Parasitology lab Exam 1

Pseudocoel

A fluid filled body cavity

Pseudolabia

“False lips” found in some species that have lost their “true lips”

Papillae

Tactile sensory projections

Where are Sensory papillae found

Near the mouth opening

Where are Cephalic Papillae found

At the base of the lips

Odontia

tooth like projections

Amphids

A pair of bilaterally cephalic chemosensory organs located on the side of the head, near the mouth

Bursa

Finger like modification of male posterior end

Used to grab onto females during copulation

Phasmids

Chemoreceptors found near the posterior

What are the three layers of the body wall?

Outermost is ___, Middle is ____, interior is ___

Cuticle; hypodermis; somatic muscles

____ is the thin, transparent, elastic, and acellular outermost layer of the body wall

Cuticle

Alae

Rigid extensions of the cuticle that aids in movement, support, and acts as sensory receptors

Cordons/Epaulets

Cephalic Alae that unite anteriorly and ventrally

Hypodermis

The thin cellular layer beneath the cuticle that secretes substances to help maintain it (the cuticle)

Hypodermal chords

Elongated thickenings of the hypodermis that extend inwards

T/F: Dorsal and ventral chords may contain nerve trunks

True

Bacillary band

A band containing pores on the ventral surface of the esophageal region

Ventral

Front of the organism

Dorsal

Back of the organism

Alimentary canal

Straight tube running the length of the organism

Stoma or Buccal cavity

The cavity in which the mouth opens

Esophagus

Muscular organ connecting buccal cavity to intestine

Can come in several phorms

Isthmus

Middle part of the pharynx between the corpus and basal bulb

Bulb

Enlarged portion of the esophagus

The intestine can be divided into three parts. Those are: ____, ____, and ____

ventriculus, intestine proper, pre-rectal

The male reproductive system consists of

Testes

May be single or multiple

Seminal vesicle

Sperm storage

Spicules

protrusible, cuticularized structures that function in mating

The female reproductive system consists of

Ovaries, oviduct, uterus, and a cuticular-lined vagina which opens to the external environment via a ventrally located vulva

Monodelphic

When an adult female has only one functional ovary

Amphidelphic

When an adult female has two functional ovaries

Polydelphic

When an adult female has 2+ functional ovaries

____ is the muscular terminal portion of the uterus.

Used to force eggs into the vagina

Ovijector

Viviparous

Female gives birth to larvae

Oviparous

Female lays fertilized eggs

Oviviparous

The female produces both eggs and larvae

Nerve ring

Makes up the central nervous system

Forms a conspicuous ring around the esophagus

Usually the only visible portion of the nervous system

What is this a cross section of?

Male nematode

What is labeled as T?

Testis

What is labeled as V

Vas deferens

What is labeled as I

intestine

What is labeled as IP

Innervation process

What is labeled as LC?

Lateral cords

What is this a cross section of?

Female nematode

What is labeled at LC?

Lateral Cords (female)

What is labeled at U?

Uterus

What is labeled at I?

Intestine (female)

What is labeled at O?

Ovary

What is labeled at OD?

Oviduct

What is labeled at M? (Circled)

Longitudinal muscles

What is indicated by C?

Cuticle

What is this a cross section of?

Nematode esophagus

What is indicated by E?

Esophagus

What is indicated by P?

Pseudocoel

What is indicated by C?

Cuticle (esophagus)

What is indicated by the circled portion

excretory tubules

What is indicated by the circled portion?

Longitudinal muscles

Trichuris trichiura

Whipworm

Ascaris lumbricoides

Giant roundworm

Toxocara canis/cati

Dog/cat roundworm

Baylisascaris procyonis

Racoon roundworm

Enterobius vermicularis

Pinworm

Ancylostoma duodenale

Hookworm

Ancylostoma canium

Dog hookworm

Necator americanus

New World hookworm

Strongyloides stercoralis

Threadworm

Parthenogenesis

Asexual reproduction in which females produce offspring from unfertilized eggs

Ventriculus

Region of midgut or intestine that produces and secretes enzymes to initiate extracellular digestion

Indirect/Dixenous life cycle

Has two or more host organisms

Juveniles pass through an intermediate (vector)

The third stage is infective to the final host

Sylvatic life cycle

Involves wild animals and forest-dwelling vectors

Humans are often incidental hosts

Direct/Monoxenous life cycle

Parasitic life cycle in which only a single host is used

Urban life cycle

Involves urban or domestic animals and humans as hosts, with urban dwelling vectors

What egg is this?

Trichuris trichuria (whipworm)

What egg is this?

Necator americanus (New world hookworm)

What egg is this?

Ascaris lumbricoides (giant roundworm)

T/F: Nematode eggs are frequently diagnostic

True

All nematode eggs contain an ______, _______, and _____ surrounding the egg cell

outer protein layer, a thick middle eggshell, a thin, vitelline membrane

Microfilariae

The larval stage found in blood tissue

Involves an arthropod vector

Trichinella spiralis

Pork worm

T/F: Trichinella spiralis has an anterior that is slightly thicker than their posterior

False

Where does Trichinella spiralis form cysts in?

Striated muscle tissue of host

The anterior consists of a short, muscular esophageal region terminating in a pseudobulb, followed by the

stichisome

Stichisome

a long chain of cuboidal epithelial cells

Male Trichinella spiralis features

No Spicule

Blunt posterior

Two large copulatory papilla

~1.6 mm

Female Trichinella spiralis features

Up to 4mm long

Blunt posterior w/ terminal anus

Vulva located in stichosomal region

T/F: Trichinella spiralis is oviviparous

True

Trichinella spiralis life cycle

1. Contaminated meat is ingested

2. Eggs hatch in female; larvae deposited in intestinal mucosa

3. Larvae enter bloodstream/lymphatic system; encyst in striated muscle

4. Larvae mature within 2-3 days; larviposition of next generation occurs within 6-7 days

Pathology of Trichinella spiralis within first week of infection

Intestinal edema, nausea, vomiting, abdominal cramps, diarrhea, fever

Pathology of Trichinella spiralis up to one month

Migration phase: high fever, blurred vision, facial edema, cough, eosinophilia (increased eosonphils in bloodstream)

Pathology of Trichinella spiralis

Muscular phase: Local inflammation, edema, pain, weakness, and fatigue

Diagnosis of Trichinella spiralis

Occurs when a group of people become symptomatic after known exposure to undercooked pork

Trichuris trichiura lifecycle

1. unembryonted eggs passed in feces

2. 2 cell stage

3. advanced cleavage

4. Embryonated eggs are ingested

5. larvae hatch in small intestine

6. migrate to cecum where larvae matures