04 integumentary powerpoint
TRANSCRIPT
THE INTEGUMENTARY SYSTEM
Integumentary System Functions
Protection (chemical, physical, and biological barriers)
Prevents loss of water Temperature regulation Metabolic regulation Immune defense Sensory receptors Excretion by means of secretion
Regions of the Skin
Epidermis
Dermis
HypodermisNOT a part of
the integumentary system
EpidermisThe epidermis is what type of tissue?? Keratinized stratified squamous
epitheliumThick skin has five layers
Thin skin has four layers
Stratum corneum
Stratum lucidum
Stratum granulosumStratum spinosumStratum
basale
Layers of the Epidermis
Stratum corneum Stratum lucidum (only in thick
skin) Stratum granulosum
Keratinization Cells still alive
Stratum spinosum Epidermal dendritic cells
Stratum basale (germinativum) Melanocytes Tactile Cells
Keratinocytes found in all layers
Cells of the Epidermis Keratinocytes-
produce keratin, most abundant
Melanocytes- produce melanin
Epidermal Dendritic Cells (Langerhans Cells)- macrophages in the immune
response
Tactile Cells (Merkel Cells)- sensory receptors
The epidermis is made of ___ epithelium.
1. Simple Squamous
2. Transitional
3. Stratified Squamous
4. Pseudostratified Squamous
Skin Color Hemoglobin – in
blood; causes pink hue in Caucasian skin
Melanin – produced by melanocytes UV exposure darkens
existing melanin and stimulates melanocytes
Carotene – found in plants; yellow to orange pigment
Jaundice – caused by elevated levels of bilirubin in the body
The epidermis is epithelial tissue so what MUST lie directly beneath??
Connective Tissue
Quick Question
Dermis
2 layers: Papillary (areolar) Reticular (dense
irregular) Epidermal Ridges
and dermal papillae
Hypodermis (subcutaneous)
Areolar and adipose connective tissue
Anchors skin to underlying structures
Allows skin to slide freely
Larger in women than men
Nails Scale like
modification of epidermis
Contain hard keratin
Grows from the nail matrix
Hair
Three types of hair: Lanugo
fine downy hair on fetuses
Terminal hair on head, pubic
region, and men’s facial hair
Vellus hair on arms and legs fine hair
Hair Consists of root
and shaft Layers of the
hair:Medulla – central
core not found in all hair
Cortex – surrounds medulla
Cuticle – outermost layer
Location and Functions
Hair can be found EVERYWHERE, except for on the palms, soles, lips, sides of fingers and toes, and parts of the external genitalia
Functions: protects from the sun senses touchreduces heat loss
Hair Growth Rate of hair growth
is about 2 mm/week
Growth cycles – active (2-5 years) and dormant phases (3-4 months)
Why are eyebrows shorter than hair on the head?
Male Pattern Baldness
Genetic and hormonal influences Genetic: 2 alleles, one for
uniform hair growth and one for baldness
Baldness gene is dominant in males
Hormonal: Testosterone causes terminal hair to be replaced by vellus hair
Exocrine Glands Sebaceous (oil) glands
Occur over entire body, except palms and soles
Produce sebum as lubricant
Sudoriferous (sweat) glands Merocrine glands – most
numerous, sweat or sensible perspiration
Apocrine glands – confined to axillary, nipple, anal and genital areas; viscous sweat
Merocrine
Apocrine
Sebaceous
What type of gland secretes oil to lubricate the skin?
1. Sudoriferous
2. Merocrine
3. Apocrine
4. Sebacceous
Burns
First-degree – damages epidermis
Second-degree – damages epidermis and part of the
dermis
Third-degree – damages entire dermis
Types of Skin Cancer
Basal cell carcinoma
Squamous cell carcinoma
Malignant MelanomaRefer to Table 5.4 for more information
Objectives for Next Lecture Describe the general structures
and functions of bone Identify the classifications of bones Understand the two types of bone
formation Describe some disorders of the
skeletal system