chapter 3

tissues

Four elements that make up the bulk of living matter.

Carbon, oxygen, hydrogen, nitrogen

Trace Elements

Calcium, iron, iodine, potassium

Cells

The building blocks of all living things. Cells are not all the same but share general structures.

Tissues

Groups of cells that are similar in structure and function

3 main regions of the cell.

Nucleus, cytoplasm, plasma membrane.

Nucleus

The control center. Contains DNA. 3 regions include the nuclear membrane, nucleolus, and chromatin.

Nuclear Envelope

Barrier of nucleus. Made of double phospholipid membrane. Pores allow for exchange of material with rest of the cell.

Nucleolus

Nucleus contains 1 or more nucleoli. Makes ribosomes. Ribosomes migrate to cytoplasm through nuclear pores.

Deoxyribonucleic Acid (DNA)

Composed of DNA & Protein. Chromatin- Throughout nucleus in thread form.

Chromosomes

Condensed DNA forms before cell divides.

Cytoplasm

Material outside nucleus and inside plasma membrane.

Cytosol

Fluid that suspends other elements.

Organelles

Machinery of cell.

Inclusions

Non-functioning units.

Ribosomes

Made of protein and RNA. Sites of protein synthesis. Found at two locations: 1. Free in the cytoplasm and 2. Attached to (rough) endoplasmic reticulum.

Endoplasmic Reticulum

Fluid-filled tubules for carrying substances. Has two types.

1. Rough ER -Studded with ribosomes. -Makes parts for membranes.

2 Smooth ER-Makes & breaks cholesterol. -Fat metabolism. -Detoxifies drugs.

Golgi Apparatus

Modifies and packages proteins.

1. Secretory vesicles

2. Cell membrane components

3. Lysosomes.

Lysosomes

Sacs of enzymes. Digest non-usable materials.

Peroxisomes

Sacs of oxidase enzymes. Detoxify harmful substances. Break down free radicals(highly reactive chemicals). Replicate by pinching in half.

Mitochondria

"Powerhouses" of the cell. Change shape continuously. Uses O2 to break down food. Provides Adenosine Triphosphate(ATP) for energy.

Cytoskeleton

Protein structures throughout the cytoplasm. Internal framework. Three different types:

1. Micro filaments

2. Intermediate filaments

3. Microtubules

Centrioles

Rod-shaped bodies made of microtubules. Make spindle fibers during cell division.

Plasma Membrane

Barrier for cell contents. Other materials include proteins, cholesterol, glycoproteins. Double phospholipid layer: hydrophilic heads, and hydrophobic heads.

Microvilli

Finger-like projections. Increase surface area for absorption.

Membrane junctions

1. Tight junctions- Impermeable

2. Desmosomes- Anchor

3. Gap junctions- Communicate

Cellular Projections

Not found in all cells. Used for movement.

Cilia

Moves materials across the cell surface.

Flagellum

Propels the cell.

Membrane Transport

Movement into and out of cells to maintain homeostasis.

Passive Transport

No energy required.

Active Transport

The cell must provide metabolic energy.

Solution

Homogeneous mixture of two or more components.

Solvent

Dissolving medium.

Solutes

What gets dissolved.

Intracellular Fluid

Inside cell. Nucleoplasm & cytosol.

Interstitial Fluid

Fluid on the exterior of the cell.

Diffusion

Particles distribute themselves evenly within a solution. Movement is from high concentration to low concentration, or down a concentration gradient.3 types: simple, facilitated, osmosis.

Simple Diffusion

Lipid-soluble materials or small enough to pass through membrane pores.

Facilitated Diffusion

Too big or not lipid-soluble; requires protein carriers.

Osmosis

Movement of water across membrane.

Filtration

Water and solutes are forced through a membrane by fluid, or pressure. Pressure gradient must exist. Solute-containing fluid is pushed from a high pressure area to a low pressure area.

Active Transport

Transport substances that can't pass because: too large, not lipid-soluble, going against concentration gradient. 2 forms, solute pumping, bulk transport.

Solute Pumping

Amino acids, some sugars, and ions are transported by solute pumps. ATP energize protein carriers, and in most cases, move substances against concentration gradients.

Exocytosis (Bulk Transport)

Moves materials out of cell in vesicle. Vesicle combines with plasma membrane. Material is emptied to the outside.

Endocytosis (Bulk Transport)

Substances engulfed by being enclosed in membranous vesicle.

Phagocytosis (1st type of endocytosis)

Cell-eating

Pinocytosis (2nd type of endocytosis

Cell-drinking.

Interphase

Cell grows, DNA replication (G1, S, G2)

Mitosis

Division of nucleus.

Cytokinesis

Division of cytoplasm.

DNA Replication

DNA is duplicated. Occurs at the end of interphase. DNA uncoils and each side serves as a template.

Steps of Mitosis & Cytokinesis

1. Prophase 2. Metphase 3. Anaphase 4. Telophase 5. Cytokinesis.

Prophase

Centromeres migrate to poles.

Metaphase

Spindle fibers attach to chromosomes that are aligned in the middle of cell.

Anaphase

Daughter chromosomes pulled toward poles.

Telophase

Daughter nuclei seen; cleavage furrow seen.

Cytokinesis

Division of cytoplasm; results in 2 identical daughter cells.

Protein Synthesis

Reading a gene to make a protein.

Gene

DNA segment that carries a blueprint for building one protein.

Messenger RNA (mRNA)

Carries the instructions for protein synthesis.

Transfer RNA (tRNA)

Transports amino acids to the ribosomes.

Ribosomal RNA (rRNA)

Forms part of the ribosomal structure & coordinates the protein building process.

Proteins

For building or for enzymes.

Transcription

Copying gene from a DNA to mRNA.

Translation

Reading mRNA and linking amino acids together in the ribosome.

Body Tissues

Cells are specialized for particular functions.

Tissues

Group of cells with similar structure and function.

4 Types of Tissues

Epithelium, Connective, Nervous, Muscle.

Locations of Epithelial Tissue

Body coverings & linings, glandular tissue.

Characteristics of Epithelial Tissue

Cells close together, cells have free apical surface, bottom surface is basement membrane.

Functions of Epithelial Tissue

Protection, absorption, filtration, secretion.

Classification of Epithelial Tissue

1. \# of cell layers. Simple\=1 Statified\=More than 1

2. Shape of Cells. Squamous- Flattened. Cuboidal- Cube-shaped. Columnar- Column-like.

Simple Squamous

Single layer of flat cells. Usually forms membranes. Lines body cavities. Lines lungs and capillaries.

Simple Cuboidal

Singler layer of cubelike cells. Common in glands and their ducts. Forms walls of kidney tubules. Covers the ovaries.

Simple Columnar

Single layer of tall cells. Often includes goblet cells, which produce mucus. Lines digestive tract.

Pseudostratiied

Single layer, but some cells are shorter than other. Often looks like a double cell layer. Sometimes ciliated, such as in the respiratory tract. May function in absorption or secretion.

Stratified Squamous

Cells at the free edge are flattened. Found as a protective covering which friction is common. Located in the skin, mouth, and esophagus.

Stratified Cuboidal (Rare)

Two layers of cuboidal cells. Found mainly in ducts of large glands.

Stratified Columnar (Rare)

Surface cells are columnar, cells underneath vary in size and shape. Found mainly in ducts of large glands.

Gland

One or more cells that secretes a particular product.

Endocrine Gland

Ductless, secretes hormones.

Exocrine Gland

Empty through ducts to surface. Include sweat and oil glands.

Transitional Epithelium

Shape of cells depends upon the amount of stretching. Lines organs of the urinary system.

Conncective Tissue

Most abundant and widely distributed. Some have good blood supply (vascularized). Some don't (avascular).

Functions of Connective Tissue

Binds tissues together, supports, and protects.

Ground substance (extracellular matrix)

Mostly water along with adhesion proteins and polysacchride molecules.

Fibers (extracellular matrix)

Produced by the cells.

3 Types of Fibers

Collagen, Elastic, Reticular.

Bone (osseous tissue) (Connective Tissue)

Bone cells in lucunae (cavities). Hard matrix of calcium salts. A lot of collagen fibers. Protect & supports body.