chapter 4 short - Dr. Rick Rauschrnrausch.com/25x/pdf/251/chapter_4_short.pdf · Glandular...
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Chapter 4-Tissues 1 Chapter 4 (Lecture Topics) The Tissue Level of Organization • Maintaining the Integrity of Epithelia • Glandular Epithelia • Epithelial Maintenance and Repair • Connective Tissue Classification • Intercellular Matrix and Fiber Types in CT • Membranes 2 Note… These are the potions of Chapter 4 that we will specifically cover in lecture because this information is not covered in lab. As you know, lab lectures are also fair game for lecture tests. 3 SECTION 4-2 Epithelial Tissues Maintaining the integrity of Epithelia 10 th edition: pp. 116 – 118 11 th edition: pp. 118 – 120 • Intercellular connections • Attachment to the Basal Lamina • Epithelia Maintenance and Repair Glandular Epithelia 10 th edition: pp. 123 – 126 11 th edition: pp. 122 – 126
Transcript of chapter 4 short - Dr. Rick Rauschrnrausch.com/25x/pdf/251/chapter_4_short.pdf · Glandular...
Chapter 4-Tissues!
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Chapter 4 (Lecture Topics)!The Tissue Level of Organization!• Maintaining the Integrity of Epithelia!• Glandular Epithelia!• Epithelial Maintenance and Repair!• Connective Tissue Classification!• Intercellular Matrix and Fiber Types in CT!• Membranes!
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Note…!
These are the potions of Chapter 4 that we will specifically cover in lecture because this information is not covered in lab.!
As you know, lab lectures are also fair game for lecture tests.!
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SECTION 4-2 !Epithelial Tissues!Maintaining the integrity of Epithelia !
10th edition: pp. 116 – 118!11th edition: pp. 118 – 120!
• Intercellular connections!• Attachment to the Basal Lamina!• Epithelia Maintenance and Repair!!
Glandular Epithelia!10th edition: pp. 123 – 126!11th edition: pp. 122 – 126
Chapter 4-Tissues!
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Review from Lab Figure 4-1!
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Cells attach via cell adhesion molecules (CAMs):!CAMs are transmembrane proteins!• Bind cells to each other!• Intercellular cement (glycosaminoglycans)
may also be present!Specialized cell junctions!• Tight junctions!• Desmosomes (spot desmosomes and
hemidesmosome)!• Gap junctions!
1. Intercellular Connections!
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Tight (Occluding) Junctions Figure 4-2!
Membrane lipids fused by membrane proteins - Acts like a Ziploc!Prevent leakage of fluids between cells!E.g. found in urinary bladder, stomach epithelia! Basal lamina!
Tight junction!
Chapter 4-Tissues!
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Desmosomes!
Resist mechanical stresses !E.g. important in epithelium of skin!• Dense area linked to intermediate filaments of
cytoskeleton!• CAMs and proteoglycans between cells link
dense areas of opposing cells!• Strong because cytoskeletons are linked!
Types:!• Spot desmosomes (like “spot welds”)!• Hemidesmosomes - anchor to basal lamina
(basement membrane)!
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Spot Desmosomes Figure 4-2!
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Gap Junctions Figure 4-2!
Cells held together by connexons (protein channels)!Allow ions, small molecules to pass from cell to cell.!Carry electrical activity from cell to cell.!Important for coordinated contractions.!• e.g. heart muscle
Chapter 4-Tissues!
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2. Attachment to the Basal Lamina!
Basal lamina (or basement membrane) has two layers:!
1. Clear layer (lamina lucida) - next to epithelium!• Glycoproteins and protein filaments
produced by epithelium!• Restricts entry into epithelium from CT!
2. Dense layer (lamina densa) - next to connective tissue!• Protein fibers produced by CT!• Strong!
Hemidesmosomes attach epithelial cells to basal lamina!
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Basal Lamina and Hemidesmosomes Figure 4-2!
Basal lamina
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3. Epithelial Maintenance and Repair!
Epithelia contain stem cells (germinative cells)!• Constantly replace epithelial cell layers!• Usually found near basal lamina!
!Much more about this in Chapter 5 on skin!
Chapter 4-Tissues!
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Exocrine glands!• Secrete into ducts that empty onto an
epithelial surface!Endocrine glands!• Release hormones into extracellular fluid →
blood (no ducts)!Heterocrine glands!• Do both!
E.g. pancreas, ovaries, testes!
Glandular Epithelia!
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Merocrine (eccrine)!• Product released through exocytosis!• E.g. sweat glands, salivary glands!
Apocrine!• Both product and cytoplasm lost in secretion!• E.g. mammary glands!
Holocrine!• Entire cell dies, releases product!• E.g. oil (sebaceous) glands in skin!
Modes of Secretion!
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Mechanisms of Glandular Secretion Figure 4-6 !
Merocrine!
Apocrine!
Holocrine!
Chapter 4-Tissues!
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Secretions by Exocrine Glands!
Serous glands!• Secrete watery solution containing enzymes!• E.g. parotid salivary glands, sweat glands!
Mucous glands!• Secrete mucins (proteoglycans)!• Mucin + water = mucus!• E.g. sublingual salivary glands, Brunner’s
glands in duodenum!Mixed glands!• Secrete both - submaxillary salivary gland!
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Unicellular glands!• Individual secretory cells!• E.g. goblet cells pseudostratified ciliated
columnar epithelium (mucous glands)!!Multicellular glands!• Organs containing glandular epithelia!• E.g. sweat glands!
Glands - Structural Classification!
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SECTION 4-4 !Connective Tissues!
Pages: 10th edition/11th edition!
• General classification of CT (p. 126/128)!• Cell types (p. 127/129)!• Fiber types (p. 128/130)!• Intercellular matrix, ground substance
(pp. 126/126 and 128/130)!
Chapter 4-Tissues!
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Connective Tissue (CT) - General Types!
1. CT Proper!a. Loose CT!• E.g. areolar, adipose, reticular!
b. Dense CT!• E.g. dense regular (fibrous), dense
irregular, elastic!2. Fluid CT!
e.g. blood, lymph!3. Supporting CT!
e.g. cartilage, bone!
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Cell Types in CT Proper Figure 4-8!• Adipocytes!• Fibroblasts!• Lymphocytes!• Macrophages!• Mast cells!• Melanocytes!• Menenchymal cells!• Microphages!• Lymphocytes!• Plasma cells!
What are some functions of each of these?!
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2. Fiber Types - All are Proteins!
Three principal fiber types produced by fibroblasts!Collagen fibers!• Stronger than steel longitudinally!• Most common type in CT proper!
Reticular fibers (a.k.a. type III collagen)!• Form interwoven network or scaffolding!• E.g. parenchyma of organs!
Elastic fibers contain elastin!• Stretch and rebound!• E.g. walls of elastic arteries!
Chapter 4-Tissues!
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Intercellular Matrix!
Matrix = ground substance + extracellular fibers!• Secreted by fibroblasts!
!Ground substance = amorphous gel!• Charged glycosaminoglycans (GAG)
(mucopolysaccharides)!• Charged proteoglycans (mucoproteins)!
ü Both are hydrophilic!ü Modified in specialized CT (e.g. bone
vs. cartilage)!
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SECTION 4-6 !Membranes are physical barriers of four types!
Membrane types!10th edition: pp. 137 – 139!11th edition: pp. 140 – 142
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Membranes Are Simple Organs!
Form barriers!• Composed of
EPI and underlying CT*!
• Cover and line body surfaces!
Four types:!• Mucous!• Serous!• Cutaneous!• Synovial!
Chapter 4-Tissues!
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Mucous Membranes (Mucosae) Figure 4-16!
• Line cavities that communicate with the exterior E.g. respiratory, digestive, urinary tracts!
• Surface kept moist by secretions (mucus, urine, semen) !
• CT layer = lamina propria
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Serous Membranes !
• Line sealed internal cavities in ventral body cavity!
• Not exposed to external environment!• Mesothelium + areolar CT!• Two layers + sealed cavity!
1. Visceral layer (= “guts”) - layer on the organ!Potential space filled with transudate!
2. Parietal layer (= “wall”) - layer lining body cavity!
3. E.g. Pleura, peritoneum, pericardium
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Serous Membranes Figure 4-16!
Figure 20-2c!
Figure 4-16b!
Chapter 4-Tissues!
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Cutaneous and Synovial Membranes!
Cutaneous membrane = skin = epidermis and dermis!• Covers the body surface• Chapter 5!
Synovial membrane !• Incomplete lining within joint cavities• Lining = macrophages, fibroblasts (not an
epithelium)!• No basal lamina!• Fluid exchanged with capillaries in CT!
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Cutaneous and Synovial Membranes!
Figure 4-16c!
Figure 4-16d!
