Histology Lecture 9: Integumentary System

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Questions and Answers

What is the embryologic origin of the epidermis?

Mesoderm

Ectoderm (correct)

Somites of the paraxial mesoderm

Endoderm

What is the function of the keratohyaline granules in the stratum granulosum?

To release lipid into intercellular spaces

To attach cells to each other

To bind cytokeratin molecules together to make keratin (correct)

To produce melanin

What is the main function of the skin as a barrier?

To protect against physical and chemical injury and infection (correct)

To excrete substances produced by glands

To synthesize vitamin D3

To regulate body temperature

What type of epithelium makes up the epidermis?

Stratified squamous epithelium Signup and view all the answers

What is the function of the stratum lucidum?

Not mentioned in the text Signup and view all the answers

What is the purpose of the lipid released by lamellar granules?

To act as a cement to prevent penetration of water and other materials Signup and view all the answers

How often do mitoses renew the epidermis?

Every 15-30 days Signup and view all the answers

What type of glands are found in the skin appendages?

Merocrine and apocrine sweat glands, as well as sebaceous glands and hair follicles Signup and view all the answers

How many types of cells are found in the respiratory system?

Four types Signup and view all the answers

What type of cartilage is present in both the epiglottis and the trachea?

Hyaline cartilage Signup and view all the answers

What cells are primarily found in the smaller bronchioles?

Clara cells Signup and view all the answers

Which structure is lined by simple squamous epithelium?

Alveolar ducts Signup and view all the answers

What type of fibers are found in the alveolar sac, and what is their function?

Elastic and reticular fibers; provide structure and elasticity Signup and view all the answers

Which layers are included in the pleura?

Parietal and visceral layers Signup and view all the answers

Which layer of the epidermis is present only in very thick skin?

Stratum Lucidum Signup and view all the answers

What is the function of keratinocytes in the epidermis?

Produce intermediate filaments called cytokeratins Signup and view all the answers

Which layer of the dermis is characterized by dense connective tissue with thick collagen bundles and elastic fibers?

Reticular dermis Signup and view all the answers

Which of the following is NOT considered part of the skin?

Subcutaneous tissue Signup and view all the answers

Which of the following is TRUE about the pleura in the respiratory system?

It is part of the conducting portion of the respiratory system. Signup and view all the answers

Which of the following is FALSE about the embryonic origin of the respiratory system?

The respiratory system is derived from mesoderm only. Signup and view all the answers

Which of the following structures is NOT derived from mesoderm in the respiratory system?

Lining of the respiratory tract Signup and view all the answers

Which of the following statements about the conducting portion of the respiratory system is TRUE?

The walls of the conducting system change in thickness and composition from region to region. Signup and view all the answers

Study Notes

Integumentary System

The skin serves as a barrier protecting against physical and chemical injury and infection, regulates body temperature, and is a receptor organ for sensory stimuli.
The skin is composed of three main components: epidermis (stratified squamous epithelium), dermis (connective tissue), and skin appendages (sweat glands, sebaceous glands, hair follicles, and nails).

Layers of Epidermis

Stratum Corneum: the most superficial layer, composed of flat, dead cells (keratin scales) that are continuously shed.
Stratum Lucidum: found only in very thick skin, consists of homogeneous, translucent cells containing keratin.
Stratum Granulosum: contains two types of granules (keratohyaline and lamellar), which help bind cytokeratin molecules together to form keratin and prevent water penetration.
Stratum Spinosum: thick layer with cells connected by spot desmosomes, appearing "spiny" or prickly.
Stratum Basale: the bottom layer, composed of cuboidal to columnar keratinocytes, melanocytes, and Merkel cells.

Cells in Epidermis

Keratinocytes: stratified squamous epithelial cells that produce cytokeratins.
Melanocytes: produce melanin.
Langerhans cells: process antigen.
Merkel cells: involved in sensation.

Dermis

Papillary dermis: loose connective tissue with capillary loops and thin elastic fibers.
Reticular dermis: dense connective tissue with thick collagen bundles, elastic fibers, larger blood vessels, and glands.

Subcutaneous Tissue (Hypodermis)

Consists of loose connective tissue and adipose tissue.
Functions to loosely bind the skin to underlying structures.

Respiratory System

Components of Respiratory System

Not mentioned in the given text.

Layers of the Respiratory System

Not mentioned in the given text.

Development of Respiratory System

Embryonic origin of the respiratory system is not solely mesodermal.
Mesoderm gives rise to the walls of the conducting system.
Endoderm gives rise to the epithelial lining of the respiratory system.

Cells in Respiratory System

Four types of cells exist in the respiratory system.
Goblet cells: produce mucus.
Basal cells: function not mentioned in the given text.
Three types of cells exist in the nasal cavity.
Clara cells: non-ciliated epithelial cells with secretory granules, function not mentioned in the given text.

Trachea and Bronchi

Cartilage in the trachea is not always present in all parts of the respiratory tract.
Cartilage in bronchi is not always hyaline cartilage.
Epiglottis cartilage type not mentioned in the given text.

Alveolar Sac

Composed of squamous epithelial cells, basement membrane, and capillaries.
Types of fibers in alveolar sac: elastic and reticulature fibers.
Function: not mentioned in the given text.

Pleura

Consists of parietal and visceral layers.
Mesothelial cells rest on a fine connective tissue layer containing collagen and elastic fibers, found mainly in the pleura.

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Description

This quiz covers the functions of skin, including its role as a barrier, regulation of body temperature, and synthesis of vitamin D3. It is based on Lecture 9 of Anthony L. Mescher's Jonquiere's Basic Histology TEXT & ATLAS.