Parasitology Lecture 3 PDF

  Unicellular organisms that occur singly or in colony formation.  Single-celled eukaryotic microorganisms belonging to Kingdom Protista are classified as Protozoa.  The single protozoan cell performs all functions. ① Trilaminar unit membrane: Bound protozoan cell. ② Cytoplasm:...

  Unicellular organisms that occur singly or in colony formation.  Single-celled eukaryotic microorganisms belonging to Kingdom Protista are classified as Protozoa.  The single protozoan cell performs all functions. ① Trilaminar unit membrane: Bound protozoan cell. ② Cytoplasm:  The outer hyaline layer.  Functions: ① Organ for locomotion ② Organ for engulfment of food by producing pseudopodia. ③ Helps in respiration, discharging waste material, and in providing a protective covering of cell.  The inner granular layer, Contains nucleus  Contains number of structures as: 1. Food vacuoles. 3. Contractile vacuoles. 2. Golgi bodies. 4. Endoplasmic reticulum.  Contractile vacuoles serve to regulate the osmotic pressure. ③ Nucleus: The most important structure:  egulates the various functions  eproduction. a. Nuclear membrane. b. Nuclear sap (nucleoplasm). c. Chromatin granules. d. Karyosome (nucleolus): DNA containing body, situated centrally or peripherally within the nucleus.   Move by pseudopodia, cilia and flagella or do not move. ❶  Direct taking of oxygen or ❷  By using oxygen liberated from metabolic processes. ① Absorption of liquid food. ② Ingestion of solid material through ectoplasm by pseudopodia or cytostome and become surrounded by food vacuoles.  Digestive enzymes assimilate the food and the undigested particles are extruded through the surface of the body or through a specialized opening (cytopyge). ❸ ❹  By osmotic pressure, contractile vacuoles, diffusion or cytopyge.   The parasite multiplies only in the trophozoite stage.  The methods of reproduction are of the following types: I. Asexual reproduction: 1. Simple binary fission: Either longitudinal or transverse into two organisms. 2. Multiple fission (schizogony): Nucleus undergoes several successive divisions Followed by division of cytoplasm into small parts to produce large number of small merozoites or sporozoites within schizont, e.g. Plasmodium. ❺ II. Sexual reproduction:  Fusion of two cells, one is female (macrogamete) & other is male cell (microgamete) → Plasmodium.  Flagella Pseudopodia Passive Cilia  Trypanosoma  Entameoba  Plasmodium  Balantidium (sleep sickness) (ameobal (malaria) coli  Leishmania diarrhea).  Sarcocystis  Giardia  Cryptosporidium  Trichomonas  Toxoplasma  Babesia  Isospora  Intestinal and luminal & urogenital protozoa require only one host, within which they multiply asexually, and transfer from one host to another directly.  Most blood and tissue parasites pass alternatively in a vertebrate and an invertebrate host, this is called alternation of generation (i.e. transmission is indirect). ① Choose the correct answer: Protozoa belong to kingdom: a. Monera b. Protista d. Animalia e. Fungi ② The following protozoa use pseudopodia for movement: a) B. coli. b) Trypansome. c) Plasmodium d) Entameoba