Google Analytics is a powerful tool that tracks and analyzes website traffic for informed marketing decisions.
Service URL: policies.google.com (opens in a new window)
__utmx
Used to determine whether a user is included in an A / B or Multivariate test.
18 months
_ga
ID used to identify users
2 years
_gali
Used by Google Analytics to determine which links on a page are being clicked
30 seconds
_ga_
ID used to identify users
2 years
_gid
ID used to identify users for 24 hours after last activity
24 hours
_gat
Used to monitor number of Google Analytics server requests when using Google Tag Manager
1 minute
__utmb
Used to distinguish new sessions and visits. This cookie is set when the GA.js javascript library is loaded and there is no existing __utmb cookie. The cookie is updated every time data is sent to the Google Analytics server.
30 minutes after last activity
__utmc
Used only with old Urchin versions of Google Analytics and not with GA.js. Was used to distinguish between new sessions and visits at the end of a session.
End of session (browser)
__utmz
Contains information about the traffic source or campaign that directed user to the website. The cookie is set when the GA.js javascript is loaded and updated when data is sent to the Google Anaytics server
6 months after last activity
__utmv
Contains custom information set by the web developer via the _setCustomVar method in Google Analytics. This cookie is updated every time new data is sent to the Google Analytics server.
2 years after last activity
_gac_
Contains information related to marketing campaigns of the user. These are shared with Google AdWords / Google Ads when the Google Ads and Google Analytics accounts are linked together.
90 days
__utma
ID used to identify users and sessions
2 years after last activity
__utmt
Used to monitor number of Google Analytics server requests
10 minutes
MT30-Histology Art AB 4 years, 1 month ago 
The integumentary system: anatomy, physiology and function of skin – PubMedThis article, which forms part of the life sciences series, examines the anatomy and physiology of skin, also termed the integumentary system. Skin is composed of two main layers, the epidermis and dermis. The structure of the epidermis and dermis are described and their functions are discussed. Acc …
The integumentary system includes the epidermis, dermis, hypodermis, associated glands, hair, and nails. In addition to its barrier function, this system performs many intricate functions such as body temperature regulation, cell fluid maintenance, synthesis of Vitamin D, and detection of stimuli.
Skin: The skin is made up of two layers—the superficial epidermis and the deeper dermis.
Hypodermis: The hypodermis lies between the dermis and underlying organs. It is commonly referred to as subcutaneous tissue and is composed of loose areolar tissue and adipose tissue. This layer provides additional cushion and insulation through its fat storage function and connects the skin to underlying structures such as muscle.
Hair: Hair is derived from the epidermis but grows its roots deep into the dermis. Its structure divides into the externally visible hair shaft and the hair follicle within the skin. The hair follicle has an intricate structure that contains the hair bulb that actively divides to extend the hair shaft
Nails: Nails form as layers of keratin and appear at the dorsal tips of the fingers and toes. The nail growth begins at the nail matrix that creates new cells and pushes old cells out distally. The visible portion of the nail is the nail plate covering the nail bed, where it adheres to the finger. Nails function to protect the fingers and toes while increasing the precision of movements and enhancing sensation.
Physical protection: Given that the integumentary is the covering of the human body, its most apparent function is physical protection. The skin itself is a tightly knit network of cells, with each layer contributing to its strength. The epidermis has an outermost layer created by layers of dead keratin that can withstand wear and tear of the outer environment, while the dermis provides the epidermis with blood supply and has nerves that bring danger to attention amongst other functions.
The skin is the body’s first line of defense as it acts as the physical barrier that prevents direct entry of pathogens. Cells are connected through junction proteins with reinforcement by keratin filaments.