BIOL122 tissue II

What is a tissue?

A group of similar cells that usually share common embryonic origins and function together to carry out specialized functions.

What are the three primary types of cellular secretion found in glandular epithelium?

1. Merocrine 2. Apocrine 3. Holocrine

Describe Merocrine secretion and provide an example.

It is a very common type of secretion where the product is released via exocytosis from secretory vesicles. An example is goblet cells.

Describe Apocrine secretion and provide examples.

It is an uncommon type of secretion where a portion of the cell membrane pinches off with the secretory product inside. Examples include the prostate gland and lactating mammary glands.

Describe Holocrine secretion and provide an example

It is a rare type of secretion where a mature cell dies and completely ruptures to become the secretory product itself, with cell division continuously replacing the lost cells. An example is sebaceous glands

What is the structural difference between Endocrine and Exocrine glands?

Endocrine glands: Ductless glands that typically secrete hormones directly into the bloodstream.

• Exocrine glands: Glands that secrete their products into ducts, which can be unicellular (e.g., goblet cells secreting mucin) or multicellular

What differentiates a Simple multicellular gland from a Compound multicellular gland?

Simple glands: The duct portion does not branch.

• Compound glands: The duct portion branches out.

Match the following simple glands to their locations: Simple tubular and Simple acinar/branched acinar.

Simple tubular: Large intestine.

• Simple acinar / branched acinar: Sebaceous glands.

What are the major functions of Connective Tissue?

Binds together, supports, and strengthens other tissues.

• Protects and supports internal organs.

• Compartmentalizes structures (e.g., the eye enclosed by the tunica fibrosa).

• Serves as a major transport and immune system (via blood).

• Stores energy (via adipose tissue).

What are the two main components of the Extra Cellular Matrix (ECM) in connective tissue?

Ground substance and protein fibers (which are synthesized by the tissue's cells).

Name the three types of protein fibers found in connective tissue and their characteristics.

1. Collagen fibers: Non-elastic, strong, and flexible. 2. Elastic fibers: "Rubbery" fibers made of fibrillin and elastin. 3. Reticular fibers: Thin, branched collagen fibers associated with other proteins.

What are the 5 major categories of Connective Tissue?

A) Loose

• B) Dense

• C) Cartilage

• D) Bone

• E) Blood

What are the three types of Loose Connective Tissue?

1. Areolar: Semifluid ground substance surrounding blood vessels and nerves with loosely dispersed fibers; fibroblasts predominate.

2. Adipose: Dominated by adipocytes; adapted to store triglycerides (fat), absorb shock, and insulate.

3. Reticular: Interwoven reticular fibers forming the stroma (supporting framework) of organs.

Where is Reticular loose connective tissue typically located?

In reticular organs such as lymph nodes, the spleen, and bone marrow.

What are the three types of Dense Connective Tissue?

1. Regular: Closely packed parallel collagen fibers; handles tension along the axis of the fibers (e.g., tendons, ligaments, cornea).

2. Irregular: Thick, randomly arranged collagen fibers; handles tension exerted in many different planes (e.g., dermis of skin).

3. Elastic: Provides strength with easy recoil capabilities (e.g., artery walls/aorta).

Name the three types of Cartilage from weakest to strongest.

1. Hyaline cartilage: Most widely distributed; provides firm support with flexibility at the ends of long bones.

2. Elastic cartilage: Rich in elastin fibers; found where strength and flexibility are needed (e.g., external ear).

3. Fibrocartilage: Strongest type; features parallel collagen fibers with chondrocytes squeezed between; highly rigid (e.g., intervertebral discs).

Describe the features and functions of Bone as a connective tissue.

Composed of numerous collagen fibers within a hard matrix of inorganic calcium salts. It supports/protects soft tissues, stores fat, and synthesizes blood cells (stem cell niche).

Why is Blood considered an atypical connective tissue?

Because it is a liquid, consisting of red and white blood cells suspended in a fluid extracellular matrix called plasma.