Chapter 3 Histology Hridaan Rochwani

What is histology?

Study of tissues

What is cell differentiation?

The development process that results in the formation of different types of cells

What are the 4 types of tissues in the body?

epithelial, connective, muscle, and nerve

What are the 3 general characteristics of epithelial tissues?

They stick closely to one another, contain no blood vessels, and often found covering a body surface or lining body cavaties

What does avascular mean?

Without blood vessels

What are 3 ways epithelial cells are classified?

Modifications, shape, layers

What are simple cells?

1 layer

What are stratified cells?

2 or more layers

How do squamous cells look?

flat

how do cuboidal cells look?

square

how do columnar cells look?

long

What are 3 types of cell modifications?

cillia, microvilli, mucus-secreting(goblet)

What types of cells do you find modifications on?

columnar epithelial cells

What are cillia?

fine motile hairs

What are microvilli?

finger like extensions the increase the surface area

What are goblet cells?

things that secrete mucus, only in columnar cells

Where do you find simple squamous epithelial cells?

Air sacs in lungs, lining of blood vessels, and various membranes

Where do you find simple cuboidal epithelial cells?

Urinary tubules of kidney, liver, pancreas,, thyroid, and other glands

What does Aden/o mean?

gland

Where do you find simple columnar ciliated epithelial cells?

fallopian tube

What do cillia on the fallopian tube do?

Catch dust

Where do you find simple columnar epithelium with goblet cells?

The lining of the stomach

What do goblet cells do?

Neutralize stomach acid

Where do you find simple columnar brush border epithelium with goblet cells?

intestine

Where do you find pseudo stratified columnar ciliated epithelium with goblet cells

Respiratory tract

What does pseudo mean?

fake

What does pseudostratified mean?

It is not really stratified because the nuclei appear at different levels

What does cillia on the respiratory tract do?

They catch dust

Where do you find transitional epitheliium.

urinary bladder

Why is it called transitional epithelium?

Because the stratified tissue can stretch as the urinary bladder fills with urine

What is lumen?

The hole in the blood vessel

What are 2 subtypes of stratified squamous cells?

non keratinizing and keratinizing

What is keratin?

a hardening protein

Where do you find keratin?

hair, nails, skin

what are non keratinizing stratified squamous cells?

no dead layers of cells.

Where do you find non keratinizing stratified squamous cells?

makes up the lining of the oral cavity, anal canal, and vaginal canal

What are keratinizing stratified squamous cells?

Dead layers of cell present.

Where do you find keratinizing stratified squamous cells?

Makes up the epidermis of the skin

What do all cells need to be surrounded by?

fluid

What is the function of connective tissue?

To connect and support the other tissues of the body

How are connective tissues classified?

Type of cell and type of intercellular matter

What is areolar loose tissue?

loose connective tissue

What are fibroblasts?

Principal type of cell that secretes proteins such as collagen and elastin into the space between cells

What are macrophages?

Type of cell that engulfs foreign agents

What are mast cells?

Secrete histamine and other chemical mediators of inflammation

What is inflammation?

The swelling of an area that has been injured

What does erythema mean?

Dilation of blood vessels

What is edema?

permeability of blood vessels (Swelling)

What 2 proteins are secreted by fibroblasts?

Collagen and Elastin

What is collagen?

Collagen's main role is to provide structure, strength and support throughout your body

What is elastin?

Elastin is a protein that provides elasticity and flexibility to tissues and organs, particularly the skin

What is adipose tissue?

Fat connective tissue

What is the function of adipose tissue?

provides a reserve for food, insulates against heat loss, supports and protects the organs it encloses

What are 3 common locations of adipose?

under the skin, around the kidneys and eyeballs, buttocks and breast

What are the 2 subtypes of dense fibrous connective tissue?

Regularly arranged and irregularly arranged

What are 5 places where dense fibrous connective tissue is present?

tendons, ligaments, dura mater, fascia,, perichondrium

What does peri mean?

"around" or "surrounding"

How do regularly arranged dense fibrous tissue look?

tightly packed, parallel wavy bundles of pink-stained collagen fibers with dark-stained, flattened fibroblast cells squeezed between them

How do irregularly arranged dense fibrous connective tissue look?

Dense Irregular Connective Tissue – Tutorial – Histology ...Dense irregular connective tissue looks like a densely packed, woven mesh of collagen fibers, giving it a somewhat random and interwoven appearance under a microscope, similar to a patchwork quilt.

What is special about cartilage tissue, unlike connective tissue?

lack of blood vessels and nerves

What are 3 subtypes of cartilage?

hyaline cartilage, fibrocartilage, and elastic cartilage

What are 4 locations of where hyaline cartilage is found?

at the ends of long bones in joints (articular cartilage), connecting ribs to the sternum (costal cartilage), in the nose, and forming the rings of the trachea and bronchi

Where is fibrocartilage found?

Intervertebral discs Pubic symphysis Menisci of the knee Glenoid labrum (shoulder joint) Acetabular labrum (hip joint) Temporomandibular joint (TMJ) discs Areas where tendons and ligaments attach to bone Fibrocartilaginous callus (during bone fracture healing) Sternoclavicular and acromioclavicular joints

Where is elastic cartilage found?

in the external ear (auricle), the epiglottis, the Eustachian tube, the larynx, and the walls of the smallest bronchi

What are osteocytes?

one of the four kinds of bone cells

What does a compact bone look like?

Compact bone is a dense, hard, and smooth tissue that forms the outer layer of bones

What does a spongy bone look like?

a porous, honeycomb-like structure or a sponge

What are osteoblasts?

the cells that form new bones and grow and heal existing bones

What are osteoclasts?

a type of bone cell that removes bone tissue

What is resorption?

a process in which cells called osteoclasts break down and absorb tissue, such as bone or tooth structure

What is ossification?

the natural process of bone formation and hardening, involving the creation of new bone tissue by specialized cells called osteoblasts

What are haversian systems?

the fundamental structural units of compact bone, found in the dense outer layer of bones

What is a diaphysis?

the main or midsection (shaft) of a long bone

What is a epiphysis?

the end part of a long bone, initially growing separately from the shaft.

What is in the medullary cavity?

yellow bone marrow

What is hemopoiesis?

What is hemopoiesis?

What is hemopoietic tissue?

the specialized type of tissue that produces blood cells.

What are erythrocytes?

specialized cells in the blood that primarily function to transport oxygen throughout the body.

What are leukocytes?

White blood cells

What are platelets?

small, colorless cell fragments in our blood that form clots and stop or prevent bleeding

What is thromboplastin?

a complex protein substance, more accurately a combination of phospholipids and a protein called tissue factor, released from platelets and damaged tissues that initiates blood clotting by converting prothrombin into thrombin

What are neoplasms?

a new and abnormal growth of tissue in some part of the body, especially as a characteristic of cancer.

What are benign tumors?

non-cancerous growths of cells that remain localized and do not spread to other parts of the body.

What are malignant tumors?

abnormal growths of cells that have the ability to invade surrounding tissues and spread to other parts of the body