Ileum and Leaf

Question 1

What are tissues?

Answer 1

Groups of cells that carry out same (or v. small no. funct)

Question 2

What is an organ?

Answer 2

Several dif types of tissue- str unit that carries out one/more funct

Question 3

Organ Syst

Answer 3

Group of organs working together to carry out several functions

Question 4

What is the serosa?

Answer 4

Outer layer of connective tissues

Question 5

What is the musc externa?

Answer 5

Consists of outer layer of long. musc (muscle that runs along length of alimentary canal)
and consists of an inner layer of circular muscle (muscle that runs around alimentary canal)

Question 5

What is serosa function?

Answer 5

Provides v thin protection and supportive lining for alimentary canal

Question 6

What do the contractions of longitudinal muscle do?

Answer 6

Causes pendular movement

Question 7

What do the contractions of circular muscle do?

Answer 7

Causes local constrictions- actions which help churn and mix food

Question 8

What do peristaltic waves do?

Answer 8

Help push food along the gut

Question 9

What is the submucosa?

Answer 9

Largely composed of connective tissue and cont. many blood vessels and lymphatic vessels

Question 10

What are the vessels in submucosa crucial in?

Answer 10

In transp abs food products

Question 11

What is the muscularis mucosa?

Answer 11

Thin layer of muscle lies between submucosa and mucosa

Question 12

State the function of the muscularis mucosa:

Answer 12

Important in moving villi present in mucosa thus increasing contact w dig food in gut lumen

Question 13

What aids musclaris mucosa in moving villi?

Answer 13

Small strands of muscle extend from main muscularis mucosa layer up thru mucosa into each villus with contr of these strands helping to prod characteristic wafting movement of villi

Question 14

What is mucosa?

Answer 14

Layer in contact with food in gut lumen

Question 15

What is its function? (mucosa)

Answer 15

Highly spec with subst increasing sa due to presence of villi and microvilli

Question 16

What is the function of the columnar epithelial cells?

Answer 16

Rich in mitochondria for active transport of abs products

Question 17

How is sa of columnar epithelium cells increased?

Answer 17

Villus have sa extended by microvilli- brush border effect

Question 18

What is the function of microvilli?

Answer 18

Increases sa so increases no. enzymes that can make contact with food

Question 19

How are lipids transp out of villi?

Answer 19

By lacteals- part of lymphatic syst

Question 20

Where are goblet cells found?

Answer 20

Dotted within columnar epithelium cells

Question 21

What is the function of goblet cells?

Answer 21

Secrete mucus prov slimy protective layer that lubr lining of alim canal facilitating movement of food and also protects against actions of digestive enzymes on ep cells

Question 22

What is the function of the cap within the villi?

Answer 22

Imp for transp aa and monosacc out of villi

Question 23

What are the crypts of lieberkuhn?

Answer 23

Intestinal glands that lie embedded in tissue between villi

Question 24

What is the function of the paneth cells?

Answer 24

Found at the base of the crypts, they have an anti-microbal funct in protecting neighbouring actively div cells

Question 25

What is the upper epidermis?

Answer 25

Upper prot layer of leaf- no chloroplasts so not directly inv w phs

Question 26

How is water loss reduced in the upper epidermis?

Answer 26

Covered with waxy cuticle

Question 27

What is the function of the palisade mesophyll?

Answer 27

Primary phs region in leaf immed below upper ep

Question 28

How is light abs max in palisade mesophyll?

Answer 28

Arranged reg to pack in as many as poss
Each cell has many chloroplasts
Large vacuole helps light pass down thru layers w min shading

Question 29

How does the lsa benefit the palisade layer?

Answer 29

More palisade layers in close prox to upper leaf surf and also fac ge with no cell being too far from a ges

Question 30

What is the spongy mesophyll layer?

Answer 30

Lies immed beneath palisade layer

Question 31

How is g.e adapted in leaf?

Answer 31

More loosely and irreg arranged- large ges surf in leaf- intercellular air spaces
Fewer chl than pal cells

Question 32

What is the vasc tissues?

Answer 32

Lies within the spongy mesophyll
Xylem transp water and inorg ions up thru plant and into leaves
Phloem sieve tubes transp sugars usually sucr prod in phs away from leaf to plant storage regions i.e bulbs and tubes- conv to starch/ actively growing region where its used in resp

Question 33

What is the lower epidermis covered with? Why is it this thickness?

Answer 33

Waxy cuticle but much thinner than that of cuticle on upper epidermis as less transpir occurs thru l.e

Question 34

Descr the stomata in l.e
Also, what happens when turgid?

Answer 34

Opening and closing contr by presence of guard cells- posses chloroplasts
When turgid, they expand and open pore of the stoma fac g.e
When less turgid, pores close- reduces water loss

Question 35

Why are stoma closed at night?

Answer 35

to reduce water loss
ev losses greater during day when warmer so stoma remain open to allow g inv in phs and resp to enter and leave
During darkness, leave met act is much lower- only resp and usually enough o2 within leaf to allow resp to take place even when stomata closed