Tissues 1

Question 1

Different shapes of epithelial cells

Answer 1

Squamous, cuboid, columnar, transitional

Question 2

Purpose of stratified epithelium?

Answer 2

Protective role. More layers = more protective

Question 3

How does epithelial tissue exchange gas?

Answer 3

They’re avascular so depend on diffusion for exchange

Question 4

How are epithelial cells renewed?

Answer 4

Basal lamina divides, producing daughter cells which move up and mature as epithelial cells. The highest layers flatten as they degenerate.

Question 5

Purpose of keratinising epithelia

Answer 5

found on stratified epithelia and protect the surface from abrasion and drying out

Question 6

How is keratin formed on epithelial cells?

Answer 6

Basal cells divide and move up. Upon losing their nucleus and cytoplasmic organelles, they degenerate and become keratinising squamous cells.

Question 7

What are the junctional complexes? (3)

Answer 7

Gap junctions allow ions to pass through adjacent cells.
Tight junctions hold adjacent cels together
Desmosomes connect cells-cells while hemidesmosomes connect a cell to the basal lamina

Question 8

Example of Simple squamous?

Answer 8

Around vessels and the heart, with short diffusion distance

Question 9

Example of Stratified squamous

Answer 9

Found in skin to withstand abrasion and prevent water loss. Can be keratinising

Question 10

Example of Simple cuboidal

Answer 10

Salivary glands + kidney tubules, good for excretion due to thinness and high SA

Question 11

Example of Stratified cuboidal

Answer 11

Rare - found in salivary ducts and sweat ducts - excretion

Question 12

Example of Simple columnar

Answer 12

Lines stomach and intestinal tract. Has cilia (goblet cells) and microvilli (large SA). Main function is protection from bacteria

Question 13

Example of Stratified columnar

Answer 13

Found in conjunctiva. Secretes mucus to protect

Question 14

Example of Pseudostratified

Answer 14

Found in respiratory tract (trachea) for protection

Question 15

Example of Transitional

Answer 15

Found in bladder as changes shape when moved

Question 16

Whats the structure and make-up of loose connective tissue?

Answer 16

Elastin and Collagen fibres loosely arranged with fibroblasts and Adipocytes. Highly vascularised. All contained in Ground Substance

Question 17

Whats the function of loose connective tissue?

Answer 17

Binds other tissues together and joins tissues into organs.

Question 18

What is the ground substance?

Answer 18

Made of 90% water, a jelly like substance which contains tissue fluid for nutrient exchange and holds the fibres and supporting cells in place

Question 19

What are supporting cells in the ground substance?

Answer 19

Fibroblasts, Adipocytes, White blood cells

Question 20

What are fibroblasts and their structure?

Answer 20

Spindle-shaped nucleated cell which produces and secretes collagen

Question 21

What are adipocytes?

Answer 21

Fat cells. Large lipid droplet with nucleus pushed to the side. Thought to have originated from Fibroblasts

Question 22

White vs brown adipocytes?

Answer 22

White is larger, brown is smaller with many small lipid droplets and many mitochondria.

Question 23

Where is adipose tissue found and its purpose?

Answer 23

Found underneath skin as fat for insulation. Also found surrounding organs. Stores energy.

Question 24

What is fibronectin?

Answer 24

Found in CT cells. A fibre that helps supporting cells stick to the ECM/ ground substance

Question 25

What makes up Dense Irregular CT?

Answer 25

Thick collagen fibres and elastin, very dense in all directions. Also has fibroblasts

Question 26

Where is Dense Irregular CT found?

Answer 26

Dermis of skin to avoid skin abrasion, submucosa of digestive tract and organ/joint fibrous capsules.

Question 27

What makes up Dense Regular CT?

Answer 27

Thick collagen, very little elastin in a highly ordered structure, All fibres go in one direction. Poor vascularisation

Question 28

Where is Dense Regular CT found?

Answer 28

Joins tendons and ligaments.