Lecture 7

Question 1

Epidermis

Answer 1

Top-skin

Question 2

Gastrodermis

Answer 2

Inner lining membrane of gastrovascular cavity
Layer of cells

Question 3

Mesoglea

Answer 3

Between endo- and ectoderm
Jellylike matrix

Question 4

Mesenchyme

Answer 4

Connective tissue
Undifferentiated cells- give rise to most tissues
Loosely organized embryonic tissue

Question 5

Polyp

Answer 5

Saclike body, tentacles, mouth
CaCO3 exoskeleton

Question 6

Medusa

Answer 6

Only phylum Cnidaria
Bell shaped body, manibrium, mouth

Question 7

Gastrovascular cavity

Answer 7

Food digestion site
Nutrient absorption site

Question 8

Hydrozoa

Answer 8

From phylum Cnidaria
Complex life cycle
Produce gametes on ectodermal
Can be colonial

Question 9

Anthrozoa

Answer 9

A class
Attachers

Question 10

What do the two embryonic germ layers become?

Answer 10

Epidermis
Gastrodermis

Question 11

What are the two adult morphologies of Cnidaria?

Answer 11

Polyp
Medusa

Question 12

Draw the body plans of hydrozoan poly vs Anthozoan polyp vs hydrozoan Medusa

Question 13

What are the lifestyles of cnidarians? (3)

Answer 13

Sessile
Sedentary or
Planktonic

Question 14

What lifestyles are associated with radial symmetry?

Answer 14

Sessile
Sedentary
Planktonic

Question 15

What is a pro of the ring of tentacles?

Answer 15

Can collect food from any direction

Question 16

Nerve net

Answer 16

Simple, decentralized, multipolar nervous system

Question 17

How are the sense organs distributed in cnidarians?

Answer 17

Radially

Question 18

What are all the cell types in the Cnidaria body wall? (7)

Answer 18

Myoepithelial
-nutritive muscular cells
-epithelio-muscular cells
Sensory cells
Gland cells
Interstitial cells
Cnidocytes

Question 19

Nutritive-muscular cells

Answer 19

Secrete digestive enzymes
One of the cell type through which cnidarians move
Cells in the gastrodermis
Range from their tissue layers to the mesoglea

Question 20

Epithelio-muscular cells

Answer 20

Epidermis
Produce vesicles containing an adhesive substance- can attach to substrate

Question 21

Describe the basal parts of myoepithelial cells in Cnidaria.

Answer 21

Flattened
Interconnected
Contain contractile myofibrils

Question 22

Contractile myofibrils

Answer 22

Groups of tendrils
Extend along length of striated muscle fibres

Performs muscle contraction via sliding-filament model

Question 23

🤌Sliding filament model

Answer 23

Filaments/muscles overlap
Result in shortening of muscle fibre length

Question 24

🤨Manubrium

Answer 24

Tube that connects mouth to stomach
In the subumbrellar cavity

Question 25

What are the two muscle-like cells that allow cnidarians to move?

Answer 25

Epitheliomuscular cells Nutritive-muscular cells

Question 26

Subumbrellar cavity

Answer 26

Located beneath the umbrella of a jelly