Histology of Integumentary System
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Questions and Answers

Where are sebaceous glands not present?

  • Face
  • Soles (correct)
  • Scalp
  • Palms (correct)
  • What type of secretion do sebaceous glands produce?

  • Eccrine
  • Holocrine (correct)
  • Apocrine
  • Merocrine
  • What is the function of myoepithelial cells in eccrine sweat glands?

  • Produce a proteinaceous substance
  • Produce a watery substance
  • Line the duct
  • Surround the gland (correct)
  • Where are apocrine sweat glands located?

    <p>Axilla, areola of breast, and anal canal</p> Signup and view all the answers

    What is the characteristic of apocrine secretion?

    <p>Viscous with proteins, carbohydrates, and lipids</p> Signup and view all the answers

    When do sebaceous glands become functional?

    <p>At puberty</p> Signup and view all the answers

    Which of the following statements accurately differentiates thick skin from thin skin?

    <p>Thick skin is present on the palms and soles.</p> Signup and view all the answers

    What primary function do melanin granules serve in the skin?

    <p>To protect genetic material from UV damage.</p> Signup and view all the answers

    What role do Merkel cells play in the skin?

    <p>They act as touch receptors.</p> Signup and view all the answers

    Which type of cell acts as a macrophage within the epidermis?

    <p>Langerhans cell</p> Signup and view all the answers

    Where are mechanoreceptors located in relation to the skin layers?

    <p>Both in superficial and deeper layers of skin.</p> Signup and view all the answers

    What characterizes thick skin compared to thin skin regarding keratin layers?

    <p>Thick skin has a thick keratin layer.</p> Signup and view all the answers

    Which of the following statements regarding melanocytes and skin color is true?

    <p>Melanocytes produce melanin granules independent of their number.</p> Signup and view all the answers

    What is the primary function of mechanoreceptors in the skin?

    <p>To relay extracellular stimulus to intracellular signal transduction.</p> Signup and view all the answers

    Which mechanoreceptor is primarily sensitive to light touch?

    <p>Meissner’s corpuscle</p> Signup and view all the answers

    Which type of mechanoreceptor is characterized as slow-adapting and found deep in the skin?

    <p>Ruffini endings</p> Signup and view all the answers

    Where are Merkel’s disks primarily located?

    <p>In the fingertips, lips, and external genitalia</p> Signup and view all the answers

    Which mechanoreceptor is sensitive to vibration and pressure?

    <p>Pacinian corpuscle</p> Signup and view all the answers

    What is the primary function of Ruffini corpuscles?

    <p>Sensing skin stretching</p> Signup and view all the answers

    Which component of the pilosebaceous apparatus causes the erection of the hair shaft?

    <p>Arrector pili muscle</p> Signup and view all the answers

    What is the primary role of the dermal papilla in the hair follicle?

    <p>Maintain the viability of the hair follicle</p> Signup and view all the answers

    What type of epithelial tissue forms the hair follicle?

    <p>Stratified squamous epithelium</p> Signup and view all the answers

    Study Notes

    Integumentary System 2

    Thick vs. Thin Skin

    • Thick skin is present on palms and soles, with five cell layers and a thick keratin layer, but no hair follicles and sebaceous glands
    • Thin skin is found everywhere else, with no stratum lucidum, and thinner stratum granulosum and corneum, and may contain hair follicles and sebaceous glands

    Melanin and Skin Color

    • The number of melanocytes per unit area varies from one part of the body to another, but is independent of race
    • Differences in skin color are due to differing numbers of melanin granules in melanocytes
    • Melanin granules accumulate above keratinocyte nuclei to protect genetic material from UV damage

    Langerhans Cells and Merkel Cells

    • Langerhans cells are a type of macrophage that arise in bone marrow, migrate to stratum spinosum, and eat foreign substances and present antigen to T cells
    • Merkel cells are present in stratum basale and function as touch receptors

    Mechanoreceptors

    • Mechanoreceptors are a type of somatosensory receptors that relay extracellular stimulus to intracellular signal transduction through mechanically gated ion channels
    • They are present in the superficial and deeper layers of skin and near bone
    • There are four major categories of tactile mechanoreceptors:
      • Meissner's corpuscles (sensitive to light touch)
      • Pacinian corpuscles (sensitive to vibration and pressure)
      • Merkel's disks (un-encapsulated nerve endings in the epidermis)
      • Ruffini endings (slow-adapting, encapsulated mechanoreceptors deep in the skin, ligaments, and tendons)

    Pilo-Sebaceous Apparatus

    • Hairs: hair follicle and shaft
    • Sebaceous glands and ducts: empty into hair follicle
    • Arrector pili muscles: cause erection of hair shaft
    • Hairs and sebaceous glands derive from ectoderm

    Hair Follicle

    • The hair follicle is a tubular invagination of the epidermis extending deep into the dermis
    • The hair shaft arises from the base of the follicle
    • The dermal papilla contains numerous capillaries and maintains the viability of the hair follicle

    Skin Glands

    • There are three types: sebaceous glands, eccrine (merocrine) sweat glands, and apocrine sweat glands
    • They arise from ectoderm and have secretory portions that reside in the dermis
    • There are three different types of secretion: holocrine, merocrine, and apocrine

    Sebaceous Glands

    • Present everywhere except palms and soles
    • Secretory portion: peripheral, flattened undifferentiated cells that burst and release sebum (holocrine secretion)
    • Duct empties into hair follicle
    • Become functional at puberty

    Eccrine (Merocrine) Sweat Glands

    • Secretory portion has three cell types: clear cells, darker cells, and myoepithelial cells
    • Duct is lined by simple cuboidal epithelium and opens onto skin surface
    • Secretory cells produce a watery substance and a proteinaceous substance

    Apocrine Sweat Glands

    • Located only in axilla, areola of breast, and anal canal
    • Have larger ducts and secretory units than eccrine sweat glands
    • Ducts open into hair follicles
    • Apocrine secretion is viscous and contains proteins, carbohydrates, and lipids

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    Description

    This quiz covers the histology of the integumentary system, including the epidermis, thick and thin skin, mechanoreceptors, and skin glands. It is based on Lecture 10 from Anthony L. Mescher's Basic Histology TEXT & ATLAS.

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