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Chapter 4

BIOB34H3 Chapter Notes - Chapter 4: Basal Lamina, Mast Cell, Holocrine

Biological Sciences
Course Code
Ted Petit

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Chapter 4 Tissues
Four major tissue types
- Epithelial (epithelium)
1. covers and lines body parts (sheets of cells)
2. glandular epithelium
a. two major types
1) endocrine glands secrete hormones to blood (no ducts)
2) exocrine secrete products into ducts that open to skin or lumen of organ
b. structural classification of exocrine glands
1) multicellular - form a distinctive structure or organ (e.g., sweat, salivary)
2) unicellular - have no ducts but still considered exocrine (e.g., goblet cells)
c. functional classification of exocrine glands
1) holocrine - cell accumulates product, cell dies, bursts open and substance secreted
(e.g., sebaceous)
2) merocrine - secrete by exocytosis (most glands)
3. epithelial sheets - special characteristics
a. continuous sheets of closely packed, tightly joined cells
b. have apical (free) and basal surface
c. attached to 2-layered basement membrane
1) basal lamina - proteins and polysaccharides secreted by epithelial cells
2) reticular lamina - protein fibers and glycoproteins secreted by underlying connective
d. avascular - exchanges occur by diffusion from blood supply of underlying connective
e. have nerve supply
f. high capacity for regeneration (lots of mitosis)
g. basic functions - protection, secretion, absorption
- Connective tissue
1. special characteristics
a. made up of living cells plus non-living extracellular matrix
1) -blasts are immature cells that secrete matrix (e.g., fibroblasts, chondroblasts,
2) -cytes are mature cells that help maintain matrix (e.g., chondrocytes, osteocytes)
3) other cell types include macrophages, plasma cells (secrete antibodies), mast cells
(store chemicals that help fight invaders)
4) matrix consists of protein fibers embedded in ground substance (polysaccharides and
proteins); supports cells structurally and functionally
5) fibers include collagen (strong, flexible), elastin (strong, very stretchy), reticular fibers
(collagen with coating of glycoprotein, forms branching networks that support tissues
and organs)
b. has nerve supply, except cartilage
c. most highly vascular, except cartilage which is avascular, and tendons/ligaments which
have a low supply
d. functions - support, protection, binding
- Muscle tissue
1. generates force, movement, generates heat
2. three types - skeletal, cardiac, smooth
- Nervous tissue
1. initiates and transmits electrical signals
2. neurons and neuroglia (support cells)
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