aerobic: Requires oxygen to generate 38 ATP molecules.
  • Anaerobic: Occurs without oxygen, producing 2 ATP molecules and lactic acid, which can lead to acidosis in trauma.
• Cellular Transport:
  • Osmosis/Diffusion: Passive transport processes crucial for maintaining fluid balance.
  • Active Transport (Sodium-Potassium Pump): Requires energy to move ions against their concentration gradient, essential for electrolyte balance, particularly in cardiac patients.
• Electrolytes and pH:
  • Electrolyte Balance: Sodium, potassium, and calcium are essential for cellular function.
  • pH: Maintain a narrow range of 7.35-7.45 to ensure optimal cellular function; acidosis (oxygen deprivation) or alkalosis (high pH) can lead to health complications.

Tissue Level

• Epithelial Tissue: Covers body surfaces, protects, secretes, and allows permeability. Found on skin, organs, and glands.
• Connective Tissue: Supports and protects organs, stores fat, and produces blood cells. Found in bones, tendons, and ligaments.
• Muscle Tissue:
  • Skeletal Muscle: Voluntary movement, attached to bones.
  • Smooth Muscle: Involuntary, found in internal organs like intestines.
  • Cardiac Muscle: Involuntary, found in the heart.
• Nervous Tissue: Sends electrical impulses, communicates with muscles and glands. Found in the brain, spinal cord, and nerves.
• Membranes:
  • Serous Membrane: Lines cavities without external openings (e.g., pleura, pericardium), secretes fluid for lubrication.
  • Mucous Membrane: Lines cavities with external openings (e.g., mouth, nose), secretes mucus.
  • Cutaneous Membrane: Skin, protects body surfaces.
  • Synovial Membrane: Lines joints, secretes fluid to reduce friction.

Homeostasis

• Body's Balance: Maintaining stable internal conditions (temperature, pH, fluid, and electrolyte levels).
• Temperature Regulation:
  • Hyperthermia: Manage with cooling techniques (ice, fans).
  • Hypothermia: Manage with warming techniques (blankets, warm IV fluids).
• pH Imbalance: Correct acidosis or alkalosis through ventilation or medication (goal pH: 7.35-7.45).
• Fluid/Electrolyte Balance: Maintain with IV fluids based on patient needs, especially in dehydration or trauma.
• Cell Turnover: The process of normal cell death and replacement.
  • Apoptosis: Normal programmed cell death.
  • Disruption of Cell Turnover: Can lead to conditions like cancer (uncontrolled cell growth).
• Regulatory Systems:
  • Negative Feedback: A mechanism used to stabilize functions. Recognize loss of regulation (e.g., sepsis, bleeding).
  • Autonomous Dysregulation: Respond to signs of unregulated systems (e.g., shock, organ failure).

Integumentary System

• Functions:
  • Protection: Prevents injury, infection, and UV damage.
  • Temperature Regulation: Vasoconstriction conserves heat; vasodilation releases heat.
  • Fluid Regulation: Maintains chemical stability and prevents dehydration.
  • Sensation: Transmits sensory information from the skin to the brain.
  • Inflammatory Response: Promotes healing by responding to injury.
• Skin Structure:
  • Epidermis: Outer layer, provides waterproof protection.
  • Dermis: Below the epidermis, contains connective tissue, blood vessels, and nerves.
  • Subcutaneous Tissue: Fat layer beneath the dermis, insulates and anchors the skin.
• Accessory Structures:
  • Hair: Protects against injury, UV rays, and particles.
  • Nails: Protect fingertips and toes.
  • Glands:
    • Sebaceous Glands: Secrete oil to maintain skin and hair hydration.
    • Sweat Glands: Regulate body temperature through sweat.

Skeletal System

• Functions:
  • Support: Provides a framework for the body.
  • Leverage: Facilitates movement through muscle attachments.
  • Protection: Shields internal organs from injury.
  • Calcium Storage: Regulates calcium levels, essential for muscle function.
  • Blood Cell Production: Red marrow produces red blood cells, white blood cells, and platelets.
• Skeleton Divisions:
  • Axial Skeleton: Skull, vertebral column, thoracic cage.
  • Appendicular Skeleton: Shoulder girdle, pelvic girdle, and limbs.
• Bone Structure:
  • Long Bones: Humerus, femur.
  • Short Bones: Carpals, tarsals.
  • Flat Bones: Sternum, ribs.
  • Irregular Bones: Vertebrae, pelvis.
• Joints:
  • Fibrous Joints: No movement (e.g., skull sutures).
  • Cartilaginous Joints: Slight movement (e.g., intervertebral discs).
  • Synovial Joints: Allow movement (e.g., shoulder, knee).
• Bone Growth and Repair:
  • Ossification: Bone growth and healing occur through ossification. Proper immobilization is key for recovery.
  • Calcium Regulation: Parathyroid hormone (PTH) releases calcium from bones when blood calcium is low.

Muscle System

• Functions:
  • Movement and Posture: Muscles contract and relax to facilitate movement and maintain posture.
  • Joint Stability: Muscles provide support to joints.
  • Heat Production: Muscle contractions generate heat.
• Skeletal Muscle Properties:
  • Excitability: Responds to stimuli.
  • Contractility: Shortens to cause movement.
  • Extensibility: Can stretch.
  • Elasticity: Return to original shape after contraction.
• Muscle Attachments:
  • Origin: Fixed attachment point.
  • Insertion: Movable attachment point.
• Muscle Contraction:
  • Motor Neuron: Stimulates muscle contraction.
  • Neuromuscular Junction: Releases acetylcholine (ACh) to activate muscle fibers.
  • Calcium Release: Calcium ions trigger muscle contraction.
  • ATP: Provides energy for muscle contraction and relaxation.
• Energy Sources:
  • ATP: Main energy source.
  • Creatine Phosphate: Provides rapid ATP replenishment.
  • Oxygen Debt: Lactic acid buildup during anaerobic respiration requires oxygen for recovery.
• Muscle Fatigue:
  • Lactic Acid Buildup: Results in an inability to contract effectively.
  • Heat Production: Muscle contractions produce heat.

Respiratory System

• Functions:
  • Gas Exchange: Oxygen intake and carbon dioxide removal.
  • Ventilation: Movement of air into and out of the lungs.
  • Protection: Defense against inhaled pathogens.
• Anatomy:
  • Upper Respiratory Tract: Nose, pharynx, larynx.
  • Lower Respiratory Tract: Trachea, bronchi, bronchioles, alveoli.
• Mechanics of Breathing:
  • Diaphragm: Main muscle of breathing.
  • Intercostal Muscles: Help expand and contract the chest cavity.
• Gas Exchange in Alveoli: Oxygen diffuses from the alveoli into the blood; carbon dioxide diffuses from the blood into the alveoli.
• Oxygen Transport:
  • Hemoglobin: Binds to oxygen in the blood, carrying it to the body's tissues.
  • Carbon Dioxide Transport: Transported in the blood as bicarbonate ions or dissolved in plasma.
• Control of Breathing: Neurons in the brainstem regulate the rate and depth of breathing.

Digestive System

• Functions:
  • Ingestion: Taking food into the mouth.
  • Digestion: Breakdown of food into smaller molecules.
  • Absorption: Movement of nutrients into the bloodstream.
  • Excretion: Elimination of waste products.
• Alimentary Canal:
  • Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, anus.
• Accessory Organs:
  • Salivary glands, liver, gallbladder, pancreas.
• Abdominal Quadrants:
  • RUQ: Liver, gallbladder.
  • LUQ: Stomach, spleen.
  • RLQ: Cecum, appendix.
  • LLQ: Sigmoid colon.

Urinary System

• Functions:
  • Filtration: Filtration of blood to remove waste products.
  • Fluid Balance: Regulation of fluid and electrolyte balance.
  • pH Regulation: Maintains blood pH.
• Key Organs:
  • Kidneys, ureters, bladder, urethra.
• Fluid Balance:
  • Antidiuretic Hormone (ADH): Promotes water retention.
  • Thirst Mechanism: Prompts fluid intake.
  • Electrolyte Imbalances: Watch for hyperkalemia and hypokalemia.

Reproductive System

• Male Anatomy:
  • Testes: Produce sperm and hormones.
  • Pathway: Testes → Epididymis → Vas deferens → Ejaculation
• Female Anatomy:
  • Ovaries: Produce eggs and hormones.
  • Uterine tubes: Transport eggs, site of fertilization.
  • Uterus: Supports pregnancy.
  • Vagina: Menstruation and childbirth.
• Key Emergencies:
  • Ectopic Pregnancy: Severe pain, bleeding.
  • Testicular Torsion: Sudden pain, swelling.
  • Sepsis: Fever, pain, altered mental state.
• Hormonal Management: Monitor for hypo/hypergonadism. Address imbalances with fluids and hormone therapy support.
• Trauma Management: Stabilize reproductive injuries, manage bleeding, and protect airways in severe cases.

Test your knowledge on the cellular structures, functions, and processes that form the basis of life. This quiz covers essential topics such as organelles, cellular respiration, and transport mechanisms. Explore how cells maintain balance and energy production in living organisms.