Comprehensive Study Notes on Cell Biology, Body Systems, and Homeostasis

Definitions

  • Cell membrane: Selectively permeable outer boundary, regulates passage of substances.

  • Vacuole: Stores water, nutrients, and waste; maintains turgor pressure in plant cells.

  • Endoplasmic Reticulum (ER): Protein and lipid synthesis; Rough ER (protein synthesis, modification), Smooth ER (lipids, metabolism, detoxification).

  • Ribosome: Protein synthesis; Reads mRNA to assemble amino acids into polypeptides.

  • Nucleus: Control center, contains DNA; Directs cell activities and heredity.

  • Golgi Apparatus: Modifies, sorts, packages proteins and lipids; Forms vesicles for transport.

  • Mitochondria: Generates ATP through cellular respiration:

  • Lysosome: Breaks down cellular waste; Contains enzymes for intracellular digestion.

  • Positive feedback: Amplifies stimulus; Drives a system away from equilibrium.

  • Negative feedback: Reduces stimulus, maintains homeostasis; Returns a system to its set point.

  • Homeostasis: Stable internal environment; Maintained by feedback mechanisms.

  • Circulatory system: Transports blood, oxygen, nutrients; Includes heart, blood vessels, and blood.

  • Lymphatic system: Removes toxins, aids immune system; Returns interstitial fluid to the blood.

  • Endocrine System: Glands producing hormones for regulation; Slow, long-lasting effects.

  • Digestive System: Breaks down food for absorption; Includes mouth, esophagus, stomach, intestines.

  • Respiratory System: Gas exchange; Oxygen in, carbon dioxide out.

  • Integumentary System: Protection, temperature regulation; Skin, hair, and nails.

  • Nervous system: Fast electrical signals; Neurons and glial cells.

  • Excretory system: Removes waste; Kidneys, bladder, and associated structures.

  • Muscular system: Enables movement; Skeletal, smooth, and cardiac muscle.

  • Skeletal system: Provides support; Bones, cartilage, ligaments, and tendons.

System Identification

  • Integumentary System: First defense against disease, temperature moderation; Regulates water loss and protects against UV radiation.

  • Endocrine System: Controlled by hypothalamus; Regulates growth, metabolism, and reproduction.

  • Skeletal System: Provides structure and support; Stores minerals and produces blood cells.

  • Circulatory System: Carries waste away from cells; Transports hormones and immune cells.

  • Excretory System: Filters nitrogenous waste; Maintains electrolyte balance.

  • Digestive System: Provides raw materials; Absorbs nutrients and eliminates solid waste.

  • Respiratory System: Exchange point between atmosphere and body; Facilitates gas exchange in the lungs.

  • Nervous System: Immediate, short-term responses; Coordinates rapid responses to stimuli.

Organelle Function in Specialized Cells

  • Skeletal muscle: High mitochondria and ribosomes for energy/protein; Supports contraction for movement.

  • Sperm: Many mitochondria for movement; Powers flagellum for propulsion.

  • Red Blood Cell: Lacks organelles for hemoglobin; Maximizes space for oxygen transport.

  • Neuron: Many ribosomes/golgi for signaling and lysosomes for waste removal; Synthesizes neurotransmitters and clears debris.

  • White Blood Cell: High lysosomes and mitochondria for digestion/immunity; Engulfs pathogens and generates energy for defense.

Hierarchy of Organization

  1. Atom

  2. Molecule

  3. Organelle

  4. Cell

  5. Tissue

  6. Organ

  7. Organ System

  8. Organism

Transport Systems (Circulatory System)

  • Arteries: Away from heart, thick walls, oxygenated blood (except pulmonary); Maintain high pressure.

  • Veins: To heart, thin walls, valves, deoxygenated blood (except pulmonary); Prevent backflow of blood.

  • Capillaries: Thin walls for exchange; Facilitate diffusion of gases and nutrients.

  • Interactions:

    • Digestive: Transports nutrients; Delivers glucose and amino acids to cells.

    • Respiratory: Transports O2 and CO2; Carries oxygen to tissues and removes carbon dioxide.

    • Excretory: Transports waste to kidneys; Delivers urea and creatinine for excretion.

    • Integumentary: Regulates temperature; Vasoconstriction and vasodilation control heat loss.

    • Muscular: Delivers O2, removes waste; Supplies oxygen for muscle contraction and removes lactic acid.

    • Lymphatic: Maintains fluid balance; Returns leaked fluid and proteins to the bloodstream.

    • Endocrine: Transports hormones; Delivers hormones to target cells.

Communication Systems

  • Nervous system: Rapid, short-term, electrical signals; Uses neurotransmitters for communication.

  • Endocrine system: Slow, long-term, hormones; Uses hormones for systemic regulation.

  • Divisions of Nervous System:

    • Central Nervous System (CNS): Brain and spinal cord; Processes information and coordinates responses.

    • Peripheral Nervous System (PNS): Nerves outside CNS; Connects CNS to limbs and organs.

Homeostasis and Disease

  • Kidney stones: Excretory system, disrupts urine flow and electrolyte balance; Causes pain and can lead to kidney damage.

  • Hypothyroidism: Endocrine system, decreased metabolic rate; Leads to fatigue, weight gain, and other symptoms.

Feedback Mechanisms

  • Negative Feedback: Maintains homeostasis by reducing the stimulus; Returns the system to a stable state.

  • Positive Feedback: Amplifies the stimulus; Leads to rapid change and instability.

  • Components of negative feedback:

    • Set Point: Desired value; Normal range for a physiological parameter.

    • Receptor: Detects deviations; Monitors the current condition.

    • Effector: Returns to set point; Adjusts the system to reach the desired value.