homeostasis_a176fcb469725be06de1c69e97363ae2_copy

Vino Dorsamy

  • Contact: dorsamyv1@ukzn.ac.za

  • Location: 4rd Floor Main Building Medical School, Room 420i past SCM Postgraduate Office

RIPA

  • Euky

  • BOTTON: 2

SpongeBob SquarePants Quiz

  • Title: Which SpongeBob SquarePants character Are You?

Physiology

  • Definition:

    • Comes from Greek "physis" (nature) + "logia" (study of).

    • Considered the "science of life".

    • Examines living mechanisms from molecular functions to integrated body behavior.

  • Human Physiology:

    • Focuses on how cells, muscles, and organs work together and interact.

Importance of Physiology

  • Fundamental science helps understand life and treatment of diseases.

  • Pathophysiology:

    • Studies abnormalities in human and animal diseases.

    • Physiologists collaborate with scientists and health professionals for translational research.

Organisation and Complexity

  • Cells:

    • Divide and differentiate: 200 types in body.

    • Form multicellular structures.

    • Group into tissues based on similar functions.

  • Types of Tissues:

    • Four main types.

Muscle Cells

  • Types of Muscle Cells:

    • Cardiac, Skeletal, and Smooth.

  • Functionality:

    • Generate mechanical force.

    • Cardiac and smooth muscle control: involuntary.

    • Skeletal muscle control: voluntary.

Neurons

  • Definition:

    • Specialized cells that conduct electrical signals in the nervous system.

    • Form nervous tissues (e.g., brain or spinal cord).

  • Structure:

    • Axons package with connective tissues = nerves.

  • Functions:

    • Initiate signaling: contract muscles and secrete substances.

Epithelial Cells

  • Functions:

    • Selective secretion and absorption of ions and organic molecules, and protection.

  • Classification:

    • According to shapes: cuboidal, columnar, squamous, ciliated.

  • Types of Epithelium:

    • Simple (single-cell thickness) vs. Stratified (multiple layers).

    • Function relates to location (e.g., trachea lined with ciliated cells).

Epithelial Tissue Architecture

  • Location:

    • Covering the body surfaces and lining tubular structures.

  • Structure:

    • Rest on basement membrane; basolateral side anchored, apical side faces exterior.

    • Tight junctions create barriers regulating molecular exchange.

Connective Tissue Cells

  • Function:

    • Connect, anchor, and support body structures.

  • Types:

    • Loose Connective, Dense Connective, Blood, Cartilage, Adipose.

Extracellular Environment

  • Components:

    • Extracellular fluid and matrix.

    • Matrix: mixture of proteins, polysaccharides, and sometimes minerals.

  • Functions:

    • Provides scaffold for cellular attachments.

    • Transmits chemical information to regulate cell activity, migration, and growth.

Organ Systems

  • Composition of Organs:

    • Composed of multiple tissue types (e.g., blood vessels).

  • Organ Systems:

    • Groups of organs working together (e.g., urinary system includes kidneys, ureters, etc.).

Body Fluids and Compartments

  • Definition:

    • Refers to the watery solution of dissolved substances in the body.

  • Types:

    • Extracellular Fluid (ECF) includes 20-25% plasma and 75-80% interstitial fluid.

Intracellular and Extracellular Fluid

  • Intracellular Fluid:

    • Located inside cells; maintains chemical composition differences crucial for cell activity.

  • Extracellular Fluid:

    • Composed of interstitial fluid and plasma; separates cell contents from external environment.

Tonicity and Osmolarity

  • Tonicity:

    • Refers to the effect of a solution on cell volume.

  • Osmolarity:

    • Indicates solute concentration.

    • Normal body fluid osmolarity ~282 mOsm/L.

Fluid Movements

  • Mechanisms:

    • Governed by hydrostatic and osmotic pressures.

    • Water moves from areas of lower solute concentration to higher concentrations.

Dehydration Effects

  • Symptoms:

    • Dry mouth, dry skin, low urine volume, potential confusion.

  • Physiological Impact:

    • Increases heart workload, leads to blood viscosity, potentially causing clots.

Oedema

  • Definition:

    • Swelling due to excess fluid accumulation in tissues.

    • Can occur from fluid exchange imbalances and pressure variations in blood vessels.

Conclusion: Homeostasis

  • Importance of maintaining fluid balance and composition across body compartments.

Diagrams in the referenced PDF illustrate key concepts of human physiology and anatomy. Major diagrams include:

  1. Cell Structures: Show the organization of various cell types, highlighting their specialized functions and structures such as nuclei, organelles, and membranes.

  2. Tissue Types: Present different tissues in the body including muscle, nerve, and epithelial tissues, emphasizing their unique roles and arrangements.

  3. Organ Systems: Depict the interrelation of different organ systems (e.g., digestive, circulatory), showing how these systems collaborate to maintain homeostasis.

  4. Fluid Compartments: Illustrate the distribution of intracellular and extracellular fluid, detailing their percentages and significance for physiological balance.

  5. Osmolarity and Tonicity: Visual representations of various solutions and their effects on cell volume, aiding in understanding of fluid movements and homeostasis.

  6. Dehydration Effects: Diagrams showcasing physiological changes during dehydration, such as increased heart workload and effects on blood viscosity.