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Anatomy Lecture BIOL 223 > The Integumentary System > Flashcards

The Integumentary System Flashcards

1
Q

Integumentary System

A
  • Largest organ in surface aera
    • Approximately 3000 square inches
    • 16 percent of body weight
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2
Q

The Integumentary system

A
  • Cutaneous membrane
    • Epidermis
      • Accessory structures:
      • Hair follicles
      • nails
      • Exocrine Glands
    • Subcutaneous layer
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3
Q

The Epidermis

A
  • Stratified Squamous Epithelium
    • Keratinized epithelium
      • produces keratin ex. Fingernails
    • Attached to dermis by the basil lamina
    • Cell types include:
      • Keratinocytes: produces keratinized epithelium
      • Melanocytes: pigment cells
      • Langerhans cells: Immune system
      • Merkel cells: Sensory cells (touch)
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4
Q

Dermis

A
  • Connective tissue proper
    • papillary Layer - thin layer of loose areolar connective tissue
    • Reticular layer - thick layer of dense irregular connective tissue
  • Provides structural strength and elasticity to skin
    • Collagen, reticular, and elastic fibers
  • Contains the blood vessels and nerves of the skin
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5
Q

Subcutaneous Layer (subQ) (Hypodermis)

A
  • Connects skin to underlying tissues
  • Loose Fibrous connective tissue (Adipose tissue) for strength and elasticity
  • Contains fat (Adipose connective tissue) for padding and insulation -Body shape
  • Contains many blood vessels and nerves
  • Also called Superficial Fascia
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6
Q

The fascia of the body wall

A
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7
Q

Integumentary system Functions

A
  • Nutrient storage
  • temperature regulations
  • Excretion
  • Vitamin D3 Synthesis
  • Sensory Detection
  • Protection
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8
Q
  • *Integumentary system:**
  • *Nutrient Storage**
A
  • To meet body’s requirement for constant supply of lipids
    • Synthesis of membranes (Phospholipids and Glycolipids)
    • Synthesis of lipid hormones
    • ATP Production in mitochondria via breakdown of fatty acids
      • Fatty Acids → Acetyl coA
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9
Q
  • *Integumentary System:**
  • *Temperature Regulation**
A
  • Dermis layer blood vessels
    • Dilate for heat loss
    • Constrict for heat conservation
      • Mainly occurring in the reticular/papillary layer of dermis
  • Sweat Glands
    • Secretes water which evaporates and cools skin
  • Subcutaneous layer
    • Insulating layer of fat
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10
Q
  • *Integumentary System:**
  • *Excretion**
A
  • Excretion - Removal of waste products from body
  • Sweat glands secrete waste products along with other molecules
    • Water
    • Electrolytes (ions including NA+ and CL-)
    • Organic waste such as urea (mainly) and ammonia (very little amount)
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11
Q

Vitamin D3 Synthesis

A
  • Vitamin D3 - Steroid (cholesterol) Derivative
  • Epidermal cells exposed to UV light synthesize cholecalciferol from cholesterol
    • Cholesterol → Cholecalciferol → Calcitriol
  • Calcitriol - Hormone affecting Bone growth
    • Stimulates Ca2+ and Po42- absorption
    • Regulates Ca2+ ion concentration in body
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12
Q
  • *Integumentary System:**
  • *Sensory Detection**
A
  • Pain (Nociceptors)
    • Free nerves endings (Sensory Dendrites)
  • Temperature (Thermoreceptors)
  • Touch, Pressure, Vibration
    • Lamellated corpuscles
    • Tactile (Meissner’s) Corpuscles
    • Tactile Discs (Merkle’s discs and Merkle cells)
    • Hair root plexus
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13
Q
  • *Integumentary System:**
  • *Protection of the Body**
A
  • Layers of Keratinized cells
    • Abrasion protection
    • Water resistant
      • Insensible perspiration (uncontrollable water loss) (300-500 ml/d)
  • Resistant to Microbial invasion
  • Melanocytes
    • Protection against ultraviolet radiation
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14
Q

The structure of the epidermis

A
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15
Q

Keratinization of the Epidermis

A
  • Form by cell division of stem cells in the stratum germinativum (Basal Layer)
  • New cells push older cells upward
  • Oldest cells in the corneum layer eventually are shed (Flake off)
  • 7-14 days to move from stratum germinativum to the stratum corneum
  • 30 days (AVG) until shed from corneum
  • Accumulate large amounts f keratin in the stratum granulosum and cells dies
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16
Q

Epidermal Ridges

A
  • Epidermal ridges of stratum germinativum are interlocked with dermal papillae
    • Fingerprints
    • Improves grip
17
Q

Skin Color

A
  • Blood supply in dermis
    • Hemoglobin in RBC provides color
    • Cyanosis *blueish color* = hemoglobin with low oxygen
  • Epidermal Pigmentation
    • Beta-carotene = dietary in origin
    • Melanin - produced by melanocytes
      • Provides some UV protection
18
Q

Melanocytes

A
  • All humans including albinos, have the same number of melanocytes per unit aera of the skin
  • Darker pigmentation is due to:
    • Faster rates of melanin gene expression
    • Types of melanin produced
    • Length of melanocyte process
19
Q

Disorder of the Epidermis

A
  • Hyperkeratosis (Producing karyocytes to quickly)
    • Calluses and corns (Thickening of skin)
    • Psoriasis (Shedding skin cells to quickly)
  • Xerosis
    • (Dry skin)
  • Herpes and warts
    • Viral Infection
  • Cancers of the skin
20
Q

skin cancer

A
  • Actinic Keratosis (pre-cancerous) -Genetic
  • Basal Cell Carcinoma - Most common
  • Squamous cell carcinoma - Verry common
  • Melanoma
21
Q

Neoplasms and Cancer

A
  • Neoplasm (tumor): Abnormal tissue growth, loss of normal control of cell division
    • Genetic mutations
  • Benign: Cells usually remain with in a confined connective tissue capsule - not life threatening
  • Malignant (Invasive, cancerous): Cells spread into surrounding tissue or disperse to distant sites - establish secondary tumors
22
Q

Elasticity of Skin

A
  • Water content helps maintain flexibility and resilience of skin
  • Dermis tolerates limited stretching
  • Aging, hormones, and excess UV reduce amount of elastin fibers in dermis
  • Stretch marks caused by excessive stretching of the dermis, exceeding the elastic capabilities of the skin
23
Q

Dermal Circulation

A
  • Cutaneous Plexus: Vessels located at border between subcutaneous layer and dermis
  • Papillary Plexus: Vessels at dermis-epidermis border
    • Vessels from these plexi supply nutrients and oxygen to epidermis, dermis, and accessory structures
  • Contusion (bruise): rupture of dermal blood vessels
24
Q

Accessory structure of the skin

A
  • Hair follicles and hair
  • Nails of fingers and toes
  • Exocrine glands
  • Epidermal Derivatives
    • Originate form epidermis during embryological development
25
Q

Hair Growth

A
  • Hair types = Grows in a cyclical cycle
    • Vellus hairs (peach fuzz)
    • Terminal Hairs (Heavy)
    • Club Hair (no longer growing)
  • Hair follicles may alter hair type in response to circulating hormones
  • Hair growth sensitive to changes in body chemistry, blood circulation, and radiation
26
Q

Hair Follicle

A
  • Hair Bulb
    • Hair matrix - Germinative layer of hair bulb
    • Produces keratinocytes that form the hair
    • Has cyclic growth pattern
  • Melanocytes - Produce melanin that is taken up by keratinocytes giving color to the hair
  • Hair Papilla - Dermal CT at base of follicle contains capillaries and nerves
  • Hair shaft - composed of dead keratinized cells
    • Hair Medulla (middle) - dead cells with soft keratin and melanin
    • Hair Cortex (beyond the middle) - dead cells with hard keratin and melanin
    • Cuticle - Superficial protective layer of overlapping, dead keratinized cells
27
Q

Hair Follicle Walls

A
  • Internal Root sheath - Produced by cells at periphery of hair matrix
  • External Root Sheath - extension of epidermis from surface of skin down to hair matrix
  • Glassy Membrane - basal lamina connecting hair sheath (epidermis) to surrounding dermis
  • Dermal connective tissue sheath surrounds follicle
28
Q

Hair Follicle Attachments

A
  • Arrector Pili Muscles - Contraction raises hair roughly perpendicular to skin surface
  • Root hair plexus - sensory nerves surrounding base of each hair follicle
  • Apocrine - Sudoriferous sweat glands
  • Sebaceous oil glands
29
Q

Exocrine glands in the skin

A
  • Ceruminous - Wax producing glands of ear canals
  • Mammary - Milk producing glands
  • Sudoriferous - Sweat glands
    • Merocrine
    • Apocrine
  • Sebaceous - oil glands
30
Q

Sweat Glands - Sudoriferous

A
  • Merocrine (eccrine) sweat gland:
    • Sensible perspiration (evaporative cooling)
    • open directly into skin surface
      • Most numerous in palms and soles
  • Apocrine sweat glands:
    • Secrete fluid containing lipids
    • Bacterial action produces strong odor
    • Open into hair follicles, located in axillae (Arm pit) and genetical regions
    • become active after puberty (Sensitive to hormone changes)
  • Both use merocrine secretion
31
Q

Sebaceous Glands

A
  • Discharge waxy sebum onto hair shaft or onto epidermal surface
  • Sebum - Mixture of lipids, proteins, and electrolytes
    • Inhibits growth of bacteria
    • Conditions hair and skin
    • Holocrine Secretion
32
Q

Ceruminous Glands

A
  • Modified Sweat glands
  • Produce secretions that combine with secretions of sebaceous glands to form waxy substance - cerumen (ear wax)
33
Q

Mammary Glands

A
  • Anatomically similar to apocrine sweat glands
  • Maturation depends on hormones secreted at puberty then during pregnancy
34
Q

Nails

A
  • Nail Root - Site of nail production
    • Germinal matrix of stem cells
    • continuous growth
    • Nail growth sensitive to changes in body metabolism
  • Nail body - Dead, keratinized cells
  • Nail bed (sterile Matrix):
    • Thin layer of epithelium underlying nail body
    • Many nerve endings and blood vessels
35
Q

Wounds and Healing

A
  • Closed wounds - Contusions
  • open wounds - Abrasions, incisions, lacerations, punctures, avulsions, and burns
  • Regeneration process includes formation of:
    • Scab
    • Granulation tissue
    • Scar Tissue
36
Q

Healing of Skin Damage

A
  • Minimal scarring if edges of wound can close cleanly or easily
    • Well approximated incision or laceration
    • Parallel to tension (cleavage) lines
  • To fill in gap edges do not meet - granulation tissue, followed by scar tissue
    • Blood clot (scab) forms providing temporary covering
    • Cells of stratum germinativum divide and migrate in to form new epithelium
    • Fibroblasts migrate in to form new, typically abnormal, connective tissue of dermis
37
Q

Burns

A
  • First degree burn - some epidermal damage
  • Second Degree burn - epidermal and some dermal damage
  • Third Degree burn (full thickness burn) - loss of epidermis and dermis, extending into subcutaneous layer, loss of accessory structure
  • Burn treatments to assist repair:
    • Skin grafts (spit thickness and full thickness)
    • Synthetic skin
38
Q

Ulceration

A
  • Ulcers in skin - loss of circulation leads to death of epidermal cells allowing bacteria to invade
    • Decubitus ulcers = bedsores
    • Diabetic ulcers - peripheral neuropathy and atherosclerotic peripheral arterial disease
39
Q

With age

A
  • Integument thins- epidermis and dermis
  • Number of Langerhans cells decrease
  • blood flow decreases
  • Melanocyte activity decreases
  • Hair follicles function declines
  • Repairs occur more slowly
  • Vitamin D production decreases
  • Glandular activity declines
  • Reduced elastin production

Anatomy Lecture BIOL 223 (10 decks)

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