BIOL 3151 Chapter 4-5:
18 Feb 2019
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Exam 1 Lecture Notes - Ch. 4 -- 5
Chapter 4
1. Tissue Level of Organization
a. Group of cells that carry out a common function → tissue
i. Histology → study of tissue and their relationships within organs
b. 4 principal tissue types → formed from 3 primary germ layers
i. Endoderm becomes: (epithelial)
1. Epithelial lining of respiratory tract, GI tract, urinary tract,
reproductive tract, tympanic cavity, auditory tube
2. Liver
3. Gallbladder
4. Pancreas
5. Palatine tonsils
6. Thyroid gland
7. Parathyroid gland
8. Thymus
ii. Mesoderm become: (muscle, CT, epithelial)
1. Dermis of skin
2. Epithelial lining of blood vessels, lymph vessels; serous
membranes
3. Muscle tissue
4. Connective tissue
5. Adrenal cortex
6. Heart
7. Kidneys and ureters
8. Spleen
9. Internal reproductive organs
iii. Ectoderm becomes (epithelial tissue and nervous tissue)
1. Epidermis of skin (hair, nails, sweat glands and mammary glands)
2. Nervous tissue and sense organs
3. Pituitary gland
4. Adrenal medulla
5. Enamel of teeth
6. Lens of eye
iv. Generated by gastrulation (occurs week 3 of embryonic development
1. Sensitive to teratogens → agent that cause malformations in
embryo
c. 4 primary tissues vary in:
i. Structure of specialized cells
ii. Cell function
iii. ECM (extracellular matrix) presence
d. Epithelial Tissue
i. Serves as covering for body surfaces and lining the body cavities
1. Forms the external and internal lining of many organs
a. Boundary between environments
i. Thus nearly all substances received and released by
the body pass through the epithelium
ii. Transepithelial transport → transport across an
epithelium
ii. Characteristics of Epithelial Tissue
1. Cellularity
a. Close-packed cells; Little ECM
2. Polarity
a. Apical and basal surfaces; differ in composition/function
3. Attachment
a. Rest upon and supported by the CT
b. Connection via a basement membrane
i. Basal laminae (secreted by epithelial cells)
1. Noncellular (proteins) adhesive sheet;
selective filter; scaffolding for cell migration
a. Lamina lucida and lamina densa
ii. Reticular lamina (secreted by CT)
1. ECM material; support
4. Avascularity
a. Lack blood vessels; nourishment by diffusion
i. Always going to be of a certain thickness
5. Innervation
a. Some regions richly innervated but restricted
6. High regenerative capacity
a. Due to loss/damage; continually replaced by deepest
epithelial cells
i. Stem cells
iii. Specialized Structures
1. Due to location at free surfaces (when identifying look for empty
space) epithelial tissues exhibit some distinct structural
characteristics
2. Epithelium rests on a layer of CT; adheres firmly to secure
epithelium in place and prevents tearing
a. Basement membrane
i. Comprised of laminae → strengthen attachment and
form molecular barrier (selective filter)
1. Physical support
2. Anchor epithelium to CT
3. Regulate movement of large molecules
3. Factors present that assist to bind cells closely together
a. Glycocalyx
Document Summary
Chapter 4: tissue level of organization, group of cells that carry out a common function tissue i. Histology study of tissue and their relationships within organs: 4 principal tissue types formed from 3 primary germ layers i. Endoderm becomes: (epithelial: epithelial lining of respiratory tract, gi tract, urinary tract, reproductive tract, tympanic cavity, auditory tube, liver, gallbladder, pancreas, palatine tonsils, thyroid gland, parathyroid gland, thymus ii. Mesoderm become: (muscle, ct, epithelial: dermis of skin, epithelial lining of blood vessels, lymph vessels; serous membranes, muscle tissue, connective tissue, adrenal cortex, heart, kidneys and ureters, spleen. Ectoderm becomes (epithelial tissue and nervous tissue: epidermis of skin (hair, nails, sweat glands and mammary glands, nervous tissue and sense organs, pituitary gland, adrenal medulla, enamel of teeth, lens of eye iv. Generated by gastrulation (occurs week 3 of embryonic development: sensitive to teratogens agent that cause malformations in embryo, 4 primary tissues vary in: i. ii. iii. Ecm (extracellular matrix) presence: epithelial tissue i.
