Tissues and Organs- Topic 7

Question 1

what are tissues made of?

Answer 1

-cells that perform a common function

Question 2

what do tissues combine to form? give an example.

Answer 2

-an organ e.g. muscle, connective and nerve tissue all work together in the heart

Question 3

what is an organ?

Answer 3

-a group of tissues that carry out a particular function

Question 4

where is the ileum located?

Answer 4

-it is part of the small intestine following the duodenum

Question 5

how many layers are in the ileum and what are their names?

Answer 5

-5
-mucosa
-muscularis mucosa
-submucosa
-muscularis externa
-serosa

Question 6

where is the mucosa layer located and what adaptation does it have?

Answer 6

-innermost wall of small intestine
-thousands of villi which increase the surface area for absorption

Question 7

how many features does the mucosa have and what are their names?

Answer 7

-columnar epithelium
-crypts of Lieberkühn
-capillaries and lacteals
-microvilli

Question 8

what type of cells are columnar epithelium and what is another name for them?

Answer 8

-glandular epithelium cells are also known as goblet cells

Question 9

what do goblet cells do? why is this important in the columnar epithelium ?

Answer 9

-they secrete large amounts of mucus and digestive enzymes
-the mucus acts as a lubricant and it protects the gut wall from digestion by its own enzymes

Question 10

what is the job of the crypts of Lieberkühn?

Answer 10

-narrow crevices found at the base and between the villi
-the crevices are formed from epithelium and Paneth cells

Question 11

what are the job of Paneth cells?

Answer 11

-they secrete digestive enzymes and fluid that has antimicrobial action which protects stem cells dividing at the bottom of the crypts

Question 12

what are the jobs of the capillaries and lacteals in the mucosa layer?

Answer 12

-each villus contains a blood capillary which absorbs glucose and amino acids by active transport which requires energy
-lacteals absorb fatty acids and glycerol by pinocytosis
-vitamins and minerals are absorbed by diffusion in to the blood capillary

Question 13

what is the job of the muscularis mucosa layer?

Answer 13

-layer of smooth muscle which moves the villi in a wave like fashion to increase its contact with food

Question 14

what is the job of the submucosa layer?

Answer 14

-contains blood and lymph vessels and connective tissue for support

Question 15

what is the job of the muscularis externa layer?

Answer 15

-circular and longitudinal contractions (peristalsis) churns up food and moves it along the gut

Question 16

what is the job of the serosa?

Answer 16

-layer of connective tissue that provides protection and support

Question 17

what is the organ in a plant?

Answer 17

-the leaf

Question 18

the leaf has many adaptations for what purposes?

Answer 18

-maximizing photosynthesis and minimizing transpiration water loss

Question 19

what is the job of the upper epidermis and cuticle?

Answer 19

-waxy cuticle protects against water loss and damage from pests
-upper epidermis is transparent allowing maximum light penetration for photosynthesis

Question 20

what is the job of the palisade mesophyll cells?

Answer 20

-packed arrangement allows maximum light absorption, with many chloroplasts which are the site of photosynthesis
-chloroplasts can move around the cells so that they can get the most light

Question 21

what is the job of the spongy mesophyll?

Answer 21

-loose arrangement which create air spaces for diffusion of gases
-they also have some chloroplasts

Question 22

what is the job of airspaces in the leaf?

Answer 22

-allows gases and water vapour to diffuse quickly throughout the leaf

Question 23

what is the job of the vascular bundle?

Answer 23

-xylem transports water and inorganic ions to the leaf
-phloem transports sugars produced in photosynthesis away from the leaf

Question 24

what is the job of the lower epidermis and cuticle in the leaf?

Answer 24

-the waxy cuticle reduces water loss and damage from pests

Question 25

what is the job of the stomata in the leaf?

Answer 25

-they are openings on the lower leaf surface which allow gas exchange into and out of the leaf
-found mostly on the lower epidermis

Question 26

what are the job of the guard cells in the leaf?

Answer 26

-control the opening and closing of the stomata
-they close the stomata at night to reduce water loss by transpiration