Module 2: Histology: The Study of Tissues Flashcards
Epithelial tissue
Makes up the linings of organs, the outer layer of skin, the linings of the mouth and stomach, the thyroid gland, pancreas, liver, and forms glands.
Connective tissue
Supports, binds, and insulates. Examples include bone, cartilage, tendons, and fat.
Nervous tissue
Sends and receives signals. It makes up the brain, spinal cord, and nerves.
Muscle tissue
Allows for movement.
Free surface
The top surface of epithelial tissue.
Basal surface
The bottom surface of epithelial tissue.
Basement membrane
The glue secreted by epithelial cells that attach the basal surface to underlying tissue.
Avascular
Lacking blood vessels
Vascular
Refers to blood vessels
How do epithelial tissues receive nutrients?
The blood vessels in the underlying tissue release oxygen and nutrients which diffuse across the basement membrane into the cells.
What two characteristics classify epithelial linings?
The number of layers and the shape of the cells that make up those layers.
Simple epithelium
A one-layered epithelial lining.
Stratified epithelium
A multilayered epithelial lining.
Squamous epithelium
Flat epithelial cells.
Cuboidal epithelium
Epithelial cells shaped like a cube.
Columnar epithelium
Epithelial cells shaped like a column.
What is the function of simple squamous epithelium?
They offer a minimal barrier through which diffusion of oxygen and nutrients can occur. They are too simple for complex tasks and do not have many organelles.
What is the function of simple cuboidal epithelium?
Diffusion, absorption, and secretion. They have organelles such as rough ER and Golgi apparatuses.
What is the function of simple columnar epithelium?
Performs complex secretion and absorption tasks.
Goblet cells
Cells whose main job is to produce mucus.
Mucus
A complex mixture of fluids, proteins, and carbohydrates that covers, protects, and lubricates a free surface within the body.
Where is stratified squamous epithelium located?
The skin.
Epidermis
The top layer of skin made up of epithelial tissue that forms a barrier.
How is skin made?
The basal cells in skin divide by the process of mitosis, and they push up on the cells on top of them. When the cells reach the surface, they are dead and flake off.
Keratin
The water-proofing protein found in dead skin cells.
Moist stratified squamous epithelium
A type of epithelial tissue whose surface cells are covered with mucus and is nonkeratinized.
Where is stratified cuboidal epithelium found?
The parts of the salivary glands that secrete saliva into the mouth.
Where is stratified columnar epithelium found?
The larynx.
What are the characteristics of stratified transitional epithelium?
Multilayered, provides protection, and is able to stretch.
Where is stratified transitional epithelium found?
The bladder because it can stretch.
Pseudostratified epithelium
“Falsely layered” epithelial tissue. Some of the cells are shorter than the others and cannot reach the basement membrane. It has goblet cells and cilia.
Where is pseudostratified epithelium?
The nasal passages, the air sinuses of the skull, and the large airways of the lungs.
Exocrine glands
Glands that secrete substances outward through a duct.
Endocrine glands
Ductless glands that secrete hormones into the bloodstream.
Secretory portion (exocrine glands)
The part of an exocrine gland that contains the cells that do the secreting.
Duct (exocrine glands)
The part of exocrine glands through which the chemicals travel to reach the surface.
Merocrine glands
Exocrine glands that secrete without losing cellular material.
Example: Sweat glands
Apocrine glands
Exocrine glands that have cytoplasm in their secretions.
Example: Mammary glands.
Holocrine glands
Exocrine glands that have secretions made up of disintegrated cells.
Example: Sebaceous glands on the skin that secrete oil.
What is the main difference between exocrine and endocrine glands?
Exocrine glands have ducts and endocrine glands do not.
Capillaries
Tiny blood vessels.
How do endocrine cells secrete their hormones?
Through exocytosis. After exocytosis, the capillaries carry the hormones throughout the body.
How is connective tissue different from epithelial tissue?
Connective tissue cells are far apart and secrete extracellular materials. Epithelial tissue cells are closer together.
Extracellular matrix
The chemical substance located between connective tissue cells.
Ground substance
A gel-like mixture of special proteins that connective tissue cells excrete found in the extracellular matrix.
Collagen
A thread-like protein fiber that helps hold connective tissue together and makes up 1/3 of bone tissue.
How is connective tissue classified?
The nature of the extracellular matrix because the matrix gives it its functions.
Name the four basic types of connective tissue.
Connective tissue proper, adipose tissue, dense irregular connective tissue, and dense regular connective tissue.
What is the ground substance of loose connective tissue like?
Gel-like with some protein, fluid, and collagen fibers.
Fibroblasts
Spindle-shaped cells that form connective tissue proper.
When is a connective tissue cell technically a fibroblast?
While it is in development. Once the fibroblast is complete surrounded by the matrix, it is called a fibrocyte.
What is the function of loose connective tissue? Give an example.
Light-duty binding. It is flexible and holds things together in all directions lightly. It connects the skin to the underlying muscle.
What are the two layers of skin called?
The epidermis (stratified squamous epithelium) and dermis.
Hypodermis
Loose connective tissue not part of the skin.
What is the main difference between dense irregular connective tissue and loose connective tissue?
Dense irregular connective tissue has more collagen.
What is the function of dense irregular connective tissue? Give an example.
It has strength in all directions. Ex: The skin’s dermis and capsules around organs such as the kidneys.
What is the difference between dense regular connective tissue and dense irregular connective tissue?
The regular tissue has collagen fibers lined up mostly in direction, while irregular does not. Regular tissue does not have elastic protein fibers.
What are the functions of dense regular connective tissue? Give an example.
Strong binding that provides rope-like strength. It is found in the tendons and ligaments.
Tensile strength
Strength that cannot bear weight but is able to bend and is very strong.
Tendon
A structure made of dense regular connective tissue that holds muscle to bone.
Ligament
A structure made of dense regular connective tissue that holds bones to bones.
Why is there some flexibility in the tendons and ligaments?
The collagen fibers that make up the dense regular connective tissue that makes up the tendons and ligaments are wavy when relaxed, not because there are elastic fibers.
What is the technical term for fatty tissue?
Adipose tissue.
Adipose tissue is most similar to which other type of connective tissue proper?
Loose connective tissue.
What are the functions of adipose tissue?
Support, protection, insulation, and storage of oil and fat.
How do adipocytes form?
They fill with a droplet of oil, enlarge, and push against each other closely.
What are the three types of cartilage?
Hyaline, elastic, and fibrocartilage.
Chrondocytes
Cells that produce special extracellular material. “Chondro” means cartilage.
Lacuna
A hollowed-out space in the cartilage matrix in which cartilage cells live.
Is cartilage or connective tissue proper vascular?
Connective tissue proper is vascular; cartilage is avascular.
What is the function of collagen in hyaline cartilage?
It gives the tissue resiliency and structure.
Name some examples of hyaline cartilage.
The bridge of the nose, the framework of the larynx, the costal cartilage of the ribs (the cartilage that connects the ribs to the sternum), and smooth caps on bones within movable joints.
What is the function of fibrocartilage?
It provides tough binding and resilient support, much like the soles of your shoes.
Where is fibrocartilage found?
It is found in the joints between each vertebra of the backbone.
How does elastic cartilage differ from hyaline cartilage and fibrocartilage?
There is not as much collagen. Instead, the fibers in elastic cartilage are elastic fibers.
What is the function of elastic cartilage?
Highly flexible support.
Where is elastic cartilage found?
The outer ear and the very tip of the nose.
What is bone tissue properly know as?
Osseous tissue.
Describe the ground substance in osseous tissue.
The cells are far from one another. They secrete fibers, collagen, and fluid. The ground substance becomes hardened through calcification.
What is blood known properly as?
Vascular tissue.
What is the technical name for the skin?
The cutaneous membrane.
What are the three categories of membrane?
Mucous, synovial, and serous.
What is the function of mucous membranes?
They line tubes that open to the outside of the body, and when dust and dirt get caught in the tracts, the membranes trap them and remove them.
What is the function of synovial membranes?
They are found around the movable joints and are used for lubrication.
Describe the area in and around a joint.
The bones of the joint are covered with a cap made of hyaline cartilage. The hyaline cartilage is lubricated by synovial fluid which is secreted by the synovial membranes which from a little sac around the joints.
What is the function of serous membranes?
They form thin, double layers around organs and secrete a small amount of lubricating fluid into the space around the heart, lungs, and abdominal organs.
What two types of tissues make up membranes?
Epithelial and connective tissue.
What are the two types of tissue repair?
You either get the function back in the tissue or you develop scar tissue which does not function like the original tissue.
Stromal cells
“Supporting” cells that provide structure or support for parenchymal cells.
Parenchymal cells
“Performance” cells that provide the actual function of the tissue.
In order for function to be restored to an organ, what type of cells must be restored?
Parenchymal cells.
What are the three types of cells in terms of regeneration?
Labile, stable, and permanent cells.
Labile cells
Cells that undergo mitosis regularly and quickly.
Stable cells
Cells that do not regularly undergo mitosis but are able to if the need arises.
Permanent cells
Cells that cannot undergo mitosis.
Give an example of a labile cell.
An epithelial cell on the epidermis.
Give an example of a stable cell.
Bone cells.
Give an example of a permanent cell.
The cells of nervous tissue, skeletal, or cardiac muscle.
Why does better circulation lead to better tissue repair?
Blood brings in nutrients and oxygen, takes away the wastes, and brings in the white blood cells to fight infection. The better the circulation, the better the healing.
