NS 3410 1st EditionLectures 11Lecture 2Introduction to Specific Pathologies What are the specifics of ribosomopathies, ERAD, mitochondrial diseases?Ribosomes generate all cellular proteins needed for cell growth. Defects in a single ribosomal protein can cause tissue-specific human diseases, such as Diamond-Blackfan anemia and congenital asplenia. ERAD monitors the folding of membrane and secretory proteins, directs mis-folded proteins to proteasome for degradation and controls the turnover of specific proteins. Accumulation of mis-folded proteins leads to ER stress. Mutations in mitochondria cause neuronal dysfunction, cell death and movement disorders. Lecture 3 What types of transport are considered passive and which are considered active? Passive transport consists of simple diffusion, carrier-mediated facilitated diffusion, channel-mediated facilitated diffusion and osmosis. These processes do not require energy. Simple diffusion is when the solutes go directly through the phospholipid bilayer. Carrier-mediated facilitated diffusion requires a protein carrier. Channel-mediated facilitated diffusion is especially for ions, which need a channel to enter the cell. Osmosis is the transport of water from an area of low solute concentration to an area of high solute concentration. Active transport requires ATP to take solutes against their concentration gradient. These consist of phagocytosis, receptor-mediated endocytosis and pinocytosis. Lecture 4What is the process of iron transport?In the enterocyte, Fe3+ is reduced to Fe2+ by ferric reductase. Fe is imported into cell by DMT1 which is on the apical surface. Once in cell, Fe can be stored as ferritin if not needed . If Fe is needed, it will be exported by ferroportin to the blood. It must then be oxidized to Fe3+ by hephaestin in order to bind to transferrin. Fe3+ then binds to transferrin and can bind to any cellthat has a transferrin receptor. It will then be ingested by receptor mediated endocytosis.Lecture 5What are some of the most important characteristics of epithelial tissue?They are tissues composed of layers of cells that cover organ surfaces such as the skin and inner lining of digestive tract. They serve for protection, secretion and absorption. They also are important for filtration, excretion, secretion, sensory reception and prohormone production. They have specialized contacts, polarity (apical and basal sides), are avascular but innervated and regenerative. Lecture 6What are the characteristics of each tissue type of epithelial?Simple squamous line the heart, portions of the kidney tubules, and alveoli of the lungs. Their function is diffusion and filtration. Stratified squamous are on the surface of the skin, lining of the mouth and throat. They provide protection. Simple cuboidal line the ducts and some glands. Their function is secretion and absorption. Stratified cuboidal are rare; they line some ducts and their function is secretion and absorption. Transitional are located in the bladder and their function is to stretch. Simple columnar line the digestive tract and their function is secretion and absorption. Pseudostratified ciliated columnar line the nasal cavity and their function is protection. Stratified columnar line the pharynx and epiglottis and their function is for protection. Lecture 7What encompasses each layer of the epidermis?The stratum basale is the bottom layer. It typically consists of a single layer of cells that undergo rapid division. This layer forms epidermal ridges. Stratum spinosum is several layers thick. It contains irregularly shaped keratinocytes. The stratum granulosum is thin. Cells become flattened here and they have stopped diving. Keratohyaline accumulates here. The stratum lucidum is very thin and consists of a few rows of flat, dead keratinocytes. It is only present in thick skin. Stratum corneum is the upper layer and consists of keratinzed cells. Its function is waterproofing and protection.Lecture 8What is EB? What are the different types and complications of this disease? EB is a skin disease in which the connection between the epidermis and the dermis is not strong and the skin peels off. The common complications include: skin blistering, alopecia, progressive nail dystrophy and loss, increased dental caries, early loss of teeth, lung disease, anemia, and skin cancer. EB Simplex is the most common and least severe; blistering is mild. Junctional EB is the most severe and consists of large, ulcerated blisters that can lead to infection and loss of body fluids. Dystrophic EB consists of rough, thickened skin, scarring and disfigurement of the hands and feet. Lecture 9What are the modes of exocrine and endocrine secretion?Exocrine has three modes of secretion: merocrine, apocrine, and holocrine. Merocrine is when the products are contained in vesicles and are secreted by exocytosis. Apocrine is when a portion of the plasma membrane buds off the cell, containing the secretion. Holocrine is when the cell ruptures to release its contents. Endocrine consists of releasing hormones into the bloodstream and it has three modes of regulation: paracrine, autocrine and intracrine. Paracrineis when the hormone is produced within one tissue and regulates a different tissue of the same organ. Autocrine is when the hormone acts on the same cell type in which it was produced. Intracrine is when the hormone acts within the specific cell. Lecture 10Describe Vitamin D metabolism.D3 is produced by the skin/ ingested in diet and D2 is ingested by the diet. It binds to DBP and travels to the liver. It is hydroxylated in liver at 25-position by 25-OHase to form 25(OH)D. 25(OH)D travels bound to DBP to the kidney where it is hydroxylated at 1-position by 1-alpha OHase to form the hormone 1,25(OH)2 D (calcitriol). Calcitriol binds DBP and travels to target tissues where it has effects through genomic and nongenomic mechanisms.Lecture 11What are the differences between the anterior and posterior pituitary?The anterior pituitary consists of glandular tissue. It has multiple cell types and responds to inhibitory or stimulatory signals from the hypothalamus to produce hormones. It has a portal system that connects the hypothalamus to anterior pituitary. The anterior pituitary hormones have effects on target tissues throughout the body. The posterior pituitary consists of neural tissue. It is comprised of infundibulum and posterior pituitary. Hormones are produced in hypothalamic neurons and