Integumentary System Flashcards
List the functions of the integumentary system
Protection Excretion Prevention of tissue dehydration (dessication) Support and Shape Regulation of Body Temperature Energy Reserves Sensation Vitamin D synthesis Absorption Body Odour
List the layers of the Epidermis from inner to outer
Stratum Basale Stratum Spinosum Stratum Granulosum Stratum Lucidum Stratum Corneum
What type of tissue is the epidermis made of
Stratified Squamous Epithelium
Why is the epidermis referred to Avascular
It does not have direct blood supply. The Basal layer receives nourishment for the Dermal layer which has a rich blood supply
What are the majority of the cells in the epidermis
Keratinocytes
What type of cells can be found in the stratum basale
Stem Cells
Melanocytes
Simple cuboidal keratinocytes
What cell division takes place in the Stratum Basale
Mitosis
What promotes mitosis in the Stratum Basale
A peptide - Epidermal Growth factor
How else is the stratum basale referred to?
Basal Layer
Stratum Germinativum
How many layers of cells are in the stratum spinosum
8-10
Why is the Stratum spinosum sometimes referred to as the Horny layer?
Cells within it have a prickly shape
What are merkel discs and where are they located?
Tactile nerve endings sometimes found in Stratum Spinosum
What do merkel discs respond to?
Touch
Which layer gives skin it’s strength and flexibility?
Stratum Spinosum
In which two layers of the skin are melanocytes located?
Stratum Basale & Spinosum
What give the Stratum Granulosum it’s granular appearance?
Lamellar Granules
What function do the Lamellar Granules have?
They are secretory organelles
What substance do the cells of the Stratum Granulosum produce?
Keratohyalin
What is the precursor to keratin and where is it produced in the epidermis?
Keratohyalin produced in the Stratum Granulosum
What happens to the shape of cells in the Stratum Granulosum?
They become flatter
How many layers are there in the Stratum Lucidum?
3-5 Layers
What is the substance that is found in the Stratum Lucidum that gives it a translucent appearance?
Eleidin - substance in between keratohyalin and keratin
Which parts of the body is stratum lucidum present?
Soles of feet and palms of the hands
How many layers of cells are present in the Stratum Corneum?
25-30 layers
Are the cells in the stratum corneum dead or alive?
Dead
What is desquamation?
The process of shedding of the dead cells of the stratum corneum
What type of tissue makes up the Dermis layer of the skin?
Connective Tissue
What are the two layers of the dermis?
Papillary Layer (upper layer) Reticular Layer (lower layer)
What is the deepest layer of the integumentary system?
Subcutaneous layer or Hyperdermis
What structures make up the integumentary system?
Skin Hair Sweat Glands Nails Sensory Receptors accessory structures)
How does integumentary system provide physical protection?
Keratin - Heat, chemicals, abrasion Keratinocytes - microbes Lipids - inhibit evaporation Perspiration - acidic pH retards growth Sebum - bacteriacidal chemicals Melanin - UV damage
What are the two types of sweat glands found in the skin
Apocrine & Eccrine
What is the difference between Apocrine and Eccrine sweat glands
Apocrine glands are not active until puberty and secrete a viscous sweat directly into the hair follicle. Eccrine glands produce watery sweat that tends to be excreted directly onto the skin
What are the properties of collagen fibres?
Strength and extensibility (stretch)
What are the properties of elastic fibres?
Elasticity (recoil)
What are Striae more commonly known as?
Stretch Marks
What fibres, when combined with water give the dermis tensile strength?
Collagen Fibres
What structures in the dermis, give rise to fingerprints?
Dermal Papillae
What important structures do the dermal papillae contain?
Capillaries and pain and touch receptors
What are meissners corpuscles and where are they located?
light touch receptors found in the papillary layer of the dermis
What are pacinian corpuscles and where are they located?
Deep pressure receptors found in the reticular layer of the dermis
Secretions from which gland are affected by bacterial sometimes causing body odour?
Apocrine glands
Where in the dermis are phagocytes located?
Reticular layer
What cell types are contained in the dermis?
Mast Cells
Fibroblasts
Macrophages
What function does adipose tissue provide?
Insulation
Protection of some vital organs such as kidneys
Where on the body would you not expect to find sebaceous glands?
On the palms of hands or soles of feet.
By what other name are the eccrine glands known as?
Sudoriferous glands
Where on the body are the highest concentrations of the Apocrine sweat glands?
Axillary and genital areas
Where are sebaceous gland ducts commonly located?
Hair follicles
List the functions of Sebum.
Lubricant
keep skin and hair soft
Kill bacteria
Become active in presence of male sex hormones
Why are sudoriferous glands supplied with nerve endings?
To monitor body temperature and external temperature and when either are too high they can detect this triggering the production of sweat to aid in cooling the skin.
Are the glands located in the skin endocrine or exocrine glands?
Exocrine - they release secretions to the skin via ducts
Sympathetic Nervous system stimulates which muscle found in the dermis and linked to the hair follicle?
Arrector Pili muscle
