Cell Model & Histology study slides

These slides follow the progression in Study Guide 1. Squamous epithelium (isolated) - flat cells with centrally located round nucleus. Said to have a “fried egg” appearance.

Simple sqamous

2. Simple cuboidal- note all nuclei are very round & cells square. Find this epithelial tissue in ducts of glands This type of epithelium is thicker than simple simple squamous epithelium, so it does not allow for passive diffusion as readily.

simple cuboidal lining the ducts of the thyroid gland.

Stratified cuboidal

3. Intestines: Simple columnar- you can see all nuclei are oblong or oval shaped & lined up along epithelia. Note goblet cell appearance. These cells produce mucus. Note “brush border” which is the microvili on the ends of the columnar cells. It is called a “brush border” due to its paint-brush like appearance. Tissue is from small intestines, where primary role is absorption of nutrients.

Gallbladder: Simple columnar with microvilli

4. Pseudostratified columnar with cilia

Pseudostratified columnar with cilia

5. stratified squamous: NOT KERATINIZED (vagina)

stratified squamous nonkeritinized (esophagus)

Stratified squamous KERATINIZED: see this in epidermal layer of skin

Skin- Keratinized stratified squamous epithelium (more details of skin at end of this presentation) Fully keratinized, Dead layer

Connective tissue (CT) This is the most widespread and abundant type of tissue in the human body. Its function is primarily to support, anchor and connect various parts of the body. You need to be able to ID the CT, name cells & other structures pointed out in class as well as give a place in the body where you can find it. Areolar Dense CT (white fibrous) Dense irregular Adipose Reticular Hyaline Cartilage, Elastic Cartilage, Fibrocartilage Compact (Ground) Bone

6. Areolar connective tissue The fibers of areolar connective tissue are arranged in no particular pattern but run in all directions and form a loose network. Collagen usually appears as broad pink bands. Some elastic fibers, which appear as thin, dark fibers are also present. Reticulin are faint, branched, thin fibers.

6. Areolar connective tissue Don’t need to recognize mast cells

7. Dense regular connective tissue – White fibrous Found in tendons, ligaments Note how all collagen fibers run in parallel

Dense regular

9. Dense Irregular Connective Tissue Found in dermis of skin. Note how all collagen fibers run in different directions giving it a “swirled” appearance. Dermis of skin

10. Adipose (fat) The cells of adipose (fat) tissue are characterized by a large internal fat droplet, which distends the cell so that the cytoplasm is reduced to a thin layer and the nucleus is displaced to the edge of the cell. Adipose tissue serves as a storage site for fats (lipids), also pads and protects certain organs and regions of the body. & forms an insulating layer under the skin which helps regulate body temp.

adipose

11. Reticular Connective Tissue Dark staining wire-like fibers are the reticular fibers. Found in lymphatic tissue & spleen

11. Another reticular tissue slide

12. elastic cartilage Note the hair-like Elastic fibers in the background along with pale staining collagen.

13. Fibrocartilage chondrocytes found in rows/clusters

14. hyaline cartilage Locate the large cartilage cells called chondrocytes, which are trapped within the matrix in spaces called lacunae Hyaline cartilage

14. Hyaline cartilage

15. Compact bone Compact bone is arranged into osteons. You can see three distinct osteons in the photo. The dark centers of the osteons are central canals where blood vessels run. Concentric circles of bone matrix, called lamallae, are around the canal. The dark dots between the lamallae are lacuna where osteocytes would live. There are thread-like canals (too small to see here) connecting the lacuna to each other and the Haversian canal of the osteon. These are called canaliculi and are for diffusion of nutrients and waste to and from the osteocytes. Central canal Osteocyte (in lacuna) osteon

Compact Bone 1 central (Haversian) canal 2. Volkman’s canal 3 osteocytes 4 lamella (the bone matrix arranged in concentric rings) 5 osteon

Diagram of Skin Responsible for epidermis, dermis, hypodermis, stratum corneum, stratum basale, dermal papillae (called papillary region here).

Thin skin: note Stratum corneum is thin. Epidermis stains darker pink than dermis. Epidermis will contain many more nuclei than dermis. Dermis contains dense irregular connective tissue in which collagen fibers look swirled.

Thick skin 6 – papillary layer of dermis 7 – reticular layer of dermis 5, 4, 3, 2, 1 Are all epidermis layer

Hairy skin Thin white layer on top is stratum corneum. 1 – epidermis 2 –papillary layer of dermis 3 – reticular layer of dermis 4- sebaceous gland 8. hypodermis (adipose CT tissue)

Self quiz- Identify the type of Epithelium 1 2

3 4

5 6

7 8

QUIZ- ID type of connective tissue 1 2

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7 8

9 10

11 12

Answers: CT 1 dense irregular 2 hyaline cartilage 3 compact bone 4 areolar 5 reticular 6 dense regular 7. elastic cartilage 8. fibrocartilage 9. skeletal muscle 10. smooth muscle 11. nervous tissue 12. cardiac muscle Answers to Epithelial 1.Simple squamous (endothelium) 2.Simple cuboidal 3.Stratified squamous keratinized (thick skin) 4.Stratified squamous keratinized (thin skin) 5.Simple columnar with microvilli 6.Ciliated pseudostratified columnar 7.Simple columnar 8.Stratified squamous nonkeratinized