BSC NURSING SEM1 APPLIED PHYSIOLOGY UNIT 1 General Physiology-Basic concepts
Cell physiology including transportation across cell membrane
Synopsis on Cell Physiology Including Transportation Across Cell Membrane
Introduction
Cell physiology refers to the functions and activities of cells that are essential for life. It encompasses various processes such as energy production, metabolism, communication, and transportation of substances across the cell membrane.
Key Concepts
Cell Membrane Structure:
Composed of a phospholipid bilayer with embedded proteins, carbohydrates, and cholesterol.
Semi-permeable, allowing selective transport of substances.
Functions of the Cell Membrane:
Protects the internal environment of the cell.
Facilitates communication via receptor proteins.
Regulates transport of nutrients, ions, and waste products.
Types of Transportation Across the Cell Membrane
Passive Transport:
Definition: Movement of substances without energy expenditure.
Mechanisms:
Diffusion: Movement of molecules from higher to lower concentration.
Example: Oxygen and carbon dioxide exchange.
Facilitated Diffusion: Transport via carrier proteins or channels (e.g., glucose transport).
Osmosis: Diffusion of water molecules through a selectively permeable membrane.
Active Transport:
Definition: Movement of substances against the concentration gradient using energy (ATP).
Mechanisms:
Primary Active Transport: Direct use of ATP (e.g., sodium-potassium pump).
Secondary Active Transport: Utilizes electrochemical gradients established by primary active transport (e.g., glucose-sodium co-transport).
Endocytosis and Exocytosis:
Endocytosis: Intake of large molecules or particles into the cell.
Pinocytosis: “Cell drinking” (e.g., uptake of extracellular fluid).
Receptor-Mediated Endocytosis: Specific molecule uptake via receptors.
Exocytosis: Expulsion of materials from the cell (e.g., secretion of hormones).
Bulk Flow:
Movement of large amounts of fluids or solutes, often driven by pressure gradients.
Factors Influencing Membrane Transport
Concentration gradient: Steeper gradients increase the rate of diffusion.
Membrane permeability: Affected by lipid solubility and the size of molecules.
Temperature: Higher temperatures increase kinetic energy and transport rates.
Presence of transport proteins: Facilitates specific molecule transport.
Physiological Significance
Maintains cellular homeostasis.
Facilitates nutrient absorption and waste removal.
Supports signal transmission in neurons and muscle contraction.
Applications in Nursing
Understanding osmotic imbalances in dehydration or edema.
Management of electrolyte disturbances (e.g., potassium or sodium imbalances).
Administering intravenous fluids based on osmosis and diffusion principles.
Body fluid compartments,
Synopsis on Body Fluid Compartments
Introduction
The human body is composed of approximately 60% water, distributed into various fluid compartments. These compartments are critical for maintaining cellular function, homeostasis, and physiological processes.
Key Concepts
Total Body Water (TBW):
Comprises about 60% of body weight in adults (varies by age, sex, and body composition).
Divided into intracellular fluid (ICF) and extracellular fluid (ECF).
Intracellular Fluid (ICF):
Accounts for about two-thirds of TBW.
Found within cells.
High concentration of potassium (K⁺), magnesium (Mg²⁺), and phosphate (PO₄³⁻).
Functions:
Provides the medium for cellular metabolism.
Supports organelle function.
Extracellular Fluid (ECF):
Accounts for about one-third of TBW.
Divided into:
Interstitial Fluid (~75% of ECF): Surrounds cells and tissues.
Plasma (~25% of ECF): Fluid portion of blood.
Transcellular Fluid (small fraction): Includes cerebrospinal fluid, synovial fluid, pleural fluid, etc.
High concentration of sodium (Na⁺), chloride (Cl⁻), and bicarbonate (HCO₃⁻).
Functions:
Maintains blood pressure and volume.
Facilitates nutrient and waste exchange.
Fluid Distribution and Movement
Osmosis:
Movement of water across a semi-permeable membrane from low to high solute concentration.
Balances fluid between compartments.
Diffusion:
Solutes move from higher to lower concentration until equilibrium is achieved.
Filtration:
Movement of fluid and solutes under pressure (e.g., in capillaries).
Active Transport:
Energy-dependent movement of ions across membranes (e.g., sodium-potassium pump).
Regulation of Body Fluids
Thirst Mechanism:
Controlled by the hypothalamus.
Stimulated by increased plasma osmolality or decreased blood volume.
Hormonal Regulation:
Antidiuretic Hormone (ADH): Promotes water reabsorption in the kidneys.
Aldosterone: Regulates sodium and water retention.
Hypertonic Fluids: Draw water out of ICF (e.g., 3% saline).
Applications in Nursing
Accurate fluid assessment for IV therapy.
Monitoring for signs of fluid overload or deficit.
Understanding compartment-specific imbalances (e.g., ECF loss in shock, ICF swelling in hyponatremia).
intracellular and extracellular compartments
Synopsis on Intracellular and Extracellular Compartments
Introduction
The body’s total body water is distributed between two main compartments: Intracellular Fluid (ICF) and Extracellular Fluid (ECF). These compartments play a vital role in maintaining homeostasis, enabling cellular metabolism, and supporting physiological processes.
1. Intracellular Fluid (ICF)
Definition:
The fluid contained within the cells.
Constitutes approximately 40% of body weight or two-thirds of total body water (TBW).
Composition:
Electrolytes:
High in potassium (K⁺) and magnesium (Mg²⁺).
Contains phosphate (PO₄³⁻) and proteins.
Low in sodium (Na⁺) and chloride (Cl⁻).
Functions:
Provides a medium for biochemical reactions and metabolic processes.
Supports cell structure and maintains the integrity of organelles.
Regulates intracellular signaling and communication.
Volume:
Highly stable; fluctuations in ICF volume can disrupt cellular function.
2. Extracellular Fluid (ECF)
Definition:
The fluid outside the cells.
Constitutes approximately 20% of body weight or one-third of total body water (TBW).
Subdivisions:
Interstitial Fluid:
Surrounds cells in the tissues.
Accounts for ~15% of body weight or ~75% of ECF.
Plasma (Intravascular Fluid):
Found within blood vessels.
Accounts for ~5% of body weight or ~25% of ECF.
Transcellular Fluid:
Specialized fluids in specific compartments.
Includes cerebrospinal fluid, synovial fluid, pleural fluid, etc.
A small fraction (~1-2% of TBW).
Composition:
Electrolytes:
High in sodium (Na⁺) and chloride (Cl⁻).
Contains bicarbonate (HCO₃⁻).
Low in potassium (K⁺).
Functions:
Acts as a medium for nutrient and waste exchange between blood and cells.
Maintains blood pressure and volume (plasma).
Facilitates communication via hormones and neurotransmitters.
Volume:
More dynamic than ICF; responds to fluid intake, loss, and shifts.
Movement of water from low to high solute concentration.
Diffusion:
Movement of solutes down their concentration gradient.
Filtration:
Hydrostatic pressure pushes fluid across capillary walls.
Active Transport:
Energy-driven movement (e.g., sodium-potassium pump).
Clinical Relevance
Dehydration:
Loss of water from ECF, leading to cellular shrinkage as water shifts from ICF to ECF.
Edema:
Excess accumulation of interstitial fluid in ECF.
Electrolyte Imbalances:
Hypernatremia (ECF): Causes water loss from ICF.
Hypokalemia (ICF): Disrupts cell function, especially in muscles and nerves.
Intravenous Fluid Therapy:
Isotonic solutions: Restore ECF volume.
Hypotonic solutions: Rehydrate cells by shifting water into ICF.
Hypertonic solutions: Draw water out of ICF to ECF.
major electrolytes and maintenance of homeostasis
Synopsis on Major Electrolytes and Maintenance of Homeostasis
Introduction
Electrolytes are charged particles (ions) present in body fluids, crucial for maintaining homeostasis and supporting physiological processes such as nerve conduction, muscle contraction, and fluid balance.
Major Electrolytes
Sodium (Na⁺)
Primary Location: Extracellular Fluid (ECF).
Functions:
Maintains ECF volume and osmotic pressure.
Facilitates nerve impulse transmission and muscle contraction.
Regulates acid-base balance via sodium-bicarbonate.
Normal Range: 135-145 mEq/L.
Potassium (K⁺)
Primary Location: Intracellular Fluid (ICF).
Functions:
Maintains resting membrane potential in nerve and muscle cells.
Regulates intracellular osmolality.
Supports protein synthesis and glucose metabolism.
Normal Range: 3.5-5.0 mEq/L.
Calcium (Ca²⁺)
Primary Location: Bones and ECF.
Functions:
Essential for bone and teeth formation.
Facilitates blood clotting and muscle contraction.
Involved in enzyme activity and neurotransmitter release.
Normal Range: 8.5-10.5 mg/dL.
Magnesium (Mg²⁺)
Primary Location: ICF and bones.
Functions:
Acts as a cofactor for enzyme reactions, particularly in ATP production.
Regulates neuromuscular function and cardiac rhythm.
Normal Range: 1.5-2.5 mEq/L.
Chloride (Cl⁻)
Primary Location: ECF.
Functions:
Maintains fluid and electrolyte balance.
Helps produce hydrochloric acid in gastric secretions.
Aids in acid-base regulation.
Normal Range: 95-105 mEq/L.
Bicarbonate (HCO₃⁻)
Primary Location: ECF.
Functions:
Key buffer in maintaining acid-base balance.
Neutralizes excess acids in metabolic processes.
Normal Range: 22-26 mEq/L.
Phosphate (PO₄³⁻)
Primary Location: ICF and bones.
Functions:
Essential for energy production (ATP synthesis).
Aids in bone mineralization and acid-base balance.
Normal Range: 2.5-4.5 mg/dL.
Role of Electrolytes in Homeostasis
Fluid Balance:
Sodium controls water distribution between ECF and ICF via osmotic pressure.
Potassium maintains intracellular water content.
Acid-Base Balance:
Bicarbonate and phosphate buffer systems regulate pH.
Chloride shifts in and out of cells to balance pH.
Neuromuscular Function:
Sodium and potassium are crucial for action potential generation.
Calcium and magnesium regulate muscle contraction and relaxation.
Energy Production:
Phosphate is a key component in ATP, the energy currency of the cell.
Maintenance of Electrolyte Balance
Kidney Regulation:
Filters electrolytes and excretes excess through urine.
Reabsorbs required electrolytes to maintain balance.
Hormonal Control:
Aldosterone: Promotes sodium and water reabsorption, and potassium excretion.
Antidiuretic Hormone (ADH): Regulates water balance.
Parathyroid Hormone (PTH): Regulates calcium and phosphate levels.
Dietary Intake:
Adequate intake of electrolytes through food and beverages (e.g., fruits, vegetables, dairy).
Buffer Systems:
Bicarbonate and phosphate systems maintain acid-base equilibrium.
The cell cycle is a series of ordered events that cells go through to grow, replicate their DNA, and divide into two daughter cells. It is crucial for growth, development, tissue repair, and maintaining genetic stability.
Phases of the Cell Cycle
The cell cycle is divided into two main stages: Interphase and the Mitotic (M) Phase.
1. Interphase
Represents about 90% of the cell cycle.
Cells prepare for division by growing and replicating DNA.
Sub-phases of Interphase:
G₁ Phase (Gap 1)
Period of cell growth.
Synthesis of proteins and organelles.
Preparation for DNA replication.
Checkpoint: Ensures the cell is ready for DNA synthesis.
S Phase (Synthesis)
DNA replication occurs.
Each chromosome duplicates to form two sister chromatids.
Synthesis of histones for new DNA.
G₂ Phase (Gap 2)
Further cell growth.
Preparation for mitosis.
Synthesis of proteins needed for chromosome movement.
Checkpoint: Ensures all DNA is replicated and the cell is ready for division.
2. Mitotic (M) Phase
The phase where the cell divides.
Includes mitosis (division of the nucleus) and cytokinesis (division of the cytoplasm).
Sub-phases of Mitosis:
Prophase
Chromosomes condense and become visible.
Nuclear envelope begins to break down.
Spindle fibers form from the centrosomes.
Metaphase
Chromosomes align at the metaphase plate.
Spindle fibers attach to the centromeres of the chromosomes.
Anaphase
Sister chromatids separate and are pulled toward opposite poles.
Spindle fibers shorten.
Telophase
Chromosomes decondense into chromatin.
Nuclear envelopes re-form around the separated chromosomes.
Cytokinesis:
Division of the cytoplasm to form two daughter cells.
In animal cells: Formation of a cleavage furrow.
In plant cells: Formation of a cell plate.
Regulation of the Cell Cycle
Checkpoints:
G₁ Checkpoint: Monitors cell size, DNA damage.
G₂ Checkpoint: Ensures all DNA is replicated.
M Checkpoint: Ensures all chromosomes are attached to spindle fibers.
Key Regulatory Proteins:
Cyclins: Proteins that regulate the timing of the cell cycle.
Cyclin-dependent Kinases (CDKs): Enzymes activated by cyclins to drive the cell cycle forward.
Tumor Suppressors: Proteins like p53 that prevent the cell cycle if DNA is damaged.
Clinical Relevance
Cancer:
Uncontrolled cell division due to mutations in regulatory proteins like p53.
Leads to tumor formation.
Anticancer Drugs:
Target specific phases of the cell cycle to prevent division (e.g., drugs targeting S phase to inhibit DNA replication).
Stem Cells:
Exhibit high proliferative capacity, crucial for tissue repair and regeneration.
Applications in Nursing
Understanding chemotherapy mechanisms that target cell cycle phases.
Monitoring side effects of drugs impacting rapidly dividing cells (e.g., bone marrow suppression).
Educating patients about conditions involving cell cycle dysregulation, like cancer.
Tissue- formation, repair
Synopsis on Tissue Formation and Repair
Introduction
Tissues are groups of cells that work together to perform specific functions. Tissue formation and repair are vital for growth, development, and recovery from injury. These processes involve cell differentiation, extracellular matrix synthesis, and cellular communication.
Tissue Formation
Embryonic Origin of Tissues:
Tissues develop from three primary germ layers during embryogenesis:
Ectoderm: Forms skin and nervous tissue.
Mesoderm: Forms muscle, bone, and connective tissue.
Endoderm: Forms the lining of internal organs.
Steps in Tissue Formation:
Cell Proliferation:
Rapid cell division to increase cell numbers.
Cell Differentiation:
Specialization of cells to perform specific functions (e.g., muscle cells, nerve cells).
Extracellular Matrix (ECM) Deposition:
ECM provides structural support and regulates cell behavior.
Tissue Organization:
Cells and ECM organize into layers or structures to form functional tissues.
Types of Tissue
Epithelial Tissue:
Covers body surfaces and lines cavities.
Functions: Protection, absorption, secretion, and filtration.
Connective Tissue:
Provides support and binds tissues together.
Examples: Bone, cartilage, adipose tissue, and blood.
Muscle Tissue:
Responsible for movement.
Types: Skeletal, cardiac, and smooth muscle.
Nervous Tissue:
Conducts electrical impulses for communication.
Found in the brain, spinal cord, and nerves.
Tissue Repair
Phases of Tissue Repair:
Inflammation:
Triggered by injury or infection.
White blood cells release cytokines to remove debris and pathogens.
Blood vessels dilate to deliver nutrients and immune cells.
Proliferation:
Fibroblasts proliferate and secrete ECM components like collagen.
Angiogenesis: Formation of new blood vessels to restore circulation.
Formation of granulation tissue.
Remodeling (Maturation):
Collagen fibers realign and strengthen.
Excess cells and ECM are removed.
Scar tissue forms (if repair is incomplete).
Types of Tissue Repair:
Regeneration:
Damaged tissue is replaced by cells of the same type.
Common in tissues like skin, liver, and bone.
Fibrosis:
Replacement of damaged tissue with scar tissue.
Common in tissues with limited regenerative capacity (e.g., heart muscle).
Factors Affecting Tissue Repair
Intrinsic Factors:
Age: Slower healing in older individuals.
Nutritional status: Protein, vitamins (e.g., Vitamin C), and minerals (e.g., zinc) are essential.
Health conditions: Diabetes and infections can delay healing.
Extrinsic Factors:
Wound care: Proper cleaning and dressing.
Blood supply: Adequate circulation ensures oxygen and nutrient delivery.
Medications: Steroids may delay healing, while antibiotics prevent infections.
Clinical Relevance
Chronic Wounds:
E.g., diabetic ulcers and pressure sores.
Require advanced interventions like wound debridement and skin grafting.
Scar Formation:
Excessive fibrosis can result in hypertrophic scars or keloids.
Regenerative Medicine:
Stem cell therapy and tissue engineering aim to improve tissue repair.
Applications in Nursing
Promoting wound healing through proper nutrition and hydration.
Administering medications to manage pain, infection, and inflammation.
Educating patients on wound care and the importance of follow-up.
Membranes and glands- functions
Synopsis on Membranes and Glands: Functions
Introduction
Membranes and glands are specialized structures essential for maintaining body functions. Membranes provide protection and compartmentalization, while glands are involved in secretion and regulation of substances within the body.
1. Membranes
Definition:
Membranes are thin layers of tissue that cover body surfaces, line cavities, and separate organs or structures.
Types of Membranes:
Epithelial Membranes:
Composed of epithelial tissue and connective tissue.
Subtypes:
Mucous Membranes (Mucosa):
Line body cavities that open to the exterior (e.g., respiratory, digestive tracts).
Functions:
Secretion of mucus to trap pathogens and lubricate surfaces.
Protection against mechanical damage and dehydration.
Serous Membranes (Serosa):
Line closed body cavities (e.g., pleura, pericardium, peritoneum).
Functions:
Produce serous fluid to reduce friction between organs.
Provide a protective barrier.
Cutaneous Membrane:
The skin.
Functions:
Protection against environmental damage.
Sensory perception and thermoregulation.
Connective Tissue Membranes:
Include synovial membranes.
Synovial Membranes:
Line joint cavities.
Functions:
Produce synovial fluid for joint lubrication.
Provide a smooth surface for movement.
2. Glands
Definition:
Glands are specialized epithelial tissues that produce and secrete substances like enzymes, hormones, and mucus.
Types of Glands:
Exocrine Glands:
Secrete products onto body surfaces or into body cavities through ducts.
Examples:
Sweat Glands: Regulate body temperature via sweat secretion.
Sebaceous Glands: Secrete sebum to lubricate skin and hair.
Salivary Glands: Produce saliva for digestion and oral health.
Mammary Glands: Produce milk for nourishment.
Functions:
Assist in digestion (e.g., pancreatic enzymes).
Maintain skin hydration and protection.
Facilitate thermoregulation.
Endocrine Glands:
Ductless glands that release hormones directly into the bloodstream.
Examples:
Thyroid Gland: Produces hormones (e.g., thyroxine) to regulate metabolism.
Adrenal Glands: Secrete hormones like adrenaline for stress response.
Pituitary Gland: Regulates growth, reproduction, and other endocrine glands.
Functions:
Hormonal regulation of metabolic activities.
Maintenance of homeostasis (e.g., blood glucose levels, electrolyte balance).
Growth and development.
Key Functions of Membranes and Glands
Structure
Functions
Membranes
Protection, lubrication, compartmentalization, secretion, and sensory input.
Exocrine Glands
Secretion of substances for digestion, protection, lubrication, and thermoregulation.
Endocrine Glands
Hormonal regulation of physiological functions such as metabolism, growth, and stress response.
Clinical Relevance
Membrane Disorders:
Pleural Effusion: Excess fluid in the pleural cavity.
Peritonitis: Inflammation of the peritoneum.
Gland Disorders:
Hypothyroidism/Hyperthyroidism: Imbalance in thyroid hormone production.
Diabetes Mellitus: Dysfunction of the endocrine pancreas.
Regenerative Medicine:
Use of stem cells to repair damaged membranes and restore glandular function.
Applications in Nursing
Monitoring patients with membrane-related conditions (e.g., pericarditis, synovitis).
Administering hormone replacement therapy (e.g., insulin for diabetes).
Educating patients on maintaining glandular health through proper nutrition and hydration.