HHP 201: Module 1 - Lecture 2

go thru this

What are the 4 classes of tissues?

Epithelia, connective, muscle, and neural

What is epithelial tissue?

• Covers exposed internal (vessels, passageways, and cavities) and external surfaces

4 Functions of Epithelia Tissue

1. Physical support: or chemical/biological agents

2. Controls permeability: any substance wanting to go to a part of the body must pass through an epithelium

3. Forms glandular tissue and produces secretions

4. Specialized epithelium called neuroepithelium, which provides sensations

**7 Characteristics of Epithelia

1. Made of cells

2. Adjacent connections: tight and little space between the junctions

3. Avascular: no blood vessels

   1. Must use diffusion or absorption to get rid of waste

4. Regeneration

5. Microvilli: on the apical surface, seen in areas of high aborption (increases surface area) and secretion

6. Surfaces

   1. Apical: exposed (not outside, exposed to the fluids)

   2. Basal: connected to the basement membrane

7. Polarity: organized asymmetric structure that allows them to carry out specific functions

Classifications of Epithelia are based on?

Layers and cell shape

3 Types of Layers in Epithelial Tissue

1. Simple: one layer, thin and fragile, located in internal compartments

2. Stratified: two or more layers

3. Pseudostratified: nuclei are unequally distributed & every cell has a connection to the basement membrane

3 Types of Shapes in Epithelial Tissue

!! Look at apical surface to determine shape !!

1. Squamous: “smushed”, if looking up at them, will look like fried eggs next to each other

2. Cuboidal: boxes, nuclei centrally located

3. Columnar: rectangles (length is greater than width), nuceli tend to be closer to the basement membrane

[perhaps add in image examples of each type here?]

What is transitional epithelium? [dont have to identify based on picture]

Associated w/ the urinary system, cells stretch to hold urine

Glandular epithelia: what is a gland, secretion, and excretion?

• Gland: group of cells or an organ specialized to synthesize and release a product

• Secretion: release of a product for further use

• Excretion: elimination of a waste product

Glandular Epithelia is classified based on? What are the 2 types?

Method of product; exocrine and endocrine

What is an exocrine gland?

Releasing a product onto a epithelia surface by a duct system

What is an endocrine gland?

Releases a product directly into capillaries by diffusion

• No ducts

• No ducts or polarization (no need to “aim” product onto surface or duct)

• Ex. produce hormones

***What are the 4 mode of product releases or glandular epithelia?

we need to ask abt this

1. Merocrine: exocytosis; only the product is released (ex. saliva and sweat)

2. Apocrine: product + cytoplasm is released (ex. breast milk)

3. Holocrine: product builds up in the cell until the cell bursts and dies (ex. oil)

4. Endocrine: exocytosis into a blood vessel (ex. hormones)

***What is connective tissue and its 3 basic components? Its never…

• Supportive; extracellular matrix, ground substance, and highly specialized cells.

• Exposed to the environment

6 Functions of Connective Tissues (do we have to know this?) No single connective tissues performs…

1. Protecting and supporting surrounding tissues

2. Interconnect tissues

3. Structural framework

4. Store energy (lipids)

5. Transport liquids throughout circulatory/lymph systems

6. Defend body from infections or harmful substances

All functions

What are the 3 major classifications of connective tissue and their 2 sub-types?

1. Fluid

   1. Blood: matrix is watery

   2. Lymph

2. Proper: syrup-y

   1. Loose

   2. Dense

3. Supporting

   1. Cartilage: gel matrix

   2. Bone: calcified

What are the fibers in connective tissue proper?

1. Collagen: long, straight, and unbranching; the most abundant type in connective tissue and the strongest (only in unidirectional)

2. Elastic: branched, wavy, and highly capable of stretching

3. Reticular: thin, branched, and interwoven; better at handling forces from multiple directions

What are the three types of cartilage?

1. Hyaline

2. Fibrocartilage

3. Elastic

Characteristics of Cartilage

• Cell name: chrondrocyte

  • Surrounding it is lacunae (empty space)

• Avascular

• Perichondrium: separates cartilage from other tissues

• 80% water

What is the most abundant type of cartilage? What does it look like and do?

Hyaline

• Looks like bugs

• Reduces friction between bone surfaces

What is fibrocartilage?

• Looks like a tadpole

• Mostly made of collagen

• In areas of very hard stress (aka unidirectional areas of compression

What is elastic cartilage?

• Looks like a cluster of grapes

• Stretches and can return to its original shape