Biology Tissues and Epithelial Classification

Tissues

• Tissues are groups of cells working together to perform specific functions
• Epithelial tissue covers surfaces, lines cavities, and forms glands
• Connective tissue supports, protects, and binds other tissues
• Muscle tissue produces movement through contraction
• Nervous tissue transmits electrical signals for communication

Epithelial Tissues

• Characteristics: closely packed cells, little extracellular matrix, high regeneration capacity
• Classifications: cell layers (simple, stratified, pseudostratified), cell shapes (squamous, cuboidal, columnar)
• Locations: air sacs of lungs, blood vessel linings, lining of the uterus, stomach, gallbladder, intestines, lining of ducts of certain glands, lining of oral cavity, esophagus, vagina, and anal canal, lining respiratory passages, linings of urinary bladder, ureters, parts of urethra

Connective Tissue

• Components: cells, fibers (collagen, reticular, elastic), ground substance
• Types: loose connective (areolar, adipose, reticular), dense connective (regular, irregular, elastic), specialized connective (cartilage, bone, blood)
• Adipose tissue stores energy, insulates, and cushions organs

Muscle Tissue

• Types: skeletal (voluntary, striated, attached to bones), smooth (involuntary, non-striated, found in walls of hollow organs), cardiac (involuntary, striated, found in the heart)
• Locations: skeletal muscles (attached to bones), smooth muscles (walls of hollow internal organs like intestines and blood vessels), cardiac muscles (heart walls)
• Functions: skeletal-movement, cardiac-pumping of blood, smooth-moving substances

Nervous Tissue

• Function: transmit electrical signals for communication
• Cell types: neurons (conduct electrical impulses), neuroglia (support/protect neurons)
• Location: brain, spinal cord, nerves

Levels of Organization

• Chemical, cellular, tissue, organ, organ system, organism

Homeostasis

• The maintenance of a stable internal environment despite external changes

Feedback Loops

• Components: receptor (detects change), control center (processes information), effector (carries out response)
• Examples: negative feedback (body temperature regulation), positive feedback (childbirth)

Interdependence of Systems

• Respiratory and circulatory systems working together to deliver oxygen to tissues

Gradients and Flows

• Gradients (differences in concentration, pressure, or charge) drive processes like diffusion and oxygen entering cells and blood flow

Chemical in A&P

• Atomic structure: Protons (+), neutrons (neutral), electrons (-)
• Chemical bonds: Ionic (transfer of electrons), covalent (sharing of electrons), hydrogen (weak attraction)
• Reactions: Synthesis (A+B→AB), Decomposition (AB → A+B), Enzymes speed up reactions
• pH: Measure of hydrogen ion concentration. Normal/neutral is 7.35-7.45
• Buffers: Stabilize pH by neutralizing excess acids or bases
• Water: Solvent, temperature regulation, lubrication.
• Organic molecules: Lipids (energy storage, membranes), carbohydrates (energy), proteins (enzymes, structure), nucleic acids (genetic material)
• ATP: Main energy source of cell

Overview of Cells

• Cell is the basic unit of life for all living organisms.
• Main parts of a typical animal cell (the cell that is part of us)
  • Plasma membrane – outer boundary. Selectively permeable (controls what enters and what leaves the cell).
  • Cytoplasm – viscous fluid with organelles.
  • Nucleus – control center, contains DNA.
• Prokaryotic cells vs eukaryotic cells
  • Prokaryotic cells do not have a nucleus or other membrane-bound organelles.
  • Eukaryotic cells are larger (10x) and have a nucleus.

Cellular Transport

• Passive transport (no energy required) including: simple diffusion, facilitated diffusion, osmosis.
• Active transport (energy required)

Cellular Communication and Division

• Cellular Communication occurs when a Cell releases a signal to another cell to trigger a response.
• Cells communicate via signaling molecules that bind to receptors, triggering intracellular responses.
• Cell Cycle: Series of events that leads to cell division. Includes phases like G1, S, G2.
• Mitosis: Step-by-step division of the nucleus. Stages include: prophase, metaphase, anaphase, telophase.

Cellular organelles/their Functions

• Smooth ER: Lipid synthesis, detoxification.
• Mitochondria: Produce ATP (energy).
• Cytoskeleton: Provides structural support, facilitates movement.
• Ribosomes: Protein synthesis.
• Peroxisomes: Detoxification.
• Lysosomes: Break down waste.
• Nucleus: Stores genetic material, controls cell activities
• Nucleolus: Produces ribosomes
• Golgi apparatus: Modifies, sorts, and packages proteins.

Explore the fundamental concepts of tissues in biology, including the characteristics and types of epithelial and connective tissues. This quiz covers the functions, classifications, and locations of different tissue types, providing a comprehensive understanding of tissue structures. Test your knowledge on how these tissues contribute to the overall function of the body.