organisation of cells into tissues and organs

Question 1

is the tongue part of the digestive tract

Answer 1

yes, and it is made up of voluntary muscles

Question 2

what is the main function of saliva glands

Answer 2

to secrete saliva

Question 3

name the 3 major salivary glands

Answer 3

parotid, submandibular and sublingual glands

Question 4

what is the difference between serous secreting and mucous secreting cells

Answer 4

serous glands secrete a amore watery substance where as mucous glands secrete a thicker mucous

Question 5

what type of cells are contained within the 3 major salivary glands

Answer 5

mucous (usually paler in colour) and serous (usually pinker/redder) secreting cells
- in submandibular, they don’t secrete saliva, they just let it pass through
- in subliminar, it is a mostly mucous secreting gland

Question 6

why do salivary glands have striated ducts and how is this shown

Answer 6

doesnt seem smooth
- the striated ducts modify the saliva by pumping the salt out of the fluid so that our saliva is hypotonic (lower salt concentration) to blood

Question 7

name the three parts of mucosa and where it is situated

Answer 7

mucosa is the inner layer in the digestive tract
1. epithelium sits on a basal membrane and is the inner part of mucosa
2. lamina propia is loose connective tissue and is the bit surrounding the epithelium cells
3. muscular mucosae is a thin layer of smooth muscle and is the outer most part of the mucosa

Question 8

what and where is the sub-mucosa

Answer 8

it is loose connective tissue that surrounds the mucosa

Question 9

what and where is the muscular external

Answer 9

two thick layers of smooth muscle (the inner circular layer and the outer longitudinal layer)

Question 10

what is the outermost part pf the digestive tract

Answer 10

the serosa/adventitia
- outer layer of connective tissue that either suspends the digestive tract or attaches to other organs

Question 11

how many types of mucosa are there

Answer 11

4 (refer to power points for pictures)
- protective mucosa
- absorptive mucosa
- secretory mucosa
- absorptive and protective mucosa

Question 12

describe protective mucosa and where it is found

Answer 12

non-keratinised stratified squamous epithelium
- oral cavity
- oesophagus
- pharynx
- anal canal

Question 13

describe absorptive mucosa and where its found

Answer 13

simple columnar epithelium with villi and tubular glands
- small intestine

Question 14

describe the secretory glands and where they are found

Answer 14

simple columnar epithelium with extensive tubular glands
- stomach

Question 15

describe protective and absorptive glands and where they are found

Answer 15

simple columnar epithelium and tubular glands
- large intestines

Question 16

what is at the core, base and outside of villi projections

Answer 16

core - lamina propia
base - muscular mucosae
outer - epithelium

Question 17

name the nervous system in the digestive tract and describe its neurons

Answer 17

enteric nervous system
- most of the neurons live in a group called the ganglia between between the two muscle layers of muscular externae

Question 18

what do sub-mucosa glands do in the trachea

Answer 18

secrete mucous to keep the trachea moist

Question 19

why is cartilage required in the trachea

Answer 19

to prevent it from collapsing and to maintain the airway

Question 20

describe bronchi

Answer 20

they are large diameter airways that have hyaline cartilage in their walls

Question 21

describe bronchioles

Answer 21

smaller diameter airways with no cartilage but mainly smooth muscle in their airways

Question 22

describe alveoli

Answer 22

site of gas exchange, lined by simple squamous epithelium

Question 23

how do the epithelial change as the bronchioles decrease in size

Answer 23

the columnar cells decrease in size as you go down the respiratory tree and the epithelia change to simple columnar epithelia as the bronchioles decrease in size

Question 24

what are hepatic lobules

Answer 24

small divisions of the liver defined at the histological scale (ppt)

Question 25

describe the flow of blood in the hepatic lobules (5)

Answer 25

6 sided
- a bile duct, hepatic artery and portal vein at each side which deliver blood to the lobule
- a central vein which drains to the hepatic vein
- blood passing from the corner to the centre via hepatic sinusoids (spaces) goes over sheets of liver cells called hepatocytes
- blood always travels to the central vein from the sinusoids

Question 26

how does the pancreas contain mixed glands

Answer 26

has both exocrine and endocrine glands
- exocrine produces pancreatic digestive enzymes
- endocrine has small scattered islands of tissue called islets of langerhans which produce hormones including insulin and glucagon and where alpha and beta cells are found