Questions and Answers
The integumentary system consists of the skin and accessory organs such as hair, nails, and ______.
cutaneous glands
The skin is the most vulnerable ______ in the body.
organ
Dermatology is the scientific study and medical treatment of the ______ system.
integumentary
The expected learning outcomes include describing the histological structure of the ______, dermis, and subcutaneous tissue.
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Inspection of the skin, hair, and nails is a significant part of a physical ______.
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Hair is a slender filament of ______ cells growing from a tube in the skin called a hair follicle.
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Lanugo is fine, downy, unpigmented hair that appears on the ______ in the last 3 months of development.
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Vellus hair is fine, pale hair that replaces lanugo by the time of ______.
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Terminal hair is longer, coarser, and ______ pigmented than vellus hair.
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After puberty, terminal hair forms the axillary and ______ hair.
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The average person has about ______ hairs on their scalp.
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Hair covers most of the body except for palms, soles, and ______ surfaces of fingers and toes.
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Differences in hairiness across individuals are mainly due to variations in hair ______ and pigment.
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Sebaceous glands have a _____ secretion style.
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Ceruminous glands are found in the _____ ear canal.
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Mammary glands are modified _____ glands.
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Apocrine sweat glands are primarily located in the _____ region.
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Sebum produced by sebaceous glands keeps skin and hair from becoming dry, _____, and cracked.
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Merocrine sweat glands produce _____ perspiration that helps cool the body.
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Bromhidrosis refers to a disagreeable body _____ produced by bacterial action on sweat from apocrine glands.
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The secretion of ceruminous glands combines with sebum and dead epithelial cells to form _____ (cerumen).
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The average sweat composition is about _____% water.
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Mammary ridges, also called milk lines, are found in most _____ species.
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We lose about 50-100 hairs daily, and a club hair may fall out during ______ or telogen.
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Hair on the scalp grows approximately ______ mm per 3 days.
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Alopecia refers to ______ of the hair or baldness.
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Guard hairs, also known as ______, protect the nostrils and ear canals.
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The hard part of the nail is referred to as the nail ______.
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The ______ is the growth zone of thickened stratum basale at the proximal end of the nail.
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The area of skin underlying the nail plate is known as the nail ______.
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Pubic and axillary hair signify sexual ______ and aid in the transmission of sexual scents.
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The deepest epidermal layer is called the ______.
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The ______ contains several layers of dead, scaly, keratinized cells.
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In the stratum granulosum, keratinocytes release ______ that binds keratin into bundles.
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The layer above the stratum basale is known as the ______.
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The ______ is a connective tissue layer that lies beneath the epidermis.
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The middle layer of the epidermis is the ______.
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Cells in the stratum lucidum are packed with the clear protein ______.
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The dermis is composed mainly of ______.
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The upward extensions of the dermis are called ______.
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The term ______ refers to the outermost layer of the stratum corneum.
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Tactile cells, which are responsible for touch sensation, are found in the ______.
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The layer beneath the skin that consists of fat and connective tissue is called the ______.
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Stretch marks are also known as ______.
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Keratinocytes take approximately ______ days to migrate to the skin surface and exfoliate.
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In the dermal layer, blood vessels and nerve endings are primarily found in the ______.
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Study Notes
Integumentary System Overview
- Comprises skin and accessory organs: hair, nails, cutaneous glands.
- Skin is the most exposed organ, subjected to trauma, infection, radiation, and chemicals.
- Integral part of physical exams; dermatology focuses on its medical study and treatment.
Skin and Subcutaneous Tissue
- Skin performs critical functions related to its structure.
- Consists of three main histological layers: epidermis, dermis, and subcutaneous tissue.
- Skin color variations, both normal and pathological, have specific causes and significance.
- Common skin markings provide diagnostic clues during examinations.
Layers of the Epidermis
- Thin skin features four strata; thick skin includes five strata.
- Stratum Basale: Deepest layer, composed of stem cells; generates new keratinocytes and contains melanocytes.
- Stratum Spinosum: Multiple layers of keratinocytes linked by desmosomes; contains dendritic cells.
- Stratum Granulosum: Three to five layers of flat keratinocytes rich in keratohyalin granules.
- Stratum Lucidum: Present only in thick skin; consists of clear, compact keratinized cells.
- Stratum Corneum: Surface layer of dead, scaly keratinized cells, providing protection against abrasion and water loss.
Keratinocyte Lifecycle
- Keratinocytes originate from mitosis in the stratum basale or stratum spinosum.
- Mitosis requires oxygen and nutrients from dermis; older keratinocytes are pushed towards the surface.
- Takes 30-40 days for keratinocytes to exfoliate as skin dander; process is affected by age and skin condition.
- Formation of calluses occurs from thickened layers due to pressure.
Dermis Structure
- The dermis is a connective tissue layer beneath the epidermis, ranging from 0.2 mm to 4 mm in thickness.
- Composed mainly of collagen; contains blood vessels, sweat glands, and nerve endings.
- Includes two layers:
- Papillary Layer: Thin layer with areolar tissue, enabling immune cell mobility and rich blood supply.
- Reticular Layer: Thicker layer of dense, irregular connective tissue; prone to stretch marks from skin stretching.
Hypodermis
- Serves as insulation and shock absorber for underlying structures; connects skin to body.
Hair Structure and Functions
- Hair (pili) is comprised of keratinized cells grown from hair follicles; varies in texture and color.
- Three hair types:
- Lanugo: Fine, unpigmented hair found on fetuses.
- Vellus: Fine, light hair on women and children.
- Terminal: Coarse, pigmented hair on scalp, axillary, and pubic areas post-puberty.
- Hair receptors sense parasites, and different types use hair for nonverbal communication.
Hair Growth and Loss
- Daily loss of 50-100 hairs; growth cycles involve anagen, catagen, and telogen phases.
- Pattern baldness is influenced by testosterone, resulting in terminal hair replacing vellus hair in certain areas.
- Hirsutism refers to excessive hair growth in atypical areas.
Nail Structure and Functions
- Nails are hard derivatives of the stratum corneum; enhance tactile sensitivity and assist in grooming.
- Comprise nail plate (hard part), free edge, body, root, and various related structures (nail fold, groove, bed, matrix).
- Growth rate: 1 mm per week for fingernails.
Cutaneous Glands Overview
- Five gland types: merocrine, apocrine sweat glands, sebaceous, ceruminous, and mammary glands.
Sweat Glands
- Apocrine Sweat Glands: Located in specific regions; inactive until puberty, involved in pheromone secretion.
- Merocrine Sweat Glands: Most abundant; respond to heat and stress with watery perspiration for cooling.
Sebaceous Glands
- Flask-shaped glands releasing sebum to keep skin and hair moisturized; function through holocrine secretion.
Ceruminous Glands
- Produce earwax (cerumen), protecting the auditory canal by maintaining flexibility and blocking foreign particles.
Mammary Glands
- Modified apocrine sweat glands active during lactation, producing milk through secretion at the nipple.
Skin Disorders
- Understanding the three most common forms of skin cancer is crucial for diagnosis and treatment.
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Description
Test your knowledge on the integumentary system, which includes the skin and its accessory organs such as hair, nails, and cutaneous glands. This quiz covers the essential functions, layers, and diagnostic features of the skin. Perfect for students of dermatology and related fields.
