AP1 M7.1 Anatomy of the Integumentary System Flashcards

1
Q

The integumentary system

A

comprised of the skin, hair, and nails.

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2
Q

Skin

A

is the largest organ of the body. It is made up of the epidermis (outer layer), dermis (middle layer), and the hypodermis (inner, also called subcutaneous tissue layer)

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3
Q

Skin cells

A

absorb ultraviolet radiation to produce vitamin D, which is used to promote bone development.

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4
Q

integumentary system contains

A

the sensory receptors and glands used for protection of the skin and underlying tissues.

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5
Q

Integumentary system plays an important role

A

in protecting internal organs from extreme temperature changes as well as pathogenic (disease-causing) microorganisms. If the integumentary system is damaged and microbes or foreign objects make their way into the body, it is the lymphatic system that is responsible for mounting the attack to defend the body’s internal environment.

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6
Q

Sensory Organs

A

The skin contains several types of sense organs, each one specialized to detect a certain type of sensory input

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7
Q

Merkel’s cells and Meissner’s corpuscles

A

are mechanoreceptors that detect mechanical sensory information in the form of light touch and vibration

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8
Q

Nociceptors

A

detect pain, such as from a pin prick.

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9
Q

Pacinian corpuscles

A

detect the mechanical sensory information of pressure applied to the skin.

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10
Q

Thermoreceptors

A

detect hot and cold.

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11
Q

Sensory organs embedded in the skin

A

are designed to detect sensory information and then to relay that information to the brain. The brain then interprets the information to determine an appropriate response.

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11
Q

Glands

A

Recall endocrine glands secrete hormones, which are secreted in the bloodstream for body-wide distribution.

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12
Q

Exocrine glands

A

contain secretions released through a duct (opening) into an epithelial surface or lining. Exocrine gland secretions can also release their contents onto the surface of the skin. Other types of exocrine glands release their contents into an epithelial surface.

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13
Q

Exocrine glands

A

can be categorized by their shape and structure.

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14
Q

multicellular glands

A

Most glands in the body are multicellular glands, which are set within epithelial tissue and release their contents through a duct to the surface.

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15
Q

Sebaceous glands

A

(oil glands) produce sebum. Sebum helps to keep the skin and hair from drying out and inhibits the growth of harmful microorganisms.

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16
Q

Sweat glands

A

(sudoriferous glands) produce sweat in almost every part of the skin. Notice that the secretory portion is deep within the dermis layer of the skin. The duct extends all the way through the dermis, through the epidermis to release its contents on the external surface.

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17
Q

perspiration

A

The release of sweat is called perspiration.

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18
Q

thermoregulation

A

Perspiration helps the body to regulate its temperature through a process called thermoregulation by releasing heat from the body.

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19
Q

epidermis

A

(outermost layer of skin) is made up of stratified squamous epithelium. (Stratified means layered, and squamous means flat). The epidermis is avascular, meaning it does not have a direct blood supply. The epidermis receives its nutrients from the basement membrane (basal lamina).

20
Q

epidermis is comprised of

A

four distinct layers (listed from superficial to deep): the
1. stratum corneum,
2. stratum granulosum,
3. stratum spinosum, and
4. stratum basale

21
Q

stratum basale

A

is firmly adhered to the basement membrane. Gases, nutrients, etc. from the blood supply in the dermis diffuse across the basement membrane to the epidermis.

22
Q

cells of the stratum basale

A

are constantly dividing to rebuild the skin. As cells continue to divide, they are pushed towards the external surface until they are dead and slough off (are removed through washing or friction). The most superficial layer of the epidermis is dead because it is far away from the blood and nutrient supply of the basement membrane. It takes about 30 days for a single cell to move from the stratum basale to the external surface of the stratum corneum. Dead cells remain within the stratum corneum for about another two weeks before they slough off.

23
Q

epidermal ridges

A

The stratum basale forms epidermal ridges (notice the grooves present within the stratum basale). Epidermal ridges are unique to each person and consistent throughout a person’s lifetime. These projections extend all the way through the epidermis and form a distinct pattern commonly called fingerprints.

24
Q

Some of the cells found in the epidermis

A

are keratinocytes, Langerhans cells, fibroblast cells, melanocytes, and Merkel cells

25
Q

Melanocytes

A

produce a pigment called melanin.

26
Q

Langerhans cells

A

Langerhans cells are involved in the body’s immune responses. Langerhans cells act as a first line of defense for the body, helping to identify microorganisms before they reach the bloodstream.

27
Q

Keratinocytes

A

produce a tough substance called keratin. Cells within the epidermis undergo keratinization, which protects exposed surfaces of skin.

28
Q

Merkel cells

A

are a type of sensory receptor that respond to light touch.

29
Q

Fibroblast cells

A

produce collagen, which helps to adhere the cells of the epidermis to each other and give the skin elasticity.

30
Q

Dermis

A

Sweat glands, oil glands, and sensory organs are also found within the dermis. The dermis contains the sensory organs of Meissner corpuscles and Pacinian corpuscles.

31
Q

reticular region

A

The dermis is comprised of a superficial papillary region and the deeper reticular region

32
Q

papillary region

A

The dermis is comprised of a superficial papillary region and the deeper reticular region

33
Q

reticular region of the dermis

A

contains the main blood supply for the skin. There is an extensive network of blood vessels to supply the skin with its needed nutrients. Branches come off the main arteries to supply nerves, glands, and hair follicles within the skin.

33
Q

Both layers of the dermis

A

contain collagen fibers and elastic fibers, which enable the skin to be stretched (within certain limits) to prevent damage to underlying tissue. The dermis has a higher water content compared to the epidermis. A person who is dehydrated has decreased water content in the dermal layer of their skin. A person can be tested for dehydration by pinching the skin on the back of the hand. One indicator of dehydration is when the skin does not recoil back to its normal shape but instead stays pinched.

34
Q

contusion

A

A bruise, or contusion, is damage to one of these blood vessels. Blood leaks out of a blood vessel into the dermis, creating the color of the bruise (typically black and blue).

35
Q

Hypodermis

A

is a layer made mostly of fat cells (adipocytes). There are two layers: subcutaneous fat and subcutaneous tissue, which blend together. The hypodermis helps anchor the dermis to a layer of fat cells. Fat helps to insulate and regulate body temperature. The thickness of the hypodermis protects the deeper tissues and organs from injury.

36
Q

subcutaneous injection

A

means that the medication or vaccination is to be given in a needle that reaches deep the dermis, but superficial to the muscle (in the hypodermis layer of the skin). Medication that is given through a subcutaneous injection is absorbed by the body more slowly than if given directly into a vein.

37
Q

dermatomes

A

The skin is innervated by an extensive network of nerves. A dermatome is a region of skin innervated by one sensory nerve. Sensory signals (carrying information from sensory organs) are sent from the skin to the spinal nerve, through the spinal cord, and finally to the brain for processing. Each region of the skin is innervated by a spinal nerve except the face, which is innervated by a cranial nerve (CN V: trigeminal nerve).

38
Q

Hair

A

is made up of two parts: the root (in the dermis layer) and shaft. The root begins at the hair bulb, which has blood and nervous supply.

39
Q

shaft

A

The shaft extends through the epidermis to the external surface of the skin. Hair is made up of dead epidermal cells that are converted to keratin, giving hair its stronger texture compared to skin cells.

40
Q

sebaceous gland

A

A sebaceous gland is found at the root of each hair follicle, helping to hydrate hair with oil.

41
Q

arrector pili muscle

A

Each hair follicle is connected an arrector pili muscle, a smooth muscle that contracts when the body is cold or experiences emotional responses. Hair follicles are found throughout the skin surface and susceptible to circulating hormones. For example, hair follicles in the armpits, groin, and head change their properties after puberty.

42
Q

Nails

A

are also composed of dead epidermal cells that are converted to keratin. New cells are converted at the nail root and pushed towards the external surface in the direction of the nail body.

43
Q

nail body

A

The nail body is the visible portion of a nail, covering the epidermis in that region, called a nail bed.

44
Q

nail root

A

The nail root is not visible. The stratum corneum of the epidermis extends from the nail root covering the visible portion of the nail, called the cuticle.

45
Q

cuticle

A

The stratum corneum of the epidermis extends from the nail root covering the visible portion of the nail, called the cuticle.

46
Q

lunula

A

The lunula is the visible portion of the nail bed near the nail root, which is typically crescent shaped (and most visible on the thumbs).