Flashcards in A&P Chapters 5-6 Glands, Membranes & The Integumentary System Deck (98):
What are glands?
Organs or cells that produce a substance that is to be used by another nearby tissue, a tissue in another part of the body, or eliminated from the body (waste)
What are the two categories of glands?
Endocrine and Exocrine
What do Endocrine glands do?
Glands that produce substances that will be used by other cells or tisssue WITHIN the body.
Endocrine glands are glands that typically produce hormones that enter the BLOODSTREAM.
What do Exocrine glands do?
They produce substances that will ultimately leave the body. That substance may first be desposited into the cavity of an organ but it will end up leaving the body eventually.
What are examples of endocrine glands?
Adrenal glands, thyroid glands, pituitary gland...ect.
What are some examples of an Exocrine gland?
Sweat glands, mucous glands, the liver, pancreas, prostate, ect...
What are glands composed of?
A series of ducts and secretory cells which are all lined by Epithelial cells.
They may also possess MYOEPITHELIAL CELLS.
What do MYOEPITHELIAL CELLS do?
Contract and squeeze to move things along in a gland. They have epithelial and muscular characteristics.
What are simple glands?
In simple glands the ducts do not branch. Example: a Simple coiled tubular gland, a Sweat gland.
What are Compound glands?
The ducts have numerous branches. Examples: Compound Acinar, a Mammary gland. or Compound Tubuloacinar, the Pancreas.
What are the types of secretions a gland may produce?
Serous, Mucous, Mixed, and Cytogenic
Describe Serous secretions
Thin, watery fluids such as Sweat and Saliva.
These are also associated with Serous Membranes producing fluids to lubricate the visceral and parietal layers.
Describe Mucous secretions
Thick, stringy fluids such as Saliva and Lung Mucous.
Describe Mixed secretions
Produced by BOTH Serous and Mucous secretions.
Describe Cytogenic secretions
Cytogenic secretions are whole cells, in the Female eggs are secreted by the ovaries, in Males sperm cells are secreted by the testes.
What are the modes of secretion?
Merocrine and Holocrine
Describe the Merocrine mode of secretion
The secretory cells of a gland produce a substance which is then excoytosed into the duct. The secretory cells DO NOT rupture.
Describe the Holocrine mode of secretion
The secretory cells of a gland produce a substance and then RUPTURE thus releasing the substance into the ducts. The ducts of holocrine glands are often short.
The sebaceous glands of the skin are good examples of holocrine glands.
What are the ways to classify a gland?
The basis of its structure, the type of secretion produced, and the mode of secretion.
What are membranes?
The portion of an organ or tissue that is exposed to the lumen or external surface of that organ. Examples: The Skin, Mucous Membrane of Lungs, The Mucous Membrane of the Digestive system or Lining of the Circulatory System.
What is a membrane composed of?
An epithelial cell layer, a basement membrane and a layer of connective tissue.
The Pleural, Pericardial and Peritoneal membranes are examples of what kind of membrane?
What is the integumentary system?
The skin and all the accessory organs associated with it, ie. the hair, nails, and glands ect...
Approximatly how much of our body weight does the integumentary system comprise?
What are the functions of the skin?
1. Protection: Acts as a barrier to keep water, chemicals and foreign invaders out. The keratin in the skin makes them water proof. Tight junctions of skin epithelial prevent bacteria and viruses from entering.
2. Synthesis: When exposed to sunlight the skin plays a role in the synthesis of Vitamin D.
3. Sensation: the skin is the most extensive and important sensory organ. MERKEL CELLS are the sensory cells in the skin.
4. Thermoregulation: Receptors in the skin provide information on temperature and play a role in feedback loops that cause shivering, vasoconstriction/dilation.
5. Social functions: The skin is responsible for non-verbal communication cues.
What are the two layers of the skin?
Epidermis and Dermis
What comprises the Epidermis?
A layer of stratified, squamous, keratinized epithelial cells, stem cells an sensory cells.
What are the five cell types found in the Epidermis?
1. Keratinocytes: Responsible for sythesizing keratin and make up 95% of the cells in the epidermis.
2. Stem cells: undifferentiated cells that actively divid and give rise to cells that become the keratinocytes.
3. Melanocytes: pigment cells found near the base of the epidermis. They produce the pigment MELANIN that gives skin it's color.
4. Merkel Cells: The specialized sensory cells located near the base of the epidermis. Responsible for the sense of touch.
5. Dendritic Cells: Specialized immune cells that monitor the skin for invasion by bacteria and viruses. They help coordinate immune defense.
What are the five layers of the Epidermis (bottom to top)?
Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum, Stratum Corneum
Describe the Stratum Basale
The lowest layer of cells in the Epidermis, these cells are attached to the basement membrane. Most of the cells are stem cells that divide and produce cells that grow into the keratinocytes. The cells in this layer look cuboid or columnar in shape.
Melanocytes and Merkel cells are also found here.
What are the types of cells found in the Stratum Basale?
Stem Cells, Melanocytes and Merkel Cells
Describe the Stratum Spinosum
It is the second layer of the epidermis, also the thickest layer of epidermis. Filled with living keratinocytes.
Describe the Stratum Granulosum
The third layer of epidermis, cells contain granules of a waterproofing substance and other materials to make keratin. Cells in this layer undergo APOPTOSIS.
Describe the Stratum Lucidum
The fourth layer of the epidermis found only in THICK skin, it is a thin layer of cells filled with a precursor to keratin.
Describe the Stratum Corneum
The fifth layer of epidermis that contains layers of dead keratinized skin cells.
What is APOPTOSIS? Why do cells in the Stratum Granulosum undergo APOPTOSIS?
Apoptosis is programed cell suicide.
Cells undergo apoptosis because they get pushed too far away from the blood supply found in the Dermis.
Which layers of cells in the Epidermis divide?
The first 3-5 layers.
What is EXFOLIATION?
It is the shedding or scraping off of dead karatinized cells.
What is dandruff?
A clumped mixture of dead keratinocytes and SEBUM (oil).
Describe the Dermis
The dermis is a layer of connective tissue directly beneath the epidermis that contains various types of connective tissue, blood vessels, nerves, sweat glands and hair follicles.
What are the two regions of the Dermis?
The Papillary Layer and the Reticular Layer
Describe the Papillary layer of the Dermis
It is the closest to the Epidermis and comprised of a layer of Areolar connective tissue. The loose arrangement of collagen fibers allows leukocytes and other immune cells to occupy this space.
This layer contains MANY capillaries that supply the epidermis with O2 and Nutrients.
Makes up the finger like projections called the DERMAL PAPILLAE which gives skin it's ridges and grooves.
What makes your fingerprints and tiny grooves on your hands?
The Dermal Papillae found in the Papillary layer of the Dermis.
Describe the Reticular layer of the Dermis
It is the thicker layer of the Dermis comprising ~80% found deep to the papillary layer. It is made of Dense Irregular connective tissue and small pockets of Adipose tissue.
There are only a small amount of bloodvessels in this layer, most travel to the papillary layer and supply the Epidermis with it's blood supply.
What is Meissner's Corpuscle?
The Sensory receptor in the dermis that is responsible for detecting light or delicate touch, located closer to the surface of the skin.
What is Pacinian Corpuscle?
The Sensory receptors that detect deep pressure located deeper in the dermis.
What is the Hypodermis?
The layer directly beneath the Dermis, sometimes called Subcutaneous Tissue.
What does the hypodermis do?
It binds the skin to underlying muscle and tissue. It also provides some physical protection due to the adipose tissue found here. The hypodermis is also a very vascular layer and is the reason why HYPODERMIC injections are sometimes administered in this layer.
What are the accessory organs of the integumentary system?
Hair, Nails and The Variety of Glands
What is Hair made of?
Thin strands of dead keratinized cells that grow from Hair Follicles located in the Dermis.
What is Vellous Hair?
Thin very fine hair.
What happens to your hair as you age from child age through puberty?
Your hair typically gets thicker, more coarse and darker.
What are the three Zones of Hair Anatomy along it's length?
The Bulb, The Root, and the Shaft.
Where is the Bulb? What lives here?
The Bulb is at the base of the hair follicle, the LIVING DIVIDING hair cells reside here.
Where is the Root?
The portion anchored within the hair follicle. These are all dead cells.
Where is the Shaft?
The portion of the hair above the skin's surface.
Where is the only place living cells exist when reffering to hair?
What is very important to hair development? What does hair store or keep a record of?
Nutrition is importand to hair development and hair records past toxins and drug use.
What causes Goosebumps?
The Arrector Pili muscle.
What detects movement in the hair shaft?
Specialized Nerve Fibers
What glands have ducts that travel within the hair follicle?
Apocrine Sweat Glands and Sebaceous Glands
What are the three phases a hair strand will go through?
Anagen, Catagen and Telogen
Describe the Anagen phase of the hair life cycle
The phase with rapid cell growth.
Describe the Catagen phase of the hair life cycle
The phase when cell proliferation slows.
Describe the Telogen phase of the hair life cycle
When the production of cells stops.
What is Alopecia?
The loss or thinning of hair.
Why if your hair is going through cycles does it not all fall out at one time?
Because different strands are in different phases, this means some are rapidly growing while others are ceasing production and waiting for the cycle to start over again.
How long does the hair life cycle last for a typical hair on your scalp?
7 years, hairs go through multiple cycles in your lifetime.
What are the five cutaneous glands?
Merocine Sweat Glands, Apocrine Sweat Glands, Sebaceous Glands, Ceruminous Glands and Mammary Glands.
Describe Merocrine Sweat Glands
Also known as Eccrine Sweat glands, they are important for controling THERMOREGULATION. They function to cool our body. They are the regular sweat glands found all over the body.
They are a SIMPLE TUBULAR GLAND lined with MYOEPITHELIAL cells that contract and squeeze the sweat to the surface.
The sweat they produce is slightly acidic at ph4-6 which inhibits bacteria growth.
You loose half a liter of sweat a day without exercise.
Describe Apocrine Sweat Glands
They are a simple tubular gland that exists in the axillary, groin and anal regions.
Produces a fluid rich in fatty acids, the bacteria on your skin feed on the fatty acids and excrete a subtance that we smell as body odor.
Produces sent molecules called PHEROMONES.
What are Pheromones?
The scent molecules produced by Apocrine Sweat Glands.
Describe Sebaceous Glands
They are a form of holocrine gland and they produce an oily secretion called SEBUM. These glands open into the hair follicle.
The fluid produced by Sebaceous glands, it is the skins natural moisturizer meant to keep the skin from drying out.
Sebum is a mix of oil and cell fragments.
Decribe Ceruminous Glands
Only found in the outer ear canals, these ducts open directly to the skin surface.
Produces a secretion called CERUMEN which mixes with sebum and dead epithelial cells to make earwax.
The product of a Ceruminous gland, Cerumen mixes with sebum and dead epithelial cells to make earwax.
Cerumen keeps the eardrum pilable, it waterproofs the ear cnal and inhibits bacteria growth.
What are the 3 Classifications of Burns?
1st Degree, 2nd Degree, 3rd Degree.
In the Medical Feild they are Superficial, Partial Thickness and Full Thickness.
Describe a 1st Degree Burn
Damage is limited to the epidermis only. Superficial burn from sunburns, water scalding ect...
Describe a 2nd Degree Burn
The damage extends through the epidermis into the dermis typically resulting in visible blistering and swelling.
Describe a 3rd Degree Burn
The damage extends through the dermis and often involves the hypodermis. The result is a very serious life threatening situation often requiring immediate medical attention. Treatments typically include skin grafts because the entire integumentary system is destroyed in the area of the burn.
Why are 3rd Degree Burns potentially fatal?
The loss of body fluids and the very high risk of infection at the burn site. The major cause of death from a burn is SECONDARY INFECTION.
What are the three main forms of skin cancer?
Malignant Melanoma, Basal Cell Carcinoma and Squamous Cell Carcinoma.
What is the most common form of skin cancer?
Basal Cell Carcinoma
Describe Basal Cell Carcinoma
Its a cancer of the cuboidal cells of the stratum basale. Very high survival rate because it rarely METASTACIZES. Treatment typically involves surgical removal of the cancerous tissue and radiation therapy in advanced cases.
Often appears as a rounded raised bump on sun exposed skin. This cancer is easy to see and therefore easy to detect.
Describe Squamous Cell Carcinoma
The #1 cause is attributed to spending too much time in the sun being exposed to too much UV radiation.
Arises from squamous cells in the Stratum Spinosum. Often appears on sun-exposed skin as a red scaly ulcer. Costmetic damage can be extensive but this type of cancer is very treatable with surgery and radiation therapy in more advanced cases.
Typically spreads laterally across the skin as opposed to vertically to other areas.
Why should you be concerned regarding a potential for Basal or Squamous cell carinoma in a place where "the sun don't shine"?
Because on non-sun exposed skin the result of the cancer is usually more dangerous, the mutations causing the cancer arise from genetic damage and not a result of sun exposure. These are often more agressive and metastacize quickly.
Spreading to other non-skin organs
Describe Malignant Melanoma
It arises from the melanocytes in the stratum basale. It is the least common skin cancer but the most leathal of all skin cancers. It spreads quickly and is often fatal if not treated immediatly.
Melanoma typically originates in moles (Nevi), which are simply clusters of Melanocytes.
Melanoma is more common in men than women. Often linked to fair skin and a history of bad sunburns.
Limited treatment options, very curable through radiation if caught early enough. Typically incurable if the melanoma has spread since these type of cancer cells don't respond well to chemotherapy/radiation.
Tends to form MANY tiny areas of cancer so it is difficult or impossible to surgically remove the cancer.
Locations close to lymph nodes (back, head, neck, groin, etc..) have poor prognosis since metastasis is more common than in places like the hand or foot.
What are the ABCD's of Malignant Melanoma?
A: Asymmetry, one hlaf is different than the other.
B: Border Irregularity, the edges are notched, uneven or blurred.
C: Color, the color is uneven. Shades of brown, tan, and black are present.
D: Diameter, the diameter is greater than 6mm (pencil eraser).
What is a Wide Excision?
Surgery to treat Malignant Melanoma where two incisions are made. The first removes the epidermis, dermis and hypodermis for an ince around site, the second removes the dermis and hypodermis around the site for another inch and the epidermis is sewn up.
What are the two types of wound healing the integument may exhibit?
Regeneration and Fibrosis/Repair
Describe Regeneration of the integument
Replaces damaged cells with the same type of cells, typically seen in VERY superficial scrapes and cuts involving the epidermis only. NO BLEEDING. Damaged cells are replaced through proliferation of pre-existing cells.
Describe Fibrosis/Repair of the integument
Involves the formation of a clot, scab and eventually replacing damaged tissue with SCAR tissue. This occurs when multiple types of tissue have been damaged. Seen in most deep cuts/scraps. Needs to repair the epidermis as well as the connective tissue and blood vessels of the dermis.
What is the blood protein that polymerizes and forms the meshwork that creates a clot?
Describe the process of clotting/scab formation
After a deep cut blood from severed vessels enters the wound site. The blood allows leukocytes, antibodies, clotting factors and proteins to enter the wound.
Fibrin polymerizes and forms the meshwork that creates a clot, the scab is just the dried part of the blood clot on the surface.
Why is the formation of a blood clot important?
1. Stops bleeding. 2. Protects the open wound from bacteria and dirt.
Describe the process or repair that occurs after a clot and scab form
The wound heals inside out so the deeper dermis is repaired first. Blood vessels grow and repair connections. Macrophages enter and remove damaged tissue and the blood clot. Fibroblasts sythesize new collagen to repair connective tissue in the dermis. NEW collagen is laid down by fibroblasts very quickly and it is MORE dense and LESS flexable than the original tissue, this is scar tissue.
Once repair to the dermis has started the epithelial cells proliferate and help repair the epidermis. This phase is called REMODELING and can take many weeks.
THE CELLS/STRUCTURES DO NOT REPOPULATE. ONCE A STRUCTURE/CELL IS DESTROYED IT DOESN'T COME BACK. NOT HAIR FOLLICLES, GLANDS, MELANOCYTES, MERKEL CELLS, NOTHING!