A&P LAB 1
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- What are the four (4) distinct cell types found in the epidermis?
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1) keratinocytes
2) melanocytes
3) Langerhan's cells
4) Merkel cells - What are keratinocyte cells?
- Produce keratin
- What is keratin?
- Tough, fibrous, waterproof protein that gives skin its resiliency and strength.
- What are melanocytes?
- Spidery black cells that produce the brown-black pigment called melanin.
- What are Langerhan's cells?
- The skin's macrophagic cells and help to stimulate the immune system.
- What are Merkel cells?
- Located at the epidermal-dermal junction and are associated with sensory nerve endings aiding in the sensation of touch.
- What are the 5 distinct layers of the epidermis?
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1) stratum germinativum
2) stratum spinosum
3) stratum granulosum
4) stratum lucidum
5) stratum corneum - What is the stratum germinativum?
- The stratum basale: the deepest layer. Single row of keratocytes attached to basement membrane. Merkels cells and melanocytes also found in this layer.
- What is the stratum spinosum?
- Resemble sea urchins in histological exam. Contains sveral layers of cells along with langerhans cells in most abundance here (their slender projections form a weblike frame around the keratocytes).
- What is the stratum granulosum?
- The middle layer of epidermis. Composed of two-four layers of flattened diamond-shaped kertocytes.
- What is the stratum lucindum?
- A layer found only in VERY thick skin (most lack this layer). Microscopically appears translucent with a few rows of flattened dead cells.
- What is the stratum corneum?
- The outermost layer that dominates the epidermis. (3/4 of epidermis thickness). Appear hexagonal from above and paper thin from side view. Often known as dandruff! (AKA: cornified or horny cells).
- What are the four major tissue types in animals?
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1) nervous
2) muscular
3) epithelial
4) connective - What is the function of epithelial tissue?
- Protect, secrete, absorb.
- How is epithlial tissue connected to underlying tissue?
- basement membrane (basal lamina)
- What is the basal lamina?
- The basement membrane which is a glue-like substance secreted by the base layer of epithelial cells.
- How are epithelial cells classified?
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1) shape of outermost cell layer
2) thickness in layers
3) ciliated or secrete mucus - Where would you find simple squamous epithelia?
- capillary walls, alveolar walls in lungs, the peritoneum, the pleurae, and blood vessel lingings.
- Where would you find simple cuboidal epithelia?
- Glands such as kidney, thyroid, salivary, and pancreas. Also in ovary and lens of eye.
- Where would you find simple columnar epithelia?
- Lining of stomach, intestines, and kidney tubules are nonciliated. Ciliated can be found in respiratory tract, uterine tubes, and portions of uterus. (Goblet cells in this type of tissue)
- Where would you find pesudostratified?
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Ciliated in trachea, bronchi, auditory tube, and part of middle ear (goblet cells also).
Nonciliated in male urethra and parotid gland. - Where can you find a brush border?
- Columnar cells that line the small intestine are covered in microvilli that look like a brush border under microscopy.
- Where would you find stratified squamous?
- Skin, oral cavity, esophagus, vagina, and cornea.
- Where would you find stratifed columnar epithelia?
- Some glands, conjunctiva, the pharynx, a portion of the urethra, and the anus.
- Where would you find transitional epithelium?
- Urinary bladder, ureters, and kidneys.
- What are the two layers that make up the dermis?
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1) papillary layer
2) reticular layer - What are dermal papillae?
- nipplelike projections in the papillary layer of dermis that rise up to epidermis helping to cement layers together.
- What layer lays below the two dermis layers?
- Subcutaneous layer (hypodermis): thick layer rich with adipose, blood and lymphatic vessels, and nerves. *Allows skin to move freely over underlying bone and muscle without tension on skin!
- What are the three layers of epidermis in animals with fur?
- stratum basale, stratum spinosum, and stratum corneum.
- What are sebacueous glands?
- Found in all parts of skin except soles and palms. Ducts usually empty into hair follicle and produce sebum (preventing hair from drying and keeps skin soft and pliable).
- What does hyptonic to the cell mean?
- lower concentration than inside the cell
- What does hypertonic to the cell mean?
- higher concentratation than inside of cell.
- What is the bursting from hypotonic solution called?
- hemolysis
- What is the shrinking of a cell in a hypertonic solution called?
- crenation
- What are the two major body cavities and what separates them?
- The diaphragm separates the thoracic cavity from the abdominal cavity.
- Describe how to look at a slide.
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-Put stage at lowest setting and objective lens at 4x or 10x
-Put slide in holder on stage. Center over condenser lens.
-Use coarse focus
-Use fine focus
-eye width
-right eye fine focus
-left eye diopter ring
-switch to proper magnification and only adjust fine focus
-clean up, put back to 4x, shut down microscope.