Anatomy and Physiology
BIO 2220
Dr. Cummings
Exam 2
Lecture Objectives
Tissues
Discuss the classifications of epithelial tissues—how and why they are classified as they are—
and the functions of each.
Covering/lining
o Numbers of layers
Simple = one layer; absorption and filtration; not a lot of friction
Stratified = more than one layer of cells; exposed to friction; Naming is
based on shape of cells on apical surface
Pseudostratified = only one layer, but looks like more than one, aren’t
exposed to a lot of movement; named by shape of cells on apical surface
o Shape
Squamous
Cuboidal
Columnar
Transitional
- Dome shaped cells
- Line hollow cavities
o Urinary bladder dome shaped when bladder is empty,
flatten when bladder fills
Glandular
o Number of cells
Unicellular
Multicellular
o Functional
Merocrine
- Cells produce secretory product packaged into a vescicle by
Golgi released into duct by exocytosis product travels; cell
has not been damaged, stays active; salivary, sweat, pancreas
Holocrine
- Cell produces product and stores it as an inclusion cell
sloughed off into duct bursts and releases contents cell
dies; cell has died and is replaced by mitosis; sebaceous glands
Differentiate glandular epithelium from covering and lining epithelium.
Covering and lining – all free body surfaces, anything exposed to the environment
Glandular – one or more cells that produce and secrete a specific product
Define gland, and explain the difference between exocrine and endocrine glands.
Gland – cell or group of cells of specialized epithelium that secrete substances into
ducts, onto surfaces or into the blood
, o Exocrine: secrete into a duct
Sweat glands, gall bladder
o Endocrine: ductless, secrete hormones which travel in the bloodstream
Thyroid
o The pancreas has an endocrine portion and an exocrine portion
List the different classes of connective tissue, and identify the structural elements possessed by
all classes.
All connective comes from the mesenchyme (embryonic origin)
All connective tissue possess cells and fibers embedded in a background of matrix
Connective tissue proper
o Areolar, dense regular, elastic
Cartilage
o Elastic cartilage, hyaline, fibrocartilage
Bone
o Spongy and compact
Blood
Compare and contrast the structure, location, and function of the three types of muscle tissue.
Skeletal
o Striated
o Multiple nuclei
Cells merge during embryonic development, nuclei are pushed toward
edges
o Voluntary
Cardiac
o Striated
o Only one nucleus
o Involuntary
o Intercalated discs
Communication junction between neighboring cells
Channel proteins are fused with a gap junction connexon
Allows for heart cells to beat together
Smooth
o No striations
o Only one nucleus
o Stretched nucleus
o Involuntary
Identify the criteria used to classify muscle tissue.
Classification criteria
o Striations
o Nervous control
o Number of nuclei
, Cells modified for contraction
Provide movement and/or heat
Sarcolemma = plasma membrane of a muscle cell; modified lipid bilayer
Sarcoplasm = cytoplasm of a muscle cell
Identify the functional and supportive components of nervous tissue.
Neurons
o Detect stimuli
o Stimulus energy electrical energy (impulses)
o 50% of the tissue are neurons
Neuroglia
o Other 50% of nervous tissue
o “Nerve glue”
o Supports and connects neurons
Membranes
Describe the structure and function of cutaneous, mucous, serous, and synovial membranes.
Cutaneous – skin
o Keratinized stratified squamous epithelium
Keratinized = accumulated protein keratin
Cells start to protein keratin, cellular inclusion in squamous epithelium
cells
Top layer is dead and full of keratin
o Attached to dense irregular connective tissue (underneath)
o Exposed to air
o “dry”
o Basale = germinal cells that are dividing
Mucous – body cavities that are open to the external environment
o Most contain stratified squamous or simple columnar epithelium
o Attached to areolar connective tissue
o Line body cavities that are open to the exterior
o Moist secretes mucus
o Absorption and secretion
Serous – lining the insides of the body that are not open to the external environment
o Simple squamous epithelium resting on areolar connective tissue
o Line closed ventral body cavities
o Moist secretes serous fluid
o Where leaked blood accumulates
o Hyaluronic acid = carbohydrate-rich secretion, water-based
Combines with fluid from capillaries to produce a viscous fluid that
provides lubrication
Allows cavity to slip around organs when moving to keep organs stable
o Double layered membrane
Parietal = body cavity
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