Lecture 1: Oral Histology & Embryology

Histology

the branch of biology concerned with the microscopic study of the structure of tissues

Embryology

the branch of biology dealing with the formation and development of embryos

The human body is composed of

cells, intercellular substances, and fluid

What functions to cells carry out

functions vital to life such as absorption, assimilation, respiration, irritability, conductivity, growth, reproduction, and excretion

What surrounds each cell

intercellular substances

What do intercellular substances do

provide the cell with nutrition and take up waste products

What is fluid in the body

blood and lymph

Found in all cells except mature red blood cells and platelets

nucleus

The nucleid contains

nucleic acids such as DNA and RNA

Contains the genetic information in the cell

DNA

Carries the genetic information from the DNA to the cytoplasm

RNA

The nucleid is bound/covered by

the nuclear envelope which has an opening called the nuclear pore

The nucleus contains 1-4

nucleoli with no membrane and contains the RNA

What does the cytoplasm of a cell contain

endoplasmic reticulum, ribosomes, golgi apparatus, lysosomes, mitochondria, cytoskeleton, microtubules, centrioles, plasma membranes

Smooth endoplasmic reticulum

no ribosomes

Rough endoplasmic reticulum

has ribosomes on the surface where protein production is initiated

Ribosomes

particles that translate genetic codes for proteins. They are nonspecific particles until the messenger RNA from the nucleus carries the message to the ribosomes on the ER. Then the ribosomes translate the genetic code and activate mechanisms for the production of amino acids and ultimately proteins

Where are ribosomes made

nucleolus

Golgi apparatus function

sort, condense, package, and deliver proteins from the er. It contains vesicles that can fuse with the cell membrane and release its contents by exocytosis, release things outside the cell

Lysosomes

contain acid hydrolase and enzymes that break down substances

Mitochondria

major source of ATP, which is energy, major site for metabolic reactions

Cytoskeleton

a 3D system of support for the cell made up of microfilaments, microtubules, and intermediate filaments

Cyto

cell

Amino acids are

building blocks/chains of proteins

Microtubules

important in mitosis as force generating elements

Centrioles walls are composed of

sets of microtubules, they are important in mitosis

Plasma Membrane

envelops the cell and is a selective barrier. has channels, selective barrier regulates substances in and out of cell

Mitosis/Cell Division

many cells are continuously renewing and duplicating

Prophase

1. 1. chromatin thread thickens to become chromosomes

2. 2. each chromosome splits in half, known as chromatids

3. 3. each chromatid pair is attached to a centromere, makes an X shape

4. 4. each centriole pair duplicates and migrates to opposite poles

   1. 5. the nuclear membrane disappears

Metaphase

1. 1. chromatids (chromosomes) with the centromeres, line up on the equatorial plate

2. 2. Mitotic spindle forms

3. 3. Centrioles are at the opposite ends and attach themselves by the spindle

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Anaphase

the centromeres divide and move the completed identical sets of chromatids (chromosomes) to opposite poles

Telophase

1. 1. nucleus reappears

2. 2. chromosomes elongate

3. 3. cleavage furrow deepens until separation occurs (cytokinesis)

Cellular junctions

mechanical attachments between cells or surfaces. tonofibrils, desmosome, hemidesmosome

Tonofibrils

an attachment plaque is located near the intercellular space, the tonofibrils (intermediate filaments) from one cell loop through the attachment plaque, but do not cross into the other cell

Desmosome

junction between two cells

Hemidesmosome

an attachment of a cell to an adjacent noncellular surface