Cytology: Cell Structure and Functions

Cytology and Cellular Biology

• Cells are the smallest structural and functional units of living beings.

The Human Cell Count

• Human beings have approximately 36 trillion cells.
• Men average around 36 trillion cells, women around 28 trillion, and children (at 10 years old) around 17 trillion cells.
• There are 1,264 cell groups, 400 primary cell types, and 60 tissues.

Cell Structures and Functions

• Cells are functional and structural units in living organisms, capable of cellular division.
• Organisms are formed by cells.

Cell Functions

• Cells are responsible for vital processes of living organisms.
• Cells need energy for activities, obtained through nutrients via cellular respiration and stored as ATP.
• Cells regulate the internal environment to ensure proper functioning.
• Protein synthesis occurs in ribosomes, where DNA's genetic information is translated into proteins.
• Cell reproduction happens by mitosis or meiosis, which is fundamental in tissue growth.

Microscopy

• Microscopy is the science of using microscopes to view samples and objects invisible to the naked eye.
• Zacharias Janssen (1580-1632) invented the compound microscope in 1590, being credited as the first.
• Antonie van Leeuwenhoek (1632-1723) built microscopes with only one lens, visualizing red blood cells and bacteria.

Optical Microscopy

• Optical microscopes use light refraction to amplify images, with a maximum magnification of 1,000x.
• Light field microscopes used in labs to have structural contrast, and are frequently used for cell research.

Electronic Microscopy

• Electron microscopy produces high-resolution images with electron beams, magnifying up to 300,000x.
• Transmission and sweep microscopy exists as standard methods.

Cellular Organelles

• Cellular organelles, similar to organs, take part in essential activities.
• Organelles form internal membranes and different shapes and functions.
• Eukaryotic cells contain Nucleus, Ribosomes, Complex golgiense, Retículo endoplasmático, Membrane, Mitocondria , Citoplasma and, Lisossomo.
• Plants Cells have Nucleus, Nucleolus, Retículo endoplasmático rugoso, Retículo endoplasmático liso, Citoesqueleto, Membrana plasmática, Lisosomas, Complejo de Golgi, Mitocondria, Citoplasma, Peroxisoma, Ribosomas,Cloroplasto, Gran vacuola and Pared celular
• All cells have nucleus, genetic material (DNA), cytoplasm and ribosomes in common.

Cytoskeleton

• The cytoskeleton provides structure, support to organelles, and locomotion.
• It's composed of filaments: Microtubules, Intermediate and Actina Filaments

Plasma Membrane

• The plasma membrane separates internal cellular from external.
• It protects cell integrity and acts as barrier, permitting a controlled material transfer.
• The membrane contains molecules like proteins and lipids.

Cytoplasm

• Cytosol, a fluid along with cellular organelles compose the cytoplasm.
• Composed of water, proteins, and minerals.
• Metabolic reactions, and also molecule manufacturing happen there.

Nucleus

• Eukaryotic cells separate the nucleus and carioteca, in which théke means wrapper.
• The nucleus has two layers made of lipoproteic acids.
• Communicating holes exist between the cytoplasm for transport.
• Nucleolus produces ribosomes.

Genetics

• Genetics are protected within cromossomes in the Nucleus, that contains nucleotides.
• DNA is the central component for the function and genetic archive
• Cromatin can devide in many hetereocromatin, from eu=true.

Ribossomes

• Prokariotes and Eukariocytes are present in the nucleus.
• The synthesis and assistance of synthesis happens mainly there.
• Ribs fundamental for cell growth and metabolic control.

Endoplasmic Reticule

• This organelle has layers of function that has the purpose of synthesis, transporting substances.
• Two types of reticulum exists granular and agranular for cellular transport
• Re Rugoso creates bags called ergonamos, with grannules of synthesis protein.
• REL create smooth layer, for synthesing lipids.

Golgi Complex

• This structure has sacs of a pile of vesicules.
• Related to material secretion from the substances
• Receives and changes molecules.

Lisossomes

• Digestion happens with enzymes is the bags.
• Capable of degrading particles, recycling components of aging structures.

Peroxissomes

• Oxidation of the substance occurs in these complexs
• Located in cells, there happens degradation.
• Catalaze, also known as hidrogenoxide can be degrades from the toxic structures on the cell system.

Vacúolo

• Storage and structural support happens
• Lysossomes operate in this vacuole.

Mitocondria

• Located in Eukariotes, Algas, plants and protozoa
• Variation of types can occur because of variation
• Cellular repsiration with glicose is present.

Centrioles

• Don't have membranes.
• Helps in cell division in the cell.

Cell Wall

• Present in ALL vegetables and SOME bacterias and fungi.
• It's composition is very adaptable.