Junctions And Tissues

Question 1

What are the 3 types of junctions between cell types?

Answer 1

Adhering
Impermeable
Communicating

Question 2

What are features of adhering junctions?

Answer 2

Mechanically held together
Eg desmosomes containing plaque
Common

Question 3

What do belt desmosomes do?

Answer 3

Form continuous band around the cell, common in epithelial cells where they are associated with actin filaments

Question 4

What do spot desmosomes do?

Answer 4

Spot weld cells together, and are attached on inside of the cell to keratin filaments

Question 5

What do hemi desmosome do?

Answer 5

Attach the base of the cell to basal lamina

Question 6

What are the features of impermeable junctions?

Answer 6

Prevent the passage of molecules between cells
Eg tight junctions
No molecules between cells

Question 7

In invertebrates, what junctions form the same function as tight junctions?

Answer 7

Septate junctions

Question 8

What are the features of communicating junctions?

Answer 8

Allow passage of small molecules from one cell to another 
Eg gap
Common
Connexins form the gap
1.5nm gap

Question 9

How is the permeability of gap junctions changed?

Answer 9

Decreased intercellular pH

Increased intracellular calcium

Question 10

What happens to gap junction during cardiac disease?

Answer 10

They are reduced in numbers or changed in distribution

Question 11

What are the 4 main categories of tissue?

Answer 11

Epithelial
Connective
Muscle
Nervous

Question 12

What are the features of epithelial tissue?

Answer 12

Tightly packed cells
Fastened together via desmosome junction and tight junctions
Acts as barrier and protects against mechanical injury
Secretory functions

Question 13

What are the features of connective tissue?

Answer 13

Extra cellular matrix
Dense or loose
Blood and adipose

Question 14

What are examples of dense connective tissue?

Answer 14

Cartilage, bone, tendon, ligament tissue

Question 15

What is dense connective tissue composed of?

Answer 15

Fibrous proteins

Glyosaminoglycans attaches good protein core

Question 16

What is loose connective tissue?

Answer 16

Holds small glands and epithelia together and includes the basal lamina of cells

Question 17

What is the basic structure of collagen?

Answer 17

Triple helix

Question 18

What are the features of muscle tissue?

Answer 18

Support and movement
Actin (thin)
Myosin (thick)

Question 19

What are the 3 types of muscle tissue?

Answer 19

Skeletal
Smooth
Cardiac

Question 20

What are features of skeletal muscle?

Answer 20

Striated muscle

Voluntary movement

Question 21

What are features of smooth muscle?

Answer 21

Involuntary body activity

Question 22

What are features of cardiac muscle?

Answer 22

Contraction of the heart

Question 23

What is the role of nervous tissue?

Answer 23

Sense sense stimuli and transmit signals through an animal

Communicating

Question 24

What are nervous tissue composed of?

Answer 24

Neurons and glial cells/ glia

Question 25

What’s the role of dendrites?

Answer 25

Conduct impulses towards the nerve body

Question 26

What’s the role of axons?

Answer 26

Transmit impulses away from the nerve body

Question 27

What’s the role of Schwann cells?

Answer 27

Wrap around axon to form a multi layered membrane stealth to prove electrical insulation