Essays on Efflux

DISCUSS THE ROLE OF ION CURRENTS IN DETERMINING THE SHAPE AND DURATION OF CARDIAC ACTION POTENTIAL

Introduction Selective permeability to various ions is an important characteristic of cell membranes, one that determines myriad cellular functions. In animal cells, ion permeability and the electrical potential generated thereof determines the activity of neurons, myocytes and the like. The electrical potential depends on the concentration of the ions inside and outside any given cell, the permeability of the cell membrane to the ions and the ion channels that are present on the surface of the cell. Cardiac cells also possess different ion channels on their surface. These determine the two types of electrical potentials, namely, resting membrane ...

Lipids are a group of structurally diverse hydrophobic compounds that are not very soluble in water. Cholesterol is a common lipid that can be obtained from the diet and is synthesized in most cells of the human body. It is a component of cell membranes, maintains membrane fluidity, and acts as the precursor of other important biological compounds such as steroid hormones and bile salts (Smith, Marks, and Lieberman 54, 163). High concentrations of cholesterol in the blood can cause accumulation of fatty deposits on arterial walls that can lead to the formation of atherosclerotic plaques, which are associated with heart ...

Introduction

The thyroid gland is an essential gland found in various vertebrates, and has thyroid follicles (comprised of thyroid epithelia cells), which are supplied by a dense network of blood capillaries. The thyroid tissue’s main function is the biosynthesis and secretion of the thyroid hormone, which is an essential biological molecule existing in either of two forms, T3 and T4. The activity of the thyroid gland is controlled through the neuroendocrine system, which involves the hypothalamus and the secretory actions of the pituitary gland. TSH plays a key role in stimulating the thyroxin-binding globulin (TGB) and the uptake of blood iodine ...

BBB functions and physiology: The central nervous system (CNS) necessitates a highly controlled environment for its proper functioning. Blood brain barrier is the system which maintains the homeostasis of the CNS. It works by separating and shielding the brain from the constant changes in the nutrient and chemical composition of systemic blood. It protects the brain tissue from harmful chemicals that might be present in the blood. The key functions of the BBB are transport of nutrients from the blood to brain and metabolites in opposite direction to systemic circulation. Only a small number of molecules are allowed access through the ...

Disturbing trends in the climatic condition of the Arctic led to scientists researching this area. Upon close scrutiny the fascinating greening of the Arctic has been observed. From the space, using Normalized Difference Vegetation Index (NDVI), which is an index of vegetation greenness, the circumpolar changes in the tundra vegetation are observed. The NDVI records of the last 29 years were gathered and the Maximum NDVI was derived. According to studies the MaxNDVI was usually observed in August due to many factors such as CO2 fluxes, above-ground biomass, total eco-system production etc. Many other biophysical properties also cause the ...

Abstract

Plasmodium falciparum is the parasite responsible for the deadly disease, malaria. The parasite is transmitted through the injection of sporozoites into the human blood stream. These sporozoites are transported in the blood stream to the liver. The sporozoites invade the hepatocytes and differentiate into merozoites. The merozoites invade the RBCs of the host; starting the blood stage of infection. The trophozoite stage ingests and degrades approximately 80% of the hemoglobin in the host cell. The hemoglobin is broken down into peptides due to enzymatic action by a metalloprotease and cysteine and aspartic proteases. Haematin is first released as a byproduct of ...

Describe the Hemoglobin Digestive Process

P. falciparum, is the parasite responsible for the malaria, a disease that causes approximately one million deaths annually. It undergoes the process of erythrocytic schizogony which is responsible for the clinical manifestations of malaria. The trophozoite ingests and degrades approximately 80% of the hemoglobin in the host cell (Brayl 2005). As the trophozoite continues to develop, its endolysosomal system takes up the cytoplasm of the host cell using cytosomes which contains host hemoglobin. Cytosomes are formed by an invagination formed from the PVM (parasitophorous vacuolar membrane) and PPM (parasite plasma membrane) from which transport vesicles are pinched off. These vesicles ...