Human Physiology: Body Fluid Compartments

Human Physiology - Introduction to Body Fluid Compartments

• Physiology is the study of how living things work.
• It involves examining functions in various conditions.

Human Body Organization

• The cell is the smallest basic unit.
• Tissues come from similar cells working together.
• Organs contain multiple tissues to perform specific functions.
• Systems are made of various organs working for a shared goal.

Examples of Body Systems

• Cardiovascular
• Respiratory
• Urinary
• Digestive
• Endocrine
• Nervous
• Reproductive
• Musculoskeletal

Body Fluids

• Approximately 60% of a young adult male's weight is water.
• Intracellular fluid (ICF) makes up about 2/3 of total body water.
• Extracellular fluid (ECF) accounts for the remaining 1/3.
• ECF subdivisions include intravascular (blood plasma), and extravascular (interstitial/transcellular) fluids.
• Interstitial fluid fills spaces between cells.
• Transcellular fluids are located in closed spaces.

Composition of Body Fluids

• ICF is rich in K+ and proteins.
• ECF contains more Na+ and Cl−.

Osmolarity Function

• Water is crucial for chemical and enzymatic reactions.
• It's a medium for diffusion and filtration.
• Facilitates pH regulation.
• Maintains body temperature and lubrication.
• Acts as a reflective medium and a mechanical buffer for organs like the brain.
• Necessary for gas exchange in lungs and tissues.

Human Cells - Cell Membrane Structure and Function

• Cell membrane acts as a protective barrier, separating internal from external environments.

• It is selectively permeable, controlling substance entry and exit.

• The cell membrane is extremely thin, approximately 75 angstroms.

• Composed of phospholipids, proteins, and carbohydrates.

• Phospholipids:

  • Have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails.
  • Form a phospholipid bilayer, the core of the cell membrane.

• Proteins:

  • Determine cell membrane functions.
  • Can either be peripheral (on the surfaces) or transmembrane (integrated).
  • Include channels for transport, receptors for signals, and enzymes.

• Carbohydrates:

  • Often attached to proteins (glycoproteins) or lipids (glycolipids).
  • Involved in cell-cell recognition and communication.

Functions of Cell Membrane Proteins

• Act as receptors (respond to hormones/chemicals) and recognition sites (self/non-self).
• Form pores (channels) for specific substances.
• Are pumps to move substances against gradients.
• Are enzymes.
• Function as an active support structure.

Types of Cell Membrane Channels

• Non-gated channels are always open.
• Gated channels open or close depending on stimuli (voltage, ligands, mechanical pressure).

Carbohydrates of the Cell Membrane

• Form the glycocalyx—a carbohydrate-rich layer outside the membrane.
• Functions in cell recognition, adhesion, and protection.

This quiz explores the fundamental concepts of human physiology, focusing on body fluid compartments and their roles in the body's organizational structure. Understand how cells, tissues, organs, and systems interact, as well as the importance of intracellular and extracellular fluids in maintaining homeostasis.