chapter 4 tissue

What is a tissue?

A group of similar cells that work together to perform a specific function.

What is histology?

The scientific study of tissues using a microscope.

What are the four major categories of tissues?

Epithelial, Connective, Muscle, and Nervous.

What is the primary function of epithelial tissue?

To cover body surfaces and line cavities.

What are the five special characteristics of epithelial tissue?

Polarity, Specialized Contacts, Connective Tissue Support, Avascular but Innervated, and Regeneration.

What does polarity refer to in epithelial tissue?

The presence of a top (apical) and a bottom (basal) surface.

How does epithelial tissue maintain its structure?

Cells are tightly packed together like a Ziploc bag.

What is the basement membrane?

The supportive layer that epithelial tissue sits on.

What does avascular but innervated mean?

Epithelial tissue has no blood vessels but contains nerves.

What are the two parts of naming epithelial tissue?

The number of layers (Simple or Stratified) and the shape (Squamous, Cuboidal, or Columnar).

Where is simple squamous epithelium typically found?

In the lungs and kidneys for easy filtering.

What is the difference between endocrine and exocrine glands?

Endocrine glands are ductless and secrete hormones into the blood, while exocrine glands have ducts that lead to surfaces.

What is a unicellular gland?

A single cell gland, such as a Goblet cell that secretes mucus.

What are the three main components of connective tissue?

Ground substance, fibers, and cells.

What is the role of collagen fibers in connective tissue?

To provide strength.

What type of connective tissue is known as the body's 'bubble wrap'?

Areolar connective tissue.

What is adipose tissue primarily used for?

Storing fuel and providing insulation.

What is the only liquid tissue in the body?

Blood.

What are the three types of muscle tissue?

Skeletal, Cardiac, and Smooth.

What is a characteristic of cardiac muscle tissue?

It is involuntary and contains intercalated discs.

What is the primary function of nervous tissue?

To transmit electrical signals through neurons.

What are the two main types of cells in nervous tissue?

Neurons and neuroglia.

What are the three types of membranes in the body?

Cutaneous, Mucous, and Serous membranes.

What is the function of cutaneous membranes?

To serve as the skin, which is dry and waterproof.

What is the process of tissue repair?

Involves inflammation, organization, and regeneration.

What is the role of granulation tissue in repair?

It replaces the blood clot during the organization phase.

What are the three germ layers in embryonic development?

Ectoderm, Mesoderm, Endoderm

What does the Ectoderm develop into?

Nervous tissue and skin

What does the Mesoderm develop into?

Muscle and connective tissue

What does the Endoderm develop into?

Inner linings of the digestive system

What is the analogy used to describe the three germ layers?

A three-layer cake: Ectoderm (top), Mesoderm (middle), Endoderm (bottom)

What is Resolving Power in microscopy?

The ability to discriminate two close objects as separate

How is Total Magnification (TM) calculated?

Ocular Lens (10x) × Objective Lens

What happens to the Working Distance as magnification increases?

The distance decreases

What is the Field of View (FoV) in microscopy?

The circular area seen through the ocular

What is Parfocal in microscopy?

A microscope that remains in focus when switching between objectives

What is the Depth of Field?

The thickness of the plane that is clearly in focus

What does Contrast Enhancement involve?

Using the Iris Diaphragm Lever to improve visibility of transparent specimens

What does x.s. or c.s. stand for in slide orientations?

Cross-section (horizontal cut)

What does l.s. stand for in slide orientations?

Longitudinal section (vertical/lengthwise cut)

What is a Goblet Cell?

A unicellular exocrine gland that secretes Mucin

What is the Basement Membrane composed of?

Basal Lamina (epithelial side) and Reticular Lamina (connective tissue side)

What are Tight Junctions?

Impermeable junctions that seal cells together

What are Desmosomes?

Anchoring junctions that prevent tearing

What are Gap Junctions?

Communicating junctions that allow electrical signals to pass

What is the primary function of Neurons?

To transmit electrochemical signals

What is the role of Neuroglia (Glial Cells)?

To protect and insulate neurons

What is the Cutaneous Membrane?

The skin; characterized as a dry membrane

What is the Mucous Membrane (Mucosa)?

Lines body cavities open to the exterior; a wet membrane

What is the Serous Membrane (Serosa)?

Lines closed ventral cavities

What is Pleurisy?

Inflammation of the pleurae (lungs)

What is Peritonitis?

Inflammation of the peritoneum (abdomen)

What does Avascular but Innervated mean in relation to epithelial tissue?

Contains nerves but no blood vessels; relies on diffusion from connective tissue

What is Mesenchyme?

The common embryonic origin of all connective tissues

What distinguishes -blast cells from -cyte cells?

-blast are mitotically active and secrete the matrix; -cyte are mature and maintain the matrix