General Histology & Embryology PDF

GENERAL HISTOLOGY & EMBRYOLOGY S.Y. ‘23 - ‘24 | SEM #1 | MAIN REFERENCE ISIP, CAIA JANAE N. 3.0 THE CELL AND ITS STRUCTURE Cells: a mass of protoplasm enclosed within a cell membrane & containing a nucleus. fundamental unit of life...

GENERAL HISTOLOGY & EMBRYOLOGY S.Y. ‘23 - ‘24 | SEM #1 | MAIN REFERENCE ISIP, CAIA JANAE N. 3.0 THE CELL AND ITS STRUCTURE Cells: a mass of protoplasm enclosed within a cell membrane & containing a nucleus. fundamental unit of life Rudolf Virchow ○ In 1855, Virchow published a statement based on his observations “Omnis cellula e cellula” which means that all cells arise from pre-existing cells. 3.1 CELL THEORY PROPONENTS OF THE CELL THEORY 1. All organisms consist of 1 or more cells. Matthias Jacob Schleiden 2. Cell is the smallest unit of life of all organisms. ○ German botanist ○ The smallest cell is 0.0001 ○ Defined the cell as the basic unit of micrometer in bacteria. plants ○ The largest cell measures Theodore Schwann 170mmx130mm (ostrich egg). ○ German Physician and Psychologist 3. All cells arise only by division of pre-existing ○ Defined cell as the basic unit of cells. animal structure 2 BASIC TYPES OF CELLS ○ Schwann concluded 3 things that 1. EUKARYOTES became vital components of the cell theory ○ Group of organisms whose cells have a defined nucleus surrounded by He concluded that both plants nuclear membrane and animals were composed of cells. ○ Primary component of multicellular organisms (animal cells) Cells have independent lives. 2. PROKARYOTES These independent lives are subject to the organism’s life. ○ Cells have no nuclear membrane Robert Hooke ○ Do not have a distinct nucleus ○ He coined the biological term cell from ○ Mainly bacteria, blue green algae the monk’s cell “cellula” which means small rooms (English Father of the Microscope) PPT | LECTURE GENHISTO SEM1 MIDTERMS PAGE 1 @wonrika  GENERAL HISTOLOGY & EMBRYOLOGY S.Y. ‘23 - ‘24 | SEM #1 | MAIN REFERENCE ISIP, CAIA JANAE N. Controls cellular activity by regulating RNA 3.2 EUKARYOTES synthesis, which regulates protein synthesis 3 MAJOR COMPONENTS OF EUKARYOTIC CELLS 1. Cell Membrane The nucleus is composed of: 2. Nucleus 1. Chromatin 3. Cytoplasm ○ Major nuclear component CELL MEMBRANE ○ Made of coiled strands of DNA which is bound to basic proteins called Separates the cell from the external histones environment 2 types of Chromatin Regulates the transport of materials in & out of the cell 1. Euchromatin (dispersed chromatin) Made up of 2 layers of phospholipid bilayer ○ Loosely packed & light staining ○ Composed of many proteins and lipids ○ Represents active genetic FUNCTIONS: materials 1. Selective permeability (penetrable) 2. Heterochromatin (condensed 2. Endocytosis (inside): brings in chromatin) substances to the cell ○ Tightly packed & dark staining Phagocytosis: cell eating ○ Unused genetic materials in Pinocytosis: cell drinking storage Receptor: mediated ○ Barr Body: inactivated endocytosis x-chromosome in the nuclei of female cells (female cells only 3. Exocytosis (extraction): removal of because they have an extra X substances from the cell chromosome) 4. Compartmentalization 2. Nucleolus 5. Storage, transport, and secretion ○ Deep-staining, basophilic areas ○ Composed of granules, fibrils, and NUCLEUS chromatin The control center of the cell ○ Region of intensive ribosomal RNA synthesis Appears rounded/elongated structure 3. Nucleoplasm The reservoir of DNA & carries most of genetic information ○ semi-fluid, colloidal solution in which the chromatin materials and the nucleolus are suspended PPT | LECTURE GENHISTO SEM1 MIDTERMS PAGE 2 @wonrika  GENERAL HISTOLOGY & EMBRYOLOGY S.Y. ‘23 - ‘24 | SEM #1 | MAIN REFERENCE ISIP, CAIA JANAE N. 4. Nuclear Envelope/Nuclear Membrane ○ Include secretory inclusions (enzymes, acids, protein), nutritive ○ Double membrane inclusions (glycogen, lipids), and pigment granules (melanin, lipofuscin: ○ Maintains a separate milieu between yellow-brown pigment granules the nucleoplasm and cytoplasm considered to be one of the aging or 5. Nuclear Pores "wear-and-tear" pigments, found in the liver, kidney, heart muscle, retina, ○ Vary in size adrenals, nerve cells, and ganglion cells., hemosiderin: found in ○ Have a slit-like diaphragm that hemoglobin) regulate what enters and leaves the nucleus 3. Cytoskeleton: provides structural stability for the maintenance of cell shape ○ Protein gatekeepers ORGANELLES CYTOPLASM A gel-like substance enclosed within the cell Membrane-bound Non-membrane bound membrane About 70% to 90% water and usually colorless 1. Nucleus 1. Ribosomes 3 groups of structures: 2. RER 2. Microfilaments 1. Organelles 3. SER 3. Microtubules 2. Cytoplasmic Inclusions 4. Mitochondria 4. Intermediate filaments 3. Cytoskeleton 5. Golgi Apparatus 5. Junctions 6. Lysosomes 6. Centrosomes 1. Organelles 7. Peroxisomes ○ Usually membrane-bound 8. Secretory Vesicles ○ Structures inside the cell that have specific functions 9. Chloroplasts (plant cell) ○ Major organelles like mitochondria, ribosomes, Golgi bodies, etc. 10. Vacuole (plant cell) ○ “Little organs” 2. Cytoplasmic Inclusions ○ Structures that are generally more transient than organelles & less MEMBRANE-BOUND ORGANELLES actively involved in cell metabolism 1. Endoplasmic Reticulum PPT | LECTURE GENHISTO SEM1 MIDTERMS PAGE 3 @wonrika  GENERAL HISTOLOGY & EMBRYOLOGY S.Y. ‘23 - ‘24 | SEM #1 | MAIN REFERENCE ISIP, CAIA JANAE N. ○ Network of flattened sacs and ○ Participates in many activities branching tubules particularly those associated with secretion ○ Involved in the synthesis, packaging, and processing of various cell ○ FUNCTIONS: substances 1. Polysaccharide synthesis Types of ER: 2. Completes the processing 1. Rough Endoplasmic Reticulum substances received from the ER ○ Granular 3. Store and package cellular ○ Ribosomes are attached to secretions for export out the the outer surface of RER cell ○ Synthesis of proteins 4. Lysosomes ○ Proteins are modified as they ○ Spherical in shape move through RER ○ Membrane limited vesicles 2. Smooth Endoplasmic Reticulum ○ Main site of intracellular digestion ○ Network of tubular membrane structures ○ Contains hydrolytic enzymes that breakdown macromolecules such as ○ Continuous with RER nucleic acids, proteins, and polysaccharides ○ No ribosomes attached to the surface ○ FUNCTIONS: ○ Involved in lipid synthesis 1. Killing of pathogenic organisms ○ Assist in the control of muscle contraction in muscle cells 2. Degradation of waste products ○ Detoxifies modifications and alcohol in liver cells 3. Digest and remove worn out cell organelles 2. Mitochondria 5. Peroxisomes ○ Sites of chemical reactions that transfer energy from organic ○ Spherical in shape compound to ATP ○ Membrane limited, enzyme-containing ○ Powerhouse of the cell vesicles ○ Largest cytoplasmic organelle ○ Smaller than lysosomes 3. Golgi Apparatus/Complex ○ Also called the “microbodies” ○ A network of flattened membraneous ○ METABOLIC FUNCTIONS: vesicles that are saucer-shaped and cave-faced 1. Breakdown of fatty acids PPT | LECTURE GENHISTO SEM1 MIDTERMS PAGE 4 @wonrika  GENERAL HISTOLOGY & EMBRYOLOGY S.Y. ‘23 - ‘24 | SEM #1 | MAIN REFERENCE ISIP, CAIA JANAE N. 2. Breakdown of purines to urea 3. Microtubules 3. Breakdown of toxic ○ Long hollow tubes made of tubulin compounds proteins (globular) 4. EG: in the cells of the liver and ○ Anchor organelles and act as tracks kidney for organelle movement 6. Secretory Vessels ○ Move chromosomes around during cell division ○ Transport and delivery of their contents (EXOCYTOSIS AND ○ Makes up the cilia (short and present in ENDOCYTOSIS) large number) and the flagella (long and less numerous) ○ Cilia and Flagella NON-MEMBRANE BOUND ORGANELLES Hair-like structures that extend from the surface of the 1. Ribosomes cell ○ Some are free, some are attached to Assist in movement the ER 4. Intermediate Filaments ○ Made up of proteins and RNA ○ Fibrous proteins join to form rope-like Protein is synthesized in the structures ribosomes ○ Provide internal support RNA is packaged into ribosomes then transported to ○ Anchor the organelles in place cytosis in the cytoplasm 5. Junctions 2. Cytoskeleton ○ Connecting points joining either cells ○ A mesh of filamentous elements or other cells, or cells to their basement membrane 1. Microtubules 6. Centrosomes 2. Microfilaments ○ Contain the centrioles, which are 3. Intermediate Filaments involved in the process of mitosis ○ Provides structural stability for the maintenance of cell shape ○ Thinnest cytoskeletal elements (rod-like) ○ Composed of globular protein actin ○ Enable cells to change shapes and move PPT | LECTURE GENHISTO SEM1 MIDTERMS PAGE 5 @wonrika