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