In biology, a lumen (from Latin lumen, meaning 'an opening'; plural lumina) is the inside space of a tubular structure, such as an artery or intestine.

Cilia are found on ciliated epithelial cells, like in the lungs Cilia are found on ciliated epithelial cells, like in the lungs. They wave rhythmically to move dirt and mucus out. Microvilli are found in the small intestine, and increase the surface area for nutrient absorption. The difference between cilia and microvilli is that microvilli help in absorption whereas cilia help in rhythmic movement (sweeping).

Unit 2: Tissues

Unit 2: Tissues Tissue: a group of cell types working together for the same purpose

Unit 2: Tissues Tissue: a group of cell types working together for the same purpose 4 Types of tissues

Unit 2: Tissues Tissue: a group of cell types working together for the same purpose 4 Types of tissues Epithelial Connective Muscle Nervous

Epithelial Tissues

The following types of epithelial tissues are covered in this activity: 1. Simple squamous epithelial tissue (lungs) 2. Simple cuboidal epithelial tissue (kidneys) 3. Simple columnar epithelial tissue (small intestine) 4. Pseudostratified (ciliated) columnar epithelial tissue (trachea lining) 5. Stratified squamous epithelial tissue (mouth lining) 6. Stratified cuboidal epithelial tissue (salivary glands, sweat glands) 7. Stratified columnar epithelial tissue (male reproductive tract) 8 Transitional epithelial tissue (bladder) a. The tissue may show a full bladder b. The tissue may show an empty bladder

Figure 4.3e Epithelial tissues. (e) Stratified squamous epithelium Description: Thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers. Stratified squamous epithelium Function: Protects underlying tissues in areas subjected to abrasion. Nuclei Location: Nonkeratinized type forms the moist linings of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane. Basement membrane Stratified squamous epithelium is a type of tissue that makes up skin layers and lines some body cavities and organs. Its structure makes it an excellent protective layer. Many layers piled on top of each other to make the tissue relatively thick. The cells divide in the deeper layers and newer cells push older ones further outward where they become flattened. Locations: Skin, Oral Cavities, Esophagus, Vagina, Anal Cavity. They form the outer layer of the skin called the epidermis. As skin cells age they accumulate the protein keratin and then harden and die. The keratin creates a dry tough protective material that prevents water and other material from entering. When not on the skin, the cells DO NOT produce keratin and remain smooth and soft. Connective tissue Photomicrograph: Stratified squamous epithelium lining the esophagus (285x).

several layers of elongated cells. The basal layers are cube shaped several layers of elongated cells. The basal layers are cube shaped. Found in the male urethra and vas deferens, and in parts of the pharynx

Consist of two or three layers of cuboidal cells that form the lining of the lumen. Lines the larger ducts of the mammary glands, sweat glans, salivary glands, and pancreas. Lining of the ovarian follicles and seminiferous tubules which are part of the male and female reproductive systems

Figure 4.3f Epithelial tissues. (f) Transitional epithelium Description: Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch. Transitional epithelium Function: Stretches readily and permits distension of urinary organ by contained urine. Several layers of the cuboidal cells. Changes in response to tension. Stretched and not stretched in response to tension. Provides expanded lining. Prevents contents of the urinary tract from diffusing back into the internal environment. Location in the urinary bladder, uterus, urethra This tissue is transitional, meaning it doesn't stay the same shape for long, as it transitions from one shape to another as necessary. In simple terms, transitional epithelial tissue is an elastic-like epithelial tissue that swells, contracts, and changes shape as necessary in order to accommodate something. One of the places this tissue is found is in your bladder. When your bladder is empty, the transitional cells look to be cuboidal in shape. However, as the bladder fills up, the urine in the bladder stretches the bladder walls, which stretch out the cuboidal cells and cause them to become flat, or squamous in shape, instead. Location: Lines the ureters, urinary bladder, and part of the urethra. Basement membrane Connective tissue Photomicrograph: Transitional epithelium lining the urinary bladder, relaxed state (360X); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and become elongated when the bladder is filled with urine.

Given the previous examples (consider the morphology only) Can you name? First, the tissue type Second, where in the body the tissue is found

What kind of tissue does this represent? Stratified squamous epithelial tissue Where in the body would you find this tissue? mouth lining

What kind of tissue does this represent? Stratified cuboidal epithelial tissue Where in the body would you find this tissue? salivary glands, sweat glands

What kind of tissue does this represent? Stratified columnar epithelial tissue Where in the body would you find this tissue? male reproductive tract

What kind of tissue does this represent? Transitional epithelial tissue Where in the body would you find this tissue? empty bladder

What kind of tissue does this represent? Transitional epithelial tissue Where in the body would you find this tissue? distended (full) bladder

Epithelial tissue is characterized by each of these traits, except that…  a) It lacks blood vessels b) It functions in secretion, absorption, and excretion c) Epithelial cells are loosely packed and have much intercellular material d) It is anchored to a basement membrane

Microvilli, which function to increase surface area, are more likely to be found in ____________ epithelium simple cuboidal Simple squamous Transitional Simple columnar

Epithelium that appears layered due to the varying levels at which nuclei are found in cells, but in reality is not layered, is _________________. Transitional epithelium Pseudostratified Columnar Epithelium Stratified Squamous Epithelium Stratified Columnar Epithelium

The outer layer of the skin is composed of… Transitional epithelium Pseudostratified columnar epithelium Stratified squamous epithelium Stratified Columnar epithelium

Thickening of the basement membrane The primary purpose of stratification, or layering, in epithelial tissue is for increased _____________. Protection Secretion Absorption Thickening of the basement membrane

What type of epithelium lines the urinary bladder? stratified cuboidal epithelium Stratified squamous epithelium Transitional epithelium Stratified columnar epithelium

Under Epithelial classification simple equals how many layers? None One Multiple

Epithelial tissue is avascular.  A. True B. False

Under epithelial classification squamous equates to what shape? A. Flat B. Wide and tall C. Tall and skinny

Epithelial tissue is polar. A. True B. False