Chapter 5 - The Integumentary System Flashcards
What is the Integumentary System made of? And what are its function?
Integumentary System consists of:
Skin
Hair
Oil and Sweat Glands
Nails
Sensory receptors
Functions:
Helps body maintain temperature
Converts inactive Vitamin D to its active form
Provides sensory information
Helps maintain homeostasis
What is the Skin and Hair function in the Integumentary System?
Skin and Hair provide barrier to protect all internal organs from damaging agents in external environment
What is the Sweat Glands function in the Integumentary System?
Sweat Glands and blood vessels regulate body temperature needed for proper functioning of other body systems
What are the Layers of the Skin?
Skin has 2 Major Layers:
1- Epidermis:
Most superficial layer
2- Dermis:
Layer deep to Epidermis
Hypodermis (Subcutaneous Layer): Deep to Dermis, but not layer of skin
Made of Areolar and Adipose Tissue
What are the 4 Major Types of Cells in the Epidermis?
1- Keratinocyte:
Majority of epidermis
2- Melanocyte:
Stratum Basale of epidermis (secrete melanin)
3- Intraepidermal Macrophages (Langerhans Cell):
All tissue have them
Help auto-phagocytize bad cells
4- Tactile Epithelial cells (Merkel Cell):
For touch
What are the 2 Types of Skin?
Thin (Hairy) Skin:
Covers all body regions except palms, palmar surfaces of digits, and soles
Thick (Hairless) Skin:
Covers palms, palmar surfaces of digits, and soles
What are the 4 (5) Layer of the Epidermis?
Epidermis is composed of 4 layers in Thin Skin and 5 layers in Thick Skin
From Deep to Superficial: (British and Spanish Grandmas Like Corn)
Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum (Only in Thick Skin)
Stratum Corneum
What is Stratum Basale?
Deepest layer
Composed of single row of cuboidal or columnar Keratinocytes that contain Keratin intermediate filaments (Tonofilaments)
Stem cells undergo cell division to produce new Keratinocytes
Melanocytes and Tactile Epithelial Cells associated with tactile discs (Merkel Cells) are scattered among Keratinocytes
What is Stratum Spinosum?
8-10 rows of many-sided Keratinocytes with bundles of Keratin intermediate filaments
Contains projections of Melanocytes and Intraepidermal Macrophages (Langerhans Cells)
What is Stratum Granulosum?
3-5 rows of flattened Keratinocytes, in which organelles are beginning to degenerate
Cells contain the protein Keratohyalin (converts Keratin intermediate filaments into Keratin) and Lamellar Granules (release lipid-rich, water-repellant secretion)
What is Stratum Lucidum?
Only in Thick Skin (fingertips, palms, soles)
Consists of 4-6 rows of clear, flat, dead Keratinocytes with large amounts of Keratin
What is Stratum Corneum?
Few to 50 or more rows of dead, flat Keratinocytes that contain mostly Keratin
What is the Dermis made of?
Dermis composed of connective tissue containing Collagen and Elastic Fibers
What is the Papillary Region of the Dermis?
Superficial portion of Dermis
Consists of Areolar connective tissue with thin collagen and elastic fibers
Contains Dermal Ridges that house blood capillaries, Corpuscle of Touch, and Free Nerve Endings
What is the Reticular Region of the Dermis?
Deeper portion of Dermis
Consists of dense irregular connective tissue with bundles of thick collagen and some coarse elastic fibers
Spaces between fiber contain adipose cells, hair follicles, nerves, sebaceous glands, and sudoriferous glands
What are Skin Pigments?
Melanin:
Produced by Melanocytes in Stratum Basale
Pheomelanin
Eumelanin
Hemoglobin:
Red pigment in RBC
Carotene (Vitamin A):
Yellow-orange pigment store in Stratum Corneum and adipose tissue
What is Albinism?
Congenital disorder
Complete or partial absence of pigment in skin, hair, and eyes
Due to a defect of an enzyme involved in production of Melanin
What is Vitiligo?
Chronic disease
Causes depigmentation patches in skin
Likely a combination of genetic factors couple with an autoimmune disease
What is Hypodermis?
Subcutaneous layer
Attaches skin to underlying tissues and organs
What is Hair?
Present on most body surfaces except palms/soles and palmar surfaces of fingers and plantar surfaces of feet
Composed of dead, keratinized epidermal cells
Genetic and hormonal influences determine thickness and distribution of hair
What is Hair Structure?
Hair Bulb:
Swelling at base where hair originates in dermis
Surrounds hair papilla, composed of connective tissue
Only region with living epithelial cells
Hair Root:
Zone of hair from bulb to skin surface
Hair Shaft:
Portion of hair beyond skin surface
What is Hair Components?
Hair Matrix:
Structure at base of hair bulb
Epithelial cells divide here
Produce new cells, gradually pushed toward surface
Medulla:
Remnant of matrix
Flexible, soft Keratin
Cortex:
Flattened cells closer to outer hair surface
Relatively hard
Cuticle:
Single cell layer around cortex
Hair Follicle:
Oblique tube surrounding hair root
Extends into dermis and sometimes hypodermis
Outer connective tissue root sheath originating in dermis
Inner epithelial tissue root sheath originating in epidermis
Arrector Pili:
Thin ribbons of smooth muscle
Extend from hair follicle to dermal papillae
Elevates hair with contraction (Goosebumps)
What is Function of Hair?
Protection from injury and particles
Facial Expression
Heat Retention (prevent heat loss from scalp)
Sensory Reception (light touch)
Visual Identification (age, sex, specific individuals)
Chemical Signal Dispersal (pheromones)
What are the Hair Growth Stages?
Anagen - Growth Stage
Catagen - Regression Stage
Telogen - Resting Stage
What are the Types of Hairs?
Lanugo:
Covers fetus
Terminal:
Long, coarse, heavily pigmented hairs
Vellus:
Short, fine, pale hairs
In chronically ill people or old age
What determines Hair Color?
Primarily due to amount and type of Melanin present in the keratinized cells of the hair
What are Skin Glands?
4 Types of skin glands:
1- Sebaceous (oil) glands:
Connected to hair follicles
2- Eccrine Sweat glands:
Most numerous
3- Apocrine Sweat glands:
Mainly in hairy skin areas
4- Ceruminous glands:
Modified sweat glands located in ear canal
What are Sebaceous (oil) Glands, and what do they do?
Location:
Lips
Glans penis
Labia Minora
Tarsal Glands
Some in trunk and limbs
Absent in palms and soles
Location of secretory portion:
Dermis
Termination of excretory duct:
Mostly connected to hair follicle
Secretion:
Sebum (mixture of triglycerides, cholesterol, proteins, and inorganic salts)
Function:
Prevent hairs from drying out
Prevent water loss from skin
Keep skin soft
Inhibit growth of some bacteria
Onset of function:
Relatively inactive during childhood
Activated during puberty
What are Eccrine Sweat Glands, and what do they do?
Location:
Skin of most body regions
Specially on forehead, palms, and soles
Location of secretory portion:
Deep in Dermis (sometimes in subcutaneous layer)
Termination of excretory duct:
Surface of epidermis
Secretion:
Perspiration, which consists of water, ions (Na+, Cl-), urea, uric acid, ammonia, amino acids, glucose, and lactic acid
Function:
Regulation of body temperature
Waste removal
Stimulated during emotional stress
Onset of function:
Soon after birth
What are Apocrine Sweat Glands, and what do they do?
Location:
Skin of axillae
Groin
Areolae
Bearded regions of face
Clitoris
Labia Minora
Location of secretory portion:
Deep in Dermis and upper subcutaneous layer
Termination of excretory duct:
Hair follicles
Secretion:
Perspiration, which consists of water, ions (Na+, Cl-), urea, uric acid, ammonia, amino acids, glucose, and lactic acid
Plus lipids and proteins
Function:
Stimulated during emotional stress and sexual excitement
Onset of function:
Puberty
What are Ceruminous Glands, and what do they do?
Location:
External auditory canal
Location of secretory portion:
Subcutaneous layer
Termination of excretory duct:
Surface of external auditory canal or into ducts of sebaceous glands
Secretion:
Cerumen, a waxy material
Function:
Impede entrance of foreign bodies and insects into external ear canal
Waterproof canal
Prevent microbes from entering cells
Onset of function:
Soon after birth
What are Nails?
Made of keratinized epidermal cells
What are Nail Structures?
From beginning to end:
1- Nail Root:
Not visible
2- Eponychium (Cuticle):
The Stratum Corneum of epidermis
3- Lunula:
Thick white part of nail
4- Nail Bed:
Skin below nail plate
5- Nail Body:
Visible portion of nail
6- Free Edge:
Extends past fingers or toes
7- Hyponychium:
Secures nail to fingertip
Nail Matrix:
Epithelium proximal to nail root
Contains dividing cells which produce new nail cells
What is Thin Skin?
Location:
All arts of body except palms, soles, and palmar surfaces of digits
Epidermal Strata:
Stratum Lucidum essentially lacking
Thinner Strata Spinosum and Corneum
Epidermal Ridges:
Lacking due to poorly developed, fewer, less-well-organized dermal papillae
Hair follicles and Arrector Pili Muscles:
Present
Sebaceous Glands:
Present
Sudoriferous Glands:
Fewer
Sensory Receptors:
Sparser
What is Thick Skin?
Location:
Areas such as palms, soles, and palmar surfaces of digits
Epidermal Strata:
Stratum Lucidum present
Thicker Strata Spinosum and Corneum
Epidermal Ridges:
Present due to well-developed and more numerous dermal papillae organized in parallel rows
Hair follicles and Arrector Pili Muscles:
Absent
Sebaceous Glands:
Absent
Sudoriferous Glands:
More numerous
Sensory Receptors:
Denser
What are the functions of the Skin?
1- Thermoregulation:
Sweating
Blood flow to Dermis
2- Blood reservoir:
Many blood vessels in Dermis
Can hold 8-10% of total blood flow
3- Protection:
Prevents microorganisms from entering skin
Keratin
Lipids released by lamellar granules
Sebum
Acidic sweat
Melanin
Macrophages
4- Cutaneous sensations:
Tactile Sensations - Touch, pressure, vibration, tickle
Thermal Sensations
Pain Sensations
5- Excretion and Absorption
Transdermal drug administration
6- Synthesis of Vitamin D
UV rays activate precursor molecule Calcitriol that allows Vitamin D to be made
Vitamin D aids in absorption of calcium from foods in GI tract
What is Epidermal Wound Healing?
Occurs when superficial wounds affect only the epidermis
Division of Stratum Basale cells and migration across wound
Thickening or epidermis
What is Deep Wound Healing?
Additional steps occur when an injury extends into Dermis and Subcutaneous Layer
What develops from Ectoderm?
CNS
Skin
Extremities
Ears
Teeth
Hair
Nails
Pituitary glands
What develops from Mesoderm?
Mesoderm gives rise to the Mesenchyme
Connective tissues
Fats
Muscles
Bones
Vessels
Collagen
Elastic fibers
Tendons
Some organs like Testes and Ovaries
Adrenal Glands
Spleen
Blood vessels
Heart
What develops from Endoderm?
GI Tract
Organs
Lungs
Liver
What happens to integumentary System with Aging?
Wrinkles
Dehydration and cracking
Sweat production decreases
Numbers of functional melanocytes decreases which results in gray hair and atypical skin pigmentation
Subcutaneous fat is lost and skin thickness decreases
Nails become more brittle
What is Skin Cancer?
Excessive exposure to UV light is most common cause of skin cancer
3 Types of skin cancer:
1- Basal Cell Carcinoma
2- Squamous Cell Carcinoma
3- Malignant Melanoma
What are Burns?
Burn is tissue damage caused by excessive heat, electricity, radioactivity, or corrosive chemicals that denature proteins in skin cells
Burns are graded according to severity
1st Degree Burn:
Epidermis
2nd Degree Burn:
Epidermis and Dermis
3rd Degree Burn:
Epidermis, Dermis, and Subcutaneous Layer
What is the Rule of Nines for Burns?
Used to estimate surface area of an adult affected by a burn
Adult:
Anterior and posterior head and neck - 9%
Anterior and posterior trunk - 36%
Anterior and posterior shoulders, arms, forearms, and hands - 18%
Perineum - 1%
Anterior and posterior thighs, legs, and feet - 36%
Child:
Anterior and posterior head and neck - 18%
Anterior and posterior trunk - 36%
Anterior and posterior shoulders, arms, forearms, and hands - 18%
Perineum - 1%
Anterior and posterior thighs, legs, and feet - 14%
What is a Pressure Ulcer?
Shedding of epithelium caused by deficiency of blood flow to tissues can cause pressure ulcers (bed sores)
What is a Nevus?
Mole
Harmless localized overgrowth of melanocytes
Rarely turns malignant
What is Freckles?
Yellowish or brown spots
Localized areas of increased melanocyte activity
What is a Hemangioma?
Skin discoloration due to benign blood vessel tumor
Capillary Hemangioma:
Bright red to deep purple nodules
Usually present at birth and disappear in childhood
Strawberry-colored birthmarks
Cavernous Hemangioma:
Larger dermal blood vessels
May last a lifetime
Port-wine stains
What is a Friction Ridge?
Small conical pegs in thin skin
Complex arches and whorls on finger, palms, soles, and toes
Large folds and valleys of dermis and epidermis
Increase friction on contact
Fingerprints
What are Line of Cleavage?
Fibers contribute to skin characteristics
Stretch marks if skin stretched beyond capabilities
Incision perpendicular to cleavage lines may gape and delay healing
Incision parallel to cleavage lines more likely to heal quickly and not gape
