Question

20.1.o Explain how collagen fibrils become oriented in developing tissue

20.2.b Outline the main functions common to epithelia and list some functions of specialized epithelia

20.3.b Review the three main factors that contribute to tissue stability.

20.4.g Explain why cancer is most often a disease of old age

Answer 1

1) Collagen has great tensile strength and is the main component of fascia, cartilage, ligaments, tendons, bone, and skin. Along with elastin and soft keratin, it is responsible for skin strength and elasticity, and its degradation leads to wrinkles that accompany aging.

2) They perform a variety of functions that include protection, secretion, absorption, excretion, filtration, diffusion, and sensory reception. The cells in epithelial tissue are tightly packed together with very little intercellular matrix

The cells in this tissue are tightly packed within a thin ECM. Forming sheets that cover the internal and external body surfaces (surface epithelium) and secreting organs (glandular epithelium). Functions of epithelial tissue are secretion, protection, absorption, transportation and special sensory receptive

3)cells involved in tissue repair, their signaling ... then presents the actors and script for the three acts of the tissue repair drama. Several systemic factors may adversely affect the performance of the tissue repair drama.

4)Cancer can be considered an age-related disease because the incidence of most cancers increases with age, rising more rapidly beginning in midlife. ... Some of the same biologic mechanisms that regulate aging also may be involved in the pathogenesis of age-related diseases such as cancer.

One view is that cancer develops in older people simply because of their prolonged exposure to carcinogens such as sunlight, radiation, environmental chemicals, and substances in the food we eat. Mutations also occur as a result of random errors when a cell's DNA is copied before it divides