Ehsan

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So far Ehsan has created 24 blog entries.

Histology-Specialized structures of epithelia

2023-08-10T05:19:51+00:00

Specialized structures of epithelial Cilia, microvilli are located at the free space of epithelial cells. basement membrane, membrane infolding are located at the basal surface of epithelial cells. tight junction, intermediate junction, desmosome, gap junctions are located at the lateral surface of epithelial cells. Figure 1.  epithelial cells surfaces microvilli microvilli is type of projection in the plasma membrane. They can be found on the apical surface of some of the epithelial cells. • Striated border—on the surface of the columnar cells of small intestinal mucosa. • Brush border—on the surface of the proximal tubule cells of kidney. Function: [...]

Histology-Specialized structures of epithelia2023-08-10T05:19:51+00:00

Biology-The elements of life

2023-08-10T05:24:15+00:00

The elements of life Carbon, hydrogen, oxygen, and nitrogen make up 96% of living matter. Most of the remaining 4% consists of calcium, phosphorus, potassium, and sulfur. Trace elements are those required by an organism in minute quantities. Figure 1. the elements of life The formation and function of molecules depend on chemical bonding between atoms. Covalent Bonds: strong chemical bonds Ionic Bonds Hydrogen Bonds Van der Waals Interactions Chemical reactions make and break chemical bonds. The starting molecules of a chemical reaction are  called reactants. The final molecules of a chemical reaction are called products. Figure 2. chemical [...]

Biology-The elements of life2023-08-10T05:24:15+00:00

physiology-homeostasis

2023-08-10T05:25:25+00:00

Homeostasis Originally, homeostasis was defined as a state of reasonably stable balance between physiological variables. Maintenance of a relatively stable internal environment is termed homeostasis, Body systems maintain homeostasis, a dynamic steady state in internal environment. Homeostatic Control Systems All The activities of cells, tissues, and organs must be regulated and integrated with each other so that any change in the extracellular fluid initiates a reaction to correct the change. Factors are regulated in the human body Concentration of O2 and CO2 pH of the internal environment Concentration of nutrients Concentration of waste products Concentrations of water, salt and [...]

physiology-homeostasis2023-08-10T05:25:25+00:00

Histology-Epithelial tissue

2023-08-10T05:19:05+00:00

Epithelial tissue Epithelial tissues are composed of closely aggregated polyhedral cells adhering strongly to one another and to a thin layer of ECM, forming cellular sheets that line the cavities of organs and cover the body surface. The principal functions of epithelial tissues include the following: Covering, lining, and protecting surfaces (eg, epidermis) Absorption (eg, the intestinal lining) Secretion (eg, parenchymal cells of glands) Classification  1. Covering epithelia -- cover body surfaces and line body cavities. 2. Glandular epithelia -- form an acinus or gland part, in the body 3. Special epithelia -- myoepithelial, sensory epithelia, and germinal epithelium. [...]

Histology-Epithelial tissue2023-08-10T05:19:05+00:00

Anatomy – skeletal system (structure of bone)

2023-08-10T05:10:24+00:00

Osteology Osteology is the scientific study of bones, knowing characteristics of bones help us to understand musculoskeletal system better. The shape and classification of bones, the structure of bones, the chemical and physical properties of bones are the main subjects covered in this chapter. functions of bone and the skeletal system Support: besides your muscles you need bones to strengthen the musculoskeletal systems. The skeleton serves as the structural framework for the body by supporting soft tissues and providing attachment points for the tendons of most skeletal muscles. Protection: There are many important organs beneath the ribs of thorax, [...]

Anatomy – skeletal system (structure of bone)2023-08-10T05:10:24+00:00

biochemistry – structure of proteins

2023-08-10T05:22:20+00:00

structure of proteins  there are 4 organizational levels of proteins: Primary, secondary, tertiary and quaternary structure. By analyzing these 4 organizational levels, we can consider how complex would be the protein. primary structure of proteins  the sequence of amino acids in a protein. and these amino acids joined by peptide bonds. Note that proteins with abnormal amino acid sequences may cause genetic diseases. Figure 1. amino acid sequence of Bovine insulin peptide bond Peptide-bond formation is the linking of two amino acids which is accompanied by the loss of a  molecule of water. Figure 2. formation of peptide bond [...]

biochemistry – structure of proteins2023-08-10T05:22:20+00:00

Histology-Human body structural levels

2023-08-10T05:17:34+00:00

Human body structural levels  The human body may be examined at four structural levels as: cell tissue organ system Cells: The human body consists of cells, The smallest structural and functional units. figure 1. different type of cells Tissues: Groups of cells and extracellular matrix which are similar in morphology and function make up the body tissues. There are four main types of tissues: Epithelial tissue Connective tissue Muscular tissue Nervous tissue figure 2. one type of epithelial tissue (Simple columnar epithelium) figure 3. connective tissues figure 4. muscle tissues figure 5. composition of nerve tissue Organs: Several different [...]

Histology-Human body structural levels2023-08-10T05:17:34+00:00

Biology-Introduction to biology and DNA

2023-08-10T05:23:22+00:00

introduction to biology Biology is the scientific study of life, Biologists ask questions such as How does a single cell develop into an organism? How does the human mind work? How do living things interact in communities? different levels of biological organizations  as we all may know we can study life at different level, however, different levels of biological organizations are as follow; The biosphere, Ecosystems, Communities, Populations, Organisms, Tissues, Cells, Organelles, molecules, atoms. figure 1. Levels of Biological Organization cell The cell is life's fundamental unit of structure and function. Some organisms, such as amoebas and most bacteria, [...]

Biology-Introduction to biology and DNA2023-08-10T05:23:22+00:00

biochemistry – Amino acids

2023-08-10T05:21:05+00:00

Amino acids Amino acids are building blocks of proteins. There have been 300 different amino acids found world widely. However, proteins in mammalian bodies (including human body) made up of with 20 different amino acids. All amino acids have a central carbon atom attached to a carboxyl group, an amino group, and a hydrogen atom. The amino acids differ from one another only in the chemical nature of the side chain (R). The amino and carboxy groups of amino acids can react in a head-to-tail fashion, eliminating a water molecule and forming a covalent amide linkage, which in the [...]

biochemistry – Amino acids2023-08-10T05:21:05+00:00

Histology-Introduction to histology and H&E staining

2023-08-10T05:18:13+00:00

Introduction to histology and H&E staining   Histology consists of two Greek words, histo means tissue and logia means study or knowledge, histology literally means knowledge of tissue. Histology is study of microstructures and define the relationship between the structure and function of human body. There are four basic tissue: Epithelium, connective, muscular and nervous tissue and Organ made up of tissue, and they have special shape and functions. Histology studies the microstructures. So, we should have the aid of microscope to study. There are two common types of microscopes are available; light microscope, electron microscope. Figure 1. Light microscope [...]

Histology-Introduction to histology and H&E staining2023-08-10T05:18:13+00:00
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