chapter 4 - histology Flashcards
the study of tissues
histology
the four major types of tissues
epithelial, connective, muscle, nerve
the tissue that covers, lines, and secretes
epithelial
the tissue that contracts to cause movement
muscle
the tissue that conducts electrical messages
nerve
the tissue that holds things together and fills in spaces
connective
a group of cells working together
tissue
the type of microscope that is used most in histology
electron microscope
tiny microscopic cell extensions that increase the surface area of cells to help with absorption and secretion
microvilli
cell extensions that sweep materials along the cell surface
cilia
longer cell extensions with unknown function
stereocilia
Where in the body is known for having many microvilli?
small intestine
Where in the body is known for having many cilia
airways
Where in the body is known for having stereocilia?
inner ear and male reproductive tract
the term meaning having no blood vessels
avascular
the term meaning having a blood supply
vascular
What major tissue type is avascular?
epithelial
How does the epithelium get its nutrition?
diffusion from the CT beneath it
What is the name of the layer that separates the epithelium from the CT?
basement membrane
What are the two layers of the basement membrane?
basal lamina and reticular lamina
What term is used to describe epithelial cells (particularly columnar) that are empty at the top and full of organelles at the bottom
polar
the specialized connections between epithelial cells
cell junctions
Name the three types of epithelial cell junctions.
- gap junctions
- tight junctions
- desmosomes
Which cell junction is a passageway allowing chemical communication between cells?
gap junction
Which cell junction is water proof due to the fusion of the lipid layers?
tight junction
Which cell junction is reinforced with fibers to make it exceptionally strong?
desmosome
What is a common place to find gap junctions?
smooth and cardiac muscle
What is a common place to find tight junctions?
digestive tract
What is a common place to find desmosomes?
skin and cardiac muscle
the ability of a tissue to regrow
regeneration
the three shapes of epithelial tissue
- squamous - flat
- cuboidal - equally tall as wide
- columnar - taller than wide
the two most common layering arrangements in epithelium
simple - 1 layer
stratified - many layers
the bottom of epithelium - attached surface
basal surface
the exposed or unattached surface of epithelium
apical surface
falsely layered
pseudostratified
epithelium that can stretch or distend
transitional
Where is transitional epithelium found?
urinary bladder
Which is more protective, simple or stratified epithelia?
stratified
Name the two major types of simple squamous epithelium.
- endothelium - inner covering
2. mesothelium - middle covering
Where is endothelium found? Why?
lining cardiovascular and lymphatic vessels to allow diffusion
Where is mesothelim found? Why?
serous membranes - to be slippery
Why is simple squamous the right tissue for alveoli of lungs and capillaries?
to allow diffusion
What is pseudostratified columnar epithelium always topped with?
cilia
Why does pseudostratified epithelium appear layered?
nuclei are at various heights but each cell actually touches the basement membrane
the cells that are reproducing (2 terms)
- stem cells
2. germinative cells (germ cells)
Where in your body do you have stratified squamous epithelium?
skin, lining of mouth and throat, lining of anus, lining of vagina - places with abrasion
What is the difference between keratinized and non-keratinized epithelia?
keratinized - waterproof and dry - filled with keratin
a group of cells that secrete
gland
a unicellular gland
goblet cell
What do goblet cells produce, and what is the function?
mucus - lubricate, prevent drying, trap dirt
Name the two major types of multicellular glands.
- endocrine
2. exocrine
glands with ducts to dump their secretions onto an epithelial surface
exocrine
glands without ducts, secretions called hormones go into the blood to travel around the entire body
endocrine
Name the three functional types of exocrine glands.
- merocrine
- apocrine
- holocrine
Which exocrine secretion is the most watery because it is produced only by exocytosis of secretory vesicles? Give 2 examples.
merocrine (eccrine)
- perspiration
- saliva
Which exocrine gland is thicker because part of the cytoplasm is released with the secretion? Give 2 examples.
apocrine
- apocrine sweat - armpits and anogenital area
- breast milk
Why does apocrine sweat stink unlike merocrine sweat?
bacteria feed on apocrine sweat, and the bacteria stink
Which exocrine gland secretion is the thickest? Give an example.
holocrine
1. oil (sebum)
Why do holocrine glands have so much mitosis going on?
The cells need to be replaced.
What is the study of cells that fall off?
exfoliative cytology
Name two tests that are examples of exfoliative cytology, and say what each studies.
- Pap smear - tests for cervical cancer
2. amniocentesis - tests for chromosome errors in developing babies
Name the three major types of connective tissue (CT).
- CT proper
- fluid CT
- supporting CT