CELLULAR LEVEL - Tagged

Human Anatomy and Physiology: Cellular Level - Overview

Page 1

• Human Anatomy and Physiology, 7e by Elaine Marieb & Katja Hoehn

• Lecture 3: The Cellular Level - Focus on Cells as Living Units

Page 2: Cell Theory

• Cell Theory states:

  • A cell is the basic structural and functional unit of all organisms.

  • Structure-function complementarity: biochemical reactions in cells depend on subcellular structures present.

  • Reproduction has a cellular basis.

Page 3: Cell Diversity

• Cell Types and Functions:

  • Fibroblasts: Connect body parts.

  • Erythrocytes: Transport gases.

  • Epithelial Cells: Form linings.

  • Macrophage: Fight disease.

  • Nerve Cell: Gather information and control functions.

  • Fat Cell: Stores nutrients.

  • Skeletal and Smooth Muscle Cells: Move organs and body parts, and assist in body movements.

  • Sperm: Reproduction.

Page 4: Main Parts of a Cell

• Three Main Parts:

  • Plasma Membrane: Defines cell boundary.

  • Cytoplasm: Interior of the cell (between membrane and nucleus) containing organelles.

  • Nucleus: Contains genes, controlling cell activities.

Page 5: Generalized Cell Structure

• Key Organelles:

  • Nucleus: Nuclear envelope, chromatin, nucleolus.

  • Endoplasmic Reticulum (ER): Rough and Smooth.

  • Golgi Apparatus: Modifies, packages proteins.

  • Mitochondria: Powerhouse of the cell.

  • Lysosomes and Peroxisomes: Breakdown waste substances.

Page 6: Plasma Membrane Structure

• Fluid Mosaic Model:

  • Composed of a bimolecular lipid layer containing proteins.

  • Structure includes:

    • Phospholipids: Hydrophilic heads; hydrophobic tails.

    • Cholesterol: Stabilizes membrane.

    • Proteins: Integral and peripheral proteins.

Page 7: The Plasma Membrane

• Characteristics:

  • Thickness: 7-10nm.

  • Functions:

    • Forms the cell boundary.

    • Fluidity enables constant flux of membrane proteins.

Page 8: Membrane Proteins

• Types of Membrane Proteins:

  • Integral Proteins: Span the membrane.

    • Transmembrane Proteins: Exposed on both surfaces.

  • Peripheral Proteins: Attach to integral proteins or phospholipid heads.

Page 9: Functions of Membrane Proteins

• Key Functions:

  • Transport: Selective channels for substances.

  • Enzymatic Activity: Catalyze reactions.

  • Signal Transduction: Receptor proteins for signal response.

  • Cell-cell Recognition: Glycoproteins as identification tags.

  • Attachment to Cytoskeleton & ECM: Maintain cell shape.

Page 10: Glycocalyx

• Structure: Sugar coat on the cell's outer surface.

• Functions:

  • Cell attachment to the extracellular matrix.

  • Facilitates cell-cell recognition and interactions.

  • Protection against injury and inappropriate contacts.

Page 11: Membrane Junctions

• Types of Membrane Junctions:

  • Tight Junctions: Impermeable junctions between cells.

  • Desmosomes: Anchoring junctions connecting adjacent cells.

  • Gap Junctions: Allow ion transfer between cells.

Page 12: Membrane Transport Overview

• Types of Membrane Transport:

  • Passive Processes: No energy required (Diffusion, Filtration).

  • Active Processes: Energy needed (Active Transport, Vesicular Transport).

Page 13: Passive Processes

• Types of Passive Transport:

  • Diffusion: Movement down a concentration gradient (includes simple diffusion, facilitated diffusion, osmosis).

  • Filtration: Movement down a pressure gradient.

Page 14: Active Processes

• Active Transport Types:

  • Active Transport: Against a concentration gradient.

  • Vesicular Transport: Moves substances in bulk via vesicles (e.g., exocytosis, endocytosis).

Page 15: Diffusion Mechanisms

• Diffusion Methods:

  • Simple Diffusion: Lipid-soluble substances pass directly.

  • Facilitated Diffusion: Uses carrier proteins.

  • Osmosis: Movement of water through semi-permeable membranes.

Page 16: Tonicity Concepts

• Types of Tonicity:

  • Isotonic: No net water movement; cell remains unchanged.

  • Hypotonic: Water enters cell, causing swelling.

  • Hypertonic: Water exits cell, causing shrinkage.

Page 17: Passive Filtration

• Filtration Process: Movement of solution from higher pressure to lower pressure; occurs significantly in kidney function.

Page 18: Active Transport

• Mechanism: Requires ATP to move substances against their concentration gradient; includes Na+/K+ pump.

Page 19: Vesicular Transport Details

• Exocytosis: Movement of materials out of cell using vesicles.

• Endocytosis: Involves bringing materials into cell - includes phagocytosis and pinocytosis.

Page 20: Phagocytosis and Pinocytosis

• Phagocytosis: Engulfing solid particles.

• Pinocytosis: Engulfing fluids.

• Receptor-mediated Endocytosis: Specific uptake mediated by receptor proteins.

Page 21: Transcytosis and Vesicular Trafficking

• Transcytosis: Transport of substances across a cell from one side to another via vesicles.

• Vesicular Trafficking: Movement of substances between organelles within the cell.

Page 22: Resting Membrane Potential (RMP)

• RMP Characteristics:

  • RMP ranges from -50mV to -100mV.

  • Established by differences in ion concentrations and selective permeability of the plasma membrane.

Page 23: Cytoplasm Composition

• Components of Cytoplasm:

  • Cytosol: Fluid matrix where organelles reside.

  • Organelles: Special compartments (e.g., mitochondria, ribosomes, ER).

Page 24: Cytoplasmic Organelles

• Classes of Organelles:

  • Membranous: (e.g., mitochondria, Golgi apparatus).

  • Non-membranous: (e.g., ribosomes, cytoskeleton).

Page 25: Mitochondria Overview

• Mitochondria:

  • Known as the "power plants" of the cell; produce ATP.

  • Self-replicate and have their own DNA.

Page 26: Ribosome Structure

• Ribosome Composition: Made up of small and large subunits; two types: free and bound.

Page 27: Endoplasmic Reticulum (ER)

• ER Types:

  • Rough ER: Studded with ribosomes; synthesizes proteins.

  • Smooth ER: Lacks ribosomes; synthesizes lipids and detoxifies drugs.

Page 28: Golgi Apparatus Function

• Golgi Apparatus: Modifies, sorts and packages proteins and lipids received from the ER.

Page 29: Lysosomes Overview

• Lysosomes: Contain digestive enzymes; digest waste and worn-out materials.

Page 30: Peroxisomes Summary

• Peroxisomes: Contain enzymes for detoxifying harmful substances; neutralize free radicals.

Page 31: Cytoskeleton Components

• Cytoskeleton Types:

  • Microtubules: Largest diameter, support intracellular transport.

  • Intermediate Filaments: Provide tensile strength.

  • Microfilaments: Smallest diameter, involved in cell motility and shape changes.

Page 32: Celular Extensions

• Cilia and Flagella:

  • Cilia: Numerous, move substances across cell surfaces.

  • Flagella: Singular, propel sperm cells.

Page 33: Nucleus Structure

• Nucleus: Control center of the cell, contains chromatin and nucleolus; enclosed by the nuclear envelope.

Page 34: Chromatin Structure

• Chromatin: DNA and histone proteins, exists in two forms: heterochromatin (inactive) and euchromatin (active).

Page 35: Nucleic Acids

• Two Types of Nucleic Acids: DNA and RNA; composed of nucleotides.

Page 36: The Cell Cycle

• Phases of the Cell Cycle:

  • Interphase (G1, S, G2) and cell division (mitosis, cytokinesis).

Page 37: Protein Synthesis

• Phases: Transcription and Translation; involves DNA to mRNA conversion followed by mRNA translation into proteins.

Page 38: Genetic Code

• Translation Process: mRNA codons correspond to tRNA anticodons bringing specific amino acids.

Page 39: Summary of Cellular Processes

• Cellular Understanding: The cellular structure and functions provide a foundation for understanding complex physiological processes.