A&P Chapters 5-6 Glands, Membranes & The Integumentary System Flashcards
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?
Serous Membranes
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?
15%
What are the functions of the skin?
- 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.
- Synthesis: When exposed to sunlight the skin plays a role in the synthesis of Vitamin D.
- Sensation: the skin is the most extensive and important sensory organ. MERKEL CELLS are the sensory cells in the skin.
- Thermoregulation: Receptors in the skin provide information on temperature and play a role in feedback loops that cause shivering, vasoconstriction/dilation.
- 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?
- Keratinocytes: Responsible for sythesizing keratin and make up 95% of the cells in the epidermis.
- Stem cells: undifferentiated cells that actively divid and give rise to cells that become the keratinocytes.
- Melanocytes: pigment cells found near the base of the epidermis. They produce the pigment MELANIN that gives skin it’s color.
- Merkel Cells: The specialized sensory cells located near the base of the epidermis. Responsible for the sense of touch.
- 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).