Introduction to Cells

• Cells are fundamental to the human body
• In simple life forms like amoebas, a single cell is the entire organism
• The human body contains billions of specialized cells

Protoplasm

• A viscous liquid matrix supporting internal cellular structures
• Each cell contains a mass of this colorless substance
• It facilitates intracellular transport of nutrients, signaling molecules, ATP, and proteins

Tissue and Homeostasis

• Tissues are cells with a shared function growing in close proximity
• Organs are groups of tissues performing related jobs
• Homeostasis is the body's stable internal environment
• A disruption of homeostasis impacts the organism

Two Types of Cells

• Sex cells (germ or reproductive cells) include sperm in males and oocytes (eggs) in females
• Somatic cells are all other body cells
• Somatic cells are the main focus

Three Basic Parts of A Cell

• A cell consists of a cell membrane, a nucleus and cytoplasm
• Organelles are specialized cell structures that perform necessary functions

Cell Membrane

• The cell membrane controls the movement of substances in and out
• Extracellular located outside the cells
• Intracellular means situated inside cells
• Atoms compose molecules and consist of protons (positive charge), electrons (negative charge), and uncharged neutrons
• It allows selective communication between intracellular and extracellular compartments, assisting in cell movement
• It provides structure
• The cell membrane facilitates biological activities.
• Detects and transmits signals from outside
• Adheres to other cells to form tissues
• Selectively permeable, allowing certain elements to pass while blocking others

Lipids and Proteins

• Lipids and proteins are primary in cell membranes,
• Typically a phospholipid bilayer
• Phosphate portion forms the outer surface.
• Fatty acid portion forms the inner surface.
• Proteins periodically interrupt the lipid bilayer of cells
• These act as transporters, signal receptors, channels, and ion channels

Membrane Permeability

• A cell membrane allows selective passage to maintain stability
• Extracellular and intracellular separation does helps maintain stability
• Enzymes, sugar, and electrolytes is able to enter in freely
• Electrolytes conduct electricity when dissolved in a solvent like water.

Cell Transport Mechanism

• Mechanisms allowing material passage through the cell membrane including diffusion, osmosis, facilitated diffusion, active transport, endocytosis, and exocytosis

Diffusion

• Diffusion involves the movement of particles, or solutes from an area of high concentration to low concentration
• Diffusion depends on the membrane's permeability and concentration gradient
• Small molecules diffuse more easily, and watery solutions diffuse faster than thicker solutions

Osmosis

• Osmosis involves the movement of a solvent from low to high concentration through a membrane
• Osmotic pressure is the measure of water's tendency to move across a membrane
• Crenation is cell shrinkage from water loss
• Lysis is cell swelling and bursting from water gain

Facilitated Diffusion

• Facilitated diffusion involves a carrier molecule moving substances from areas of high concentration to areas of low concentration
• This process does not needs energy.
• The amount molecules transported is directly related to substance concentrations.

Active Transport

• Active transport is the substance moment a concentration gradient
• It requires energy and often a carrier mechanism
• Transport is opposite of diffusion
• The mechanism exchange substances

Filtration

• With filtration water moves out of plasma a cross the capillary membrane in the interstitial space
• Hydrostatic pressure drives this
• Oncotic force pulls water back from interstitial space.

Endocytosis & Exocytosis

• Endocytosis involves material uptake through membrane forming vesicle within cell protoplasm
• Phagocytosis is a cell eating solid particles
• Pinocytosis is cell drinking liquids
• Exocytosis releases cell secretions from vesicles binding with the membrane

Nucleus Structure

• The largest, most visible structure, containing DNA is the Nucleus
• Without the nucleus, the cell disintegrates in 3-4 months
• The nucleus holds genetic instructions used to synthesize proteins to determine cell function and structure
• Enclosed in a double membrane with inner and outer lipid layers its typically round
• It enables the exit of specific molecules with protein lining

Nucleoplasm

• Nucleoplasm suspends the nucleolus (with RNA and protein, site of ribosome formation) and chromatin
• Chromatin of coiled DNA and protein then condense

Cytoplasm

• Cytoplasm contains all cellular material between the cell membrane and nucleus
• The setting of chemical reactions
• It comprises most of cells volume
• The space where organelles are stores
• Cytosol is the fluid portion containing water, glucose, and ATP

Organelles

• Important organelles including centrioles (for spindle apparatus), cilia (hair-like structures moving materials) and flagella (tail-like structures, sperm motility)

Ribosomes

• It contains RNA and protein interacting with RNA from cell parts for protein formation, mainly in the endoplasmic reticulum

Endoplasmic Reticulum

• It manufactures specific proteins and fats (or lipid) through membranes

Golgi Apparatus

• It associates carbohydrates with large protein groups

Lysosomses & Peroxisomes

• Lysosomes has enzymes work as digestive system
• Peroxisomes are like that of lysosomes but detoxes alcohol in liver

Mitochondria

• Rod-like organelles for cell metabolism center
• Use oxidation to produce Adenosine Triphosphate or ATP
• ATP stores / transfers energy cells can use

Genetic Material

• 2 Types of Genetic Material in the nucleus
• The deoxyribonucleic acid (DNA) contained in chromosomes.
• The ribonucleic acid (RNA in nucleoli ) within spherical intranuclear structures,

Cell Division Types

• Remodeling is the ongoing renewal by active cell division
• 2 parts of cell division includes meiosis and mitosis
• Meiosis are special cells dividing in sperm and ova production.
• Normal cells contain 46 chromosomes
• Sperm and ova contain only 23 chromosomes, labeled haploid
• Final organisms unit contains 46 chromosomes
• Cytokinesis divides cytoplasm of a cell precisely
• Mitosis works on all cells divide beside sperm and eggs

4 Mitosis Steps

• In Prophase centriole pairs moving
• In Metaphase chromosomes aligning equatorially with spindle fibers
• During Anaphase centromeres separate individually
• In Telophase chromosomes arrive

Types of Tissue Traits

• Tissues share is defined by a working group with same tasks
• Consisting of epithelial, muscle and nerves

Epithelial Traits

• Covering skin surfaces, linings organs, and forming glands which will secrete
• Basement membrane will always protects the layer
• Categorization of epithelial depends on cell layers amount, as well as the structure shape

Epithelial Cell Shapes

• The layer includes squamous with smooth sheets, as well as cuboids with box figure
• Lastly the columnar with skinny form factor

Other Epithelials

• Simple tissues involves 1 layer, with a singular link point
• Stratified form more than 1 layer, connected at singular point
• A single differing cell height makes pseudostratified
• A transitional involves layer of the cuboidal changed to stratified by stretching an organ

Connective Tissue

• Binding other types of tissue
• As connective proper types includes a syrup like filler space, combined with cell and fibres
• Loose involve underlying types

Supporting Tissue

• Cartilage a supporting dense structure with jelly filler
• Bones forms a hard dense framework with high protection from bone

Fluid Tissue

• Involves cells floating with a water filler for transfer
• The blood transfer red and white blood in the plazms
• Lymph drains to vessel then cardiovascular system

Muscles traits

• Overlies structures as classified function
• And it involves types either smooth or striated
• Movement is either involuntary, and/or forced
• Lastly in type with all 3 involves heart, muscle, smooth

More on Muscle

• Skeletal types are for will purposes, and moving a skeletal muscule
• Cardiac is for involuntary heart
• Smooth can be made again, is the core of core organs

Nerves

• To conduct electricity to the body
• Made of both glia and neuron cells
• Neuron carry signal
• Gila is supportive

Organs

• Tissues work is for organ tasks
• Together tissues will help to distribute the circulatory, plus others
• Together Skin protects you

Systems and Regions

• Systems involves skeleton and more like digestion
• Body separated appendicular and axial
• Appendicular includes arms
• Axial involves head and other core organs

Skull

• 5 Tissue layers are skin, muscle, bones, and marrow
• In sutures are the skull joints
• 3 Triangular neck involves other areas

Structure and Fluid

• Fluid stores organ protection
• As cavities store organs
• Diaphragm divides torso
• The membrane can be serous, that fills core in body