BSC 215: Lecture Exam Two

Look at lab 1 exam knowt for histology (started terms)! Lecture 12 labeling

What does histology study?

Tissue

What are tissues?

Groups of cells, similar in structure that cooperate to perform a function

What are cells embedded in?

An extracellular matrix

What is the extracellular matrix made of?

Ground substance and fibrous proteins

What are the four primary tissue classes?

1. Epithelial

2. Connective

3. Muscular

4. Nervous

What kind of tissue has tightly packed cells?

Epithelial

How much extracellular matrix is visible in epitheila tissue?

Little

What kind of cell has long. cylindrical or spindle shaped cells?

Muscular

How much extracellular matrix is visible in muscular tissue?

Little

What kind of tissue has loosely scattered cells?

Connective

How much extracellular matrix is visible in connective tissue?

Much

What kind of tissue has a mostly fluid extracellular matrix?

Nervous

In the extracellular matrix, what do cells do?

Secrete and maintain extracellular matrix

In the extracellular matrix, what is ground substance?

Extracellular fluid, gel or solid

In the extracellular matrix, what is ground substance made of?

Water, ions, nutrients, glycosaminoglycans, proteoglycans and glycoproteins

In the extracellular matrix, what are the three types of fibrous proteins?

1. Collagen fibers

2. Elastic fibers

3. Reticular fibers

In the extracellular matrix, what do collagen fibers of fibrous proteins do?

Resist tension

In the extracellular matrix, what do elastic fibers of fibrous proteins do?

Exhibit elasticity

In the extracellular matrix, what do reticular fibers of fibrous proteins do?

Provide support due to glycoprotein coat

What does cell morphology relate to?

Cell size and shape

What are cell junctions?

Physical connections between tissue cells

All cells except __________ are anchored to each other or their matrix by intercellular junctions

Blood

What are the three types of cell junctions?

1. Tight junctions

2. Desmosomes

3. Gap junctions

What are tight junctions?

When integral membrane proteins of adjacent cells lock together to form an impermeable seal

What are desmosomes?

When integral membrane proteins interweave between cells to resist mechanical stress

What are gap junctions?

Interlinked protein pores that allow substances to pass between cells

What are the two broad types of epithelial tissue?

1. Coverings/linings

2. Glands

What are the six characteristics of epithelial tissue?

1. Polarity (apical surface, basal deep layer)

2. Specialized contacts (tight junctions, desmosomes, gap junctions)

3. Avascular

4. Supported by connective tissue

5. Innervated (nerve endings present)

6. Regenerative

What are the four simple types of epithelia?

1. Simple squamous

2. Simple cuboidal

3. Simple columnar

4. Pseudostratified ciliated columnar

What are goblet cells? What do they secrete?

Wineglass shaped cells amongst columnar cell tissues; mucous

What are the four kinds of stratified epithelia?

1. Stratified squamous

2. Stratified cuboidal

3. Stratified columnar (rare)

4. Transitional

If an epithelial tissue is cuboidal, what is its function?

Absorption/secretion

If an epithelial tissue is columnar, what’s its function?

Absorption/secretion

What kind of tissue is ciliated in the lungs?

Simple cuboidal epithelium

What are five examples of transcellular transport across epithelia?

1. Osmosis

2. Simple diffusion

3. Facilitated diffusion

4. Active transport

5. Vesicular transport

Why is paracellular transport across epithelia less common?

Tight junctions

What is the most abundant epithelia in the body?

Stratified squamous

What are glands?

Cells or organs that secrete or excretes substances

Exocrine glands maintain contact with _____________ via _________

Body surfaces; ducts

Do endocrine ducts have ducts?

No

Where do endocrine ducts secrete substances into?

Blood stream

Timeline of substances getting to ducts in multicellular exocrine glands:

Parenchyma (culdesac)→Septa (neighborhood)→ducts

In multicellular exocrine ducts, what is the parenchyma?

The starting point; cells that synthesize and secrete

In multicellular exocrine ducts, what is the septa?

Second point; connective tissue that compartmentalizes interior

What are the three types of exocrine secretion modes?

1. Merocrine/eccrine

2. Apocrine

3. Holocrine

What is merocrine/eccrine secretion?

Products released as vesicles during exocytosis

What are examples of merocrine/eccrine secretion?

Tear glands, sweat

What is apocrine secretion?

Similar to merocrine, but part of cytoplasm broken off along with vesicles from apical portion

Example of apocrine secretion:

Mammary glands

What is holocrine secretion?

Cells accumulate product, then rupture to release it

Example of holocrine secretion:

Sebacious glands on scalp

How do connective tissues bind organs together?

Tendons bind muscle to bone; ligaments bind bonds to bone

How do connective tissues provide support?

1. Bones support body

2. Cartilage supports nose and ears

3. Fibrous tissues provide framework

How do connective tissues provide physical protection?

Bones like rib cage to protect thoracic cavity

How do connective tissues provide immune protection?

Leukocytes (WBC) are immune cells

How do connective tissues provide movement?

1. Bones provide levers

2. Cartilage moves vocal cords

How do connective tissues provide storage?

1. Adipose tissue serves as an energy reserve

2. Bone tissue serves as calcium and phosphorus reserves

How do connective tissues provide heat production?

Brown fat catabolism generates heat in children

How do connective tissues provide transportation throughout the body?

Blood transports nutrients, gases, hormones and wastes

In connective tissue, what occupies the most space?

Matrix

In connective tissue, are cells in direct contact with each other?

No

How do fibroblasts form connective tissue proper?

Produce and maintain fibers/ground substance

How do adipocytes form connective tissue proper?

Fat cells; store triglycerides

How do mast cells form connective tissue proper?

Immune cells; stimulates inflammatory response

How do phagocytes form connective tissue proper?

Immune cells; ingest/destroy foreign cells and damaged host cells

Cartilage is produced by _____________ that, when trapped in lacunae, become _____________

Chondroblasts; chondrocytes

In cartilage, what do chondroblasts do?

Secrete matrix formed of GAGs, collagen and elastic fibers

Cartilage relies on ____________ for nourishment and further growth (like a basement membrane)

Perichondrium

Bone tissue is produced by _____________ which is turned into ____________ after being trapped in lacunae

Osteoblasts; osteocytes

If osteoblasts don’t become osteocytes, what else do they do?

Remain in the periosteum

What is bone matrix layers called?

Lamellae

What are canaliculi?

Delicate channels that connect lacunae in bone tissue

What dissolves bone tissue in remodeling?

Osteoclasts

What is the only liquid connective tissue?

Blood

What is blood’s ground substance?

Plasma

What are the two types of cells found in blood tissue?

1. Erythrocytes (RBC)

2. Leukocytes (WBC)

Connective tissue must have fibers. Where are these fibers found in blood?

Only form during clotting; fibrin

What are the three types of connective tissue proper?

1. Loose connective tissue (areolar)

2. Dense connective tissue (adipose)

3. Reticular

What are the three types of specialized connective tissue?

1. Cartilage

2. Bone

3. Blood

What kind of tissue is this?

Areolar connective tissue

Where is areolar connective tissue found?

Around organs

What is the function of areolar connective tissue?

Cushions organs

What kind of tissue is this?

Dense regular connective tissue

Where is dense regular connective tissue found?

Tendons/ligaments

What is the function of dense regular connective tissue?

Resist predictable tension

What kind of tissue is this?

Dense irregular connective tissue

Location of dense irregular connective tissue:

Around organs

Function of dense irregular connective tissue:

Resist unpredictable tensions

What kind of tissue is this?

Dense elastic connective tissue

Location of dense elastic connective tissue:

Blood vessels

Function of dense elastic connective tissue:

Allows tissue and organs to stretch

What kind of tissue is this?

Adipose connective tissue

What are the two types of adipose connective tissue?

1. White fat

2. Brown fat

Location of white adipose connective tissue:

Adults

Location of brown adipose connective tissue:

Infants; between shoulder blades

Function of adipose connective tissue:

Insulation/protection

What kind of tissue is this?

Reticular connective tissue

What is reticular connective tissue made of?

Special fibroblasts called reticulocytes

Location of reticular connective tissue:

Stroma of spleen and lymph nodes

What about cartilage makes it so resistible to tension and compression?

80% water; fluid nature allows quick recovery after compression