L3: Medical Protozoology

Question 1

What are Protozoa?

Answer 1

These are unicellular organisms that occur singly or in colony formation. Each protozoan is a complete unit capable of performing all functions.

Question 2

What is the morphology of Protozoa?

Answer 2

Protozoa have a wide range of sizes (1-150μ). The structure of a protozoan cell is formed of a cytoplasmic body and a nucleus.

Question 3

What is the Cytoplasm of Protozoa formed of?

Answer 3

Ectoplasm and endoplasm

Question 4

Ectoplasm of protozoa

Answer 4

Ectoplasm: The outer hyaline layer that is responsible for (REPSI) ingestion of food, excretion, respiration, protection, and sensation.

Some structures develop from ectoplasm as:

• Organs of locomotion; pseudopodia, flagella and cilia.
• Organs for food intake or excretion; peristome, cytostome, and cytepyge

Question 5

Endoplasm of Protozoa

Answer 5

The inner granular part of the cytoplasm is responsible for nutrition and reproduction. The endoplasm contains a number of structures as food vacuoles, foreign bodies, contractile vacuoles, and chromatoid bodies and may contain RBCs.

Question 6

Nucleus of protozoa

Answer 6

is the most important structure, as it regulates the various functions and reproduction. It is formed of:

a. Nuclear membrane.
b. Nuclear sap (nucleoplasm).
c. Chromatin granules.
d. Karyosome (nucleolus or endosome): It is a DNA-containing body, situated centrally or peripherally within the nucleus.

Question 7

What are the parts of protozoa responsible for nutrition?

Answer 7

Endoplasm and ectoplasm

Question 8

What are the parts of protozoa responsible for reproduction?

Answer 8

Entoplasm and nucleus

Question 9

What is the protoplasm?

Answer 9

It is the cytoplasm + nucleus

Question 10

Movement of protozoa

Answer 10

Protozoa may move by pseudopodia, cilia, and flagella with or without undulating (wavy) membrane.

Question 11

Respiration of protozoa

Answer 11

It may be by direct taking of oxygen or by using oxygen liberated from metabolic processes (anaerobic).

Question 12

Nutrition of protozoa

Answer 12

It is through:
a. Absorption of liquid food.

b. Ingestion of solid material through the ectoplasm by pseudopodia or the cytostome (mouth) and become surrounded by food vacuoles.
- Digestive enzymes take in the food and the undigested particles are forced out through the surface of the body or through a specialized opening (cytopyge - anal canal).

Question 13

Excretion of protozoa

Answer 13

It is performed by osmotic pressure, contractile vacuoles, diffusion, or cytopyge.

Question 14

Secretion of protozoa

Answer 14

A protozoan cell can secrete “Cd chat PP” cyst wall, digestive enzymes, pigments, proteolytic enzymes, hemolysins, cytolysins, toxic and antigenic substances.

Question 15

Reproduction of protozoa

Answer 15

The parasite multiplies only in the trophozoite stage. The methods of reproduction are of the following types: Asexual, sexual

Question 16

Asexual reproduction of protozoa

Answer 16

1. Simple binary fission: It is either longitudinal or transverse into two organisms.
2. Multiple fission (schizogony, merogony, or sporogony): In this process, the nucleus undergoes several successive divisions followed by the division of cytoplasm into small parts to produce a large number of small merozoites or sporozoites within the schizont, e.g. Plasmodium.

Question 17

Sexual reproduction of protozoa

Answer 17

Gametogony or Syngamy: It means fusion of two cells one is female (macrogamete) and the other is the male cell (microgamete), e.g. Plasmodium.

Question 18

What is the common type of reproduction in protozoa?

Answer 18

Asexual

Question 19

Can plasmodium reproduce in two ways?

Answer 19

Yes, asexual and sexual

Question 20

Transmission of protozoa

Answer 20

1. Simple life cycle: Intestinal and luminal protozoa require only one host, within which they multiply asexually, and transfer from one host to another directly.
2. Complex life cycle: 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). Sexual multiplication occurs in one host and asexual multiplication in another host.

Question 21

Classification of protozoa Acc to the organ of locomotion.

Answer 21

1. Phylum: Sarcomastigophora (Amoebae and Flagellates):
   a. Subphylum: Sarcodina (Amoebae): e.g. E.histolytica
   b. Subphylum: Mastigophora (Flagellates): e.g. G.lamblia
2. Phylum: Ciliophora
3. Phylum: Apicomplexa e.g. Plasmodium falciparum (malignant malaria)

Question 22

What are the general prevention ways of protozoa and control strategy?

Answer 22

 Environmental sanitation
 Health education
 Case treatment
 Pure water supply
 Safe and clean food
 Sanitary disposal of feces
 Insect control