Organization of cells into tissues and organs

Question 1

What are the 4 basic tissue types?

Answer 1

Epithelium
Connective tissue
Muscle
Nervous tissue

Question 2

What is made up of combinations of these 4 types?

Answer 2

Nearly all tissues and organs.
Although the cell of organs perform specific, specialized tasks, organs are essentially composites of the 4 basic tissues.

Question 3

What are the 3 major salivary glands?

Answer 3

Parotid (which sits behind the ear), submandibular and sublingual glands.
There are many smaller glands scattered in the oral mucosa.

Question 4

What is an unusual feature of salivary glands and why?

Answer 4

striated ducts. In most glands with ducts the duct only conveys (transports) the secretory product, but the striated ducts actually modify the saliva that is passing through them by pumping salt out of the fluid so that our saliva is hypotonic (has a lower osmotic pressure than blood) to blood (which is why saliva doesn’t taste very salty)

Question 5

What are the role of the basal striations in the striated ducts of the salivary glands?

Answer 5

They are infoldings of the cell membrane accompanied by lines of mitochondria to power the molecular pumps in the membranes.

Question 6

What type of glands are salivary glands?

Answer 6

epithelial glands

Question 7

From the oesophagus to the anal canal the architecture of the digestive tract is composed of 4 major layers (starting from the lumen and going out) what are these?

Answer 7

Mucosa
Submucose
Muscularis Externa
Serosa/Adventitia

Question 8

Mucosais composed of 3 parts what are these?

Answer 8

Epithelium: sits on a basal lamina
Lamina Propria: loose connective tissue
Muscularis Mucosae: thin layer of smooth muscle

Question 9

What is submucosa comprised of?

Answer 9

loose connective tissue that allows the mucose to slip around.

Question 10

What is Muscularis Externa composed of?

Answer 10

2 thick layers of smooth muscle, an inner circular layer and an outer longitudinal layer

Question 11

What is Serosa/Adventitia composed of?

Answer 11

An outer layer of connective tissue that either suspends the digestive tract or attaches to other organs

Question 12

What lines the digestive tract proper?

Answer 12

Epithelium lines the digestive tract proper. you will always find epithelium lining a tract like this.

Question 13

In the digestive tract what are the 4 variations of mucosa?

Answer 13

Protective
Absorptive
Secretory
Protective and absorptive

Question 14

What is the protective mucosa comprised of and where is it founds?

Answer 14

It is comprise of non-keratinized stratified squamous epithelium.
It is found i the oral cavity, pharynx, oesophagus and anal canal.

Question 15

What is the absorptive mucosa comprised of and where is it found?

Answer 15

It is comprised of simple columnar epithelium with villi and tubular glands.
It is found in the small intestine.

Question 16

What is the secretory mucosa comprised of and where is it found?

Answer 16

It is comprised of simple columnar epithelium with extensive tubular glands.
It is found in the stomach.

Question 17

What is the protective and absorptive mucosa comprised of and where is it found?

Answer 17

It is comprised of simple columnar epithelium with tubular glands.
It is found in the large intestine.

Question 18

What are the clear cells found in the small intestine?

Answer 18

Goblet cells

Question 19

What is the name of the digestive system’s own nervous system?

Answer 19

The enteric nervous system.

It has the same number of neurons as the spinal cord.

Question 20

Where does the enteric nervous system (ENS) receive it’s input and what is it capable of coordinating?

Answer 20

The ENS receives input from the autonomic nervous system, but is capable of coordinating gut mobility locally.

Question 21

Where do most of the neurons in the Enteric nervous system live and what are these groups of neurons called?

Answer 21

Most of the neurons live in groups called ganglia between the two muscle layers that make up the muscularis externa.

Question 22

What is the role of the goblet cells in the trachea?

Answer 22

The goblet cells of the epithelium together with the submucosal glands (SM) produce a viscous fluid that coats the surface of the airway, trapping particles that are then propelled out of the airway by the cilia.

Question 23

What is the difference between bronchi and bronchioles?

Answer 23

Bronchi are large diameter airways and have hyaline cartilage in their wall. Bronchioles are smaller airways, have no cartilage and smooth muscle predominates in their wall.

Question 24

Do the columnar cells of the epithelium remain the same size all the way down the respiratory tree?

Answer 24

No, thy tend to get shorter the further down the respiratory tree you go. It is important to realize that gas exchange does not occur across the epithelia.

Question 25

What are alveoli lined by?

Answer 25

They are lined by simple squamous epithelium (an extremely thin epithelium).

Question 26

What is the liver made up of and how is it all arranged?

Answer 26

The liver is made up of a large number of lobules each with a similar hexagonal arrangement.
At each corner there is a hepatic portal vein and hepatic artery, each delivering blood to the lobule. In the centre is a central vein (CV), which drains to the hepatic vein. Blood passing from the corner to the centre via hepatic sinusoids passes sheets of liver cells called hepatocytes.

Question 27

What are the spaces for blood flow in the liver called?

Answer 27

sinusoids

Question 28

What is in the portal triad (in the liver)?

Answer 28

Hepatic portal vein
Bile duct
Hepatic arteriole

Question 29

Why is the pancreas unusual?

Answer 29

It has both an exocrine and endocrine gland.

Question 30

What is the role of the exocrine pancreas?

Answer 30

The exocrine pancreas produces about a litre each day of digestive juices containing proteases to breakdown proteins, lipases to breakdown lipids, nucleases to breakdown DNA/RNA, etc. These enter the duodenum via the pancreatic duct.
The exocrine pancreas is very similar in appearance to the parotid gland.

Question 31

What does the endocrine gland consist of and what is it’s role?

Answer 31

The endocrine gland consists of small, scattered islands of tissue called islets of Langerhans, which produce a number of hormones including insulin.
The islets of Langerhans are scattered and so only occupy a small volume.