Histology of Epithelial Tissue

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Questions and Answers

What is the primary function of neurons?

To maintain the blood-brain barrier

To produce cerebrospinal fluid

To transmit information as action potentials (correct)

To support and protect the brain

Which type of neuroglia is responsible for myelinating axons in the central nervous system?

Schwann cells

Satellite cells

Oligodendrocytes (correct)

Astrocytes

What is the main role of astrocytes in the central nervous system?

Maintain the blood-brain barrier (correct)

Produce cerebrospinal fluid

Myelinate peripheral axons

Remove waste and pathogens

Which part of the neuron is responsible for receiving stimuli?

Dendrites Signup and view all the answers

Which of the following is NOT a function of the integumentary system?

Production of cerebrospinal fluid Signup and view all the answers

What type of cells myelinate axons in the peripheral nervous system?

Schwann cells Signup and view all the answers

What is a primary function of skin in the integumentary system?

Protect against foreign objects Signup and view all the answers

Which cell type is involved in the production of cerebrospinal fluid?

Ependymal cells Signup and view all the answers

What is the primary function of the epidermis?

Prevents water loss and resists abrasion Signup and view all the answers

Which layer of the epidermis is responsible for the production of keratin?

Stratum Granulosum Signup and view all the answers

Where is thick skin primarily found?

Palms of the hands and soles of the feet Signup and view all the answers

How long does it take for new cells to reach the surface of the skin?

40 to 56 days Signup and view all the answers

Which layer of the dermis contains blood vessels?

Papillary Layer Signup and view all the answers

What type of tissue primarily composes the dermis?

Dense collagenous connective tissue Signup and view all the answers

Which of the following layers of the skin is the most superficial?

Stratum Corneum Signup and view all the answers

What anchors the stratum basale to the dermis?

Basement membrane Signup and view all the answers

What type of epithelial tissue has a layer of flat, tile-like cells?

Simple squamous Signup and view all the answers

Which epithelial tissue is primarily found in the kidneys and consists of square-shaped cells?

Simple cuboidal Signup and view all the answers

Which type of gland secretes substances through ducts?

Exocrine Signup and view all the answers

What type of epithelial tissue appears to be layered due to the varying cell heights but is actually a single layer?

Pseudostratified columnar Signup and view all the answers

In which locations can nonkeratinized stratified squamous epithelium be found?

Mouth and esophagus Signup and view all the answers

Which type of epithelial tissue is characterized by cells that can change shape from cuboidal to squamous?

Transitional Signup and view all the answers

What is the function of cilia found on certain epithelial cells?

Move materials across the cell surface Signup and view all the answers

Which of the following cell connections creates mechanical links between cells?

Desmosomes Signup and view all the answers

What is the role of the hair papilla?

Supplies the hair bulb with nourishment Signup and view all the answers

Which type of sweat gland is primarily responsible for body odor?

Apocrine sweat glands Signup and view all the answers

What distinguishes eccrine sweat glands from apocrine sweat glands?

Eccrine glands release sweat primarily made of water and salts. Signup and view all the answers

What is the function of arrector pili muscles?

They cause hair to stand up. Signup and view all the answers

Which part of the nail is responsible for its growth?

Nail matrix Signup and view all the answers

What is sebum primarily composed of?

Lipids Signup and view all the answers

What is the lunula in the nail structure?

The whitish crescent-shaped area at the base of the nail Signup and view all the answers

What type of secretion is employed by sebaceous glands?

Holocrine secretion Signup and view all the answers

What is the primary function of melanocytes in the skin?

To produce melanin Signup and view all the answers

How do dermal papillae contribute to fingerprint formation?

They shape into parallel ridges. Signup and view all the answers

Which layer of the skin accounts for 80% of the dermis?

Reticular layer Signup and view all the answers

What role does melanin play in the skin?

It provides protection against ultraviolet light. Signup and view all the answers

What is the substance that provides padding and insulation beneath the skin?

Adipose tissue Signup and view all the answers

What are the two major glands associated with the skin?

Sebaceous and sweat glands Signup and view all the answers

Which statement about the hypodermis is correct?

It consists mainly of loose connective tissue. Signup and view all the answers

Which areas of the body lack hair follicles?

Palms and soles Signup and view all the answers

Study Notes

Epithelial Tissue Types

Simple squamous: Single layer of flat cells; found in blood vessels, heart, lymphatic vessels, alveoli, kidney tubules, and serous membranes.
Simple cuboidal: Layer of cube-shaped cells; located in kidney tubules, glands, choroid plexuses, terminal bronchioles, and ovaries.
Simple columnar: Narrow cells; found in bronchioles, auditory tubes, uterus, fallopian tubes, stomach, intestines, gallbladder, bile ducts, and brain ventricles.
Pseudostratified columnar: Appears stratified but is a single layer of ciliated tall cells; located in nasal cavity, sinuses, auditory tubes, pharynx, trachea, and bronchi.
Stratified squamous: Multiple layers of flat cells; nonkeratinized forms found in the esophagus, vagina, and pharynx; keratinized forms found in the mouth.
Stratified cuboidal: Rare type comprised of multiple cube-shaped layers; found in sweat, salivary glands, and ovarian follicles.
Stratified columnar: Rare, with surface columnar cells and irregular or cuboidal deeper cells; located in mammary gland ducts, larynx, and parts of the male urethra.
Transitional: Specialized cells that change shape; squamous when stretched and cuboidal when not; found in urinary bladder, ureters, and superior urethra.

Structural Units of Epithelial Tissue

Microvilli: Increase surface area, especially in the small intestine.
Cilia: Move materials across cell surfaces, found in the trachea.
Goblet cells: Produce mucus, found in the stomach.

Cell Connections

Tight Junctions: Bind adjacent cells together.
Desmosomes: Provide mechanical links between cells.
Hemidesmosomes: Anchor cells to the basement membrane.
Gap Junctions: Channels allowing molecule passage between cells.

Glands

Composed primarily of epithelium supported by connective tissue.
Exocrine glands: Connected by ducts; examples include sweat and oil glands.
Endocrine glands: Secretions directly into blood without ducts.

Nervous Tissue

Specialized for conducting electrical signals (action potentials).
Found in the brain, spinal cord, and ganglia.

Neurons

Transmit information as action potentials and process data.
Composed of:
- Cell Body: Contains the nucleus, performs general cell functions.
- Dendrites: Receive stimuli leading to electrical changes.
- Axon: Transmits action potentials to other neurons.

Glial Cells (Neuroglia)

Support neurons; protect, nourish, and form sheaths around axons.

Neuroglia Types

CNS (Central Nervous System):
- Astrocytes: Maintain blood-brain barrier, recycle ions and neurotransmitters.
- Oligodendrocytes: Myelinate CNS axons.
- Ependymal Cells: Line ventricles and produce cerebrospinal fluid.
- Microglia: Remove debris and pathogens through phagocytosis.
PNS (Peripheral Nervous System):
- Schwann Cells: Myelinate peripheral axons.
- Satellite Cells: Regulate nutrient and neurotransmitter levels around neurons in ganglia.

Integumentary System

Comprises skin and accessory structures (hair, nails, glands); serves as the body's first line of defense.

Skin Functions

Protection: Prevents water loss, UV damage, abrasion, and foreign invaders.
Sensation: Contains sensory receptors for various stimuli.
Vitamin D production: Facilitates calcium and phosphate absorption.
Temperature regulation: Maintains homeostasis around 37°C (98.6°F).
Excretion: Skin glands can secrete sweat.

Skin Structure

Composed of two main layers: epidermis (outer layer) and dermis (inner layer).
Epidermis: Made of stratified squamous epithelium, prevents water loss and abrasion.
Dermis: Contains dense connective tissue, blood vessels, nerves, and other structures.

Epidermis Layers

Stratum Basale: Deepest, mitotically active layer.
Stratum Spinosum: Contains spiny keratinocytes.
Stratum Granulosum: Contains keratin-rich cells, appearing grainy.
Stratum Lucidum: Found only in thick skin, translucent layer.
Stratum Corneum: Outermost layer with dead, keratin-filled cells.

Dermis Layers

Papillary Layer: Thin connective tissue with blood vessels; forms fingerprints.
Reticular Layer: Deepest layer, accounts for 80% of dermis.

Skin Color Factors

Melanocytes: Produce melanin, contributing to skin color; varying melanin amount affects pigmentation.
Melanosomes: Vesicles containing melanin.
Protect against UV light: Melanin serves as a natural sunscreen.

Hypodermis (Subcutaneous Layer)

Attaches skin to bone and muscle, contains loose connective tissue and adipose tissue.
Serves as padding, insulator, and reservoir for lipids.

Accessory Structures of Skin

Hair: Found almost everywhere except palms, soles, and various other areas.
Nails: Composed of dead keratinized cells, offering protection.
Glands: Include sebaceous (oil-producing) and sweat glands (eccrine and apocrine).

Nail Structure

Nail Body: Visible part.
Nail Root: Covered part by skin.
Cuticle: Skin extending over nail body.
Nail Matrix: Produces most nail tissue.
Lunula: Whitish crescent shape at the base of the nail.

Burn Definition

Injury to tissue caused by heat, cold, chemicals, electricity, or radiation.

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Description

This quiz covers the different types of epithelial tissue, including simple squamous, cuboidal, and columnar cells. Explore their characteristics and locations within the body, from blood vessels to the intestines. Perfect for students studying human anatomy and histology.